LT1 Missing/Backfiring..
Thread Starter
Race Director
Joined: Nov 2000
Posts: 17,103
Likes: 39
From: stop the fun suckers
LT1 Missing/Backfiring..
Sometimes after an extended drive (over 30+ mins) the car starts to miss then after while of missing, backfires (muffled - not the loud pop). I'll let the car sit for a few hours and take it to the store and it rides fine.. it also doesnt seem to have a problem in the morning on the way to work (30+ min drive)... I'm thinking maybe the MAP sensor..
BTW: the Car is a 1993 LT1 Speed density ECM.
BTW: the Car is a 1993 LT1 Speed density ECM.
Burning Brakes
Joined: Oct 2002
Posts: 983
Likes: 1
From: Bergen County NJ
Hmmmm, sounds a lot like the problems I was having last year! I had a O2 sensor that would fail intermittently (not the typical way they fail). The car would drive great for 20-30 miles, then start to misfire under load.
good luck hunting
good luck hunting
Thread Starter
Race Director
Joined: Nov 2000
Posts: 17,103
Likes: 39
From: stop the fun suckers
I hooked the car up to my laptop.. everything looks normal.. although it was running like dog dung... the 02 sensor readings were sweaping like they were supposed to and the BLMs were right on target.. timing looked good and no knock retard.. also no DTC codes.. I pulled the coil wire and the end that goes into the opti loked a little toasted.. so i replaced it.. it seems to run good now.. but its had a few hours to cool off.. i guess we'll find out tomorrow on the way home or at lunch!
Boy, I sure like the ECM and FI when tuning..etc... but for old fashioned reliability I like the old days better with glass fuse's, Early HEI, 8 spark plug wires, a tach wire a fuel line and 400+ cubic inches with a 8 track..
Boy, I sure like the ECM and FI when tuning..etc... but for old fashioned reliability I like the old days better with glass fuse's, Early HEI, 8 spark plug wires, a tach wire a fuel line and 400+ cubic inches with a 8 track..
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
2027 Corvette vs The World: Every Model vs Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Originally Posted by jdawgC4
How do you hook up to a labtop and what are the estimated costs for hardware and software if you dont mind answering.
Thanks
Thanks
Craig Moates has some options, too.
http://members.tripod.com/moatesenhe...mecm/index.htm
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Originally Posted by 383_BluByU
NOPE. that wasn't it... ARGHHHH ok, this is pissing me off! Can anyone recommend a ignition diagnostic procedure?
If not, we can always talk by phone and go over the testing processes.
I have a 92 manual, the cars are essentually the same.
Thread Starter
Race Director
Joined: Nov 2000
Posts: 17,103
Likes: 39
From: stop the fun suckers
Thanks for such a generous offor bogus! I've got a helms manual and started peaking through it.. i found the section on ignition.. wow are those things complicated to navigate through.. I'll post an update of my results tonight
Thread Starter
Race Director
Joined: Nov 2000
Posts: 17,103
Likes: 39
From: stop the fun suckers
ok last night I checked the fuel system as outlined in helms.. everything checked out ok... next I moved to the ignition system.. it was on of the C- tables.. I forget which one.. C-3 I think or C-2 the one on how to check the DI system.. I hooked my spark tester up to a wire and plug and turned the motor over.. got spark and lots of it.. also no MIL's are being set.. I think I have a bad wire or plug.. I'm gonna pull them all and inspect tomorrow am.. does this sound logical?
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Originally Posted by 383_BluByU
ok last night I checked the fuel system as outlined in helms.. everything checked out ok... next I moved to the ignition system.. it was on of the C- tables.. I forget which one.. C-3 I think or C-2 the one on how to check the DI system.. I hooked my spark tester up to a wire and plug and turned the motor over.. got spark and lots of it.. also no MIL's are being set.. I think I have a bad wire or plug.. I'm gonna pull them all and inspect tomorrow am.. does this sound logical?
I think you are getting close.
How old are the plugs and wires? Which brands?
Thread Starter
Race Director
Joined: Nov 2000
Posts: 17,103
Likes: 39
From: stop the fun suckers
Plugs are A/C delco Platniums..wires are NAPA premium 7mm.. I pulled the driver side and noticed the #1 wire was corroded where it connected to the Opticrap.. also, I noticed a white discolored area on the #5 area.. I think it was arcing.. I replaced all four wires on the driver side.. and took ti for a test run.. although i didnt run it long enough to see if the ehat soak problem was gone (i'll do taht on the way to work tomorrow) I did notice my radio noise on AM channels is gone!! maybe i'm on to something.. maybe not.. will post results of the ride in to work tomorrow am..
Thanks guys!
Thanks guys!
