ZCar Forum banner

Status
Not open for further replies.
1 - 15 of 15 Posts

·
Registered
Joined
·
279 Posts
Discussion Starter #1
Okay the z finally has all its wiring hooked up so i went to turn on the ignition to check the fuel lines for leaks and the fuel pump comes on runs for a little bit and then its starts bogging down and gas starts leaking from the gas tank area. I never had a problem with a gas leak before so im thinking the regulator may not be bleeding off the pressure? and this cause one of the old hoses to rupture?
What do you guys think?
 

·
Registered
Joined
·
4,279 Posts
probably one of the hoses, even if it's the FPR it shouldn't leak from tank at all, probably one of your hoses is getting old and not handeling presure any more.
 

·
Registered
Joined
·
279 Posts
Discussion Starter #3
but how come it did this just now after i rebuilt the engine>?

and are these hoses coming out of the tank, bent or shaped in any way that i would have to order them from the dealer or can i just go buy some efi hose?



Post Edited (May 11, 6:52pm)
 

·
Registered
Joined
·
782 Posts
hoses tend to dry up but running to much fuel pressure probably made it happen a little faster than it would have.
 

·
Registered
Joined
·
279 Posts
Discussion Starter #6
i hooked up my fuel send line and fuel return line together and the pump runs fine and there are no leakes from the rear, is there some kind of relief valve on the tank? that might have caused it too leak out under high pressure?

So I guess I need a new FPR cause I blasted out my fuel rails with the air hose before i put them on so its not clogged there, and the only thing left is the FPR.
 

·
Registered
Joined
·
1,644 Posts
In the past I have had an intermittent startup problem which was rectified with another FPR.
I still have the bad FPR somewhere but I haven't got around to opening it up for a look inside.
My fuel pump made an odd squeal when the problem occured. I assumed the squeal was the pressure relief in the pump operating.
FSMs spec the fuel pump "Cut-off discharge pressure" at 61-71psi.

If there is some problem with the FPR not releasing pressure then you could expect 61-71psi in the pressurised (but maybe not the return) lines. That may be more than some 20 year old hoses can handle.

As for the fuel pump turning itself off once it builds up pressure: no. The fuel pump is controlled by the ECU. When you first turn on the ignition, the ECU will run the pump for five seconds and then shut it off until you turn the key to "Start".
The ECU does not monitor the fuel pressure and relies on the FPR to control it.

On a FPR side note, while the USA fiche does not show different part numbers for FPRs apart from an alternate, FSMs for 85 and 88 show different fuel pressures between NA and T for "The moment accelerator pedal is fully depressed", NA = 37psi, T = 44psi.
The 84 FSM does not differentiate between NA and T, at 37psi.

If the FPRs are same enough, how do the turbo fuel systems have 7 extra psi "The moment the accelerator pedal is fully depressed" (manifold atmospheric pressure?).
 

·
Registered
Joined
·
1,644 Posts
At idle and other low demand conditions, the ECU should ground the fuel pump at a lower voltage.
When the ECU decides the pump should run at battery voltage, the ECU grounds the pump through a relay.
If someone has screwed around with the wiring then the fuel pump may ground through the relay continuously.
 
1 - 15 of 15 Posts
Status
Not open for further replies.
Top