Break up!

[Backlash2032]

I canNOT figure this out. I've had this break up for as long as I can remember.. From 5000 rpm to the rev limiter it breaks up. Badly.

MODS: Walbro 255, rebuilt 7mgte, stock turbo @ 11 psi of boost. Full front mount and 3 inch turbo back exhaust. I originally thought my coils were kicking the bucket, so I replaced them with the morganson COP setup.. Still does it. Rewired the CPS with a weatherpack connector, still does it. I've unhooked the TPS to see if it was screwing with the ECU, still does it. Checked and set airgaps in the CPS to .008", what the TSRM spec is, and it still does it. Replaced spark plugs, gapped to .028, still does it.

Now, here's the strange thing. Most people would say spark blow out.. Right? Well.. It can't be. A) I have coils that nearly double the output of the factory coils.. B) It's done it with the factory coils and this hotter coils, with no change between them. At all. and C) It does it at WOT free revving as well as under boost. It WONT, however, do it at part throttle revving to the limiter.

Another common thing someone might say is my walbro is out flowing my FPR.. In which case I respond... Why would it pull fine while the fuel demand is low (2000 rpm - 5000 rpm) and then start breaking up when fuel demand is higher? If anything it should be the exact opposite....

If you have any ideas, it would be greatly appreciated. I'm tired of losing to my buddies WRX when I should 100% wipe the floor with him...

Also, heres a video of what it's doing.

https://www.youtube.com/watch?v=8YOreS-MCRo&feature=youtu.be

 

[kdog1988]

I had a similar problem with mind it ended being that two of the wires going to the tps had rubbed together and shorting between the two

Sent from my LG-E739 using Tapatalk 2

 

[KKZ SupraMan]

Idle is supposed to be 650 rpm if I remember right do you have wideband to see if you are having bad fuel afr's I suggest wiring fuel pump to constant 12v instead of the stock variable voltage setup.its been a while sense I have put a stock ish supra on the dyno but i do t think they make much more power if any more over 5000 rpm I did notice on the first pull in your video you did hit the rev limiter is that maybe the brake up you are talking about

 

[Backlash2032]

I had a similar problem with mind it ended being that two of the wires going to the tps had rubbed together and shorting between the two

Sent from my LG-E739 using Tapatalk 2

I ohmed out the harness when i put it on literally 5000 miles ago, everything was fine.

Idle is supposed to be 650 rpm if I remember right do you have wideband to see if you are having bad fuel afr's I suggest wiring fuel pump to constant 12v instead of the stock variable voltage setup.its been a while sense I have put a stock ish supra on the dyno but i do t think they make much more power if any more over 5000 rpm I did notice on the first pull in your video you did hit the rev limiter is that maybe the brake up you are talking about

Its 750, and that wouldn't change anything. Where the issue is is where it would be at 12 volts anyway. And no.. The rev limiter is not the break up I was talking about....

 

[KKZ SupraMan]

Sorry just trying to help you out here but is seems like you have it all figured out then. I had that same problem on a customers supra couple years back it wasn't switching the pump to go fast mode lol I rewired pump before tune good as new. it makes it a lot easier to tune also afr's are not all over the place because of what the pump is trying to do different things and sorry about the idle rpm thing i am not really used to supra's idling that low most of the ones i deal with have a pretty high idle. p.s. I said I couldn't really remember.

 

[Backlash2032]

Sorry just trying to help you out here but is seems like you have it all figured out then. I had that same problem on a customers supra couple years back it wasn't switching the pump to go fast mode lol I rewired pump before tune good as new. it makes it a lot easier to tune also afr's are not all over the place because of what the pump is trying to do different things and sorry about the idle rpm thing i am not really used to supra's idling that low most of the ones i deal with have a pretty high idle. p.s. I said I couldn't really remember.

I will jumper the fuel pump resistor and see if it changes anything.

 

[Backlash2032]

Nope! No change.

 

[KKZ SupraMan]

Does it sound and feel like spark blow out or more like steady rpm climb just loss of power wiped cams mite be the cause is it a fresh build if not how many miles on it.are you hearing any valve train noises it seems like you have taken alot out of the equation here with what you have already done fuel filter been changed sense this problem has occurred maybe clogged updo you have a way to check afr's also are you running a catalytic convertor if so are you getting a rotten egg smell after you get on it for a whille.a little more info on what all is done to the car would help

 

[Backlash2032]

It's not spark blowout. There's no reason for it to blow out at zero boost. And it's done it with two different sets of cams... And it doesn't do it at part throttle but does do it at full throttle.. No cats, and i have no idea last time the fuel filter was changed. Probably the factory one.. Car only has 110k miles on it.

 

[KKZ SupraMan]

It's not spark blowout. There's no reason for it to blow out at zero boost. And it's done it with two different sets of cams... And it doesn't do it at part throttle but does do it at full throttle.. No cats, and i have no idea last time the fuel filter was changed. Probably the factory one.. Car only has 110k miles on it.

I would change the filter just because no harm in that next step test and calabration tps and timing check and set after.

 

[Backlash2032]

No point in doing either of those. It's not fuel delivery. If that was the case then it would break up at full throttle, free revving, and then break up a shit load worse under boost. The tps is calibrated. Not that it really matters. Disconnecting the TPS doesn't change it.

 

[supraguy@aol]

Ohm your plug wires.

Oops- edit: I see you went to DG500 setup, which would negate that possibility.

Are the spark plug areas completely dry of water?

 

[Backlash2032]

Yes sir they are.

 

[KKZ SupraMan]

No point in doing either of those. It's not fuel delivery. If that was the case then it would break up at full throttle, free revving, and then break up a shit load worse under boost. The tps is calibrated. Not that it really matters. Disconnecting the TPS doesn't change it.

again looks like you have it figured again then just trying to help you again good luck to you my good sir. O by the way if ran with tps disconnected you should run into other problems but what do I know I am only get paid to do this every day and have been doing supra's for only 15+ years

 

[Backlash2032]

Well if you posted something that made sense then maybe I'd believe the part about 15 years of experience.

 

[kdog1988]

We're all on here just trying to help you out man if you don't want our advise don't ask for it.

Sent from my LG-E739 using Tapatalk 2

 

[3p141592654]

Do you have a wideband to monitor the A/F ratio? You need more diagnostics at this point IMHO.

 

[Backlash2032]

No i don't. Planning on picking one up with my next paycheck. Any idea on what to check? I've basically ruled out what I would assume would cause it..

 

[KKZ SupraMan]

Do you have a wideband to monitor the A/F ratio? You need more diagnostics at this point IMHO.

he has already stated that I he is not willing to diag the car he wants us to tell him what it needs without us asking questions it's people like this guy that keeps people like me in business bring the car to ohio I will diag it and tell you what it needs for you to try to fix it yourself and and mess It up more then bring it back to me fix god I hate u uneducated people like this pull up the tsrm and start testing parts and don't bash people trying to help you that will get you no where

 

[Backlash2032]

Kkz, I'd really appreciate if you would stop posting in this thread. you're just cluttering it up with nonsense.