Rb30 Stuttering Engine Problem

[Rbrenn]

Hey all,

Recently bought an aussy 1987 r31. Have been loving it but have encouted a problem just recently. The car was running awesome until a gerni'ed and degreased the engine bay. Ever since the engine (stock rb30) has been idling pretty rough, revs high and then goes to normal idle. Also shakes the whole car off and on during idle. Also during acceleration the engine stutters but very quickly. Also pulling up to lights the car also shtutters but much more violently.

Have assumed that I have got water somewhere such as in a sensor, coil pack, spark plug whels, or even in the distributer. Therefore I left the car for a couple of days to dry, but it's still doing the same thing. Have now got some water despersent spray and gave all the spark plug lead caps and distributer lead caps a good spray and checked the spark plug whels for moisture but nothing.

From there I checked the resistance of the coil pack and is within limits so I have run out of ideas and not sure what to do next.

Any help would be appreciated,

Thanks,

Riley

[Rbrenn]

Also forgot to mention that these problems only really start after the car has been run for 5 or so minutes and there is a little bit of heat built up

[AngryRB]

Have you cleaned the AFM? does it puff out black smoke when its stuttering?

[Rbrenn]

No I haven't, will buy some spray and try that. Not sure, will let it idle tomorrow and see

[Rbrenn]

Also used a spark plug tester on all 6 today with all good results. So I'm ruling out ignition system.

[GH05T]

you havnt got coilpacks, but you do have a dizzy, check that, they love holding water.

[r32-25t]

Yes take the distributor cap off and blow the water out

[Rbrenn]

Already done both those things boys. Will try cleaning air flow meter this arvo

[GH05T]

i had a similar issue which was my leads which looked perfect, were arking on the rocker cover due to tiny cracks and general insulation break down, the degreaser could have just failed the rubber?
have you tried NEW leads and NEW plugs?

[MrStabby]

^ yep. OP give it a rev at night with the bonnet open - you might be able to see arcing

[Rbrenn]

Yeah haven't tried new leads, and only fitted plugs 400ks ago... Thinking could be even fuel lines or fuel filter needs a change.

[jiffo]

These old jiggers have an ignition module on the front of the distributor and a CAS somewhere inside.

Might be worth pulling it apart, giving it a good dry out plus WD40.

Check the carbon brush down the centre electrode of the distributor cap too. When they wear the spark is erratic.

[Rbrenn]

Ran it at night and had look to check for sparks jumping where they shouldn't . Found it jumping inside the spark plug whels of one of the cylinders. Will change leads and hopefully should fix it. Thanks dudes!!

[GH05T]

always good to find an issue, especially when its a cheap fix.