1984 Sentra stalling...

Hi,

I'm working on an '84 Sentra with the 1.6 liter E16(s) engine, this car is really worn out and has not been taken very good care of, the new owner would like to get it running. This cars problems are mainly caused by the previous owners being absolute [insert creative words here].

Anyway...

Problem # 1, the car stalls when you press on the gas pedal, I cannot find any loose vacuum hoses. If you slowly press the gas pedal the engine stumbles but keeps running, if you double tap the gas pedal then stomp it when the engine is in high RPMs it will take off and keep going, I was able to hold it at 4000 RPMs for a couple of minutes it seemed to do ok.

I'm assuming that the problem is being caused by a worn out accelerator pump seal or the pump is just not working at all, any other suggestions?

Problem # 2, a few mintues later after holding it at 4000 RPMs the engine's RPMs starting going up and down while sitting at idle then stalled but started right back up again with the ignition key. I'm assuming that this is either a fuel pressure problem or something to do with the timing or something that is overly retarding the timing to the point that the engine stalls.

Problem # 3, the SENSOR light above the steering wheel is on, this is an automatic FAIL at the emissions testing stations where I live, how do I pull the codes out of the engine computer? Considering the year of this car I'm assuming that I can short two pins together and make the SENSOR light blink or do I need to use one of those scanner boxes? I left the battery unhooked for over 10 mintues, the light came right back on.


Help!

Hmmmmmm... easy fix. Sell your can and run by the store and pick up one of these:
http://www.subaru.com/shop/overview.jsp?model=IMPREZA&trim=WRX_STI

Thanks, but that is not an option.

well to be sure, you need to do a compression check, fuel pressure check, and hook up a vacuum guage. also, get a timing gun and check timing.

Hi,

From what I have read online there is supposed to be an ECM buried somewhere in the car, there is a little adjustment screw that can be turned all the way to the right that will cause its light to flash the trouble codes.

Does anyone know if this is true? And if so where the ECM is buried at?

Well,

I found the ECC module, it is directly under the driver's seat mounted in a bracket, it has a recessed on/off switch and two LED's, one red one green, they both turn on when the iginition is on, if you flip the switch to ON the red light goes off but blinks once when the engine stalls.

Anyone have any idea what the red light and the on/off switches functions actually are?

hook up a 400 shot of nitrous and clean out those cylinder heads with a spray at 3500 rpm, what it come alive dawg!

Hi,

Thanks for replying, this engine is not set up for NOS, if I were to use NOS on it it would explode which I guess would sort of fix the problem as I would be getting a new engine for it.

Anyway, please don't reply to my original questions or further comments unless you have something feasible and relivant to contribute to actually fixing the problem. Aside from annoying me the moderators may come down on you for wasting server space and everyone's time.

Back to the subject...

Thanks for you suggestion Slideways, I thought the timing might have been off as the distributor did not look like it was set in the right place, the timing had been advanced 15 degrees, it is much happier at 8 I might drop it down to 5. A funny thing happens when your power stroke runs out of power before the piston reaches TDC (it stalls).

I thought there may have been a problem with the O2 sensor but it started out low then steadily climbed until it went into the 1000+ mV range which I'm not sure is ok or not. From what I have read this O2 sensor should fluctuate between 100 and 900mV, it just seems to keep climbing higher and stays there which may be from the engine running lean or low fuel pressure (see next paragraph).

I also think there IS a fuel pressure problem, after running for about 15 minutes the engine finally warms up, the engine's idle will start to swing back and forth then a minute later it dies but starts right back up again stumbles around for a bit then levels out. I could not find any fuel pressure before or after the fuel filter.

Anyone know if the fuel pump comes AFTER the fuel filter? if it does what I am seeing would make sense.

The temp sensor had me worried but after getting the engine nice and hot the fan finally came on.

I am not going to have a chance to pick up a manual until Tuesday, does anyone have a PDF of where the fuel pump is located that they could send me?


Thanks.

ok ive been on these forums for over two years now helping what i consider to be my friends and also some new comers to fix and or learn about their cars, i guess its too much to ask for everyone to have a sense of humor who comes on this site, also there is no such thing as running NOS in your car, you can run a nitrous oxide system that you bought from a company called "NOS", but there is no such thing as a power adder called NOS, and even an sr20 equipped sentra will only run about a 100 shot without requiring colder plugs, lower comp, and retarded timing, hence the 400 shot joke, now that weve got that out of the way your fuel pump should be in your tank, on newer models the filter and pump are right there in one place but your car was made 2 years before i was born so i really couldnt tell you, jgycustoms may have a manual or some information on their site, if not you can always call a nissan tech and see if hes got enough free time to answer a few simple questions, on a car that old double check to see if your dist cap may be warped. As far as your fuel pressure, click your ignition to "on" with your door open and listen for the fuel pump, if it takes more than 1-2 seconds to quit humming you need a new one, also at fault could be your injectors and or fuel rail. Concerning your issue with O2 sensors, they control fuel mix in low rpm conditions I.E closed loop mode in your ecu, the heater coil may be going out in your sensor causing false readings at low temps and just a general crappiness in performance, pull it out of the exhaust and turn your car all the way on without cranking and see if you get voltage and heat coming from the sensor, i would also check your incoming air sensor for its performance as well, check those and get back with us. And hey, lighten up dude, were here to help but were also here to have a bit of fun, loosen up and youll fit right in

pwned by teh double post

Hi,

Sorry for my lack of sense of humor, I have one (really I do), will try to lighten up.

Just for clarifications sake, I was born in 1970, when Nitrous Oxide systems became commonly available sometime in the 1980's NOS was the major company that produced them, and at least in my day NOS was a nickname for Nitrous Oxide which I why I used "NOS" in my earlier posting.

I know what needs to happen if you plan on using a blower or Nitrous, if you don't build the engine correctly either your heads end up in low earth orbit or what is left of your crankshaft ends up in someone's back yard in China sticking up out of the ground.

This engine has the carb. it does not have fuel injection.

The O2 sensor is the one wire version, there is no heater circuit, although I have a 99 Suzuki Esteem that has the four wire version so I know what you are talking about.

I left the fuel line unhooked from both ends of the fuel filter and started the engine, there is no fuel pressure at all, zero, none, yet the fuel filter had fuel in it when I disconnected it. From the filter the hose goes down to something under the intake manifold that looks like a very odd regulator or fuel pump, then there are possibly two other hoses that come off of that but I cannot see where they go there is too much stuff under there. As far as the fuel filter goes I was able to blow out the remaining gas in it with my mouth so I know that it is not clogged.

I believe that this has an air sensor in it that is built into the air filter housing, I'm not sure though.

Buying a manual for this car either tomorrow or the day after.

Thanks for the help : )

I have found out one other thing regarding the fuel pressure, the voltage at the connector to the fuel pump (which is under the trunk (THANK YOU Nissan for putting in a fairly easy to remove cover plate inside the trunk!)) keeps switching between 0 and 12 volts...

0 12 0 12 0 12 0 12 0 12 0 12........

I cannot find this switching voltage at any of the fuses in the fuse panel, I get the same thing if I disconnect the connector from the fuel pump.

Any suggestions on what is doing this?

if this helps you should be able to find a whole other complete and running motor for what its going to cost in time ad money to diagnose this, id look into how expensive it is to swap to a ga16, same displacement but i dont know if it mounts the same, plus you get EFI and its easier to work on, i think fugiot said you could snag a whole motor and all for around 300 bucks

Thanks, as much as I would rather have a fuel injected engine than the carb. version it currently has that is not an option at this time.

While reading the manual I bought I found out that the unit under the trunk is nothing more than the sending unit for the fuel gauge on the dash, the 0 12 0 12 0 12 0 12... is probably some kind of square wave that works with the variable resistor in the sending unit.

The actual fuel pump is mechanical and is bolted to the engine underneath the intake manifold (where I thought it was), so I need to hook my fuel gauge up to the carb and check the fuel pressure there.

More tomorrow...

Well,

I'm still having problems with the car...

1 - Fuel pressure is at 2.5psi, stated rating for fuel pressure for this car is 2.8 to 3.8psi, I'm not sure how accurate my gauge is (its over 20 years old), the glass sight in the side of the carb says there is fuel in their even right after the engine stalls.

2 - Engine seems to get cranky and starts running weird when it gets too hot, eventually it stalls but starts right up again. See #3.

3 - Engine seems to run ok if you just let it sit at idle until the temp gauge goes into the middle of the normal range. Manual says that the temp sensor is a two wire version and is actually a switch, it is supposed to turn on at 122 degrees (F) and turn back off below 122 degrees (F).

The radiator is warm with steam coming off it from water I spilled on it, I held the gas pedal down and held the engine at 5000 rpm for several minutes, eventually the temp gauge started climbing until it was nearly into the overheated zone.

At this point the fan has still not turned on, I disconnected the connector at the bottom of the radiator, it was reading infinity, after several minutes of sitting there nearly overheated it finally switched over to reading 0 ohms, but when I plugged it back in the fan still would not turn on.

So it looks like I have two problems, a bad sensor, and either a bad fan or bad wiring going to it.

Two other things happened when it nearly overheated, the warning lights for the FUEL and HEADLIGHTS came on, they turned back off the next time the engine stalled but the SENSOR light is on and will not turn off, anyone know how to clear it (without just removing the bulb)?

disconnect the ecu overnight, im not sure of a reflashing procedure on a car that old unless your comfortable shorting pins on your ecu to clear the codes

Left it unplugged for three days, still had the SENSOR light on when I turned the car on (without starting it). Well, long story short there are two light green wires under the steering wheel that you have to unplug to get the SENSOR light to turn off. They have a male and female whitish plastic connectors.

Also figured out that the thermal radiator fan switch down at the bottom of the radiator works fine and the fan runs if I hook 12 volts up to it.

More to fix tomorrow...

Well, in the last few days (when it is not raining) I figured out the following:

1 - Engine temp sensor (the one next to the thermostat) is out of spec. and has been replaced.

2 -

a: The thermal switch at the bottom of the radiator is turning on (closing).

b: If I run power to the radiator fan it will turn on.

c: If I jumper the connector that the thermal switch plugs into the fan will turn on.

d: If I plug the two together the fan still will not turn on, assuming there is a bad connection in the connectors. I am going to make two male/female jumpers and see where the voltage is not getting through.

3 - Engine's electrical system is ok at 14 volts IF nothing is turned on, if the above mentioned 2c happens the electrical system's voltage plummets to 12.8 volts and then engine starts to ran bad, eventually it stalls.

Long-story-short two different shops tested the alternator, it is bad, looks like I may have found the problem (or at least one of them).

4 - On the 84 Sentra unplugging the two light green wires to get the SENSOR light to turn off was intentional, at 30k miles the sensor light comes on so that the car will be brought back in for service to have the emissions equipment evaluated and repaired if needed. After that they unplug the two green wires and just leave them that way.

I made the jumpers to go between the two connectors for the thermal switch, the radiator fan turns on by itself now. My guess is that the original connectors have oxidized to the point where they are no longer making contact with each other. Will have to look around for some new connectors or just leave them the way they are.

I took this car out on the road Tuesday to burn the crud out of the engine, the car is absolutely gutless, it takes about 4 blocks just to get up to 30 MPH, it seriously looses power going up any kind of hill.

Once it gets up to around 35mph it picks up speed and seems to drive ok but is still seriously lacking power, eventually it just will not go any faster with the gas pedal pressed all the way to the floor, if I let up for a few seconds it gains a little bit of power.

Yesterday I took it to emissions testing, while in line to get tested it constantly stalled, mainly when the radiator fan came on. I had to hold the gas pedal down with my foot just to keep it idling. Needless to say it failed (hydrocarbons were high on the 1st and 2nd idle test), oddly though it was putting out zero ppm of CO (carbon monoxide). Other things it is not tested for.

I have a few theories on this, one is that due to the defective alternator there is not enough power to fire the spark plugs and they are only firing a very weak spark and therefore the engine is making very little power.

The second is that the catalytic converter is very plugged up and the back pressure is backing up into the engine preventing it from exhausting the exhaust and the mixture is getting seriously diluted with exhaust fumes.

And the third is that there is something wrong with the carb.

I'm going to pull the plugs tomorrow and see what they look like, if they are covered with black soot I'll know that I have a combustion problem. Alternator will get replaced in a week or so.

Found out a few more things...

1 - The reason that I earlier found the timing set at 15 degrees is because that is what is listed in the Chilton manual for this car, BUT it also says to check the sticker under hood and go by whatever it says.

2 - The vacuum operated Idle Speed Control Actuator and the Throttle Positioner are out of adjustment and not even touching anything which is probably why it will not idle.

3 - The spark plugs are fine, correct plug number, gapped correctly and are nice and clean.

Did a compression test on the engine too...

#1 - 195psi
#2 - 180psi
#3 - 155psi
#4 - 180psi

I'm not worried about #3, there is a valve ticking while the engine is warning up that is probably out of adjustment that will bring the compression back up once I fix it.

More later...

One thing I forgot to mention in my last posting is that when I removed the spark plugs it took no effort at all to break them loose, seems that whoever replaced them (they look brand new) snugged them down, was going to get a torque wrench to finish them them forgot about it.

Car accelerates way better now but is still having problems with stalling at idle and going up hills.

More later...

The alternator was finally replaced, the car runs way better and idles a lot more like it should, it is still having some carb. problems but the voltage is up where it should be now.

I found an official Nissan manual for this car at a used book store today, couldn't believe it, was only $15.

Taking it to emissions testing tomorrow.

More later...

I have decided to overhaul the carb. the accelerator pump barely quirts any fuel at all into the barrel of the carb, we were also told when we bought the car "That a drunk guy overhauled the carb" but it started and seemed to run ok so we looked the other way on that comment.

Anyway, it took two hours (and jacking up the car (no I'm not kidding)) but the carb is finally out, does anyone know where the part number for this carb is located, I'm assuming that it is "conveniently" located on the bottom of the fuel bowl?

This is the Federal (Non-California) version with several sensors screwed into various places.

Never mind about the part #, I did enough research online to figure out that this has the Hitachi DFE2832 carb on it.

I bought a rebuild kit for it and found out a couple of things while tearing the carb apart...

One: there was debris in a passage for the idle circuit below the throttle plate, one of those little tiny passages that you can barely see in the carb's throat, there is no way for debris of this size to get in there except during assembly.

And two: the MORON who overhauled this thing last time didn't grease the O-ring for the "Air/fuel ratio solenoid valve" and ripped it when they reassembled the carb. I was so pissed that I had to stop and go inside, more tomorrow...

The overhaul went well, found out a few things...

- No gasket between carb and what it sits on, there may possibly be no gasket between what it sits on and what it sits on.
- Accel. pump lever assembly was not installed correctly.
- Four bolts that hold the bottom of the carb to the center section were very loose.
- Layer of pinkish-brown silt in bottom of fuel bowl.
- Screws that hold top of carb to center section were loose.
- Vacuum secondary diaphragm (opens the secondary butterfly) will not hold a vacuum (is basically a big vacuum leak now).

Regarding the vacuum secondary diaphragm, does anyone know where I can order one online, I have a picture of one at: http://home.comcast.net/~lj_robins/vacsec/

Carb = Hitachi DFE2832 (non-California).

Never mind about my last question, I have a place ordering a new vacuum secondary for me.

Vacuum secondary finally came in, surprise of all surprises it was the correct part, after everything I went through now the car will not start due to no fuel pressure, if I dump gas down the carb it will start and run.

I can suck gas with my vacuum gun through the fuel filter from the gas tank, yes this car is weird that way... /Gas Tank - Fuel Filter - Fuel Pump - Carb/ personally I would have put the filter after the pump in case the pump internally self destructs, filter is $5.00, carb is $300 plus.

I get zero vacuum when I try to suck from the output side of the fuel pump, Nissan pumps don't have any kind of internal vent to prevent vapor lock that would killing my test would they? Considering all the curve balls this car has thrown at me the fuel pump dying is no big surprise, it was actually one of the first things I was suspicious of, but my PSI gauge is old so I thought the pump might actually be ok.

My final word before I hit Google is an FYI...

FYI: Vacuum secondary for this car is called a "Secondary Diaphragm" (yes that is the correct spelling), it is made by a company called "Standard Motor Products, Inc.", part # "DT160-131.HY", UPC = "0-91769-06223-1".

If you need one of these for an '84 Sentra but can't find one have your local parts house contact them.

Heh,

This car is still in my driveway, bought another pump, it only put out 0.5psi, luckly the parts place gave me the $25 back.

Appears the lack of fuel pressure is due to the engine no longer being able to drive the fuel pump. I found a block off plate for the fuel pump hole (Chevy Big Block cover plate fits over the hole (with no modifications)) and will be installing an electric pump as soon as I can find one cheap enough.

More later...

Heh,

This car is still in my driveway, bought another pump, it only put out 0.5psi, luckly the parts place gave me the $25 back.

Appears the lack of fuel pressure is due to the engine no longer being able to drive the fuel pump. I found a block off plate for the fuel pump hole (Chevy Big Block cover plate fits over the hole (with no modifications)) and will be installing an electric pump as soon as I can find one cheap enough.

More later...

Hey Torch,

You are one persistant dude! I would have given up about 3 months ago. This forum seams to be a little thin on help. Have a lot of respect for someone that pushes on alone.

Any way, about your fuel pump issue. You said you found a manual for this beast, does it show a push rod from the cam (or what ever is driving the fuel pump). I had an abused Chevy small block that the push rod from the cam to the fuel pump would stick due to poor maintenance (I don't think the oil had ever been changed). A little carb cleaner and some oil freed it right up and she ran great.

Post back and let me know, I'll try to keep an eye on this forum.

Sparky

Nope, no push rod, I know what you are talking about I used to have a Chevy that worked the same way.

I would have not even worked on this car if it did not belong to a relative who has another working car that they can drive, I made a rule for myself a long time ago that I will not work on 1980's 4 cylinder carb. engines, they are just too hard to work on with miles of vacuum line and sensors and switches all over the place.

The diagram for this engine shows a jack-shaft that is driven from the timing belt, it has a gear that runs the oil pump and a lobe that cycles the fuel pump, not the way I would have done it, but then again I didn't design this engine.

Also figured out that the original pump has a vapor return line that feeds off the pressure output going back to the fuel tank which is why my vacuum gun could not pull a vacuum on it. Am going to block this line off when the electric pump is installed.

Hey Torch,

Interesting! Can you get a look at the lobe that drives the fuel pump? Is it worn? Kind of find that idea out there a little, would probably wipe out the arm on the pump first.

If the cam is ok why didn't the new pump work? Can you stroke the pump by hand, maybe if you clamp it in a vice? If you can hand operate it with a pressure gauge on the output, the input line going to a cup of gas or carb cleaner and return lines open you should be able to measure about 10 psi (I think, never worked on a Nissan before). If you get good pressure you should be able to do the same with the inlet side and get 15" Hg (don't need the fluid for this part). I don't have a clue about the return line.

The reason I'm asking this is to find out if the pump is working ok, then I would look at a clog up stream some place. At some point you said you had redish orange stuff in the float bowl so I am thinking rust in the tank. Maybe you plugged the fuel line someplace. The filter is another question, I don't recall if you put a new filter on it but even if you did if there is enough crap in the tank you could have plugged up the new filter. I don't know how much they cost but it may be worth taking the filter off and cutting it in half and looking at the paper element (the inside).

My concern is even if you put an electric in you'll still be in the same place if the line is plugged.

If you are bound and determined to switch to an electric pump make sure you add a safety cut out in case the engine stalls. Before electronics they use to add an oil pressure sensor that would shut the pump off if you lost oil pressure, in the event of a crash the pump would shut off the fuel flow when the engine stopped. When you went to start the car it would run on the fuel in the bowl until you got pressure, the only tricky part is if you ran out of gas you had to crank it long enough to get oil pressure in order for the pump to start.

Good luck,

Sparky

Hi,

Old and new pump have/had too much internal pressure to operate by hand.

There are no clogs in the line, in an earlier posting (yes I know there are a lot of them) I said that I was able to hook my vacuum gun up to the line and get gas all the way to where it hooks up to the fuel pump.

I've considered the safety cutout, may or may not do it, I have had problems with them in the past.

I have been through this problem before regarding the drive lobe going bad, I had an old pickup that did the same thing, only it would start out with fluctuating pressure that would slowly drop to zero after a couple of minutes at that point the engine would stall. Went through three different mechanical pumps from three different places they all did the same thing, installed an electric, pressure shot up to where it was supposed to be and the truck ran fine after that.

No there is no way to look inside the hole at the lobe, the fuel pump is bolted to the back side of the engine facing the firewall, there is so much stuff in the way I can barely get my hands up in there.

So, that is where I am at for now, hopefully I can find a cheap electric pump soon.

Have you tried replacing the little inlet needle and seat filter in the carburetor? I worked on the "hopeless chokeless" B11 Sentra carbs at a dealer in the eighties. Unless you've rebuilt these carburetors, you would never know this filter exists. It very small and looks like a sewing thimble. Remove the carb top, the float and needle. Then use a 10mm socket to remove the fuel inlet seat. The filter is right there, pressed onto the brass seat assembly.

If that filter is clogged, it will look like the fuel pump is bad, and it might not be.

Mike

hey torch...i give you credit for being persistant also! hey if in fact you run out of answers from this site you can always head over to nissanforums.com.
No im not selling anything.It just that i too have had weak responses to nissan troubles on this,and other sites also.Not to say i have not had any help..but hey...the more help the better ....right.good luck

blownb210: While that may be a problem it is not the cause the the carb. not getting any gas, there is/was gas getting to the fuel pump, there was nothing coming out of the output hose.

Also, while rebuilding the carb. it was extensively sprayed out with carb. cleaner.

roonie: Thank you for the advice, I already had that site book marked, I think I already have a posting over there for this.

Everyone else: Please read -everything- before asking me "Have you done this?", I know it is a lot to read but it will help prevent repeat questions and questions for which there are already answers.

Persistence can get you to the top of a mountain or the bottom of a very deep hole, at this point I'm not sure which direction I am heading :-)


Thanks again.

hey torch...there is also www.sentra.com ya know.
torch my post is right next to yours ..any chance you could have a look at the pic i posted and tell me where i might find the idle switch on this baby.The car goes down the road just fine but at idle the car sounds like a tractor as it is crackling and popping back through the throttle body.Anyway just looking to find the idle switch as that code came up.any help would be great.later

Finally found an electric pump with (nearly) the correct output PSI (4.5 instead of 3.8), I don't think 0.7 psi is going to make any difference, I'm going to try to hook it up tomorrow.

Car has fuel pressure and starts now, but still stalls when you press on the gas, I'm not sure what to do at this point, catalytic converter might be plugged up, I just don't know.

Is also leaking oil somewhere and has a vacuum leak somewhere near or under the the air filter housing, something might have wiggled loose while I was putting it back on.

-sigh-

More later...

Well, things have not changed much.

I think the vacuum leak I am hearing it just air going down the carb's throat now that the engine is actually running. I pulled the air cleaner housing off and plugged all the loose vacuum hoses except the ones that were supposed to suck air, the only problem with this is that the exhaust return hose that connects a small exhaust pipe to the air cleaner when exposed to air got so hot that it actually caught fire, so now I need to find one of those.

I also unbolted the catalytic converter from the engine's exhaust pipe to see if the cat was plugged up and causing the problems, with it unhooked the engine has an obvious miss in it which you can hear and feel, even at 4-5k rpms you can still feel it.

My eyes do odd things right as the sun goes down, I noticed an odd fog cloud sitting right over the carb throat that I could not see in the day light, I shined a flashlight down the carb and could see gasoline pooling up on top of the primary butterfly valve and when I full throttled it you can actually see a heavy spray of gas coming out of the venturi.

Back at idle the engine runs a little rough, I found that if I carefully place a shop rag over the carb throat and slightly adjust it the engine rpms will go up a little and then the engine runs very smooth, I'm not sure what would need to be done to make the engine run like this on its own, maybe it just needs a new carb.

hey torch, did you get it purring yet? the manual has a part in it that tells how to get the codes or it should. its been a couple of years since i read my '86 codes. but as i remember you have to flip the switch on the ecc one way and turn the key on but don't start it.the light will blink io let you know it is in check mode the it will put out the code then it will pause then put out the next code.its tricky to keep up with. but the manual will have the code meanings in it. one other thing what kind of distributor is in it ? one type has a pick-up coil and then one has a disk in it with a circuit board. the one with the disk will make it stall like you cut the key off and after it cools off it will run again for about the same length of time then quit again. i have had to put two in mine around $200.00.

My first Sentra was an '83. it had a carb, but no O2 sensor. i had a problem once or twice, and i cleaned the carb and it ran great. the bowl would get some sediment in it and the passages in the carb would need to be cleaned. the carbs are not hard to rebuild/clean. try that, too.

yeah the carbs aren't too much unless it's got tbi then a little more to rebild. don't know if the put the little black round thing behind tbi on '84 but '85 had and it had a lot to do with the idle you could plug the hole in it and the motor would run at 3 grand take the plug off and it would idle back down. torch you ever figure out how to read the codes? check and see which distributor you have......pickup coil or disk...

No, not running yet but I am finally getting somewhere with it...

Talked to an independent import shop who (so far) has given me good advice in the past. He said that the rebuild kits don't always have accurately sized O-rings and gave me two brand new Nissan O-rings for the A/F solenoid. He also said to check the fuel level in the site glass and adjust the float if the level is too high.

Something else that I did not realize was a problem is that I accidentally left the pin out of the anti-diesel solenoid which I didn't think was going to be a problem because the electric fuel pump shuts off when the ignition is turned off and cannot have run-on, but he said that it causes an internal vacuum leak inside the carb. which may explain the hissing that I have been hearing.

I also disconnected the cat from the exhaust pipe so the engine is breathing into free air, but the engine is still running the same way.

The engine computer under the seat is NOT the one mentioned in all the manuals, I did figure out that it is the non-California computer, it has a little recessed ON/OFF switch and a red LED and a green LED, from what I remember the red light comes on and stays on and the green flashes once. This computer does not have the toggle switch that you can rotate back and forth, I also removed the circuit board from the engine computer, it looks fine nothing is burnt or even looks odd.

Distributor... not sure what it has internally, I think it has a pickup coil but I'm not sure.

I already cleaned out the carb, will be tearing it apart again if the gas level is too high.

Lots to do, more later...

Wow, finally getting somewhere!

For some reason today I thought of the idle adjuster screw on the back side of the carb, my old 77 Ford pickup would run just like this if I adjusted it in too far. Someone was nice enough to have already drilled out the plug/cap for me so I didn't have to deal with that.

Anyway, I turned it all the way in then backed it out 2.5 turns, I was able to get it to run a little smoother but it still runs rough and if I choke off the carb throat with my hand or a rag the engine smooths out, which almost seems like it is correcting a major vacuum leak, which brings me too...

I can still hear a vacuum leak and I don't think it is just the sound of air going down and through the venturis, this is too high pitched. I cannot find any hoses anywhere that are loose, all of them had been replaced by the previous owner.

When I rebuilt the carb the part number was half gone from the side of the carb so the parts guy and I had to guess as to which one would be the correct rebuild kit, everything went together as it should have but one thing that I did not notice when I put it back together was that right next to the secondary diaphram on the front of the carb was a little 1/8" hole that went straight down to the manifold plenum.

Well, choices, choices, I decided to take the short road and hope for the best, I put a BIG blob of high temp black RTV over the hole and am going to let it dry for 24 hours and start the car tomorrow and adjust the idle again, I think this will finally solve the stalling problem.

Still makes me wonder though, this carb comes apart into three pieces, I'm wondering if this is actually parts of two or more carbs and the bottom piece was from another year that had something that went to that hole?

More tomorrow...

Hey Torch, R U a man on a mission or what? As far as the vacuum leak, put everything together including the air cleaner etc. and hook up every vacuum thingy you can find and then start judicously spraying carb cleaner around the carb. If there are any more leaks the engine will smooth out or speed up, depends on the size of the leak. The air cleaner makes sure that the carb cleaner isn't getting sucked into the throat of the carb, that really screwed me up once.

Good Luck.

Sparky

hey torch, did you find the pvc hose and make sure it is connected under the intake . you will be able to see it from underneath the motor . hose on mine runs from pvc valve back under distributor then back side of motor then runs up to the bottom of the intake. when i got it the pvc hose was just hanging
down by the starter,like to have never found the fitting it went to . only way is to look up from under neath. carb was fun to get off too . two bolts from top rest from the bottom with a two foot extention. good luck

Thanks for the replies...

The engine is way smoother now, between adjusting the idle screw (air/fuel mixture) and plugging up that hole you can barely see the engine vibrate, at high RPMs it used to have audible and vibrational "thuds" (for lack of a better word), they are barely noticeable now.

But... as luck would have it with this car the block off plate from removing the mechanical fuel pump is dripping oil on the ground quite badly, I used a Chevy Big Block block off plate (the bolt holes are in the identical place as the Nissan fuel pump's) but it did not come with a gasket and a Nissan fuel pump gasket is nearly $6.00 which I did not want to spend and just used hight temp RVT to seal it with.

Live and learn, at least I know what is wrong and what I need to do to fix it, I'll just have to spend $

More tomorrow...

Well, I ended up buying a whole roll of gasket for $6.00 and just cut my own, then I found out while I was cleaning the old gasket sealer off the fuel pump seat that the stupid spacer was still installed and had a gouge across the bottom of it that was causing the leak, amazing what you can see under the car with a 500watt shop light.

Got it as smooth as I could with various scrapers, there is just no room to move under there. Ended up using the spacer as a spacer (on top of the block off plate (instead of under it)) instead of stacking 3/4" of washers to make up for it not being there.

I hope this is the last of the problems, will find out tomorrow.

NO MORE OIL LEAK!!!

Fuel pump cover worked great, no more oil leak.

Carb was still acting odd though when slowly pushing on the gas the engine was still trying to stumble and die, so I started pushing and pulling on things, and looking things over.

On the back side of the engine there is this big "thing" that has a 0.5" (inner dia.) hose going into and back out of it that connects the bottom of the intake manifold to the bottom of the air cleaner housing, I noticed that if I covered the hole that goes to the air cleaner and gave it gas that it ran a little better, not hugely but better.

When I pulled the little vacuum hose off of it the engine suddenly ran horrible and nearly died. Well, this little vacuum hose had a 0.5" crack going down it. I put a new hose on, the engine runs even better now when you give it gas and has a little stumble in it but no longer tries to die.

I adjusted the a/f mixture down a little more and lowered the idle as well about down to where it should be.

Tomorrow I'm going to bolt the air cleaner back on and hook all the hoses up like they are supposed to be (instead of having bolts and screws plugging them) and see how it runs with everything hooked up.

More later...

It is all back to together and will start now but the "Fast Idle" is not making the engine run fast when it is cold (the weather is getting cold here again), I thought this was computer controlled but it turns out there is a fast idle screw on the driver's side of the carb that has to be adjusted.

By snaking my hand and a screw driver through a labyrinth of hoses and pipes I was able to get to the fast idle screw but it will not speed the engine up to where it should be, the manual says it should be between 2,700 and 3,400 RPMs it will not go anywhere that high.

I'm going to try again in the morning when the engine will be around 40-50 degrees (F), if the fast idle will not go to where it is supposed to the carb is going to be replaced, I am to the point where I am sick of dealing with this.

Well, the Fast Idle will not go above 1,900 RPMs and the Acc. Pump is stumbling at around 1,500 RPMS despite the new seal I installed when I rebuilt the carb.

Guess I have bad news for the owner, on the flip side the O2 sensor is reading 0.167 volts and I don't smell any gas coming out of the tail pipe so I think that the O2 sensor is ok.

I pulled the cat. off as well and looked in both holes, the mesh/screen is intact without any discoloration, although on the outlet side there is an approx. 1.5 inch gray spot. So physically this thing looks ok but chemically it could be dead, will have to talk to the owner.

More later...

Hey Torch,

About the fast idle screw, does the manual say that the screw should be adjusted when the engine is warm or cold. 2700-3400 RPM sounds way to fast for a cold fast idle. Usually the fast idle spec. is the setting on the high step (most throttle open) of the cam when the engine is fully warmed up.


Sparky

It doesn't say but I would have to assume that it means COLD, the base idle is listed at 700 to 800 RPMs in (D).

What is odd about this cold idle is that there is an adjustment screw that -will- make the idle go up or down, but, it has no stepper like I have seen on other carbs the will lower the RPM as the engine warms up. I have had older Chevy's and Fords and had a stepper on the side of the carb that would lower the RPMs in 3 or 4 steps but this one doesn't have one which makes me wonder how the idle is supposed to come down once the engine is warmed up?

The only thing I can think of is that what ever moron worked on this thing last time couldn't figure out how to get the stepper to work so he just took it off and left it off, or this carb has some unexplained meta-physical qualities to it that -magically- bring down the idle.

The adjust screw itself is a royal pain in the butt to get to since you have to squeeze your hand between a hot water hose and a hot exhaust pipe going to the EGR valve to get down low enough to get the screw driver at the right angle to adjust the screw. The air/fuel mixture screw is tons of fun as well, you cannot even see what you are doing once the air filter housing is back on and have to go by feel.

Well, right in the middle of trying to adjust what had been a very smooth running engine it suddenly without any warning started running horribly, I knew it wasn't from trying to adjust the A/F mixture screw. What I found is that when I unplugged an electrical connector from the one of the vacuum units over on the passenger side inner fender the engine smoothed out and and ran fine.

That led me down the not-so-fun road of this is an emissions problem and not a carb. problem. Long story short the BPT and AB valves both have blown vacuum chambers and will have to be replaced, so far only the dealer has them, total = $146.xx (US) for the two of them, not exactly something I want to tell the owner two months before Christmas.

So close, and so far away...

Wondering through U-Pull-It in the rain resulting in getting wet and finding out that every single car that had the same AB and BPT valves as this car had blown vacuum chambers in them as well.

After the long drive there I had forgotten about the fact that there are two electrically operated vacuum switches that will not hold a vacuum either, will make one more run on Monday to check again.

Dealer in addition to the $146 for the AB and BPT valves wants another $108 each to replace the vacuum switches, total bill for the four parts = approx $362 (US).

At this point I don't know what to do, the owner paid $200 for the car, put $170 into it already, she is not going to be happy about this.

I cannot believe it has been over a year and this car is still in the driveway, two vacuum switches, BPT valve, AB valve, two plugged up vacuum air filter canisters, and (finding out from a book at the library) that a majority of the vacuum hoses were hooked up wrong were what was causing this car to stall when you put it in gear and gave it gas.

It is finally running under its own power and went back and forth in the driveway without stalling, I have a little more work to go on it and then will take it out on the street.

I will never, ever, work on another 1980's car unless it has fuel injection, "Take it to a garage" will be my answer from now on, more later...

I took it out on the street yesterday, she doesn't like going slow but will cruise along if you step on it, the high idle when you first start it is rather erratic but once she is warmed up she seems to run ok. I think the biggest problem right now is that the gas in the gas tank is over a year old and probably has water in it too from sitting so long.

I dumped a bottle of carb. friendly fuel cleaner in the tank and completely filled the tank with brand new 87 octane gas. Going to let her run for a while tomorrow and see how well she does. I'm hoping for the best!