Page 1 of 1
Sitting 12 hours - no PSI at old start injector
Posted: Mon Sep 28, 2015 7:58 pm
by rjkoop
In preparation for checking the hissing noise near my fuel pump on my '81, to relieve the fuel pressure I took off the FI line for the cold start injector (car had been sitting for 12 hours or so). I expected fuel to squirt out. I got nothing when I took the hose off. Is that normal? Or should I expect PSI even after sitting overnight? I'm thinking the fuel is draining back into the tank when the car is off. I have no fuel leaks anywhere. Should the fuel pump or the pressure regulator maintain pressure when the car is sitting to ensure car starts quickly when cold? I noticed that it now takes a bit of time to start when before it started immediately. Maybe there is a 1-way valve in the fuel pump that has gone bad causing this issue and the hissing noise. Just guessing here...
Re: Sitting 12 hours - no PSI at old start injector
Posted: Tue Sep 29, 2015 5:42 pm
by rjkoop
Any thoughts on this issue?
Personally I think the hiss noise is from a minor crack in the plastic section of the fuel pump. It sounds worse when I adjust the angle of the pump because it opens the crack a bit. And when I shutoff the car is looses pressure and then takes a while to start to rebuild the pressure. Like I said no leaks anywhere.
Re: Sitting 12 hours - no PSI at old start injector
Posted: Wed Sep 30, 2015 1:56 pm
by rjkoop
And here's the sound of the fuel pump running (not great quality sound but hopefully you get the idea).
https://www.youtube.com/watch?v=u7Mn1Ve ... e=youtu.be
I took off the AFM boot and opened the flap manually to get the fuel pump to run. Sound normal?
Re: Sitting 12 hours - no PSI at old start injector
Posted: Thu Dec 10, 2015 8:22 am
by RRoller123
I am pretty sure that you should have gotten fuel to spurt out of the CSI fitting when it was removed, even after sitting.... but I am not sure if it would hold pressure for 12 hours. Maybe hook it back up, run the pump and then pull the CSI fitting within a few minutes, don't rush. Beware it should spurt with great force!! Wear safety glasses and wrap a rag around the fitting, don't do this with warm engine!
Pete
Re: Sitting 12 hours - no PSI at old start injector
Posted: Thu Dec 10, 2015 8:33 am
by rjkoop
Thanks for the info.
I did some more fuel related work on the car (eg. ensuring the gas vapor lines/valves are working correctly, all fuel lines are tight with no fuel smell) and the car starts within a second of turning the key and runs and accelerates fine. So I think I won't worry about this anymore unless I have an issue.