Car is breaking up when I stab the throttle

01yellercobra

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Depending on boost and fuel type it might be worth stepping down a heat range. I switched to the BR7EF's a while ago and they've been treating me good. My gap is .028" at 20psi.
 

olympic

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The only thing that jumps out at me from that last log is the fuel pump duty cycle. You would think it should show 100% all the time with a return fuel system?

Battery voltage looks good, MAF appears to be working. Only other parameter I'd like to see is "pressure drop across injectors", see if you're losing fuel pressure somewhere.
 

termcobra281

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For some reason I would be concerned with the fuel injectors at this point. Did you check the fuel filter? Sometimes its the little stuff that gets you. What injectors are you running?
 

2001Bullitt

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Sounds exactly like the issue I’m chasing as well with my Turbocharged Bullitt. Thing was a beast for like 2 years after I built the motor in 2015 and had it at 14psi, 509/518 numbers. After about 2 years it started breaking up just like yours, cutting out and backfiring. I recently installed twin 340s and a return system, new 80lb injectors, oem cam and crank sensors, oem coils, new TR6 gapped at .028 (per my very reputable local tuner). Retuned it at 15.6psi and it made 604/626. Did pop a few times after he let off on the dyno, but then after some tweaking it was fine. But it’s still doing the same thing on the street lol… driving me nuts just as I assume yours is. He told me I may need to check the reluctor ring behind the timing cover to see if the keyway is worn out, it’s the only thing I reused during the engine build.. im lost as well and about to just give up hope and let it rot in the driveway
 

Boostedsvt3660

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Well at this point I think I am going to pull the motor and check timing. It was the only other thing touched on this car and has a 3 degree advance. I'm wondering if something moved and timing is off.
 

Boostedsvt3660

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I want to bring this back and give some insight for anyone that has been helping with this issue.

I ended up switching to e85 and used his e85 tune and car was alot better. No idea what changed there. Aside from some small bugs this car made a crazy amount of power for what it is. Only issues on this tune was idle won't go under 1100 and after wot the car will not return to idle, it will just die out as rpms return.

Idle issue is better as I installed a dowel in the IAC tube to restrict air and he Is going to take some out in the tune. Apparently this is very common with the crusher setups.
 

Boostedsvt3660

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Worked with him tonight on the tune and still cannot find the cause of break up under 2k rpm and the car dies after wot.

Still trying to figure this part out. The car pegs on the af gauge to 18 and then to 10 as it stumbles. We keep checking over and over for boost/vac leaks with no issues.
 

BlckBox04

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Did you try changing to a cooler plug or even a different gap?
 

Boostedsvt3660

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Yea I went down a heat and closed gap to .22. I can send a video of the issue. It will not allow me to add it.

It's odd being the car after 2k made way more power than I am comfortable with, but under 2k she bucks bad.
 

badcobra

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This is what a wobbled out keyway on your trigger wheel looks like. It causes all kinds of timing problems. How it happens is many guys pull their balancer on with the crank bolt and the balancer doesn't seat all the way on this is the result. Make sure you are using a balancer install tool and NOT the bolt to pull your balancer on. Use red loctite on the bolt also.

cRrNvagl.jpg
 

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