Fuel Pressure varries

[Nulluser00]

2002 S60
Fuel Pressure varries between 40~50PSI at idle.
Engine runs rough and disconnecting the MAF helps.
I searched the messages and couldn't figure out how to narrow the returns down to something managable.

Thank you
Noel

[abscate]

You can try a used Pump electronic module or PEM

Without an oscilloscope you can’t really diagnose waveforms in the fuel delivery, which is CEM PEM and fuel pump all linked

Junkyard $30

New $335

[Nulluser00]

You can try a used Pump electronic module or PEM

Without an oscilloscope you can’t really diagnose waveforms in the fuel delivery, which is CEM PEM and fuel pump all linked

Junkyard $30

New $335

I'm an EE so the scope isn't a problem but I suspect this will involve trying to decypher the chatter
on the on board network.

I suspect this car is headed for the boneyard. Too bad the body is in great shape.

Thanks
Noel

[abscate]

Lots of detail including waveforms on the XC90 board for user shockwave. He kicked butt troubleshooting a fuel delivery problem on hisnXC and covers the whole system

[Nulluser00]

Lots of detail including waveforms on the XC90 board for user shockwave. He kicked butt troubleshooting a fuel delivery problem on hisnXC and covers the whole system

Thank you, I will go search and see what I can learn.

[reverend]

For a dirt-cheap test, swap the fuel pressure sensor. On the fuel rail, front of engine. One screw holds it in. Bleed fuel pressure, remove screw, hold a towel around it and twist it while you pull it out, swap it with another one from the junk yard and see how your car is after that.

[Nulluser00]

None of the "auto salvage yards" in Central KY keep cars older then ~10 years, they crush them.
Will this part fit?
https://shop.advanceautoparts.com/p/bec ... ure+sensor

Or this one, which looks like what I see in the youtube how to videos,
https://shop.advanceautoparts.com/p/int ... 10432212-p

ie
https://www.amazon.com/Bosch-Original-E ... 8719&psc=1

[oragex]

That is a MAP sensor
Try Fcpeuro.com for FPS sensor
If the PEM is bad, about the only place for a used one is Ebay

[Nulluser00]

OK, color me confused.

In an attempt to understand the fuel system I visited: https://www.swedishautoparts.com/S60/Vo ... ystem.html

And I found this information:
FUEL PRESSURE REGULATOR VOLVO 2001~2016
S60/S60R 2001–2006 Fuel Pressure Regulator cars w/o EGR Located on Fuel Rail

60/S60R 2001~2009 Fuel Pressure Regulator Located on Fuel Rail
Fits Engine code up to 2815192

S60/S60R 2001–2009 Fuel Pressure Sensor Located on Fuel Rail
I've inspected the fuel rail and there are the 5 injectors, from the far left side when standing in front about 2 inches from the end left end there is what appears to be:
S60/S60R 2001–2009 Fuel Pressure Regulator Located on Fuel Rail
· Fits Engine code up to 2815192
There is no EGR no the fuel rail and there is only one line that has to be the fuel inlet.

Other then the Shrader valve test port, there are no other connections to the fuel rail.

Could this " Fuel Pressure Regulator" be a problem and where might I obtain a replacement?

Noel

[Nulluser00]

I want to thank everyone for their advice and comment. I'm a bit embarrassed to admit I should have investigated a short vacuum line that was just hanging there. Sunday after church I decided that hose was important so I pulled and moved it around. It just fit under the front piece where the hood attaches. When I looked I found two wires in a protective sleeve. I followed the wires and found a module with a nipple. Once I knew where I was looking I found it was the MAP sense. I reconnected the hose but it didn't make much difference. The rubber hose is covered with a woven sleeve and connects to the second nipple behind the throttle body. Volvo used one of those odd hose clamps that are next to impossible to loosen because there isn't enough space. I destroyed the clamp and once I had the hose and off and removed the sleeve I found several splits. I replaced the rubber hose with a piece of high temperature neoprene tubing I had on hand. I used a different hose clamp, installed the hose, connected it to the MAP sensor and the engine runs PERFECTLY. The OBDII scan tool from Harbor Freight and the secret read your engine error codes did not flag the error.

I drove to the nearest fuel station, filled up with premium and headed for Lexington. I live south of Berea Kentucky and I drove on the Interstate to Lexington, had dinner with a friend and drove home on the back roads. I drove slow, stopped, started, sped up, let the car coast and there was no hesitation.

I guess the morals here are:
1) Don't start working on a car when you've just entered a graduate EE program
2) Always check each and every vacuum hose and if one is loose find out where it goes before doing anything else.

I'd feel worse but I'm a complete novice when it comes to cars. The car was given to me just over a year ago and we drained the fuel (PITA) flushed the tank with pure alcohol, drained it and left the car in a cousin's barn. The tires had a bit of a flat spot and felt really weird for the first 20 miles.
I have another question but I'll post that under another thread.
Live and learn.