03 350z powerlab kit studders at 4k cel comes up misfire cyc 1 i regapped all plugs to .032 they were outa whack. Hasnt solved issue still studders , im going to replace all plugs. Car has 116k 60k boosted . Coils seem fine afr believe is 11.2 wide open 13-15 afr at idle

 

Check the compression on Cyl 1 and report back

 

Bought comp tester an iridiums should gap stay at .044 or what thought u cant gap iridium

 

This should be in the FI forum.

 

sorry posted in haste on the run on the iphone, hate the mobile version :X

 

I've been told iridiums might be too hot for turbo applications as was told on my turbo application.

Can't offer any advice on your problem though I can offer spelling advice on the word 'stutter', not 'studder'.

 

You and me both.

The stutter remark was pretty funny.

 

ok so compression test , needle hit 155 psi and stayed. I replaced all the plugs back to my original setup, iridiums step colder. At 4k it still stutters if i get off it and back on it feels fine boosst all the way by the time i hit 4th and get to 4k i throw a cel cyc 1 misfire. any input ? please drop a line. this is a 03 350z 116k miles 60k have been boosted with powerlab kit.

 

Tune is the same as always and problem just came out of nowhere? Swap coils 1 and 2, or 1 and 3... whichever are easiest to switch on your car. If problem follows coil to new cylinder then you need a new coil. If not, look into replacing the UTEC or upgrading ems.

 

hal's suggestion on swapping coils would be the first thing i would try. very simple to do and rules out coil problem.

After that it sounds like the dreaded transition studder that a lot of utec users have issues with. I know nothing about utec but i have read quite a few threads where people have a studder at a certain point going into boost on those things and it's very hard to tune it out.

 

^ I fear it's not the common transition problem (assuming it is same tune as before and just started this issue), but rather it is the dreaded 'random failure' problem that also plagues UTECs...

 

oOo, ya, i'm not fluent in utec. It didn't seem like something i wanted to mess with.

 

shop says its the tune, to rich at 4500-5k

 

So its fixed now?

 

No it's not fixed. Going to replace plugs and try a diffrent utec. don't think it's the tune since I can do a 2nd gear pull and not get the stutter but I'll get flashing cell.

 

flashing CEL is very bad misfire. That can def be the tune, as well as the plugs

 

That would make complete sense if it was the tune of the Utec... If your utec is fine, and you begin to have issues with it through the transition, I personally found that alot of the transitional issues I had going in and out of boost were solved by getting an Uprev reflash on my stock ecu and having the TPS set to 100% v.s the factory setting which was like somewhere around 85% or in that neighborhood. That also stopped the random limp mode issue too commonly found in the utecs (Only took two years to figure that one out) Eventually went to a pro-efi and solved all issues, but as Hal said upgrading ecu might help alot, and as of currently, I would recommend the Haltec or Vipec over the proefi.

If tune and hardware all appear fine, then your looking at plugs or coils...

 

Just wanted give everyone a heads up on this old post. Between work and having no time for anything we finally got it fixed.

We changed out all 6 coils and the car seems to be back to normal. Did a bunch of pulls on the highway in 3rd and 4th from 2k rpm up to redline and all the stuttering or weird issues I was having have gone away. No CEL llight flashing either. The Utec doesn't seem to have been the issues. My coils had 120k on them though and 50+ of that was boosted so maybe one or a few of them weren't putting out enough juice. She's pulling hard all the way just like she used to now though

Thanks for all the feedback as well with trouble shooting.

 

UTECs are known to burn up coils too (I lost two during my courtship with UTEC before switching to osiris).

 

Thanks for that info. I had no clue they could do that lol I'll keep that in mind if I experience the same issue but if it does happen again. Might time for something better like Osiris or Haltech..