06 S60 Intermittent long crank

Post by **erikv11** » 19 Jan 2023, 14:58

Was doing it this summer, then went away, now doing it again: on first startup the car doesn't want to start right up. Suspecting a bad check valve in the fuel pump I checked cycling the ignition three or four times before cranking - then it always fires right up.

I replaced the FPS with a Bosch unit about 20k ago. That gave a code and different symptoms but I suppose it could be bad again e.g. leaking internally.

Bad check valve in the fuel pump or ... something else? Not a PEM issue, right?

Has anyone solved this symptom recently with an inline check valve and can make recommendations? Not too interested in replacing the fuel pump.

Bigbishop · Post by **Bigbishop** » 03 Apr 2024, 13:30

Hi, been experiencing same symptoms. Car starts on second, third or fourth cranks. Replaced fuel pump (unit only not module), fuel filter, air filter, and spark plugs. Just done some reading that faulty check valve causes hard starts. Did you sort it out?

Post by **jonesg** » 03 Apr 2024, 16:25

have you read the fuel pressure and pump duty cycle.

Bigbishop · Post by **Bigbishop** » 03 Apr 2024, 17:20

I have only read fuel pressure at rail, I believe I got about 60 psi

Post by **jonesg** » 03 Apr 2024, 17:24

60 psi is good.
read the pressure after one key cycle ..not several.

i had a new but bad ect sensor give crank no start 2 weeks ago.
installed the old one and cured the no start.
i think it was flooding the engine at cold start.

Bigbishop · Post by **Bigbishop** » 03 Apr 2024, 17:44

Oh OK I will read pressure as you have guided. It's almost 2 am so I will get to it around 8 am. Thank you

Post by **cn90** » 03 Apr 2024, 18:17

Get a good used PEM, swap it in and see what happens...

Bigbishop · Post by **Bigbishop** » 03 Apr 2024, 18:50

Yes worth trying out, thanks.

Post by **erikv11** » 03 Apr 2024, 21:29

Check out my first post more carefully: Cycle the key to position two (all lights illuminate on the dash but engine not cranking) then off, do that cycle three or four times, without ever cranking it. If the car now starts right up on the first crank, then the problem is the check valve and not the PEM.

In fact check I'd check the pressure several times, as per jonesg:
- after the car is sitting all night, i.e. at zero cycles
- after each time you move the key to position two

jonesg is describing a different problem with his ECT issue, more of a generic crank no start. Only if fuel pressure is right up to 60 psi on the first crank, would ECT be a possible problem.

Summary
- Everything working: fuel pressure pops up to 60 psi the first time key goes to position 2, car starts right up.
- ECT failure: fuel pressure pops up to 60 psi the first time key goes to position 2, but engine will not start because too much fuel is dumped through injectors.
- PEM failing: pressure is either 60 (PEM working) or zero (PEM not working); engine sputters after starting due to inconsistent fuel supply.
- Check valve failing: pressure gradually raises up to 60 psi, after a few cycles position 0 - 2 - 0 - 2 - 0 - 2. Problem is intermittent.

Bigbishop · Post by **Bigbishop** » 05 Apr 2024, 10:16

@erikv11

1. So I just did 4 cycles as you suggested and crancked on the 5th cycle and lo and behold, car started up immediately.
2. I hooked up a gauge at the fuel rail. Did several 0-2 cycles and observed that on first cycle, needle on gauge rose from 0 psi and stopped at about 20 psi. On second cycle went from 0 psi to about 28 psi. On third cycle went to about 33 psi and kept rising following additional cycles. Never did it go from 0 psi to 60 on any individual cycle.
3. When the car did start nicely after 4 cycles, needle was at 60 psi and maintained 60 psi even during revving points.
4. When car was shut down, needle went down from 60 psi to 0 psi literally within a minute.

What do you think?