1984 Sentra stalling...

[Torch]

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)?

[nismo_pilot]

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

[Torch]

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...

[Torch]

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.

[Torch]

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.

[Torch]

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.

[Torch]

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...

[Torch]

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...

[Torch]

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...

[Torch]

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.

[Torch]

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...

[Torch]

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).

[Torch]

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

[Torch]

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.

[Torch]

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...