5 GT Turbo EFI - GT Turbo

[Mark Davis]

Lol, did metal to manifold today, that's how'd I done it before.

Anyway, update.

New binx nuts, washer, turbo/manifold gasket, down pipe gasket, head/manifold gasket - all fitted and done up. Start car, no change.

Notice car is missing very obviously and although before I could sense a miss at start up not quite as bad as this, managed to narrow miss down to cylinder 3. Pulled plug only to be greeted with one very fucked and melted BR9EIX, see pics.

Pictures don't do it justice, it's fucked.

 

[Mark Davis]

Did comp test - all fine.
155/155/155/160

New plugs and gapped, runs fine. Still tappy as fuck but going to have to live with it. Going to change oil too.

 

[TNT Andy]

Ha! Not getting involved in this old chestnut again

We disagreed about this years ago LOL.

 

[Brigsy]

Did you chop the holes out on the new gasket to suit the head ? Hardly any meat next to the outer exhaust ports might have problems with that blowing tbh

 

[Mark Davis]

Yeah it's all matched up and sealed up well this time, no question.

The tapping I can hear is definitely top end and started after we were out testing that day. Everything else seems really healthy, breathes well, not losing oil/water, good compression.

Was also fine on the rollers and took a good kicking until push rod bent. I've triple checked valve clearances too, even redone them.

I think I'm just going to have to live with tappy C1J until I finally need to rebuild it.

 

[Mark Davis]

Starting to think EFI is a total wanker.

So riddle me this, new plugs in, gaps set, start car and all is well apart from I notice once again it Idling rich and then as the car gets warmer starts to feel a little lumpy and afrs being erratic, mainly a much richer cruise. Anyway drove around for a good 30 mins to warm car up, decided to test fuelling on boost at which point I'm getting misfires and mid 12s 6k in 3rd, needless to say I let off.

Straight after this car started running on 3 cylinders so cruised home. Decided to check and lo and behold it was number 3 again. I pulled plug and look what I was greeted with. Exactly the same as last time, covered in what looks like black tar (carbon/unburnt fuel) or something similar. These are brand new plugs and done no more than 15 miles.

Compared to number 1 and 2 plugs which are normal.

So what's the fault ? Comp tested again today, all good. Using no oil, water, engine running fine other than this.

Thoughts ? @DaveL485 @Brigsy @Clarkey

 

[Brigsy]

Whats the compression on that cylinder and the rest of the cylinders ? I have had issues like this with plugs fouling up due to oil on one cylinder due to damaged rings.

I would get a borescope down the cylinder and see whats going on as i can imagine some damage might have happened if its melted a plug. The tapping could be a cracked ring

 

[Mark Davis]

The plugs haven't actually melted Jon but just covered in what looks like unburnt fuel or like you say crusty oil. I was getting ahead of myself using the word melted, more likely massively fouled.

All 4 cylinders are around 155psi, I did them again tonight. Confused!

 

[Mart]

What heat-range are the plugs?

Edit. Just seen they're 9. That's probably the reason they're fouling. Try an 8 range, although with efi, you should be able to run a 7.

 

[Mark Davis]

They are 9s.

Ran fine on these plugs before, plugs one two and four are fine. Just number 3 looking fucked.

 

[Mart]

Yeah, just seen they're 9's. Edited my previous post.

Could be a weak spark on that cylinder, but imho 9's are too 'cold' for c1j engines, even more so given yours is efi'd.

 

[Mark Davis]

We had to change from 8s to 9s on the rollers on advice from Scoff. They've ran fine previously, I don't think it's plug choice specifically. Definitely something else odd going on.

 

[Mart]

Just out of curiosity, why did Scoff advise running the colder plug? I can't recall any of the high boost/power c1js running anything colder than an 8, and they were without the luxury of efi.

 

[Mark Davis]

I can't remember, think we were having some issues with 8 rated plugs. I think Clarkey runs 9s on his set up too.

 

[Brigsy]

I would determine if its fuel or oil fouling the plug. Probably one of these three causing it

Oil finding its way into the cylinder - damaged rings or valve stem (doubt its valve stem oil seal as i do not run them)
Fuel - duff injector - could swap injector to another cylinder and see if the problem follows ?
Spark - weak spark for some reason (bad lead, wrong gap, ecu settings ? too cold a plug ?)

With the knocking i would probably be prepared to be pulling the engine to bits tbh. What sounds like top end might be coming from the bottom. Piston might have decided its not having loads of boost - i have heard the ring landings can crack over 25lbs but who knows

 

[Mark Davis]

I tend to agree Jon, too much of a coincidence I think.

 

[DaveL485]

Start swapping things to other cylinders.

Injector first, just switch one around. Could be a duff injector.

Then swap the coil lead with the other cylinder on that wasted spark side but dont change it at the coil side.

Then swap the coil side.

Process of elimination by following the fault, if its not fuel or spark it has to be mechanical. Its cylinder specific so that helps trim down options.

 

[Fordy]

Find local Ansu machine get all injectors tested [emoji106]

 

[Mark Davis]

Thanks all, I'll get to investigating this weekend and see where I'm at.

Will report back.

 

[Clarkey]

I can't remember, think we were having some issues with 8 rated plugs. I think Clarkey runs 9s on his set up too.

We run 8.s mate.

Start swapping things to other cylinders.

Injector first, just switch one around. Could be a duff injector.

Then swap the coil lead with the other cylinder on that wasted spark side but dont change it at the coil side.

Then swap the coil side.

Process of elimination by following the fault, if its not fuel or spark it has to be mechanical. Its cylinder specific so that helps trim down options.

As above... hopefully something faulty giving you grief and nothing more sinister.