Died while driving and no start

Hello.

I have '95 Lumina 3.1L w/ ~150K mi.

This morning just as I was pulling into work the car completely died while driving and will not start back up. Cranks over but will not start.

The car was driving completely fine before and I just drove ~100mi. just yesterday w/ no issues.

My first guess is fuel delivery in the following order.
-Fuel pump relay
-Fuel pressure reg.
-Fuel filter
-Lastly but hopefully not....Fuel pump

How do I test if the fuel pump relay is good?

Any other ideas?

Thanks.

When you turn the key on do you hear the fuel pump running for a couple of seconds. If not check for fuel pressure. If there is no fuel pressure than check for power to the pump. If there is power than you can eliminate the fuses/relay/wiring and start pulling the tank.

You can also spray a shot of car spray into the intake while somebody cranks it over. If it starts than you are on the right track with the lack of fuel theory. If it doesn't than I would start by checking for spark.

Down
95 Lumina 3.1 won`t start - no spark (http://www.automotiveforums.com/vbulletin/showthread.php?t=980041)

24x or 7x cranksaft sensor.

Thanks for the tips.
I just borrowed a fuel pressure kit and will measure it this evening.

For the crank sensor, if I still have a spark, then can I assume my crank sensors are working?

Thanks.

7x or 24x if sulfur is not a spark (at least for me).

check 7x crank sensor... you will NEVER notice it unless you are specifically looking for it.. it is easily burned on the exhaust manifold and will short to the block. you can move the wire around and it might start up. Happened To Me a few years ago.


this will cause a NO SPARK condition. check to see if you getting no spark or no fuel.

pic....
http://www.automotiveforums.com/vbulletin/attachment.php?attachmentid=38654&d=1269150248

It was an interesting evening. Apologies in advance for the long story, but I do not want to miss any details.

Before I measured the fuel pressure or even inspected the crank sensor wires, I figured I would try to start my car just for grins. Well, it started right up like there was never a problem. It had been sitting for about 10 hours.

However, no more than a couple miles down the highway on the way home, just as I was accelerating to get on the highway, the car died just as this morning and I was unable to start it back up. Luckily I glided once again into a parking lot. I let the car sit for 15 minutes and it started right back up again and I made the last few miles home.

Once home I let it idle for another 10min, then held it at 2K RPMS for a minute, and the car never died. I popped the hood and checked the crank sensor wires and jiggled them around while the car was running and no issue found. Then I began to rev the engine and finally it hesitated, stuttered, and the engine died. I tried starting it back up but no success. I then immediately checked the fuel pressure with the ignition on and car not running and it measured only 5psi.

I left the pressure gauge connected and noticed that as the car sat with the ignition on and not running, the pressure slowly began to build. After 10min. of sitting it was just above 10psi. Per the manual it should be ~45psi with the ignition on and car off. However, 10psi was enough to get it started again. I then immediately watched the fuel pressure at idle and the needle erratically moved up and down in 2-3psi jumps but after a few minutes of idling eventually worked its way up to 35psi and became stable.

The only way to get the fuel pressure to go back down was to disconnect the fuel pressure regulator, at which after it dropped down to 15psi it then worked its way up to 45psi. Another way to drop the fuel pressure was to rev the engine. When revving the engine, the fuel pressure would eventually drop to 5psi and the engine died.

After it died, while sitting with the ignition on and not running, the pressure would build back up to 10psi and the car would start as before.

Does this sound like a clogged fuel filter or bad pressure regulator?
Does the fuel system remain pressurized even with the ignition off?
Any other ideas or thoughts?

I was planning to first replace the fuel filter.
If no improvement, then I will replace the fuel pressure regulator and vacuum line.
Finally, if none of the above works, I guess it is time to try the fuel pump.

Thank you.

--Does this sound like a clogged fuel filter or bad pressure regulator?
could be either. disconnect vacuum line from FPR (and plug up vacuum line). pressure should not drop when revving with it disconnected.

--Does the fuel system remain pressurized even with the ignition off?
Yes. You should have pressure even after several hours of sitting. In a good system, you should still have pressure a day later.

--Any other ideas or thoughts?
You are going in the correct order - Fuel filters are cheap so start with that. You need a quick-disconnect tool for one side of the fuel filter. In front of fuel tank. If you swap out the FPR, keep towel underneath to soak up all the gas that will come out of the fuel rail.

I left the pressure gauge connected and noticed that as the car sat with the ignition on and not running, the pressure slowly began to build. After 10min. of sitting it was just above 10psi.


This was a result of a hot engine heating up the liquid fuel and causing it to expand. The fuel pump will not run with with the key left on and the engine not running.




Does this sound like a clogged fuel filter or bad pressure regulator?
Sounds like a bad fuel pump

Does the fuel system remain pressurized even with the ignition off?
Any other ideas or thoughts?
Yes it should hold pressure


I was planning to first replace the fuel filter.
It can't hurt but will likely not solve the problem.



If no improvement, then I will replace the fuel pressure regulator and vacuum line.
I wouldn't bother until after you replace the fuel pump


Finally, if none of the above works, I guess it is time to try the fuel pump.
This should be your second choice after replacing the fuel filter. With fuel pressure starting at 0 you should only have to cycles the key a couple of times in order to get fuel pressure back up to spec.

Make sure you are getting power to the pump when the problem is occurring!

Make sure you are getting power to the pump when the problem is occurring!

Is there an easier way to check the power w/o dropping the gas tank to get to the fuel pump connector?

Thanks.

fuel pump will engage for 2 seconds when you turn the key to the On position (dont have to crank)... if its doing that then your electrical/relay is OK.

btw. our fuel filter is LARGE in comparison to some fuel filters, gonna be pretty hard for that entire filter to clog up to cause that much of a pressure loss. whether you have a bad pump or bad regulator, replacing the filter at that time isnt a bad idea.

All it takes is one fill-up with contaminated fuel to plug the filter to the point of not allowing enough fuel thru to operate properly.

I replaced the fuel filter today and still have low pressure. I measured before and after replacement w/ the key ON engine OFF, turning the key several times to make sure the lines were full, and the pressure is still only 10-15psi.

I started it up and the pressure increased to 25psi. I disconnected the vacuum line to the pressure reg. and plugged the line w/ my finger and the fuel pressure stayed at about 25psi for a minute or 2 and began to work its way down. Once I re-connected the pressure reg. the pressure went back up to 25psi briefly and then began to drop.

I am leaning more towards a weak fuel pump at this point.

Does anyone know if a '95 LS model Lumina has a fuel pump access port under the back seat or trunk or do you have to drop the tank?

Thanks.

I have had two fuel filters cause a driveability complaint and only 1 cause low fuel pressure. The one with low fuel pressure was on a late model ford and installed backwards. The other one was an older Astro van that had lack of power on hard accel.

"plugged" fuel filters are less likely to be the cause of low fuel pressure but can be what caused the pump to fail possibly prematurely. The longest lasting GM fuel pump I have run across is out of a silverado that went a tad over 260k miles. The owner was meticulous about filter replacement and was rewarded with roughly 3 times the average service life of a pump that never saw a filter replacement.


You'll need to drop the tank to replace the pump.