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The mkiv Supra Owners Club

Where to adjust idling ?


Matti85

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After a lot of reading it seems BCC and change in idling after is a common thing, BCC is working as it should btw.

 

I don't think you read that on here. If you did I'd like to see the threads.

 

The idle is controlled by the ECU. If it's idling wrong, there is a problem. Shimming the throttle plate open does not fix this problem.

 

Is it some BCC that scales the entire airflow range down? That'd shaft your idle, and indeed your engine in short order.

 

-Ian

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Which BCC do you have? If its a TRL (known as the 'Thor' unit) then they have been known to cause problems. I had 4 of them qand they all messed the idle up, one of them even wouldnt ley the car start. I then fitted a Greddy BCC and all was good.

 

Just out of curiosity, how do you clean the idle control valve?

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Just to back up what's already been said, fitting a BCC shouldn't change the idle. A BCC 'should' only come into effect at high boost levels. Everything below should stay the same.

 

As Ian said, there are some nasty BCC's that re-scale the output from the MAP sensor so that the ECU never thinks it's reaching high boost. I'm still not convinced that it would have any effect on the idle, but if that's the case, change it for a decent one.

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Maybe the threads was about the Thor unit mine is Greedy, but dont say that BCC and idling problem dont exist, Chris just agreed that all of his 4 units messed up his idling, regardless if it was Thor, thats a BCC to.

 

Im curious to about how to clean the idle control valve, where is it located ?

 

I was told about adjust idling after BCC install from Scandinavian forums and expert. But have seen threads here to about idling probs after BCC install, don remember if they posted the how to solve the issue though, can digg up and repost them later.

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You can't really adjust the idle. The only way you could do it would be to wedge the throttle butterfly open a smidgeon, but that's a hell of a hack.

 

As has been said before, a correctly installed BCC that doesn't "fudge" the airflow figures, shouldn't effect the idle at all. It just doesn't work like that.

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but dont say that BCC and idling problem dont exist, Chris just agreed that all of his 4 units messed up his idling, regardless if it was Thor, thats a BCC to.

 

but the thor units were faulty and messing the idle up. A good unit shouldnt, unless you have a faulty unit or the dials inside the box are the wrong settings for you're car.

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Forgot to add, if you're determined to clean your idle solenoid nonetheless, you'll find it at the back of the inlet plenum. Near the bulkhead, on the side of the engine. It's the black round thing. When you take it off, you'll notice there is a one way valve between it and the plenum. Make sure you make a note of it's orientation.

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Which BCC do you have? If its a TRL (known as the 'Thor' unit) then they have been known to cause problems. I had 4 of them qand they all messed the idle up, one of them even wouldnt ley the car start. I then fitted a Greddy BCC and all was good.

 

Just out of curiosity, how do you clean the idle control valve?

 

I had exactly the same with 2x Thor units - car just wouldn't idle and ran really rough. I was even told by Pete at Thor / TRL that the 1st one I'd sent back had benchtested just fine and there was no problem with it! When I then sent the 2nd one back with the exact same problem I got a refund and ordered up a GReddy BCC - this worked absolutely perfectly and my idle was spot on. Those Thor units wasted endless hours of my and my Dad's time and completely ruined my perception of the quality of Thor / TRL electronic parts..... they were quite obviously defective yet I was told they checked out fine... :rolleyes:

 

I have since fitted a MAP2 ECU so had no need for the GReddy BCC any more and once again the car runs fine with no idle issues.

 

As people have said - you don't adjust the idle on these cars, the ECU will just readjust to compensate, you need to find the root cause of your poor idle. I'd start by checking all your vacumn lines, especially around the OEM map sensor. Failing that, try another BCC should the car run fine without it fitted.

 

Cheers,

 

Brian.

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I had exactly the same with 2x Thor units - car just wouldn't idle and ran really rough. I was even told by Pete at Thor / TRL that the 1st one I'd sent back had benchtested just fine and there was no problem with it! When I then sent the 2nd one back with the exact same problem I got a refund and ordered up a GReddy BCC - this worked absolutely perfectly and my idle was spot on. Those Thor units wasted endless hours of my and my Dad's time and completely ruined my perception of the quality of Thor / TRL electronic parts..... they were quite obviously defective yet I was told they checked out fine... :rolleyes:

 

I have since fitted a MAP2 ECU so had no need for the GReddy BCC any more and once again the car runs fine with no idle issues.

 

As people have said - you don't adjust the idle on these cars, the ECU will just readjust to compensate, you need to find the root cause of your poor idle. I'd start by checking all your vacumn lines, especially around the OEM map sensor. Failing that, try another BCC should the car run fine without it fitted.

 

Cheers,

 

Brian.

 

 

The guys at thor told me that they all worked fine when they tested them aswell. The wierd thing was is that all of 4 units produced slightly different idle problems. One would make the idle bounce up and down by 100rpm or so, another would make it idle really low to the point that the engine sounded as if it was going to stall and then they said they will sent me one out that they have tested and that it should work but that was the worst one, it wouldnt even let me turn the car over :blink: Like I said earlier they then gave me a Greddy unit and everything worked fine.

 

Allthough it did waste alot of my time and I wouldnt buy another thor unit again, the guys were very helpful trying to get the problem solved.

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He's not from Basingstoke is he?

 

Is this him?

 

http://i186.photobucket.com/albums/x50/dirrtydug/paulk.jpg

 

Is that meant to laugh about or to make me look like a fool ?

He built an 8 sec supra, and several 10 sec cars for customers, Ive now reason to doubt his words, maybe he found something you missed for 13 years on these cars.

 

Everything is possible, be happy for new knowledge insted of laughing at it. If their method works or not i dont know, ive got a new BCC and my problem is solved so i wont keep pursuing this.

But they obviously can adjust the idling (after reading several threads), i dont think they would do that and let the ECU readjust itself, maybe they got a diffrent method. Ive posted a question and will get back if i get answer.

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