Knowledgeable Tech -Starting/Performance problem needing assistance - ZR-1 Net Registry Forums

sjs · 04-28-2011

Hello everyone, I am new so please bear with me. I am new to the forum and this is the first zr-1 I have owned (90 model w/100k). Bought it last year, runs pretty good but secondary actuator does leak. I am an engineer but hate to admit I haven't bought a service manual yet (toys never break do they? LOL) Anyway, drove it for about 3k miles last year, wife drove it the first day of spring and as she turned in the drive it ran rough and died. Would start and run, but sounded and smelled flooded - would start after it dried out ... but would die. Put it in clear flood mode and will start but runs tough for a few seconds and dies. It used to start wonderful and run hard .. now it is becoming an annoyance and a reluctant wife is starting to loose faith and trust in her first vette. So if anyone has any ideas I would love to hear from the people who know the most about them. When it does run it pulls 11in of very steady vacuum at a low/rough idle , I thought it sounded throaty but funny (faint popping through the intake (had filter out), and tested fuel pressure at 39 psi (it does hold pressure too). So I am at a loss for what its malfunction is as I am NOT heavily familiar with this engine - not near as well as an l98 i used to have in a trans am. Could this exotic 4 cam engine have a jumped cam as they are known to have tensioner problems? But why does it have steady and almost good idle vacuum? Bad injectors ? But why will it run good for a few seconds before going down and why do the hold pressure (ie not leak), Scanner showed only lean code and secondary actuator code (i assume from its slow secondary vacuum leak) ... So I assume spark and ecm are okay since it kinda runs ....

Anyway, LT5 experts ..... please help and thanks in advance.
sjs

04-28-2011	#1
sjs Join Date: Apr 2011 Location: kansas Posts: 10	Knowledgeable Tech -Starting/Performance problem needing assistance Hello everyone, I am new so please bear with me. I am new to the forum and this is the first zr-1 I have owned (90 model w/100k). Bought it last year, runs pretty good but secondary actuator does leak. I am an engineer but hate to admit I haven't bought a service manual yet (toys never break do they? LOL) Anyway, drove it for about 3k miles last year, wife drove it the first day of spring and as she turned in the drive it ran rough and died. Would start and run, but sounded and smelled flooded - would start after it dried out ... but would die. Put it in clear flood mode and will start but runs tough for a few seconds and dies. It used to start wonderful and run hard .. now it is becoming an annoyance and a reluctant wife is starting to loose faith and trust in her first vette. So if anyone has any ideas I would love to hear from the people who know the most about them. When it does run it pulls 11in of very steady vacuum at a low/rough idle , I thought it sounded throaty but funny (faint popping through the intake (had filter out), and tested fuel pressure at 39 psi (it does hold pressure too). So I am at a loss for what its malfunction is as I am NOT heavily familiar with this engine - not near as well as an l98 i used to have in a trans am. Could this exotic 4 cam engine have a jumped cam as they are known to have tensioner problems? But why does it have steady and almost good idle vacuum? Bad injectors ? But why will it run good for a few seconds before going down and why do the hold pressure (ie not leak), Scanner showed only lean code and secondary actuator code (i assume from its slow secondary vacuum leak) ... So I assume spark and ecm are okay since it kinda runs .... Anyway, LT5 experts ..... please help and thanks in advance. sjs