1987 3.2 Carrera Backdate project - Sladeys hotrod

[markm]

That just bad luck mark, these things happen and probably giving it to a fresh pairs of eyes when you get back isn’t a bad thing

I’m fairly sure you will still have a good time on your holidays in the GT4

[sladey]

Thanks guys.

In the middle of the night I started thinking that the problem could still be with the injection loom. I know it got stretched when I first removed the engine and I know some of the wiring has splits in it.

I checked for shorts but didn’t check each plug for continuity. If there was a semi-break then it would affect the pulsing of one or more of the injectors and give the symptoms I’ve been experiencing.

When I get back I can try some tests on each individual injector - or just put a new one in

[DustyM]

I’m still thinking air leak or
Mixture problem, the fact that it runs better as you increase the revs is what has me thinking this. The more revs the less impact a small air leak has on the mixture.

Also are you running a MAF or do you
Still have the barn door?

An injector problem wouldn’t go away
as the revs rise, it would get worse surely?

But all guess work. I’d take a look for you Mark but don’t have the facilities I used to.


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[sladey]

I think I’m maybe not explaining it very well. It was rough in different ways throughout the rev range. At about 4k it sounded more normal but when I lifted off it sounded wrong as well.

I don’t have enough experience listening to bad running engines

I’ll also admit I tend to jump at one diagnosis.

I have gone through looking for leaks quite thoroughly though and really couldn’t find any - spraying carb cleaner at the base on the inlet stacks also produced no change at all

[Bruce M]

Once you get back, some diagnosis using the ECU software & laptop should get to the root cause.

Can the software record a log file?

[sladey]

Yes it does - I’ll try that when I get back

[Jonny Hart]

Thanks guys.

In the middle of the night I started thinking that the problem could still be with the injection loom. I know it got stretched when I first removed the engine and I know some of the wiring has splits in it.

Given that the injector driver circuit in the ECU was damaged, that could certainly have been caused by wiring in the loom being shorted to ground.

[sladey]

Also looking at the things I fcuked up during the work suspending the engine by the injector loom probably wasn’t good for it

[markm]

Awesome work mark. That could be the problem

[RobFrost]

I think checking manifold temps was good advice. The more you can narrow down the possibilities, the less guesswork is required.

Then I'd probably clip a timing light on each spark plug wire.

Soon you'll know which cylinders are affected and whether it's fuel or spark.

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