Help- engine issues
Thread Starter
Cruising
Joined: Aug 2008
Posts: 11
Likes: 0
Help- engine issues
I have a 91 z that runs perfectly. I recently installed a Haibeck chip, and today I drove he car for about 25 miles and parked it for abouy 20 minutes.
When I started it again it went to full throttle like my foot was mashed to the floor. It felt like it was banging off the rev limiter fot 3 or 4 seconds till I could shut it down.
Tried an immediate restart and it did it again. Let it sit for an hour or so and had a normal restart.
A few hours later, same scenario. Drove about 15 miles, parked for 20 minutes, full power restart. Shut down, waited a few and had a normal restart.
98% of the time it starts normally. It goes to about 1800 rpm for 3-4 seconds and then settles down to 900
The engine still runs fine on the road from idle (rock steady) to redline.
Any thoughts?
When I started it again it went to full throttle like my foot was mashed to the floor. It felt like it was banging off the rev limiter fot 3 or 4 seconds till I could shut it down.
Tried an immediate restart and it did it again. Let it sit for an hour or so and had a normal restart.
A few hours later, same scenario. Drove about 15 miles, parked for 20 minutes, full power restart. Shut down, waited a few and had a normal restart.
98% of the time it starts normally. It goes to about 1800 rpm for 3-4 seconds and then settles down to 900
The engine still runs fine on the road from idle (rock steady) to redline.
Any thoughts?
Race Director
Joined: Dec 2003
Posts: 14,164
Likes: 941
From: Fremont Ca
2022 C4 of the Year Finalist - Modified
Melting Slicks
Joined: Dec 2004
Posts: 3,285
Likes: 52
From: Jacksonville, FL
St. Jude Donor '08 thru '26
I'd do a KOEO code search, both the ECM and the CCM to see if a DTC was stored...?...or maybe do a KOEO and go look at the cruise control diaphram to see if it is advancing the T-blades. JMHO:o
Tom
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
5 Best & 5 Worst Corvette Daily Drivers
Joe Kucinski
The Headlights of Every Corvette Generation Explained
Joe Kucinski
5 Best & 5 Most Overrated Corvette Track Packages of All Time!
Joe Kucinski
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
Thread Starter
Cruising
Joined: Aug 2008
Posts: 11
Likes: 0
I spoke with Mark. He seems to think it's electrical, possibly a sensor or even a cold solder joint on the board. He went through a long theory of operation explanation on possible causes that I won't even attempt to try to explain here. Anyway, many starts later, all is still good.
Team Owner
Joined: Jul 2002
Posts: 37,067
Likes: 69
From: This city NEVER sleeps! Frank's back yard!
Lets keep it simple here guys: If the prom was replaced, and then he had issues, it is likely the prom. It may well be the board as Marc says, but if you continue to experience issues, switch back to the old prom, reassess!
Race Director<br><img src="/forums/images/ranks/7k-10k.gif" border="0">
Joined: Feb 2001
Posts: 13,013
Likes: 26
From: HOME OF THE FREE. BECAUSE OF OUR BRAVE. Babylon NY
St. Jude Donor '06 thru '20
Pull the prom out and make sure none of the connectors got messed up when the prom was installed. Then look at the receivers on the prom. If not change out the prom. Proms are very sensitive , just by rubbing the prom against some cloth will damage them quickly.
Thread Starter
Cruising
Joined: Aug 2008
Posts: 11
Likes: 0
Lets keep it simple here guys: If the prom was replaced, and then he had issues, it is likely the prom. It may well be the board as Marc says, but if you continue to experience issues, switch back to the old prom, reassess!
Agreed.
Agreed.