The dreaded Breakup/ Misfire under boost..[RESOLVED]

Ponderthis · May 23, 2018

beefcake said:
there is a difference between misfire and breakup.

if it's breaking up, i would double check the plug gap,

Never have had issues @ .028 and this car has had boost for almost a year and seen upwards of 15psi at times... it's currently turned down to 10 while I try and adress the issue.

Tommy V · May 23, 2018

Any of the fuel parts u mentioned would show up in the fuel trims,especially when breaking up,so if your a/f and trims are good i doubt that is your problem.I also think if it was a bad coil u would be getting a misfire but its also possible not too either.If u can get a log i will give u my email to send it to me.

Slamdcoop0428 · May 23, 2018

Welcome to modded cars..

Ponderthis · May 23, 2018

Swapped coils from one side to another to see if any change in log... Here it is.. https://we.tl/Izj6pgojA1

kodypiccirilli · May 23, 2018

I’m interested in your solution because I am having the same issue with my twin turbo v6 around 9-10psi on E85 and 93. I read misfire in cylinder 1 and then realized I had a cracked coil pack but have since swapped coil packs and still has the same issue

I’m using NGK 6510 .43”. My next step will be to go ~.35” gap and hope it solves

Ponderthis · May 23, 2018

Decided to swap the injectors from one side to another to see if changes the issue to the other bank, While I was in there I went ahead and installed my 18' Intake and IMRC Lockouts to cross that possible issue off the list also!

Dennisn · May 23, 2018

tsloms said:
I had been running 17psi of boost with my Whipple previously and the car ran perfect.

Now I'm seeing the same thing with my newly added Boostworks kit with Comp 6062's. Any boost over 10psi or so will cause terrible misfiring. I've seen different cylinders throw a code but I'm seeing P0300 the most for random misfire.

Lund and Boostworks told me I needed to run stronger valvesprings so I switched to the recommended Livernois ones that Boostworks said to run. I'm still seeing practically the same misifiring over 10-12psi of Boost. My 6510 plugs are also gapped at .028".

Lund says they can see in my logs that the exhaust cam is losing control yet due to valve float even with the new springs and I need to reduce exhaust backpressure. I'm trying to order the upgraded Boostworks headers to replace my modified stock headers now.

I'm in the same boat as you. Does the Hellion kit have custom good flowing headers?

Did they shim the springs? And if so correctly??? I had the livernois springs installed and the guy didn't shim em. Needless to say I had to completely redo the springs. Second time in I put drop in springs that didn't require shimming. Fuck those livernois springs. They are barely better than the boss springs.

tsloms · May 23, 2018

Dennisn said:
Did they shim the springs? And if so correctly??? I had the livernois springs installed and the guy didn't shim em. Needless to say I had to completely redo the springs. Second time in I put drop in springs that didn't require shimming. Fuck those livernois springs. They are barely better than the boss springs.

I installed them myself and they said they didn’t need to be shimmed but would be good to 20psi of boost. I tested tonight and I can run 11psi just fine but at 12psi it starts to break up. It’s really feels the exact same as the stock springs were.

What kind of springs did you go with? I hear the PAC 1234x springs are really nice. Livernois told me the ones I got are just a step below the 1234x’s but still made by PAC.

Dennisn · May 23, 2018

Livernois only sells one spring for the coyote and I can tell you they need to be shimmed. Take em out and throw them in the garbage. Call Tim at Mpr, he will set you up with the correct springs that are true drop in springs.

tsloms · May 23, 2018

Dennisn said:
Livernois only sells one spring for the coyote and I can tell you they need to be shimmed. Take em out and throw them in the garbage. Call Tim at Mpr, he will set you up with the correct springs that are true drop in springs.

How much boost are you able to run on his springs? If they handle the boost I’ll be sending these right back to Livernois.

Dennisn · May 23, 2018

tsloms said:
How much boost are you able to run on his springs? If they handle the boost I’ll be sending these right back to Livernois.

I'm only running 15-16 lbs. Tim told me when I bought them they are the stiffest spring you can run and retain vct. Should be able to run 20 lbs I would think no problem.

Dude I feel your pain. I did all that work thinking I was doing it right and could not have been any wronged.

While your in there I'd stud the heads. That'll be the next thing. Start lifting the heads under boost.

tsloms · May 23, 2018

Dennisn said:
I'm only running 15-16 lbs. Tim told me when I bought them they are the stiffest spring you can run and retain vct. Should be able to run 20 lbs I would think no problem.

Dude I feel your pain. I did all that work thinking I was doing it right and could not have been any wronged.

While your in there I'd stud the heads. That'll be the next thing. Start lifting the heads under boost.

To the OP I didn’t mean to crap on your thread. Just hoping we can all get some insight to this issue together.

I’ll call him tomorrow. I stopped by their shop a couple months ago and chatted with Tim for a couple hours. Super nice guy and willing to help out.

I did the studs when I was in last time actually. With the 17psi from the Whipple my heads were seeping a touch of coolant in the rear. Lol

Ponderthis · May 24, 2018

Welp after breaking down and pulling my brand new as of 2 days ago NGK plugs to do a compression test I found 3 of the 4 plugs on bank 2 had cracks in the porcelain! Still cannot believe it and definitely a first for me.. car runs great with good plugs.

pwny · May 24, 2018

Nothing wrong with just buying (or warrantying) a new set of plugs. That's a hell of a lot cheaper than what it could of been. So... Does this count for TBR's suggestion of spark blow out? :lol: Glad it's resolved though.

Crackerjack17 · May 24, 2018

Damn. How tight were you tightening them down? You think it was install issue or defect?

The dreaded Breakup/ Misfire under boost..[RESOLVED]

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