ZL1Killa

iTrader: (17)

I got the car back and when I heard it I couldn't quite pick it out but I thought the car was missing slightly. They had already driven it around and tuned it...so I just took it and drove it home (25 miles). tuner also said the fuel trims were way split from each other.

I then noticed on the way home in 5th and 6th gear at ~1500-2000rpm at about 15% throttle or more the shifter shook violently and the car shuddered, so I downshifted to raise the rpms and change the load and it went away. Something felt funny.

got it home, checked for motor mounts, transmission mount....looked the car over, didn't see anything. drove it to work that Monday (50 miles round trip). Got home as the shudder and shaking was still there and noticed that for all of these miles #8 plug wire was not connected to the spark plug, but all plugs were in and tight.

So basically #8 ran for ~100 miles without firing. Should I be worried?

I'm having a compression / leak down check done and it re-tuned. Opinions - thoughts?

I connected #8 and fired the car up and it fired up first time (previously noticed it was kind of hard to start) and let it run and warm up. drove it down the block and all seemed fine. fuel trims were back in line with each other. I have driven the car twice since then and all seems fine, no shudder, no shaking. It also appears to be firing fine on all 8 cylinders

should I be worried about cylinder #8
Opinions - thoughts?

Bob@BruteSpeed

iTrader: (16)

It should be just fine, but I wouldn't ever take it back to the place you had it tuned at as they should of caught that. I would get the air/fuel ratio checked now since all eight are firing. Bob

2005vetteTT

iTrader: (1)

I ran on 7 cylinders at 9psi for 4 months. Fixed the wire and haven't had an issue since. I did have to adjust my tune though

Moter

iTrader: (20)

really?? so you had it tuned or tuned the car yourself with an engine running on 7?? wow...

ZL1Killa

iTrader: (17)

Sometimes the simplest things are overlooked.



good god!



My only concern is the cylinder & rings were exposed to direct gas (likely as the car is new, I probably have slight "leakby" of fuel to oil mix). the valvetrain was still operating, so the cylinder was compressing the gas & pushing it out and sucking in fresh air. With this one cylinder being cold and all others being hot.... ahh hell...engineer in me

I guess all I'm looking to be absolutely certain of is that #8 cylinder is ok and all other cylinders are ok. It seems to be fine, but I just got the car back and I'm worried like there is no tomorrow. My motor builder that I trust a LOT says all is ok. Its just one of those things you know...

2005vetteTT

iTrader: (1)

Tuning myself - thing is, when I went to the dyno the tuner there said my log looked fine. I think the spark plug wire was on far enough to get spark some of the time so the cylinder wasn't 100% dead all the time.

All cylinders seem to be fine when checked with HPTuners Cylinder Test and car runs great so I assume it's fine

ddnspider

iTrader: (26)

I just had almost the identical issue, how random is that? Same vibration in 5th and 6th but went away at a lower gear and higher rpm. Same large split fuel trims. Ended up being a lose fuel injector connector. swapped plugs and all was well. Actually going to retune tomorrow for more power.