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Author Topic: Fuel Delivery Gremlins  (Read 123 times)

Online Wonderingraven

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Fuel Delivery Gremlins
« on: 04:41:44 PM / 23-Nov-17 »
So a brief history. in 2015 I was plagued with the fuel pump still running after shutting off the car, and after 15 minutes it would flood my car with gas and it would pour fuel all over from the intake to the ground and about 1 maybe 2 gallons of it (thats alot of fuel)

1986 XE - CA20e mk1.5

Motor blew a headgasket back in November of 2015, rebuild the system and rewired the fuel pump so it is running as if I swapped a KA into it..

So just today I have experienced a new thing where you would have to switch the fuse panel off and back on but doing so it will be drive-able right after that.
Wired in with the master power coming from the actual fuel pump 12v line
wired in from the rear wiper fusepanel as the key on power source

So I have both fuses running just fine just there was no power to the fuel; pump
an dthis was all turning off the car, walk into the store, 10 minutes later return to the car and attempt to start it up. Fuel pump you can hear because there is no carpet to cover the noise.

Before i just run a 30amp fuse / relay with 12-14g wire from the engine bay to the rear of the car eliminating the full 12v power from the fuse panel. I was wondering if there is anything to check on that 12v line.
it seems to be an issue with that 12v fuel pump line and not necessary at the fuse panel but a weird gremlin since I have picked this car up.



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1987 - Project: Fairlady Silvia
1986 - Project: Serenity
1986 - Project: Dread Pirate Robin
{Blogged builds} www.g-funk.net/blog/

Offline rednucleus

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Re: Fuel Delivery Gremlins
« Reply #1 on: 11:34:35 PM / 23-Nov-17 »
I had years of intermittent no start or no pump problems. Even replaced the pump but still off and on. Finally became more consistently no run and found if I wiggled the ecu wires I could replicate the problem. Ended up finding that wiggling components on one corner of the board consistently killed it. So I took a solder gun and hit every solder point on the board and it has been 100% reliable ever since.

Online Wonderingraven

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Re: Fuel Delivery Gremlins
« Reply #2 on: 12:13:33 AM / 24-Nov-17 »
That is something I somehow kinda figured, Something to look at for sure.
1987 - Project: Fairlady Silvia
1986 - Project: Serenity
1986 - Project: Dread Pirate Robin
{Blogged builds} www.g-funk.net/blog/

Offline BOSSMAN

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Re: Fuel Delivery Gremlins
« Reply #3 on: 02:19:57 PM / 27-Nov-17 »
I had a problem with the fuel pump running after the engine is shut off and it turned out it was a faulty fuel pressure regulator.  There was a pin hole in the diaphragm and fuel was leaking back into the intake manifold from the vacuum line from the regulator.  You can check if it's the regulator by pulling the vacuum like out and see if fuel is coming out from there, do this when the engine is cold or you might  get a small fire like it happened to my trusted mechanic!
86 CA18ET....owner since 1990.
The name is Bossman, but you can call me Mr. Panda....My other car is a Buick....
My Skyline is here!  My Skyline is here!

Online Wonderingraven

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Re: Fuel Delivery Gremlins
« Reply #4 on: 02:21:35 PM / 27-Nov-17 »
I had a problem with the fuel pump running after the engine is shut off and it turned out it was a faulty fuel pressure regulator.  There was a pin hole in the diaphragm and fuel was leaking back into the intake manifold from the vacuum line from the regulator.  You can check if it's the regulator by pulling the vacuum like out and see if fuel is coming out from there, do this when the engine is cold or you might  get a small fire like it happened to my trusted mechanic!
Yeah that part is all good now, just something is still randomly grounding out the circuit for the fuel pump.
1987 - Project: Fairlady Silvia
1986 - Project: Serenity
1986 - Project: Dread Pirate Robin
{Blogged builds} www.g-funk.net/blog/

Offline BOSSMAN

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Re: Fuel Delivery Gremlins
« Reply #5 on: 02:17:18 PM / 28-Nov-17 »
Have you checked the wires on the top plate for the fuel pump cage on top of the fuel tan?.  Those rubber isolators will harden over time and break apart allowing the wire to ground (totally forgotten about this one), check the ground too and make sure you have a good ground.
86 CA18ET....owner since 1990.
The name is Bossman, but you can call me Mr. Panda....My other car is a Buick....
My Skyline is here!  My Skyline is here!