Engine stalls on idle caused by fuel problem(I think)

[kclo4]

So here I was bleeding my brakes today when something unexpected happened on the test drive.

The car started fine and ran fine for about a minute. I got on the gas a little to test my brakes and I went to stop hard the car wouldn't. I turned back into my neighborhood only to find that the wheel was hard to turn. Looked down at the tack and it was at 0. I can't figure out why the car would have died. I start it back up and after and it would not rev and after a few moments it died. This was repeated for the rest of the day.

Car starts perfectly fine, then bogs out and dies. It sounds normal till it seems like it runs out of fuel.

There are NO engine codes being thrown which is even more wierd.

If I start the car and give it some gas it will bog out heavily and hesitate. It will rev, bog, rev, bog but it never revs very far before it bogs.

In the troubleshooting I found that the fuel pump runs for its allotted time when the ignition is turned on, but it seems there is no fuel pressure after that initial surge. I haven't got a fuel pressure tester to find out for sure, but I will try that tomorrow.

We took out the fuel pump and gauge and the leads on the fuel pump show about 1Ohm which is in spec. The fuel filter does not appear to be clogged because we unhooked the hose behind the filter to test to see if the pump was working when the ignition was turned on.

This is all completely unexpected as I drove the car last 2 days ago and it performed well.

Any other ways to test the fuel pump or anything else that could be involved?

I did read one interesting thing in the FSM involving the camshaft position sensor. It seems like the fuel pump will not do anything unless the ignition is turned on or the camshaft position sensor is telling the computer that the engine is turning.

The car is a 95 S14 with stock engine.

Beyond this I am stumped. Any help would be great. Tomorrow I will play around some more, but tips on what to try would help out.

Thanks

Paxton
Modified by kclo4 at 4:32 AM 10/24/2004

[johna_99_99]

do you have any problems with power?i ahd the exact same problem....after driving the car for a while i couldnt start it up again after about 30 minutes of letting it sit. The car would seem to idle fine for about 1 second then then it would struggle to stay idle and finally it would stall.....it seemed to get worse as i would keep trying to start it(it simply wouldnt rev at all). but after letting the car sit for about an hour or so it would start up no problem. i brought it in to a garage and they hooked a fuel pressure gauge and found that the fuel pump was the problem...i got a new fuel pump and ive never had the same problem again. before the new fuel pum was installed in my car(92 240sx) i had problems with power. my car simply had no power...but after getting that new pump installed it didnt feel like i was driving the same car at all...i had a lot more power. anyways i hope this helps with your problem.

[mss5413]

check your fuel filter or just replace it. Also if you have a fuel pressure gauge you might want to check your pressure with the ignition on only and also after the car is started. I realize you mentioned that the car sometimes doesn't run, but when it does run. Good Luck!

[kclo4]

The car starts every single time I turn the key. It then runs for about 5 seconds at idle then bogs out.

With the fuel hose that goes to the fuel rail disconnected fuel flows readily from the fuel filter when the ignition is turned on. It appears that at least when the ignition is turned on that the fuel pump generates a lot of pressure.

I borrowed a fuel pressure tester, but it is the normal shredder valve type. I went all over the place (except NAPA) and I could not find a tester that I can hook up inline on a T like the FSM says.

[mss5413]

what you need is a tee adapter because you don't have the schrader valve application, either borrow one from the same person that loaned you their gauge or if nothing else O'Reilly has the tester kit with the correct adapter for about $45. It is a lot of money to spend just to do a little bit of troubleshooting at the moment, but later on in the future you should find that you will get more use out of it if you have another fuel problem, and it should almost pay for itself. Good Luck!

[kclo4]

So I found the proper brass fittings to make a T and have tested the fuel pressure between the fuel filter and the fuel rail.

As listed in the FSM, when the ignition is turned on the gauge reads right around 43PSI which is good.

After the pump charges the line the gauge drops down to about 40PSI.

When the engine in started the gauge reads about 40PSI and then fluctuates around 40PSI as the engine bogs out and dies. The FSM says the gauge should read 34PSI at idle. What could this mean?

I will do the vacuum pump test when I can borrow the pump dealio.

Any other tests that I can do with the pressure tester gauge or anything else that may help?

This all appears to point at the fuel pressure regulator but what do I know?

[mss5413]

Since you are getting a higher pressure than specified by the FSM, my guess is you fuel pressure regulator is sticking open. I don't really know how this would cause your car to die, but you might want to look into that.