06 S60 Intermittent long crank

Post by **erikv11** » 05 Apr 2024, 14:10

I think bad check valve! Especially evident from the quick drop to 0 psi when you shut down the car but the other observations too.

Known options:
1 - just live with it, always cycle the key 4 times before starting
2 - replace the fuel pump
3 - install an inline, aftermarket check valve

I have chosen option 1 on our S60. It comes and goes, sometimes it will start up properly for a couple months, then it starts leaking again and have to cycle. Option 3 has been very popular over the years but I don't have experience with it.

Bigbishop · Post by **Bigbishop** » 06 Apr 2024, 03:04

Okay, thank you for your help. I will first look into installing a check valve, I gathered it's a 5/16 size. Then will take it up from there. Thanks again.

dikidera · Post by **dikidera** » 06 Apr 2024, 04:22

Isn't it possible for there to be a leaky injector as well, dropping the fuel pressure as the fuel is dumped in thr cylinder?

Bigbishop · Post by **Bigbishop** » 06 Apr 2024, 08:35

@ dikidera

Yes a leaking injector is possible but I tried out injectors from my 04 C70 T5, the car still had a hard start so at this point, it's most likely the check valve. Thank you for your insight.

Post by **erikv11** » 06 Apr 2024, 08:36

Sure that's a good idea - In theory yes but I would expect to see codes (lean, rich, misfire) and poor idling if an injector was leaking so badly.

Post by **volvolugnut** » 07 Apr 2024, 10:12

Bigbishop wrote: ↑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?

The immediate fuel pressure drop to zero indicated the fuel check valve is leaking. It should hold for hours, maybe days.
volvolugnut

yanga001 · Post by **yanga001** » 07 Apr 2024, 11:38

My independent mechanic spoke to me about this issue before. My car intermittently had this issue and he said it was common for the check valve to go bad as stated by volvolugnut. Cycling the key will prime the pump and should let the car start.

Post by **jonesg** » 07 Apr 2024, 14:19

yanga001 wrote: ↑07 Apr 2024, 11:38 My independent mechanic spoke to me about this issue before. My car intermittently had this issue and he said it was common for the check valve to go bad as stated by volvolugnut. Cycling the key will prime the pump and should let the car start.

duty cycle will show if the pump has to run more than 40% to keep it running.

Post by **erikv11** » 07 Apr 2024, 22:31

yanga001 wrote: ↑07 Apr 2024, 11:38 My independent mechanic spoke to me about this issue before. My car intermittently had this issue and he said it was common for the check valve to go bad as stated by volvolugnut. Cycling the key will prime the pump and should let the car start.

Yes, see my post at the top of this page (page 2). Same behavior. It's the check valve.

06 S60 Intermittent long crank

Re: 06 S60 Intermittent long crank