topmover

I've been chasing an issue with my C5z since June last year which ultimately resulted in my intake exploding in Oct.

As a result of that incident I had the motor pulled, freshened, new intake, rails, injectors, TB etc. and a new wire harness installed as the old one had some wires that were burnt.

Just like last year the car was run on the dyno and ran fine, then I take it to the track yesterday and it did the exact same thing as in the past. When operating in track conditions and pulling G's it picks up a miss between 4600 and 4800 rpms and will not clear it self to run at a higher rpm, it almost acts like a govenor. Last year I tried continually to push it thru this ceiling, unltimately the motor quit and when it refired the intake blew up from pent up fuel........so lack of fuel doesnt seem to be the issue.

Because I'd had issues with Service Active Handling last year I tried the car both with ACT/HD(off) and ACT/HD "defeated" as was spelled out in a Thread a few months ago..........the car did the exact same thing. Obviously since this issue only happens in track conditions I was hoping that defeating the ACT/HD might be the fix however it wasnt.

This car has been to countless "experts" and no one seems to be able to figure this out.............anyone here got any idea's??

jbondfl

It sounds crazy, I know, but check all your grounds. I had a friend with a similar problem (at a lower RPM). Oddly enough his car would run better when he turned on his emergency flashers....... He had a bad ground near the right rear wheel.

John Shiels

what did the experts see? Can they not read the computer history?

topmover

Thanks, any idea's are welcomed as this car is very potent and I hate to give up on it.

John Shiels

why give up any motor issue can be resolved.

topmover

To date the codes were associated with active handling, all the protocal's were followed and fixed. Still the same issue. A burnt wire harness and battery positive were found and fixed. Still the same issue.

k24556

spark knock sensors causing spark retard? (bad connection, ground?) Your CEL would come on, though if that was the case, I think.

PA Z06

Had the same issue, took awhile to fix, and also know of two other people that had the same issue.
There is a wiring harness on the drivers side, all the way in the back, like just past intake manifold, that when the motor twist or the is are G's the wire harness fouls the motor.
Like I said this happened to two other people and I was able to help them

topmover

So this is a different harness than the main engine harness?

vette6aut0x

You might want to check all the pin outs at the connector and make sure they are snapped into place.

GettReal

I'll throw this in there as a last resort if you are up to checking this. I went through a similar issue 2 seasons ago and went nuts trying to diagnose it. I changed what seemed like every possible part, but at 5000 rpm every single time, it was like hitting the rev limiter and it only would only show a miss (0300 I think) and a TC in the codes. Turned out to be the crank I put in was off and at that rpm it was just enough to move the reluctor so the crank sensor wasn't getting a full read.

I finally as a last resort pulled the motor, pulled the crank and sent it back to Callies... they admitted it was out of spec and fixed it. When I put it back in, it was fine... what a PITA.

I really hope this isn't your issue but if you can't find anything else, it might be your problem too.

topmover

I appreciate all the suggestions so far. I pulled the codes off the DIC:

SDM: No Comm
PCM: No Codes
TCS: C1222 H, C1221 H, C1248 H, C1282 H, C1287 HC, C1288 HC,
U1000 H, U1016 H
BCM: No Codes
60 IPC: No Comm
AO LDCM: No Comm
RDCM: No Comm
A6 SCM: No Comm
BO-RFA: U1000 H, U1064 H, U1225 H, U1096 H

mgarfias

check the star connector in the pax side kick panel. theres an SST for this that lets you replace the bridge bit, and dial in the module you want to talk to via OBD2. I'd just jump the leads to test. The service manual has more info.

OH, i'm assuming you have all the modules still in place in the car.

topmover

It looks like this issue has been resolved as the car ran great yesterday at VIR. We were able to load the dyno and get the car to repeat what was happening at the track. As I understand it the primary fix was replacing the map sensor and turning off the oxygen senors.

I appreciate everyones ideas on this and want to especially thank, Anthony from LG who offered a number of suggestions. Chad Golen my engine builder who stayed engaged throughout the whole process and finally the folks at All Aspects in Cheasapeake Va. who ulitimately found and fixed the problem.