stalling problem

[Joe C]

My VX stalled out on me twice this morning on the way to work. The first time was at very low speed, basically idling in drive. The second time was at idle with the vehicle stopped and my foot on the brake. The AC was on (defrost) and I was in stop and go traffic both times. There was no stumble or sputter involved. The engine stopped like I had turned off the ignition. Both times it restarted right away. I turned the AC off after the second incident and the problem did not recur during the rest of my commute.

Looking through the archives on VMAG it seems that for others this problem has been fuel system related. I'm going to try to reproduce the stalling tonight with a fuel pressure gauge hooked up to the rail (if I can find my FPG). Does anyone happen to know what the stock static fuel pressure is supposed to be on the 3.5? Thanks in advance.

[Tone]

40 PSI - I’d recommend changing the fuel filter, located on the passenger side frame rail about even with the back seat - bleed pressure first if you can and please report back the pressure you measure.
PNs:
Wix - 33310
Puralator - F67221
AC/Delco - GF-516

Having just replaced my fuel pump, I highly recommend draining the fuel tank a bit every 15K miles or so - just remove the 12mm bolt visible through the tank skid guard and let a cup or so of fuel run out - I had a bit of gunk in mine that may have contributed to the pump’s failure.

[VX crazy]

How do you bleed the pressure? I need to change mine.

[Tone]

There is a schrader valve on the fuel rail - just be careful as fuel will still go everywhere and if the engine is hot....we could change it on Friday.

[VX crazy]

Its going to be COLD friday!! Do you think we will have time to change it? Out of the filter listed, which is best? I know questions questions questions.

[Tone]

All the same - I have a heated garage - no big deal.

[Joe C]

Fuel pressure was right on 40psi with the vac. line disconnected, and 30-31psi with it on. The vac line came off very easily and seemed a little brittle, so I used a small zip tie as a hose clamp when I put it back on. I think I'll replace that line this weekend. The inside of the vac line was dry so I believe the regulator is okay.

I let the car run for about 30 minutes in drive with the wheels blocked and the AC running. It did not stall nor did the fuel pressure fluctuate. I Changed the fuel filter anyhow as a pre-emptive measure. Thanks for the advice Tone and btw, I got the popper kit in the mail yesterday, looks great.

[andy454]

One thing to remember is that even the pressure may be good there may be a concern with volume. To check this start the vehicle and while it is running depress the fuel valve or open the port on your gauge. The engine should not stall. I don't think the vacuum line on the regulator would cause this. If it were off then you would have higher pressure. One other thing to try is to clean the idle air valve. It may have carbon on the the tip causing it to learn a higher value. Just remove it and clean with carb cleaner. Just a few things to try

[Joe C]

Andy454 wrote:

One other thing to try is to clean the idle air valve. It may have carbon on the the tip causing it to learn a higher value. Just remove it and clean with carb cleaner. Just a few things to try

Thanks Andy. Looking through the TB into the intake manifold and it's pretty messy in there. I'm going to take off the TB and clean it and the IAC passage this weekend.

Poking around the engine bay last night I noticed that the vehicle has a 450/525 CCA/CA replacement batt. in it. Definitely on the small side for a vehicle with all power accesories, electromechanical center diff, etc. Both times the the vehicle stalled on me I was running the climate control fan at max with AC on, radio going, headlights and brakelights on. window and mirror defrosters, etc. Do you guys think that a sudden drain on the elec. and accessory drive systems, say an AC clutch engagement, would be enough drain and drag to shut her down? Just throwing out theories.

[SGT.BATGUANO]

If batt got low I'd think you'd get an idiot light before it died.

[andy454]

If the pcm sees a calibrated low voltage ( usally around 9v) it will stall. I bet the throttle body cleaning will help a great deal.