Ford Mustang Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
6,402 Posts
Discussion Starter #1
will you check to see how long it holds pressure when you turn the key on, then back off? I got a 255 from houston performance, and noticed that if I turn the key on, psi goes up to 35 or so where it should then back down to 0 in less than a second, regardless if I leave the key on or not. HP said it was normal for the 255s to bleed off pressure like that :bs: :rolleyes: . I think I got a bad pump and the return line check valve is screwed up and stuck open. I have no external leaks and no smell of gas anywhere, and thats way too much pressure to bleed out through the injectors in 1 second. It's also making it harder to start, but once it is started, it does hold the pressure where I set it.
 

·
Registered
Joined
·
2,028 Posts
If you leave the key on, you should settle near 30-35psi. I have a 255 and elec. gauge and on key-on it goes from 0-50+ and settles at 30psi. When I turn the key off, it does bleed off fast, it's already 25psi by 1 minute, but eventually holds above 20 for my setup (mainly stock).

sounds like a bad pump, i.e. it will not hold the pressure well.

--C
 

·
Registered
Joined
·
723 Posts
Yea dude, no way...mine holds pressure for quite a while. Probably doesnt get back to 0 for like 15-20 min. I do have a 190 tho, I dont see it making a difference, maybe im wrong
 

·
Registered
Joined
·
108 Posts
I can hold over 30psi for hours with the 19#ers, but will bleed down to 0 in 15-20 minutes with 42# injectors. Sounds like something is not quite right. You might want to check your pressure sender unit to make sure that there are no leaks at the base.
 

·
Registered
Joined
·
550 Posts
Fuel pumps have nothing to do with holding fuel press. when the engine is off. The FP reg. is responsible for that. If the reg. doesn't keep fuel in the rail then the vehicle wil have a hard start, long cranking etc. I'm guessing the regulator is at fault. Just my $0.02
 

·
Registered
Joined
·
149 Posts
mine holds pressure for quite a while like 20 min I think 255 in tank w/ Crane? f/p reg
 

·
Registered
Joined
·
6,402 Posts
Discussion Starter #7
Bling said:
Fuel pumps have nothing to do with holding fuel press. when the engine is off. The FP reg. is responsible for that. If the reg. doesn't keep fuel in the rail then the vehicle wil have a hard start, long cranking etc. I'm guessing the regulator is at fault. Just my $0.02
I swapped out my kirban for a new stock one that I had and it did the same thing.

Also, I don't have a FP sending unit. I just hooked the gauge onto the schraeder (sp?) valve.

Thanks for the responses.
 
1 - 7 of 7 Posts
Top