Fuel pressure maxing out to 111 psi?

ChattownXC70 · Post by **ChattownXC70** » 06 Apr 2025, 20:05

Well, I have put a little over 300 miles on this car since buying it and swapping the bad transmission for one from the junkyard and all seems well with that. However, on 3 separate days now, it has had a strange stumble while just cruising along. The first time was in the rain at 70mph on the freeway. The car just acted like someone reached over and turned the key and cut the engine off for about 1 second. I lifted off the throttle for a second in surprise and when I reapplied throttle it was back to normal.

Second time was 2 days ago driving on a back road around 45mph or so just cruising but climbing a bit of a hill so applying a little throttle. Same type deal where it’s like the engine just cuts off. Lift off the throttle then back to it and it’s fine again. Did this a few times on the way home. It was dry this day.

Third time was today. Again it was raining and wet but not sure how much that matters. At first I thought maybe it was something shorting out due to the wet conditions. But today I was a bit more prepared and had my obd2 scanner in the car. Car was running fine. I kinda gave her the beans getting around some folks in traffic and right after that it started cutting out a good bit. Maybe 10-12 times in a mile. So I stopped and plugged my scanner in and started logging what I thought may have been causing the issue which was throttle position, commanded throttle actuator and fuel pressure. I was thinking maybe the tps or something of the like.

Well I caught it twice while logging and each time the fuel pressure shot up to 111psi. I’m assuming that’s the max reading. Otherwise while driving it was 48-53psi.

My questions are. Could the high reading make the pump supply too little fuel because it thinks it’s giving way too much causing the stumble? What the heck is telling my reader that measurement and can I check or replace it?
And does this sound like a faulty fuel pump or some sort of controller for the fuel system? I have not worked on the fuel system at all as of yet with the exception of replacing the fuel filter when I first got the car.

Vova585 · Post by **Vova585** » 06 Apr 2025, 20:12

111psi? That sounds crazy for regular electric injector system. If you would have direct injection i would say it is too low..but currently I would be questioning fuel pressure sensor.
I heard that they are as reliable as water pump on f150. So for $35 I would be replacing that first(might be parts cannon, but not cost prohibitive). Based on description from fcp it fits your scenario
https://www.fcpeuro.com/products/volvo- ... 0261230238

Post by **Krons** » 06 Apr 2025, 21:17

Same cutout while accelerating on my 08 S60 2.5T a while back — was the pressure sensor on the fuel rail, easy fix with Schroeder valve there to drain fuel pressure and swap out.

ChattownXC70 · Post by **ChattownXC70** » 07 Apr 2025, 02:52

I agree that is crazy high and probably not the actual pressure. Thank you both for the info! I will order a sensor today.

Post by **vtl** » 07 Apr 2025, 15:44

Check that your PEM was relocated to spare wheel well. If not, it sits by the fuel filter, and you need a harness to relocate it.

ChattownXC70 · Post by **ChattownXC70** » 15 Apr 2025, 04:22

Vtl, I’m sorry I missed your reply. I will look at that today although I didn’t see it while replacing the filter a while back. But I wasn’t looking for it so will double check today.

The pressure sensor has resolved the issue so far as I can tell. Almost 200 miles now and no more issues. The one that was linked above was not the correct one for my car but got me pointed in the right direction. I appreciate everyone’s help with my questions and issues!

ChattownXC70 · Post by **ChattownXC70** » 15 Apr 2025, 08:15

There is a plastic bracket with nothing on it to the rear of the filter so I assume it’s been relocated. I didn’t even know that was a thing haha. Thank you for the info!

Post by **jonesg** » 15 Apr 2025, 19:11

ChattownXC70 wrote: 15 Apr 2025, 08:15 There is a plastic bracket with nothing on it to the rear of the filter so I assume it’s been relocated. I didn’t even know that was a thing haha. Thank you for the info!

see if its in the spare tire well.