Starting issue

Specs Nissan Sentra 1.8s 120000 miles. Have never had any problems until now.


Here is some history on this issue:
1) The car has always had starting problems (bought the car with 70K on it). It takes two tries to get the car started, the first try the car starts up, the rpm’s jump to about 2.5 and on the way down it just dies, sometimes with no hesitations sometimes with a little. The second try it starts with no problem.
2) In the last month (4 times total) it would not start at all. It would crank but not turn over. When I tap the gas pedal it would turn over and then die. I have to flood the cylinders (hold the gas down) for it to start and stay on. This mainly happens if the car sits for more than 8 hours (overnight or after work). Once it is on, it drives with absolutely no problems, shifts through all gears, doesn’t skip, rpm’s hold very strongly when coming to a complete stop. The check engine light is not on, and I just can’t figure out what is wrong. So far I have replaced the spark plugs and checked the battery, but that did not fix the problem. Has anyone had a similar experience that could offer me some help and direction?

i would check fuel pressure

Do you mean the fuel pressure regulator, or if there is actual fuel pressure in the line itself?

Specs Nissan Sentra 1.8s 120000 miles. Have never had any problems until now.


Here is some history on this issue:
1) The car has always had starting problems (bought the car with 70K on it). It takes two tries to get the car started, the first try the car starts up, the rpm’s jump to about 2.5 and on the way down it just dies, sometimes with no hesitations sometimes with a little. The second try it starts with no problem.
2) In the last month (4 times total) it would not start at all. It would crank but not turn over. When I tap the gas pedal it would turn over and then die. I have to flood the cylinders (hold the gas down) for it to start and stay on. This mainly happens if the car sits for more than 8 hours (overnight or after work). Once it is on, it drives with absolutely no problems, shifts through all gears, doesn’t skip, rpm’s hold very strongly when coming to a complete stop. The check engine light is not on, and I just can’t figure out what is wrong. So far I have replaced the spark plugs and checked the battery, but that did not fix the problem. Has anyone had a similar experience that could offer me some help and direction?



My nissin sentra has some safety thing on it. I have to push the gear shift up before I start it on it wont start.
christmas20082009.ecrater.com

I’m going to take it to a mechanic to check for fuel pressure in the line, but before that I think I’m going to replace the crankshaft position sensor. The fuel pressure regulator was my next thought, but I’m going to take this one step at a time. Any advise on what else to look for while a mechanic has his hands on it (things I can’t check in the garage with a wrench and a screw driver). I mainly want a diagnosis and fix the problem myself, unless it’s the fuel pump then it’s going in the shop.
I’m not quite sure about the gear shift and a safety feature are you saying it won’t start at all, or it’s just hard to start? Because mine will start just not on the first try, and it seems to be showing signs of getting worse.

Everything is pointing to fuel pressure. If it runs at any time the crankshaft sensor is fine. THE crank sensor lets the computer know where the crankshaft is so it can fire the spark plugs and also fire the injectors period. Like a coil when they go bad they quit and don't come back. Save your time and money on the crank sensor idea.

Two things it could be 1) Fuel pressure not adequate when starting either due to a clogged fuel filter or pump on the way out. Usually when a pump is on the way out it gets noisier. Also the engine starts to get sluggish on occasion.
2) could be a sticky throttle position sensor.

I have an Autozone nearby and they pretty much have rental tools for free. You pay entirely for the tool and when you bring it back as long as it is in the same condition you get 100% of you money back.
Need to attach a fuel pressure gage to the fuel rail and verify you have adequate fuel pressure. Check you specs on the correct fuel pressure.

Fuel filter is my bet on this one.:smokin:

these cars are known for bad check valves in the fuel pump which creates drainback into the tank. If this occurs you would notice a long crank time after a cold soak (ie 8hours later). this vaguely is the conditon you describe for condition #2.

to verify the problem...cycle the key to run for 2second, turn off, turn back to run for 2 seconds and repeat for 4cycles. This primes the fuel line that has drained back as the fuel pump runs for 2 seconds each time you cycle from off to run. after 4 cycles start the car normally.

if your going to get a fuel pressure test done make sure they test for fuel pressure leakdown which would confirm or deny this diagnosis.

for your info...holding the gas to the floor when starting puts the car in clear flood mode that shuts off the injectors during starting; no fuel

My nissin sentra has some safety thing on it. I have to push the gear shift up before I start it on it wont start.
christmas20082009.ecrater.com

if auto trans sounds like a out of adjustment or bad park/neutral postion switch. Does it start normally in neutral?

Alright over lunch break I tried to do some of the things suggested above.
1) I tried to cycle the key for 2 second 4 times, and then on the 5th try I started the car. The car started the rpm’s jumped between .5 and 1.5 the car acted like it wanted to die then they stabilized (it did what it normally does, sometimes it dies sometimes is stabilizes).
2) Next I turned the car off and put it in neutral, to check the park/neutral position switch. The car started and again the rpm's jumped and the car acted like it wanted to die. This time I noticed the rpm's dipped lower than the first time.
3) I put the car back in park and tried to start it a third time. The car started the rpm’s jumped to 1.5 on the way down it went to 0 and the car died. I tried starting it again and had to give it gas (held it at about 1 rpm) to help the car stay on.

So what do you guys think? Are these signs of bad fuel pump (04 sentra 1.8s does not have fuel filter; the fuel filter is in the fuel pump)? What about fuel pressure regulator, fuel injector, or throttle position sensor. Keep in mind the car has had this starting problem for the past 4years/50000 miles. We have just ignored it. And here lately it has been showing signs of getting worse, be requiring gas pumping/flooring to stay on. I have not yet had a chance to check the fuel pressure, I’m dying to know myself but don’t think I can get to it till tomorrow.

sorry... step 2 post was for christmas20082009...shouldn't have posted like that.

sounds like iac valve but they ususally set p05XX dtc. as coolant runs through intake it can get past the seal and short out the iac circuit back to the ecm. you need to look at the live data with a scan tool. fuel pressure test in never a bad idea.

It’s alright not like I hurt anything by putting it in neutral and trying to start it.
Would the IAC cause a starting issue? When the car is running I have no issues with rpm’s at idle. Plus there is no check engine light one. Also I never really done this before (turned the car on and off several times in a row) but now that I have I’m a bit troubled. The car got worse the more times I started it and turned it off. What would cause a parked car to get worse the more times you start it up? When I take the car to a mechanic I will ask him to check the MAF and IAC, even though none of them are tripping the check engine light.

the car starts then dies (unless you touch the throttle) that is an idle issue. the starting part is ok...the part after the start is the problem as it should idle after start. That's why i would check iac first.

when you start and and shut the car off many times in a row with a short or no run time in between it basically creates a near flood conditon as the fuel builds up. I've seem people create a no start (flooding) by just repeatedly moving their car in there driveway.

I would agree the fact that it idles normally with no codes suggest the iac is ok. You can get skewed data from a sensor that doesn't cause a code...the car tries to use the bad sensor data and it creates drivibility issues. That is why viewing live data is important and why its hard to diagnose without.

the maf on all nissan's are sensitive to contaimination. Just running a non nissan air filter will cause this. I've seen it all the time; the replacement air filter is clean but the maf screen behind the filter is black. Open your air filter and wipe the screen with your finger...if a streak is left all that crud is on the maf sensor wire. this causes a lean running conditon which usually sets a lean bank code. so look at fuel trim #s. Doesn't sound like a maf issue but one look at the trim numbers will tell.

keep us posted

A fuel pressure gauge is $12.00 at HarborFreight. Or borrow one and check your fuel pressure.... Replacing fuel pump is definitely DYI.... you get to fuel pump by lifting up the back seat and accessing the top of the gas tank.

FYI as consultIII said there is a TSB (NTB05-052a September 8, 2006) for "long crank" problem:

This is a ten page bulletin,basically what it is,is a repair procedure for the fuel pump. There is a problem with the fuel leaking back into the tank instead of staying up at the injectors.This kit resolves the problem

Classification: Reference: Date:


EC05-001a NTB05-052a September 8, 2006


2002 - 2006 SENTRA; LONG ENGINE CRANK TIME BEFORE START
APPLIED VEHICLES: 2002 Sentra (B15) with QR25 engine only.



2003 - 2006 Sentra (B15) with QR25 or QG18 engine


APPLIED VIN: 2002 with QR25 engine; all VIN's.


2003 - 2006; all VIN's


This bulletin amends NTB05-052. This version is expanding the model year range.
Please discard all previous copies of this bulletin.
IF YOU CONFIRM:



When starting the engine, it cranks longer than 3 seconds before it starts.


ACTION:


Install the Fuel Pump Repair Kit (listed in the Parts Information).


PARTS INFORMATION
DESCRIPTION PART # QUANTITY



Fuel Pump Repair Kit 22670-8U70C 1
Fuel Tank Gasket (O-ring (http://www.justanswer.com/questions/1ddr5-my-05-nissan-sentra-cranks-longer-than-it-should-before-starting#)) 17342-01A00 1




http://www.courtesyparts.com/nissan-fuel-pump-repair-kit-2002-2006-sentra-qr25-2003-2006-sentra-qg18-engine-tsb-ntb05-052a-p-622217.html

Hope this helps.

I agree with the initial long crank problem and the throttle control valve all good valid points. Initially I thought it was a slam dunk case and the culprit the fuel pump. But what doesn’t make sense to me is how I can run into a bank for 10 minutes or less and it still gives me starting trouble. And it’s never consistent sometimes the longer it sits the better it starts (although lately as mentions above it would not start after a long period of sitting, had to hold down the gas pedal). My last car was a Volkswagen and the fuel pump went out on it, it took about 5 cranks to start the car up. But it was consistent in the fact that the longer the car sat the more cranks it needed, which made sense because it was bleeding the gas back. But I’m trying to get in with a mechanic to get a live data.

Hope he's got a fuel pressure gauge. FYI fuel pressure should be 51 psi at idle.

And check out the field service manual at:

http://www.nicoclub.com/FSM/Sentra/2004_Sentra/

fuel pump stuff is in ec.pdf and fl.pdf

Hope this helps.

Guys, I have been really busy traveling back and forth for work and have not been able to take the car to the mechanic. But today a “new” symptom appeared. Today on the interstate the gas pedal stopped working. I was going 70mph and noticed my car slowing down, I gave it gas and nothing happened. I had enough momentum to pull to the side and came to a stop, and then I noticed the engine was still running and rpms were holding! The car was still in drive, I tried to give it gas and nothing happened, then I floored it and nothing happened (except for a check engine light came on). I put the car in park turned it off and started it back up, and the car worked fine, and has been working since this morning. I took the car to AutoZone and had them hook up an OBDII, and it gave me a P2135 code. That is the throttle positioning sensor.

I did some looking on line and found one site that, “that code would require the throttle assembly to be replaced and relearned.” I’m not sure what that means, but I know the throttle assembly is about 500 bucks. My other option is to replace the throttle positioning sensor alone. What do you guys think, am I even on the right track? What about the IAC, or fuel pump (remember the car did not die).

RockAuto.com has throttle body (electric throttle control actuator)

A-1 CARDONE Part # 670005 http://www.rockauto.com/catalog/images/MoreInfo.gif A-1 CARDONE Part # 670005 http://www.rockauto.com/catalog/images/MoreInfo.gif

for $90. But they also have a separate throttle position sensor listed under their "emissions" section of parts. I'm not sure if '04 sentra 1.8s have separate TPS or combined TPS/throttle actuator. You could get p/n off yours to make sure.

Also, from service manual:

page EC-47
Accelerator Pedal Released Position Learning UBS00B2V
DESCRIPTION
Accelerator Pedal Released Position Learning is an operation to learn the fully released position of the accelerator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time harness connector of accelerator pedal position sensor or ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Turn ignition switch OFF wait at least 10 seconds.
4. Turn ignition switch ON and wait at least 2 seconds.
5. Turn ignition switch OFF wait at least 10 seconds.

Throttle Valve Closed Position Learning UBS00B2W
DESCRIPTION
Throttle Valve Closed Position Learning is an operation to learn the fully closed position of the throttle valve by monitoring the throttle position sensor output signal. It must be performed each time harness connector of electric throttle control actuator of ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON.
3. Turn ignition switch OFF wait at least 10 seconds.
Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.

The manual has procedure for checking output of TPS; there's actually two sensors TPS1 and TPS2, they should put out 0.36-4.75 volts (S1) and vice-versa for (S2) as throttle goes from full-closed to full-open.

Manual also says to check/clean the two engine grounds on the back of the intake manifold, always a good idea with sentras.
Hope this helps.

Alright I bought a throttle positioning sensor (71 bucks Advanced Auto Zone). I tried to replace it myself, but there seems to be 4 rivets holding the housing of the sensor on. Except they are not rivets, a website says they are “special torque bit set up.” I tried to find out what kind of tool I need to remove them but I’m having trouble. Any suggestion on what I need to removed these “rivets”?

Thanks.

Alright I bought a throttle positioning sensor (71 bucks Advanced Auto Zone). I tried to replace it myself, but there seems to be 4 rivets holding the housing of the sensor on. Except they are not rivets, a website says they are “special torque bit set up.” I tried to find out what kind of tool I need to remove them but I’m having trouble. Any suggestion on what I need to removed these “rivets”?

Thanks.

Is it a torx with a round stud in the middle? If yes, it is a torx tamper proof security screw (the maf uses the same type of fastener). There are special bit sets you can get to remove them. I have seen people knock out the center stud with a small pin punch and then use a regular torx driver.

They turned out to be rivets; I was able to take them all out. But now I have a new issue, I can’t find the throttle positioning sensor. There is a black housing next to the firewall, down flow of the MAF. That is where I thought the throttle positioning sensor should be. I removed the cover as mentioned above and all I saw was gears inside but no sensor, nothing that matched what I have purchased. I bought the sensor so I know what I need to look for, but I have not been able to find it. Can any one tell me where this sensor is at because I just can’t find it?

Alright here is an update. I took the car to a mechanic, it turns out that my engine (1.8 S) does not have a standalone throttle positioning sensor; it is built in the throttle body. This is why I could not find it. The Mechanic replaced the whole throttle body. The car seems to be running just fine at first, the starting issues went away the car starts right up without acting like it going to die (sometimes actually dying), and the gas pedal feels way more sensitive. The problem now is when I start the car it revs up to 2 rpms, I let the car sit there for a minute and it slowly comes down. Also when driving the rpm needle is not very smooth like it was, it jumps and jerks around. For example when I coast on the interstate the needle jumps down and up then down (I’m not giving it any gas just coasting/slowing down with not breaks). Then finally the check engine light came back on. I have not had the chance to read the code, but I’m really bummed it seemed to work, then the rmps got really jumpy and now the check engine light is back on.

You've got to check the codes, could be a vacuum line or sensor didn't get re-connected.

Alright so an update, took the car back to the mechanic, they tried to re-teach the ECU (the method mentioned by Skeeter123), but the car would not take. So they had to send it off to a dealer and they plugged it up and now it works almost just fine. See when we first got the car back in 2007 it has always had a particularly weird starting issue. It would take a long crank and the rpms would jump around, shaking the car for a second before the rpms would stabilize, and it always did it on short trips (basically once the car wormed up, overnight it starts right up). But it had never not started or died. Then 3 years later the starting issue began to get worse. The car would start dying, have starting troubles all the time (over night or over 1 hour rests didn’t matter), require pumping gas pedal to start, and finally gas pedal giving out on the road. Now after about 500 bucks and a new throttle body, its back to acting “fine”. And by fine I mean just like when we bought it in 2007 starts right up over night or long sitting time, but short runs (once wormed up) it hesitates. I almost feel like the original issue was never really addressed, but rather masked by the throttle body going bad. I don’t know I do know not to mess with this particular type or Nissan or the engine.