Leaky fuel injectors or bad check valve?

owowl · Post by **owowl** » 06 Apr 2018, 20:31

I think I've finally narrowed down a hard start problem I've been having to low fuel pressure when the car sits for a little while. I noticed that after a few hours the pressure will drop to essentially zero, with no fuel coming out of the schrader valve when I press it with a screwdriver. I borrowed a pressure gauge and pressure comes up properly when the key is turned to on and stays fine while the car runs but drops near zero in about an hour or two. I'm not sure how to test whether or not this is a leaky injector or a bad check valve in the fuel pump. Replacing both is an option with 110k miles on the car, but I'd rather not have to spend the money to do both if it's not necessary.

In order to have the car start properly I have to turn the key and wait for the fuel pump to stop running or else it will shudder when it first lights off and fuel pressure is still low. I've tried to smell the oil to see if I can get a whiff of gasoline in it but I only smell normal dirty engine oil when I do. Any tips on how to check these things?

Post by **abscate** » 07 Apr 2018, 03:24

Bleed down is normal , I think the Volvo spec calls for about 60% of operating pressure after 20minutes.

Search for ‘fuel pressure specification’ to find this in this forum

Post by **chrism** » 07 Apr 2018, 07:11

You can pull all the injectors out of the intake, leaving them connected to the injector rail, and then power up the pump and see if any of them are dripping. You may have to improvise the fuel line connection to the rail if it doesn’t want to reach the rail.

owowl · Post by **owowl** » 07 Apr 2018, 07:15

I just did a double check (I don't know exact pressures because I don't have the gauge right now) and I don't get any fuel at the valve within about 15 minutes after running the car.