I have a 08 T/C with 50k miles and recently it has been having problems where it misfires at high rpm's on my trifecta tune at 24 psi. Current mods are tntake, catless downpipe, exhaust and Trifecta tune on 24 lbs.

I am only seeing misfires on cyl 1 and 2 so I changed the coil packs on 1 and 2 over to 3 and 4 but still had misfires on 1 and 2, none on 3 and 4 so that ruled out the coil packs. I put in new NGK spark plugs and gaped them at .028 and was still having issues. So I replaced my injector seals on the injectors because that seemed like the current fix for the high rpm high boost "popcorn" sounding misfire. After I changed them out it is still misfiring.

When I had the manifold off the valves looked fine and I also cleaned off the tips of the injectors. I also went back to an older tune I had but still the same issues, I have also checked the grounds on the car and I have done a compression test and it was fine all all cyl's.

So right now I'm out of ideas to what to check any ideas would be greatly appreciated.

 

Injection window misfire.

 

Yup and possibly valve coking from DI

 

Is that possible that that can be a problem? I haven't changed anything on on car and have been running the same tune for 6 months until this problem started happening. The injection windows misfire is tuning related right?

 

Coked valves OR you have clogged injectors, I do but my car is currently being worked on, the body, heavily, the frame atleast.

 

I've been chasing down a misfire issue again as well. I run trifecta 24 psi e47. Swapped coils, ran boiled distilled water and seafoam (biggest smoke cloud ever this time!), regapped plugs .028, replaced o2 sensor, cleaned maf and map.

Car was running great during the summer until it got colder, but even in the summer if I didn't let the oil get to temp it would misfire a bit; now that its 30-40 degrees colder, it misfires a lot when tune is engaged, but will occasionally pull clean if it is good and hot 190+. I've noticed if I ease into boost it will not misfire as much. With the tune disengaged it pulls clean at 13-15 psi.

This has been a recurring problem for the past few years when it gets cold. Now I'm convinced it's the tune after you mentioned this!

I have a coolant leak that is letting air into the system and a small exhaust leak after the o2 that I intend to fix tomorrow.....

 

Yes. Colder denser air coupled with how rich Vince tunes is the perfect recipe for injection window misfire.

 

Yup. Wheres the like button!

 

Thanks for the advice! Emailed Vince to get a leaner version of the tune.

 

I run like 11.8 to 12.2 lol.

 

Way too rich!!

 

The symptoms my car has to yours are nearly identical. This is the first winter I have had to tune on as well.

 

I'm on trifecta e47 and around 12.3-12.4 AFR WOT(I know, still rich) spiking 26psi at ~33-3400rpm. Car only runs in altitudes 950-1200 ft......No such problem here and I've been boostin allll winter when roads allowed

And I didn't know you guys were running gaps all the way down to .028, that's seems pretty tight. I'm at .032

 

Good luck, I haven't been able to get a hold of him for a while.

 

Got a hold of Vince after a min, he looked at datalogs and all appeared good: hpfp, maf and map readings, etc.

I read about problem solved with replacement of spark plug boots...whatcha know playas

Rubber in my coil boots had deteriorated and was caught in the springs, as well as dielectric grease baked onto springs from me putting a dab almost everytime I changed plugs. I sprayed MAF cleaner in boots and let it sit, then scrapped away the mess in the springs, reapplied a sensible yet masculine coating of dielectric grease on the exterior of boots and ITS FIXED!!!!!!!!!!!!!!RAPED APE status again WOOT!!! THANK GOD!

Next step was a compression test, blown injector seals and valve gunk can cause similar.

 

Forgot to mention fresh plugs as well

 

Edit: I double checked and found I'm must be dyslexic lol. I'm actually closer to high 12s down low and 13.3 up top NOT 12.3 my bad

Awesome, glad u got it fixed.

 

This is interesting because I posted about an issue exactly like this a few months ago. I contacted trifecta and they pretty much told me to get bent and that I should go replace everything in my engine bay.

 

What confuses me is after I clear my CEL codes I don't have this misfire issue, the car pulls hard and dosent misfire. The next day I get in my car and try and do some pulls it just misfires like crazy.

 

I fixed my issue by doing what Soofisahab did by removing the spark plug boots then re attaching them. There were no visible signs of damage or wear I simply pulled them off and put them back on and I no longer have a misfire problem.

 

so how many apes have you been raping since it got fixed?

 

Just pointing out that the stoich of e47 is around 11.96:1 not 14.7:1 like gasoline, so you're not at 12.3-12.4 wot or your engine would be toast on E. Thats why we use lambda instead of AFR. So you're at .84 lambda on gasoline, so youre around 10.04:1 on e47.

Just saying :P

 

Ahhh, I see. Very helpful thank u. I did correct my post if u scroll up but still, great to learn something new.

 

I have a 2009 ss tc stage 1 sensors I just put an intake on it worked great for 2 days then started to misfire I changed my plugs with the good ones and also all 4 coil packs still missfire when I run full boost but if I feather it it will not misfire. Should I just put stock intake back on or do I need to re tune my car for the intake ?

 

I thought I should give this an update since a recent development.

My car has always had slight issues with misfires and I seemed to have always "fixed" them by changing different things, tunes, plugs, seals etc... Just recently my car started misfiring excessively when it hit 10lbs of boost. I did a compression check today and found 120lbs on cyl 1, 90 on 2 and 150 on 3 and 4.

Clearly there is an issue with the internals and ideally I should be able to just replace the rings unless anything else is damaged but I wont be able to tell until I take the motor apart.

Make sure you do a compression test if you are having issues resolving misfire issues, I should have done this long ago.