High Fuel Pressure? Leaky Injector? Or something else.

JohnnyBee323 · Post by **JohnnyBee323** » 25 May 2019, 13:56

2004 Volvo S60 2.5T

My car is getting a P2188 running rich code for sometime. Can't seem to find out the cause. I suspect it is a leaky injector. My car will start hard and surge a bit until it levels out. Once it levels out, the ]the car will consistently have 57 psi of fuel rail pressure, according to my scanner. However, I notice when I cut off the engine, it jumps up to about 80 psi, and over about a 30 minute period is will drop down to about 60 psi. Is this normal? I imagine the higher psi is causing the injector to leak, leading to the hard starting and rich condition, so perhaps an injector(s) needs to be replaced.

How about the higher fuel pressure, is it suppose to shoot up that high after the engine is turned off? I would like to know before I go looking to replace the injector, if I could remedy it by looking elsewhere. The car runs fine otherwise, its only during start up that it surges and "hiccups". Any help would be greatly appreciated.

Here is a video of me starting the car warm after it being off for a few minutes. The FRP is in the high 60s when the engine surges and levels out, and then it drops down to the normal rate of 57 PSI before the end of the video.

See video here [youtube][/youtube]

Attached is an image of my scanner immediately after I turned off the engine, you can see the fuel pressure jump up to the 80s.

Post by **oragex** » 25 May 2019, 19:11

55psi is about normal for the turbo engine

The 80psi spike may be form the PEM (google). Can grab a used one off Ebay for cheap from any year, no programming (all volvo had the same, just different brackets , even the S40 had the same) . Look from a recent car, without corrosion

I'd start with that. Be aware of mechanics who want to replace the pump

Post by **abscate** » 26 May 2019, 00:36

Get a fuel pressure gauge in to the fitting and make a direct measurement of the pressure rather than through OBD.

ILL check my P2 when I get home later today and see how mine behaves.

JohnnyBee323 · Post by **JohnnyBee323** » 29 May 2019, 16:12

oragex wrote: ↑25 May 2019, 19:11 55psi is about normal for the turbo engine

The 80psi spike may be form the PEM (google). Can grab a used one off Ebay for cheap from any year, no programming (all volvo had the same, just different brackets , even the S40 had the same) . Look from a recent car, without corrosion

I'd start with that. Be aware of mechanics who want to replace the pump

Hooked it up to the fuel pressure gauge, and it was actually read low pressure at the rail (7 PSI). My mechanic thought this was from a failing pump. Do you still think this is the PEM?

Post by **vtl** » 29 May 2019, 17:13

What is your MAF reading on idle revs?

Post by **abscate** » 29 May 2019, 17:15

If your mechanic doesn’t know how to look at the waveforms from the PEM, you are paying for guesswork

Try a used PEM FOR $15

JohnnyBee323 · Post by **JohnnyBee323** » 29 May 2019, 17:46

vtl wrote: ↑29 May 2019, 17:13 What is your MAF reading on idle revs?

[youtube][/youtube]

It seems to be fluctuating a bit between 2.25 - 3.25 g/s at Idle. What should it be at?

Post by **vtl** » 29 May 2019, 17:50

12-14 kg/h (3.8 g/s). 3.25 is exactly 18% less than 3.8, your LTFT is -18%. Replace MAF, it is common to fail at this age.

JohnnyBee323 · Post by **JohnnyBee323** » 29 May 2019, 18:22

vtl wrote: ↑29 May 2019, 17:50 12-14 kg/h (3.8 g/s). 3.25 is exactly 18% less than 3.8, your LTFT is -18%. Replace MAF, it is common to fail at this age.

Really? Even though I am not receiving any codes for the MAF? First, P2188 (running rich) sets, and then P2178 (running lean) shortly thereafter. I hope that is the case, because I am not receiving any codes for a fuel pump.

Post by **abscate** » 30 May 2019, 04:45

Try the PEM first. The definitive way I see to check fuel pressure with a gauge. I don’t like that reading of 7 psi though, I don’t think the car will run at that low pressure?