Intermittent stalling

[vtwinpilot]

OK, bought a fuel pressure gauge and tested it. The pressure held steady at 54 psi both idling and hitting the accelerator. After turning the car off, it dropped to about 40 psi and held steady.

I also cleaned all the engine grounds I could find.

I just ordered a new fuel pressure sensor and should have it installed by later this week.

[VOLVOBOY]

Hi.
What was the baseline fuel pressure? - gauge connected to fuel rail and just ignition on.
The pressure at idle seems OK , as does the increase of throttle.
You need to test the pressure when the engine is really hot. Turn the engine off, wait 10 min or so and then turn the ignition on. The baseline pressure should be at its highest to alleviate fuel vaporisation . This avoids a long cranking hot start. Start the engine - does it fire right up?
You said that it did struggle to fire up when hot , and that the weather had been very hot.
The check valve in the fuel pump is another known weak point. This could be failing - not allowing enough fuel to go to the fuel rail and just making it cycle through the pump.

[vtwinpilot]

I tested the pressure after having driven it and getting the engine hot. Shut the car off, waited 10 mins, then connected the gauge. Some fuel of course sprayed out as I was screwing down the adaptor. I'm not sure if that lowered the pressure, but in any event, I then turned on the ignition to position II, and the pressure was 14 psi.

The engine always fires right up, whether cold or hot. I've never had a problem starting the car; even after stalling, it'll crank right back up.

[VOLVOBOY]

Hi.
Apologies. I am getting your post confused with someone else.
I`m inclined to think that if the FPS change does not fix this the problem is more likely to be with the PEM rather than the fuel pump. In any event try to locate the PEM and clean the electrical plug contacts. If you can , remove the PEM and give it a shake. If it rattles then moisture/ corrosion has got inside .
After all said, it could be the pump but I would expect a failing pump to be more problematic ( plenty of stalling , poor starting and misfires).

[vtwinpilot]

Originally Posted by VOLVOBOY

Hi.
Apologies. I am getting your post confused with someone else.

Ah, no worries, mate, I sincerely appreciate your and the others' help on this.

I received and installed the new FPS a couple of days ago. So far, so good. Stalling wasn't consistent - nor every day - so it's too early to tell if this is the final resolution. If it goes another week stall-free, I'll be inclined to say voila.

I agree regarding the pump. I think stalling would be much more prevalent than what I've experienced.

I'll have a look at the PEM and its connector soon. I just ordered a bunch of front suspension parts given the car has 175k miles on it, so the control arms are totally knackered. I'll replace the tie rods and ball joints while I'm in there, since it'll be apart, and those parts are cheap anyway.

I'll post up again after either a week free of stalling, or after the next stallling episode.

[vtwinpilot]

It's been three weeks since I installed a new Fuel Pressure Sensor ($40 on Amazaon). Happy to report neither stutter nor stall since!

It's been driving perfectly ever since. I wouldn't have guessed it was a bad FPS, but thanks to y'all here on the board, it seems - unless Murphy strikes - that this particular story has a happy ending.

If things go sideways and it sh*ts the bed, I'll post up.

Thanks again for the support!

[VOLVOBOY]

Good to hear.
All the best.