1jz cutting out

[Little_Matt]

So my 1jz is cutting out as soon as it sees 9-10lbs of boost in 1-3 gears and stumbles in 4th and is just fine in 5th. I have a Stinger EMS standalone so I know its not boost cut. It seems like the faster it hits boost the harder it cuts. It goes a little lean when it cuts. My car was tuned on a dyno by a professional tuner.

Here is my mod list.
Stinger EMS
Aeromotive FPR
Supra TT fuel pump
2.5'' to 3'' Y pipe
3'' intercooler and pipe
3'' straight pipe exhaust
14lbs of boost

Any help is greatly appreciated.

 

[mkiiichip]

Coils have cracks under the boots?

 

[Little_Matt]

I havent checked under the boots. I will do that this evening when I get home. I have also replaced plugs 3 times.

Also when free reving it there is no issues and revs just fine. Sometimes I can hit all my gears and it wont have any issues. But thats a rare occasion.

 

[te72]

Have you checked the gap on your plugs before putting them in? You'd be surprised how far the range of pre-gapped plugs can be...

 

[Little_Matt]

Yes the plug gap is .022".

 

[te72]

Did you get around to checking out your coils then? That's the other big electrical gremlin I've seen pop up a lot with 1j's.

 

[Little_Matt]

Yes I did last night and 3 were cracked under the boots. I epoxied them and wrapped all 6 up with electrical tape good. It now just stumbles instead of cutting. So in other words it got better. I'm goin to change my plugs tonight and see of that takes care of the rest. I'm pretty sure there fouled out.

 

[Little_Matt]

So I installed new plugs and its still breaking up/missing at 9-10lbs of boost. I think it could be I have a bad coil or 2 or 3. What do you guys think?

 

[te72]

Do you have access to another set of known working coils? If you do and you still have the problem, I'd be looking at possibly your ignition tuning. Try to track down some verified good coils first though.

Edit: I just noticed you said you installed NEW coils. "New" new, or new-to-you new? Hmm... Can you verify that the ignitor is working? I don't think it would run as well as it does if it weren't though.

 

[Little_Matt]

I made an error. I installed new plugs not coils. I ordered 6 brand new coils from Toyota this morning and I will have them Friday.

 

[Little_Matt]

I installed 6 brand new coils and plugs and same thing. I'm lost.

 

[IBoughtASupra]

Since you have a Stinger, how are all the sensors reading? Coils are usually the problem and I you installed new ones, so that should be fine.

I highly believe it is in your map. When you say stumble, you mean it stalls or is it more like a misfire?

Call up your tuner and take it on the dyno and let him log data and he will be able to find or get a hint at what the problem is.

Are you using a stock map sensor or a GM 3Bar?

 

[Little_Matt]

I did a log pull and when it breaks up the temp goes from 175 to 220 and back down and the voltage and air temp go funky also. Im using the built in MAP sensor in the stinger setup. Is it possible I am getting interference from someplace?

 

[IBoughtASupra]

Use the stock Map sensor. Are you using electric fans? If so, get a 2JZ- GTE fan clutch and 2JZ-GE blade.

 

[Little_Matt]

I have a 2j pump and electric fans. I am getting a false reading when its stumbles. Im not really at 220 degrees. When I meant that the temp goes up and down I mean that it is bouncing around like 1 sec its 175 and 1 sec later its 220 and back down and back up.

 

[IBoughtASupra]

How are your engine grounds? You should have a cable that goes to the engine block to the negative battery terminal.

Also, how is your alternator? Can you have your laptop on and log voltage of your alternator as you are doing a pull?

Sounds like you have a electrical issues if the temperature gauge is bouncing back and fourth. Check the ground and charging rate and report back.

 

[suprayo]

Have you checked your coolant temp sensor?

 

[Little_Matt]

Everything is charging good and the grounds are good. Hell I added another good ground but still no change. I also replaced my coolant temp sensor and again no change. Im lost.