HELP - GM V8 EFI issues (1 Viewer)

[NZBJ71]

Here's one for all you EFI V8 experts out there.

I have a Holden 5litre EFI V8 (Holden is a branch of australian GM). Its basically and SBC block with their own heads and is 304ci. It uses a GM 1227808 ECU.

The engine developed a stumble once up to temp (running for 10 or so minutes). this quickly turns into a misfire and backfire through the intake and then dies or barely has enough to keep turning over.

If the engine is turned off and restarted it usaully goes away and is good for a few more minutes.

I have changed the coil with no success, The ECU isn't storing any codes.

I am at a loss, Could it be a faulty EFi module or ECU?

any idea would be fantastic.

Cheers

Tony

 

['74 UA FJ]

May be a bad temp sensor. Does it run progressively richer as it heats up? Do you have any black smoke?

If that's not it, my next guess would be that it is a timing issue.

 

[inkpot]

Howdy! Sounds like a fuel supply problem. Filter plugging up, or a soft line collapsing. On my 91 Camero, I had to replace the filter element on the pump, in the tank, as it fell apart and slowly plugged up the intake tube on the pump. Actually did this twice. Bought cheap on the first one, went hi dollar on the second one, which worked OK for years. John

 

[Gumby]

I like an ECT or fuel supply problem.

mass air flow could be a problem,


need to get it on a scan tool.

I suspect a sensor that adjusts once the engine goes into closed loop.

 

[zebrabeefj40]

May be a bad temp sensor. Does it run progressively richer as it heats up? Do you have any black smoke?

Had this on my '93 GMC van. Once I swapped the temp sensor it ran like it was supposed to. Before the new sensor the motor would hit closed loop and the tailpipe would blow nothing but black smoke...then stall out.

I thought fuel first myself and swapped out the fuel pressure regulator. Still ran like poop.

Good luck with it!
Nick