Fuel pump does not seem to be priming 08 S60 Topic is solved

yanga001 · Post by **yanga001** » 14 May 2023, 20:10

So I sometimes come across a hard start issue and decided to monitor with my scantool.

While running the fuel pressure according to the scantool is 400 kpa on the dot, i have not had issues with fueling while running.

On startup though it seems the fuel pressure does not want to increases. After leaving the car for about 30 minutes I hooked up the scan tool and took a reading of approximately 300 kpa according to the scan tool. The car cranks once or twice before firing up which is fine. What did worry me is on occasion i have had issues where the car will stutter or require a second key turn to start.

I tried to prime the pump by switching the car to position 0 then position 2 and noted 100% duty cycle on the fuel pump but no corresponding increase in pressure. I have good soldering skills so i am tempter to resolder the pins if that may help however i have a long distance trip booked for the coming weekend and was wondering if i should pick up a spare fuel pump computer.

My fuel trims are on the money, 1.03 (assumed to be 3%) on the long term and very similar on the short term. She doesnt smell rich and gets good mileage. Plugs were just changed and i ran a bottle of RP fuel atomizer through it today (issues originated before today, not any worse today then any other day).

Post by **cn90** » 14 May 2023, 20:11

Search forum for "PEM"...

yanga001 · Post by **yanga001** » 14 May 2023, 20:25

cn90 wrote: ↑14 May 2023, 20:11 Search forum for "PEM"...

From the pages i checked most if not all have a code associated with the issues. Car checks clean and has not thrown a code in that area at times prior to my purchase and since my purchase. I appreciate the guidance though...

Added info:
The misfire counter increases by 1-2 at startup which i suspect is a fueling related issue. My guess is my injectors leak a tad and thats where the pressure is dissipating. Why the fuel pump does not bring the system back up to pressure is either by design or an issue in my mind atm.

If anyone has taken a measurement of fuel pressure immediately prior to starting the car then that would be appreciated.

My understanding is it should be around 400kpa which is the standard fuel pressure for the 2.5t.

Post by **jonesg** » 15 May 2023, 02:59

You should be able to hear it prime for 2 seconds at key on.
I think pem was introduced on the 03 cars onward.

Post by **Krons** » 15 May 2023, 05:08

When was the last time the fuel filter was changed?

yanga001 · Post by **yanga001** » 15 May 2023, 09:44

The fuel filter is on my list of things to change. I spoke to my mechanic and he thinks its unlikely that the PEM as its mounted in the car in my year and has no corrosion. He thinks its probably a check valve issue but to not worry about it for now.

I was told to try priming the engine 2-3 times to see if it makes a difference. The car runs fine so ill mark this as solved. Thanks for the help.

Post by **cn90** » 15 May 2023, 13:31

- OEM failure: no codes

- I suggest that you find a good used PEM and test it.

Post by **abscate** » 17 May 2023, 04:39

Another one who had a no-code PEM failure here. I would have a slight skip under load and after about three months a crank, no-start

Post by **cn90** » 17 May 2023, 10:42

My 2004 V70 with 120K did exactly that...intermittent no start.

New PEM from junk yard solved the problem.

yanga001 · Post by **yanga001** » 26 May 2023, 12:40

Issue occurred today where i tried to crank the car and it sputtered. Flipped key twice tried to try to start again and it would not turn over (no starter engagement). Battery was full, waited 2 minutes flipped key again and it started right up.

I think the starter is on the way out and will go to a yard to pick one up as it doesn't seem to be a common failure point.

Will overhaul the starter first by cleaning terminals and what not and see if it persists.

Set up a deal for 100 cad for a PEM + headlight switch with front foglight option (convenience as yards are not plentiful with these and its from a newer one where it was mounted in the car. The place is on my way to work. Will pick up a spare coil pack as well to have it parts ready in case of failure).

Thanks for the advice, will report if the starter fixes it.

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