92Q - Wont Start, Sometimes

[Jesda]

Last night I went out to run an errand and the Q wouldnt start. I held the gas pedal down and kept cranking and it finally did.

This morning it was fine. After class it was fine. Then 4 hours after parking in the garage I went to make a grocery run, and it wouldnt start.

I swapped FPCUs, nada.I removed and examined the fuel pump fuse, looked fine.I turned all accessories off, nada.I tried starting with the gas pedal down, nada.

I got frustrated and went inside to ponder what the hell was going on. I came out and tried again and it started fine, coughing just a tiny bit as it came to life.

Any hunches? Thanks in advance.

[elwesso]

Did it seem to want to do anything?? meaning did it chug a little bit and then die??

Maybe your fuel pump relay is flaky......

MY old Q did this when it would start on a warmish restart... but it would fire and then die.....

[Jesda]

No slight chug-chug-death like with a dead FPCU or fuel pump. Just a straight up no start, like you get on a car with a broken timing belt.

Warmish sounds like a good description, since the car isnt at operating temp nor is it cold. Seems to want to happen after a few hours of sitting.

[CJQ45]

I have the same problem with my 97Q. It happened twice. No idea - possibly related to the fuel pump but the fuel pump seems fine - no humming sound - nothing. The car starts and immediately dies. I have to hold down the pedal until it kicks in. Once it happened when the engine was dead cold the other time was when the engine was "warmish".

97Q 70k miles.

CJ

If you figure it out, please share.

[metaverse3]

Hmm.. One thing to look for is the injector leakdown test.. Slow dripping injector(s) along the cylinder walls can cause a hard start issue from cylinder vaporlock to prevent ignition state... I resolved the same issue on my maxima 2+ years ago by replacing injectors...

The way to test is to hook a fuel gauge and drive around with it.. Check to see if the fuel pressure drops over time. Best way is to go for a drive..park the car and check back in a while..a couple of hours. See if the gauage goes down.. Then you will know where the system stands..

[Q45tech]

The 34 psi may initially [at turn off] drop to 25-30 psi but it should stay there for a long time [overnight] without injector leaks or bad antidrain back valves in fuel pump.

2 years ago I bought an electronic fuel pressure gauge and lazily still haven't installed it.

[metaverse3]

Another thing to add to the list is the coolant temp sensor..check it out to see if it works..failure of it won't report to the ecu the need or lack thereof for fuel enrichment upon hot/cold startup.

[Jesda]

Another thing to add to the list is the coolant temp sensor..check it out to see if it works..failure of it won't report to the ecu the need or lack thereof for fuel enrichment upon hot/cold startup.

That could explain my high idle too! Thanks

[timatt]

Jesda:

My Q did the same last year. VERY occasionally it would not start in the morning. Actually it would start briefly, then die immediately. After that I would crank it and it sounded like not compression at all. After holding my foot to the floor and cranking for like 20 - 30 seconds, I could get it to catch and then after a few coughs, it would run fine. This happened three times very infrequently. I could hear some fuel pump hum at idle, so I went ahead and changed the fuel pump. I have not had the problem since and it has been over a year. At the time I checked my FPCU for signs of overheating of solder joints but found none.

Tim'91Q

[Jesda]

Tim:Good pointer! This morning it started fine, but this afternoon I had some issues. I went to the trunk to see if I could hear the fuel pump, and I could not. I went inside, left the key in, came back 10 minutes later (made myself some coffee) and I could hear the pump. The car started fine.

Pump time! Only two years and 40k later *sigh*

Thanks Tim, and everyone

[elwesso]

You might check the relay... Theres a relay sperate from the fuel pump.....

My old Q did the same thing and it hsa the same fuel pump in my current Q and i suspect the relay could be flaky.....

[SOCAL91Q45a]

Pump time! Only two years and 40k later *sigh*

Thats troubling ... is this just a symptom of something even more problematic? Should we really need to replace $250 fuel pumps every 40k?

What could be causing FP's to be going bad like that ....

Sorry your having this trouble Jesda ...

[Jesda]

Update...

Left the Q sitting for three days. Started it up with no problems at all. So nothing seems to be leaking, like injector seals. And the fuel pump I guess is okay, since it isnt making any weird noises yet, and looked okay when I took it out a couple months ago, so its time to check out the relay.

[gniknave]

You might want to do a wiggle test on the Crank Angle Sensor connector. If the car dies when you wiggle it just a little, that may be one problem. I'd also suspect the connectors on the ignitors. I sometimes have problems starting, then I go under and wiggle the ignitor connectors on both side. Almost always fixes the problem (though it rarely happens).