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The mkiv Supra Owners Club

Misfire question?


Crouch

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So here's my problem that i need help with people.

 

I have a problem with my car when i come on boost it misfires, No big deal i know the plugs are needing changed but of course i've read how bad coil packs or clips cause the same problem and they look like they've been in there a long time (I've owned the car just under 2yrs and the car came with the ones in it). Now just for peace of mind i looked up info on here about the HKS Twin spark amp. This is where i think i may also have a problem the info stated that the led should pulse with the ignition! How often and how bright? i ask because my led seems dull all the time and just gets a little brighter when you rev the engine is there a video/demo of how it should look? can this be tested in any way?

 

I don't want to replace plugs,coils and clips and find the twin spark amp thingy's goosed and i've blown over 400 quid for nothing!

 

All help and input welcome as i need this sorted as the cars for sale to fund the new one i'm building but i can't sell it if it does'nt work.

 

Thanks Gary Crouch

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Stock turbos? What boost are you running?

 

When a coil pack gives up the ghost it tends to stop firing on that cylinder completely.

 

The usual causes of misfire at higher boost are worn/wrong heat range/wrongly gapped plugs or broken coil pack connectors, both are relatively cheap and simple to replace, so start there.

 

If you still have a misfire after replacing these then I would remove the HKS Twin Spark to see if this is causing the issue. I'd also clean and secure all the earth points and battery terminals.

 

FAQ - Spark Plugs

 

How to refurbish coil pack connectors

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Thanks for the reply Mr Nic to answer your questions.

 

The car has a GT4088r single and i believe that the car should run about 612hp @ 1.6bar (although i've never seen it go past 1bar on high and 0.3bar on low boost.) The car done a 1000 mile journey with no problem last weekend all the way to the south east of Germany but when i took it out i try'd to hit boost and it started missing really bad. If the HKS twin spark turns out to be faulty i was wondering Mr Whiffin does coil packs 10% better than normal OE ones can i use them without the twin spark amp and be fine?

 

I'll order the plugs (they don't stock iridium ones where i checked) and try them first and the clips will follow if the problem persists!

 

Many thanks Gary Crouch

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I was presuming you were running stock turbos and ECU.

 

If you're still having problems after a spark plug and coil pack connector change, I would get the car back to whoever mapped it and get them to check it.

 

Stock coil packs should be fine without the HKS Twin Power.

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The car I believe was last mapped at TDI the problem is that the car is in the south east of Germany with me! I don't know any where near here that even has a rolling road.

 

Any way after checking 5 different shops i finally found one that can atleast order the NGK plugs from the part no in the link Mr Nic gave but firstly it does'nt sat they are Iridium and it says that they are for LPG cars does this sound right?? I started to wonder if they are correct ones when he said that they are 11 Euro each!..does this amount seem right with the costs in the UK?

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