2002 S60 high fuel pressure

wrgallant · Post by **wrgallant** » 17 May 2022, 07:43

Idle speed is 800
Mass air flow rate is 1.1lb/min at idle

Post by **vtl** » 17 May 2022, 07:53

wrgallant wrote: 17 May 2022, 07:43 Idle speed is 800
Mass air flow rate is 1.1lb/min at idle

That's about 8.3 grams/s. Should be around 11 for 800 RPMs. Check for air leaks? Also MAF itself can be bad.

wrgallant · Post by **wrgallant** » 17 May 2022, 08:04

I disconnected the battery because I read that you should reset fuel trim - new readings at idle are as follows
short term fuel trim 1.6%
long term fuel trim 0%
Mass air flow rate 0.4lb/min

Post by **vtl** » 17 May 2022, 08:14

Now you need to drive the car for some time in order to get the correct fuel trims

Until it reports the monitor is ready.

wrgallant · Post by **wrgallant** » 17 May 2022, 08:24

Thanks - I've learned a lot from you

Post by **vtl** » 17 May 2022, 09:04

Did you change the fuel pump only or the whole assembly?

wrgallant · Post by **wrgallant** » 17 May 2022, 17:00

Replaced the whole assembly. I’ve tried a Bosch, Delphi and now a volvo pump with the same results

Post by **vtl** » 18 May 2022, 06:34

What part numbers? For Bosch and Volvo.

Post by **vtl** » 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.

wrgallant · Post by **wrgallant** » 18 May 2022, 15:22

volvo part number is 30761743
bosch PN is 69746
say it is correct up to chassis 234999
mine is 121587