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Fuel pump strange issue

VN_SS_CM

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Hey guy's

I have a wired issue. I'll start the car and it will idle and out of no where it will die...tested and fuel pump wasn't priming, replaced fuel pump and oil pressure sensor and ecu and the issue continues, even when I bridge the relay the pump should turn on but it doesn't. Sometimes turning it off and on again gets it going.....
Vn 5l would anyone what is going on?
 

gtrboyy

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Possible wiring or loose plug issue.

Pop the whole relay/plug off bracket then stick test light underneath check signal wire then power wire to relay...if all good check at f/pump if not then check signal at ecu.

Swap relay out with another one in there.

Ecu will prime pump for 2-3 secs then turn off won't go again untill engine starts.

So are you sure it's 100% fuel issue with fuel pressure guage or spark/signal?
 

MikeC

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Does the pump run when you apply 12V to the upper LH (violet) terminal of the ALDL connector- this is the fuel pump ALDL test terminal.
 

VN_SS_CM

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Doesn't run.....it will if I give it 5 mins or 15 mins and it will run for 5 mins then die off..
New fuel pump new plugs and wiring is spot on only has 130,000 on the clock.
 

MikeC

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The 130k is pretty irrelevant in a 30+ year old car. How did you test the fuel pump and find out it wasn't priming.
 

91SS

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I assume your car runs only 1 pump? Does it always cut out after same number of minutes?
Did you try remanufactured ECU or SH?
Did you try known good relay?

Had all sorts of weird issues with ECUs. Dad had an ED falcon XR8 that would cut out almost precisely after 25 minutes. Mechanics changed loads of stuff for 2k and finally I replaced ECU and it fixed it. My VN had a flickering engine light for years turned out to be ECU and when i replaced it with SH unit had late spark. Finally put a remanufactured unit in and problem solved.
Also I believe the coolant temperature sensor cuts in after certain time. Is it happening only cold or roughly after this time. Reseat and clean plugs related to engine management.
Just some thoughts.

Good luck.
 

VN_SS_CM

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Problem solved guys ended up being a burnt out relay on the alarm circuit board...replaced relay and its working fine now :)
 
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