3 Cyls Only. Not Coil Problem.

[ShiftyTys]

Hey all.

This is currently at the shop. It's just had a gtx3076 installed and they won't give it back till they find what's causing this:

After like 45 mins to potentially a couple hours of idle. It will drop back to 3 cylinders. Only for a couple minutes. Then fix itself. Apparently they can sometimes make it do it with a few "blips of the throttle".

The guys are stumped.

Injectors swapped and checked. Slarkplugs swapped and checked. I already have spitfires but they were swapped and checked.

Ecu is still sending injector pulse etc etc etc. They have done some ecu tests apparently that doesn't appear to be it.

Crank angle sensor fouled earlier in the dyno runs. But has been replaced and is holding steady. They even swapped my whole injector AND rail setup to a siemens top feed setup just too see. Still did it.

I've had them reinstal the AFM to use as a dummy setup. (pull plug it stalls) that was completely removed just invade the wiring way funny. Still does it.

Any ideas?

Please help. I'd like my car back b

[r32-25t]

Could be the ignitor

Edited May 19, 2011 by r32-25t

[Don Dada]

^^^^

and make sure its earthed properly too

If its a series 2 well.........

[blk94r33]

  On 19/05/2011 at 10:53 PM, ShiftyTys said:

Hey all.

This is currently at the shop. It's just had a gtx3076 installed and they won't give it back till they find what's causing this:

After like 45 mins to potentially a couple hours of idle. It will drop back to 3 cylinders. Only for a couple minutes. Then fix itself. Apparently they can sometimes make it do it with a few "blips of the throttle".

The guys are stumped.

Injectors swapped and checked. Slarkplugs swapped and checked. I already have spitfires but they were swapped and checked.

Ecu is still sending injector pulse etc etc etc. They have done some ecu tests apparently that doesn't appear to be it.

Crank angle sensor fouled earlier in the dyno runs. But has been replaced and is holding steady. They even swapped my whole injector AND rail setup to a siemens top feed setup just too see. Still did it.

I've had them reinstal the AFM to use as a dummy setup. (pull plug it stalls) that was completely removed just invade the wiring way funny. Still does it.

Any ideas?

Please help. I'd like my car back b

-What cylinders does it drop?

-The ECU is still sending injector pulses, is it getting through to the loom?

-Are you still getting spark and switching to the coils on all cylinders?

-Is it a consistent miss, or does it generally run like ass and you can't really tell?

If it comes and goes you're going to be chasing an electrical fault...

[Rolls]

Swap the ignitor with another one.

[ShiftyTys]

  On 20/05/2011 at 2:13 AM, blk94r33 said:

-What cylinders does it drop?

-The ECU is still sending injector pulses, is it getting through to the loom?

-Are you still getting spark and switching to the coils on all cylinders?

-Is it a consistent miss, or does it generally run like ass and you can't really tell?

If it comes and goes you're going to be chasing an electrical fault...

Not too sure about Wich cyls. I'll find out

Yes pulse Is getting to loom.

Yes getting a spark and switching to the coils on all cylinders (awesome gramma me have)

It sits idle. Then drops under those circumstances and apparently sounds like a pig for a couple mins. Then clears up mint till the next episode.

[ShiftyTys]

  On 19/05/2011 at 11:50 PM, Don Dada said:

^^^^

and make sure its earthed properly too

If its a series 2 well.........

Wouldn't that be a consistent issue apposed to every hour or so then clearing on it's on till the next episode?

Cheers

[ShiftyTys]

  On 20/05/2011 at 5:00 AM, ShiftyTys said:

Wouldn't that be a consistent issue apposed to every hour or so then clearing on it's on till the next episode?

Cheers

Nvm Its a series 2. Didn't think when I replied. No igniter.

[blk94r33]

  On 20/05/2011 at 4:58 AM, ShiftyTys said:

Not too sure about Wich cyls. I'll find out

Yes pulse Is getting to loom.

Yes getting a spark and switching to the coils on all cylinders (awesome gramma me have)

It sits idle. Then drops under those circumstances and apparently sounds like a pig for a couple mins. Then clears up mint till the next episode.

You might be in trouble...

If you have air, spark and fuel, only really one other option if all the above have been checked properly:compression. Not necessarily a stuffed engine, but maybe a few lifters getting upset? My car will miss if I leave it sitting for a few days then start and idle it...

Other options:

-Fuel pressure issue causing lean/rich misfire

-Timing going out of whack, but this should affect all cylinders

-IAC valve or control acting up lowering the idle until the car can't run properly

-As above, maybe dud lifters?

How did they check spark to all cylinders? In-line spark tester?

[ShiftyTys]

  On 20/05/2011 at 7:56 AM, blk94r33 said:

You might be in trouble...

If you have air, spark and fuel, only really one other option if all the above have been checked properly:compression. Not necessarily a stuffed engine, but maybe a few lifters getting upset? My car will miss if I leave it sitting for a few days then start and idle it...

Other options:

-Fuel pressure issue causing lean/rich misfire

-Timing going out of whack, but this should affect all cylinders

-IAC valve or control acting up lowering the idle until the car can't run properly

-As above, maybe dud lifters?

How did they check spark to all cylinders? In-line spark tester?

Ok. Your bang on. It dropped 3 cyl as normal. They immediately turned it off and compression tested 4,5,6. No compression. So Now it gone from potentially electrical. To mechanical. They seem to think lifters too. It's a real odd one but they said it can't really be anything else as they have tested all other possibilities.

Monday they are swapping lifters. Will report back.

[blk94r33]

  On 20/05/2011 at 11:19 PM, ShiftyTys said:

Ok. Your bang on. It dropped 3 cyl as normal. They immediately turned it off and compression tested 4,5,6. No compression. So Now it gone from potentially electrical. To mechanical. They seem to think lifters too. It's a real odd one but they said it can't really be anything else as they have tested all other possibilities.

Monday they are swapping lifters. Will report back.

Drops compression. at random, on the three rear cylinders?

Broken cam? Does it only do it when hot? IE. head gasket fault?

That's a very weird problem....

[ShiftyTys]

  On 21/05/2011 at 2:54 AM, blk94r33 said:

Drops compression. at random, on the three rear cylinders?

Broken cam? Does it only do it when hot? IE. head gasket fault?

Extremely weird. That's why the guys are so bloody stumped. They seem to think it's lifters. So I guess Monday will tell. I'll definitely report back.

That's a very weird problem....

[ShiftyTys]

  On 21/05/2011 at 2:54 AM, blk94r33 said:

Drops compression. at random, on the three rear cylinders?

Broken cam? Does it only do it when hot? IE. head gasket fault?

That's a very weird problem....

Ok. Not lifters. Possibly valve springs. Valve was stuck down. Hit it with a hammer. Popped up. Possibly valve guide. Head coming off today to see Wich it is. There's another 1k labour. Great.

Will keep u posted.

[Rolls]

If the valve was stuck down how on earth did the piston not hit it?