2002 S60 high fuel pressure

Post by **vtl** » 18 May 2022, 15:44

Does you car have a PEM? It either sits near fuel filter or relocated into a spare wheel well.

wrgallant · Post by **wrgallant** » 18 May 2022, 16:10

No PEM

Post by **vtl** » 18 May 2022, 18:41

I'm puzzled then. Fuel pressure should be 55 PSI relative or 70 absolute.

Post by **br0dy519** » 18 May 2022, 20:50

In refrigeration, if you have a kink or obstruction in the line, it can cause your pressure to go way out of spec, since the compressor is dead-heading.

Does this same theory possibly apply to this fluid pump? Could it possibly be a fuel line kinked or some contamination got into a hose somewhere? Perhaps you should try and drain and clean or replace your fuel filter.

wrgallant · Post by **wrgallant** » 19 May 2022, 05:08

With no feedback to the ECM, there has to be some mechanical means of controlling fuel pressure.

wrgallant · Post by **wrgallant** » 19 May 2022, 08:55

As I try to understand the high fuel pressure - wouldn't fuel trim be high negative to compensate for high fuel pressure?
My short and long term fuel trim are both close to zero.

wrgallant · Post by **wrgallant** » 20 May 2022, 08:47

Anyone know where the fuel pump return line connects to on a 2002 S60 2.4?

wrgallant · Post by **wrgallant** » 23 May 2022, 06:26

vtl wrote: ↑18 May 2022, 10:53 The theory is you put a PEM-controlled pump into your older car that does not have a PEM.

ECM tells the PEM how much load is required for the pump, PEM adjusts its PWM duty cycle, the pump develops fuel pressure accordingly.

When PWM line is connected to constant +12V, the pump thinks 100% load is required and works hard, until an internal pressure relief valve is triggered, which happens at about 100 PSI. I remember seeing that number when ECM cuts the fuel sharply right on fuel injectors, and the pressure raises momentarily to about 100 PSI.

I figured it out - a previous owner replaced the fuel line from the pump to the fuel filter. When they did, they eliminated the T that feeds back to the return port on the pump. I added a T after the fuel filter back to the return port. Now when pressure gets above 50, the regulator inside the pump dumps fuel back to the pump.

Thanks for helping me understand the system

Post by **vtl** » 23 May 2022, 06:39

wrgallant wrote: ↑23 May 2022, 06:26 I figured it out - a previous owner replaced the fuel line from the pump to the fuel filter. When they did, they eliminated the T that feeds back to the return port on the pump. I added a T after the fuel filter back to the return port. Now when pressure gets above 50, the regulator inside the pump dumps fuel back to the pump.

Huh... Good hunting

Post by **abscate** » 24 May 2022, 03:29

wrgallant wrote: ↑23 May 2022, 06:26
vtl wrote: ↑18 May 2022, 10:53 The theory is you put a PEM-controlled pump into your older car that does not have a PEM.

ECM tells the PEM how much load is required for the pump, PEM adjusts its PWM duty cycle, the pump develops fuel pressure accordingly.

When PWM line is connected to constant +12V, the pump thinks 100% load is required and works hard, until an internal pressure relief valve is triggered, which happens at about 100 PSI. I remember seeing that number when ECM cuts the fuel sharply right on fuel injectors, and the pressure raises momentarily to about 100 PSI.
I figured it out - a previous owner replaced the fuel line from the pump to the fuel filter. When they did, they eliminated the T that feeds back to the return port on the pump. I added a T after the fuel filter back to the return port. Now when pressure gets above 50, the regulator inside the pump dumps fuel back to the pump.

Thanks for helping me understand the system

Well done figuring out an undocumented unsupported fix, known as a Charlie Foxtrot

2002 S60 high fuel pressure

Re: 2002 S60 high fuel pressure