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My 5 cylinder Supra :-(


Steve Cargill

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I had a bit of a problem a TSCIII on Sunday......

 

Prior to that on good days it would hesitate a bit around 17-18lbs (just like it did about 15lbs with the original platinum plugs in). I was told the plugs were fine and it was probably the VSV keeping the boost down.

 

On my 1st run it was doing that for about the last 1/2 of the track with the boost getting to 19psi. After the run the tickover was lumpy, but seemed OK.

 

On the second run it was very much down on power (10lbs boost and rough) so I aborted and used it as a speedo check :)

 

Had a good look at it (thanks Alex) and concluded all the big bits were still in place, phew.

 

Changed the plugs when I got home (not easy under a streetlamp), starting at the front and becoming a little worried that it was something else after taking out 4 perfect plugs.

 

Then...... spot the difference...

 

New plugs in, gapped to .8mm and it was running well today, still a bit lumpy at idle though.

 

These are BKR7E's and had been in for about 7k miles, taken out and checked about 1k ago.

burnplugs.jpg

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I may be wrong here, but that looks like it's gotten very hot and just melted. ie you have had an overboost or a mixture problem sometime in the last 1000 miles! I don't think plugs just melt on an engine that's running right - I'd get to the bottom of this if I were you!

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Originally posted by Steve Cargill

I had a bit of a problem a TSCIII on Sunday......

 

Prior to that on good days it would hesitate a bit around 17-18lbs (just like it did about 15lbs with the original platinum plugs in). I was told the plugs were fine and it was probably the VSV keeping the boost down.

 

On my 1st run it was doing that for about the last 1/2 of the track with the boost getting to 19psi. After the run the tickover was lumpy, but seemed OK.

 

On the second run it was very much down on power (10lbs boost and rough) so I aborted and used it as a speedo check :)

 

Had a good look at it (thanks Alex) and concluded all the big bits were still in place, phew.

 

Changed the plugs when I got home (not easy under a streetlamp), starting at the front and becoming a little worried that it was something else after taking out 4 perfect plugs.

 

Then...... spot the difference...

 

New plugs in, gapped to .8mm and it was running well today, still a bit lumpy at idle though.

 

These are BKR7E's and had been in for about 7k miles, taken out and checked about 1k ago.

 

When that happens you are // that close to a melted piston or detonation it's untrue. Too hot, far too hot, and cooler plugs may not be enough. Needs the fuelling checking. Hows the IC? Are the fins knackered? That won't help (Caveat, I sell replacement IC's, but a knackered one WILL give excess temps). It needs sorting before any more serious damage occurs, if it hasn't already. If you know a vet ask to borrow his endoscope and have a look at the piton tops.

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I/C fins are OK, they are fragile but all there.

 

It's running OK now, apart from the idle was lumpy this morning but apart from that was running very well today so it looks like the turbos have survived....

 

I'll take it easy and get it booked in again soon for a checkup :( and take it easy until then.

 

The other 5 plugs all look OK, this was no. 5 that went. Would that imply a problem with an injector, or it just happened to be that one that went.

 

Time for an EGT meter?

 

I hope there's no major damage, I've had enough of that in the past - I was hoping to keep reliability by keeping the boost down to sensible levels.

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On Sunday, I was pretty much driving by the EGT gauge.

 

I was running 1.35 on the quater mile, at which time, the gauge was showing 925 and climbing slowly.

I then turned the BC down a tad to run at 1.2 for the rest of the run. The temps were running at just under 900 by the end of the run.

 

Best I'd better have a look at my plugs I think...

 

Hopefully this is the extent of your problems Steve.

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One of the reasons why we never use any plug other than the HKS ones.....

 

I'm not saying the plug was the prime cause but it could easily have been a nasty secondary one. If it had of let go any more then you may well of been looking at an engine rebuild. Personally I would be looking skyward and thanking someone right now.

 

Using a plug that won't fall apart in the first place will at least move the goalposts a little. It's one less thing to think about whilst you are flat out checking your EGT's and lambda.

 

We've run HKS plugs up to 1150 deg C EGT before with no problems whatsover. I don't advise it but like I was saying..goalposts moving...

 

Regards

 

Nathan

TDI PLC

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Adam - we're not sure yet, but we think that either the piston has come apart, or the big or little end on that cylinder has failed, hammering the piston into the head, all as a result of oil pump failure.

 

Not too much of a problem as a spare engine is available to the guy in question, just a case of swapping over all the bits...

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