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The mkiv Supra Owners Club

Missing under boost....and now on light throttle.


bigbloodyturbo

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Well this may be the last thread I write looking for help as i'm about to pull the plug on this car. Putting a single on the car was VERY good fun, however the actually getting it going bit is driving me mental.

 

Right now the car was mapped with a syvecs however suffered from a igntion break up while on boost. It also seemed to have high egt's but as discussed elsewhere on here that is prob down to a crappy defi gauge. Well today I just swapped the coilpacks over to another set i bought from a member and the miss under boost is still there however when filling it up with petrol and driving to my parents house the car has now developed a severe miss on light throttle/cruise. When I got out and lifted the bonnet it seemed very hot, I couldn't even unscrew the oil cap as it was so hot.

 

My question is could the cylinder head being REALLY hot cook the coils and cause missfire's? has anyoen experienced this?

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Did you swap clips as well as the coilpacks?

 

I changed the clips just before I went single as they were all brittle. They've been on the car for probably 2 years now but very few actual miles as the car was sorned while i worked on it in my spare time.

 

- - - Updated - - -

 

When you went single did you change the plugs to a colder grade?

 

Yeah i'm on 7's right now. Going to try my iridium 8's next.

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I just spoke with Ryan and it looks like the reason for my miss under boost is most likely fuel or ignition cut due to me using the stock map sensor instead of the one that came with the syvecs so atleast thats something. However this miss at light throttle and cruise(and its quite an agressive miss) is now caused me to have to stay at my parents for the night as i cant get bloody home.

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Looks like you might be needing a new 02 Sensor, if you have not already relaced it then i would definately be looking to replacing it now. I had some serious missfiring on my old NA-TT and after changing all the clips and coils + Plugs i still had the miss, after changing out the dodgy 02 Sensor she was purring like a kitten.

 

Any reason why you did not get Ryan to MAP your Syvecs?

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Looks like you might be needing a new 02 Sensor, if you have not already relaced it then i would definately be looking to replacing it now. I had some serious missfiring on my old NA-TT and after changing all the clips and coils + Plugs i still had the miss, after changing out the dodgy 02 Sensor she was purring like a kitten.

 

Any reason why you did not get Ryan to MAP your Syvecs?

 

Just bought and fitted a brand new toyota o2 sensor about 2 months ago. I didn't get ryan to map it for a couple of reasons. firstly I was retarded, secondly he is really far away from me, and thirdly I work overseas a lot and it was hard enough arranging the logistics of getting it mapped 25miles away from me never mind the other end of the country:-(

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Apologies if going over old ground again. But has the car ever run perfectly since you changed the coil pack clips?

Only mention as it's worth double checking the wires are the correct way round on the coil pack, especially number 5 as the wires are similarly colored. The black wire with the brown/orange trace on it goes to the clip side.

Again, sorry if I'm teaching you to suck eggs here.

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Apologies if going over old ground again. But has the car ever run perfectly since you changed the coil pack clips?

Only mention as it's worth double checking the wires are the correct way round on the coil pack, especially number 5 as the wires are similarly colored. The black wire with the brown/orange trace on it goes to the clip side.

Again, sorry if I'm teaching you to suck eggs here.

 

No need for apologies mate, at this point I'm open to anything, the missus is ready to put her little undersized foot down on this one and I cant blame her.

 

The car ran absolutely beautifully on the stock ecu once the single turbo conversion was finished. Drove like stock and other than being a little rich it was perfect. It has developed this miss on part throttle today, it started off every now and then when cruising but then after starting her after filling up with petrol it was all downhill.

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