Misfire when warm... Doing my head in!!!!

[Commo_Carl]

Basic history

Turbo VR V6 only 37,000km on clock

Been pretty good for close to a year now then last week after I gave it a hit it started misfiring and driving like a pig (decel was fine)
I limped it home and the next day I checked and put new plugs in, checked leads and they were ok, checked fuel pump strainer, changed fuel filter and still ran ****.

Got NRMA to come round and try diagnose it, the guy said its electrical and it's most probs leads or coils. So I got a new set of top gun 10mm pro racing leads and didnt fix problem, then I got a hold of a 2nd hand set of coils and DFI. I swapped the coils only and the car ran better than EVER it was going like a mad ape... (for a day)

then that afternoon i gave it a small hit and then the same kinda thing happened again, started missing under load.

Today I took it to the auto electrician and they were pretty much useless, they just confirmed I had spark...

I am so freaking stumped, it runs fine when the motor is cold. I have a feeling it's electrical, but the auto elec wont touch my car to try confirm cause its 'modified'

Also i should add that I noticed a loom connector plug had slightly melted cause it touched the exhaust manifold and would of heated up the cables a fair bit, im also getting a prob with the fuel pump and fan stay on for 10 sec when engine and ignition are off. (Not sure if these would be related, but hey)

Could someone please try help i'm starting to go crazy lol

 

[aussie4life]

Could be your cas being a v6

 

[Commo_Carl]

Ive been umming and ahh-ing about the CAS. The sparky reckons it wouldnt be as they either work or dont. But i am going to try swap it with a new gmh one. Does anyone think it could be something in the loom? Im also considering getting another engine loom and swapping that to see.

 

[Jonah 101]

Disconnect the coolant temp sensor. If it improves replace the temp sensor.

 

[Commo_Carl]

Disconnect the coolant temp sensor. If it improves replace the temp sensor.

Hmm thats an interesting point. I shall try that. Is it the sensor behind alternator or the one on back of inlet i cant remember lol

 

[Jxfwsf]

yeah cas's either work or don't... when they work it runs great. when they don't it could either not run at all, only work when they're cold and either run like crap when hot or not run at all when hot.......

 

[Commo_Carl]

Yeah i originally thought they worked or if they didnt the car wouldnt start. But i have read cases of them playing up when warm. I have a little bit of hope that it could be CAS. I will try grab a new one tomorrow and try my luck. Has anyone ever experienced or heard of this?

 

[aussie4life]

yes. my vr v6 N/A has a dodgie CAS and basically it will run great for a long time with only a slight miss on idle but then other times i will drive 5 km down the road to the super market and when i jump back in it to go home it refuses to start for about 5 mins. so in my thinking they can be partially faulty.

 

[Commo_Carl]

yes. my vr v6 N/A has a dodgie CAS and basically it will run great for a long time with only a slight miss on idle but then other times i will drive 5 km down the road to the super market and when i jump back in it to go home it refuses to start for about 5 mins. so in my thinking they can be partially faulty.

Thats good to hear. I could well be in luck with CAS. Mine hasnt had a problem starting... although i dont know if i have actually turned it off and restarted when warm.

Did yours miss under acceleration?

 

[aussie4life]

It doesnt miss under load. However if i slow down and then speed back up, like going around a corner, if the revs are to low and it sits around 2000rpm then it will drop to first or second, rev out to 3k rpm and then slot into second or third. Hunting is the term i think or maybe surging