[Supra93TT]

It is most noticeable through second gear. and also it makes a different sound out of the exhaust when it does this almost like a popping sound and most of the power of the second turbo never fully kicks in because each time it tries, it jolts back as if hitting some kind of boost barrier. What is the problem and what do i need to do to fix this? Any help would be appreciated. Thanks.
Zach Payne
P.S. my supra is a 6 speed. modifications include, greddy P.E. exhaust, Greddy BCC, K&N intake. and a EVC III boost controller which only reaches .9 Bar max since it doesn't work well with sequential turbo's, but its never given me any problems before so i don't think its the boost controller.

 

[Joose]

Sounds like fuel cut but you say you have a BCC so im clueless after that.


By the way how do you like your exhaust? I was thinking of picking that up

 

[Supra93TT]

Sounds like fuel cut but you say you have a BCC so im clueless after that.
By the way how do you like your exhaust? I was thinking of picking that up

I love the power extreme exhaust. at idle, the sound has a very nice low deep rumble. And isn't loud at all while driving normal but gets quite a bit louder if you are racing. its a good choice. Do you think my installer could have possibly installed my BCC incorrectly??

Zach

 

[Supra-Holic]

What gap are your spark plugs? You could be missing, or maybe not because I had NGK 3330's gapped @.034 and I would miss at 18psi and it feels like what you described. But if may not be that because I was still hitting high boost.

 

[Supra93TT]

What gap are your spark plugs? You could be missing, or maybe not because I had NGK 3330's gapped @.034 and I would miss at 18psi and it feels like what you described. But if may not be that because I was still hitting high boost.

Not sure what my spark plugs are gapped at. Can i find out myself without being a mechanic? If the spark plugs i have are still the originals, do they need to be replaced when you modify your car? Thanks,
Zach

 

[SupraDreamer]

Sounds alot like the problem I was having and it turned out to be my plugs. I would notice it in every gear except first when the second turbo would come on. I regapped my plugs down to .030 and it works beautifully now. Believe me I tried next to everything to figure out the problem and it sounds like it may be the same. All you have to do is get a spark plug gapping gauge and take your spark plugs out and see what the gap is out. You may want to just throw a new set in there if you don't know when they were last changed. Hope you figure it out.

 

[Chappy]

its been along time since i checked but there use to be a bcc install article on the mkiv site (if you think it is installed wrong). it mentions how to tune the bcc too.

 

[Supra-Holic]

I bet it's the plugs if you don't know what there're gapped at. I changed from the NGK's to the denso's it had on there because when you have the NGK's gapped at .030 it idles rough. So I have the denso's on their at .030 and hitting 19 psi with no probs.
You don't have to be a mechanic to take the plugs out, but if its your first time doing it. I would set aside some time cuz its a real bitch cuz you have to lean over the engine a lot.

 

[Supra93TT]

Sounds alot like the problem I was having and it turned out to be my plugs. I would notice it in every gear except first when the second turbo would come on. I regapped my plugs down to .030 and it works beautifully now. Believe me I tried next to everything to figure out the problem and it sounds like it may be the same. All you have to do is get a spark plug gapping gauge and take your spark plugs out and see what the gap is out. You may want to just throw a new set in there if you don't know when they were last changed. Hope you figure it out.

Yeah, thats exactly it. i don't have it happen in first gear either but every other gear it does so now that you said that i'm sure thats what the problem has to be.. Thankyou for your help.
I assume i can buy this guage at an auto parts store so this weekend i'll find some time.
Zach

 

[Supra93TT]

its been along time since i checked but there use to be a bcc install article on the mkiv site (if you think it is installed wrong). it mentions how to tune the bcc too.

True. forgot about that. Hopefully the spark plugs will solve everything. I think it will.

 

[Supra93TT]

I bet it's the plugs if you don't know what there're gapped at. I changed from the NGK's to the denso's it had on there because when you have the NGK's gapped at .030 it idles rough. So I have the denso's on their at .030 and hitting 19 psi with no probs.
You don't have to be a mechanic to take the plugs out, but if its your first time doing it. I would set aside some time cuz its a real bitch cuz you have to lean over the engine a lot.

Yeah, i might as well get new spark plugs anyways so i'll look into those denso's that work well for you. Thanks for the info. Did you have a boost controller problem before changing the stock plugs in terms of not being able to reach your desired boost? This whole time i've though my HKS EVC III was crap and maybe it still is but maybe the spark plugs would fix everything....
Zach

 

[Mike Hughes]

Plugs or BCC.

This is almost definitely your spark plugs or BCC. Either way, it's related to the amount of boost you're running, since you're only experiencing problems after first gear (less boost in that gear).

Go to Sears or radio shack and get a $15 multimeter. Go to mkiv.com and tune the BCC to the exact voltage for your car; it's not hard... once you set it right, you never have to touch it again. It's a lot better than driving your car a bunch of times until you stop hitting fuel cut. But if you say you're only boosting 0.9kg/cm2, your BCC shouldn't be the problem.

Before you voltage tune your BCC again, swap out your plugs or gap them a little lower. NGK 3330s should be fine for 0.9 bar of boost. (By the way, fix your boost controller; 0.9 is like stock boost... yuck.)

 

[Supra93TT]

Re: Plugs or BCC.

This is almost definitely your spark plugs or BCC. Either way, it's related to the amount of boost you're running, since you're only experiencing problems after first gear (less boost in that gear).

Go to Sears or radio shack and get a $15 multimeter. Go to mkiv.com and tune the BCC to the exact voltage for your car; it's not hard... once you set it right, you never have to touch it again. It's a lot better than driving your car a bunch of times until you stop hitting fuel cut. But if you say you're only boosting 0.9kg/cm2, your BCC shouldn't be the problem.

Before you voltage tune your BCC again, swap out your plugs or gap them a little lower. NGK 3330s should be fine for 0.9 bar of boost. (By the way, fix your boost controller; 0.9 is like stock boost... yuck.)

I know for a fact my BCC was preset to the voltage on the directions but didn't realize that it varies with each car. So that could be a problem for sure. Oh, i've never been happy with .9 bar. i've always had my boost controller set at 1.2 and tried many many different ways of achieving that boost with no luck and still only getting .9..... do you think after i do the maintenence you described on the plugs and then the BCC that this could also allow my boost controller to function properly? Thankyou very much for your reply.
Zach

 

[watermnp]

If your check engine light (the big "!" in the middle) comes on when it does this, then yes, you're hitting fuel cut, and you need to fix your BCC. This should be pretty obvious, though.

If it's just sputtering through the powerband, though, then you're having problems. Fix your plugs, make sure you don't have bad gas in the car, etc. You'll smooth it out eventually (gas and plugs are the culprit there 90% of the time).

-Pete

 

[namahs]

I am having almost the same problem, It sputters and spits and the blowoff opens and closes rapidly. It happens the most on the highway in 4th, 5th and 6th. I can keep the gas pedal moving to the floor quickly and avoid it but I have to take the engine to red line and then slam the clutch in and shift and do it again to avoid the jerking. I can cruise down the highway at 4000 to 5000 rpm with 8-10 psi of boost in 5th gear and the car will be fine but if I give it any more gas the engine jerks and the blowoff goes crazy. Will tuning and plugs get rid of this?

 

[Supra93TT]

If your check engine light (the big "!" in the middle) comes on when it does this, then yes, you're hitting fuel cut, and you need to fix your BCC. This should be pretty obvious, though.

If it's just sputtering through the powerband, though, then you're having problems. Fix your plugs, make sure you don't have bad gas in the car, etc. You'll smooth it out eventually (gas and plugs are the culprit there 90% of the time).

-Pete

Yep, theres no "!" turning on. So i hopefully should have it fixed by the weekend. Thanks,
Zach