Fuel Pressure problem or not?
Thread Starter
|
Tuned
Joined: Aug 2005
Posts: 305
Likes: 1
Fuel Pressure problem or not?
My 95 5.0 bronco takes two or three trys to start. I tested the fuel pressure with the engine on and it is 38psi. When I shut the enging off the fuel pressure goes away (slowly but after about 10-20 seconds there is zero pressure) When I turn the key back to the run position, I hear the fuel pump kick on, stays on for a few seconds and then there is a click ( a relay I presume) and all is quiet. Sounds normal right? well the guage shows no pressure. Once I try to start it two or three times (hearing the pump everytime) then it starts. Any ideas? Is the fuel pressure supposed to hold when shutting the engine off? Why doesnt it build up pressure when I first turn the key? Could it be a vacuum problem?
Posting Guru
Joined: Apr 2007
Posts: 1,191
Likes: 0
From: Lockport, NY
well I do not know about your ford but on a 96 s10 blazer with I had , I was having the exact same problem, took it to a shop because I was feeling lazy, to have them change the pump and they said it had 50psi and that it was the spyder injector? $500 to fix it, well guess what they were wrong! a buddy of mine that runs a shop got a pamphlet like the next day that stated this was a common problem with the s10 and that they need atleast 60 psi to start! I changed the pump and the problem went away, so i would guess that this is your problem too. oh and yes I do beleive that they should hold the pressure
Last edited by rsalter66; Oct 4, 2007 at 07:44 PM.
Post Fiend
Joined: Mar 2002
Posts: 19,402
Likes: 38
From: Bonita Springs FL
Originally Posted by rsalter66
so i would guess that this is your problem too. oh and yes I do beleive that they should hold the pressure
He is right, though, about the system holding pressure. It should stay and not drop off. This usually means that the check valve inside the fuel pump is shot. It could also mean that you have an injector stuck open, but unless you're getting terrible gas mileage, I wouldn't worry about that.
Pressure doesn't usually build up right away. It takes about 10 seconds of the fuel pump running to build up 38 psi of pressure. But yours will probably take longer with the bad check valve.
Thread Starter
|
Tuned
Joined: Aug 2005
Posts: 305
Likes: 1
The injectors are new so unless some crud passed through the line I'll assume its the fuel pump. Also, the truck has 197000 miles on it, and I bought it at 141000 so who knows how old the fuel pump is. Do you have any suggestions as to where to buy the fuel pump? I've read in other posts not to buy from autozone.
Senior User
Joined: Apr 2004
Posts: 443
Likes: 1
From: Central Va.
If it does't hold pressure after shut off, you need a fuel pump.It is part of testing your fuel pressure.As for the s-10= IF the fuel pump relay is not working as it should, the fuel pump will not presurize untill oil presure is enough to energize fuel pump.Back up system---Noted on AllData site!!
Posting Guru
Joined: Apr 2007
Posts: 1,191
Likes: 0
From: Lockport, NY
I fixed the s10 by changing the pump, and the truck ran high oil pressure, it had nothing to do with bad relays, beleive me I checked everything before I pulled that tank because the pump that went bad was only 1 year old ,and when they dont hold pressure its called bleed back and its not good, if possible I would make an acess door over the pump after you pull the tank so if you run into future problems it is an easy access, I dont know why the factory dont do this? or just install an inline aftermarket pump!
Senior User
Joined: Jan 2003
Posts: 117
Likes: 1
I bought my fuel pump at Autozone....
for my 1990 Bronco a few years ago. haven't had any problems. I also used the same model from a Bronco, from Autozone, for my fuel injection conversion on another car. So far so good.
Thread
Thread Starter
Forum
Replies
Last Post
cityjack
1968-Present E-Series Van/Cutaway/Chassis
1
Jul 13, 2013 03:22 PM
Rebeltn
1978 - 1996 Big Bronco
16
Dec 14, 2008 01:24 PM
