LT1 intermittent bucking, overheated converter
LT1 intermittent bucking, overheated converter I should first specify this is a 1994 Trans-Am with an LT1. I'm posting in this forum because I didn't see diagnostic-related in the LT area.
I just swapped an LT1 for another LT1 (new one has Hot Cam kit and ported heads). The car was running fabulously with the new engine. It has much more power and still a pretty smooth idle, revs high and did not show any issues during the first two trips (about 3 miles each). Then I took it on a longer drive (about 5 miles) and it started cutting out momentarily and bucking. It continued that way until I could drive home (about 2 miles). It ran like crap, but it still ran. I looked all around under the hood and didn't see anything disconnected. So after about 15 minutes, I started it up and it ran great again. I took it for another drive and the same thing happened after a few miles. This time the Check Engine light came on twice briefly, but when I checked codes after I got back, nothing was stored. On the way home, I started smelling something burning that I couldn't identify. By the time I got home, there was smoke in the car. After checking it out, it seems the passenger-side floor got so hot that it started the carpet padding smoldering. I poured some water on the carpet to stop the smoking. Apparently, the converter got REALLY hot! I'm inclinded to think this is an ignition problem, causing excess fuel in the exhaust to overheat the converter. Since I just put in a new engine, I'm thinking maybe I didn't secure a connector all the way or something like that. I should also point out that I have an LTCC coil-per-cylinder conversion and an MSD Opti that was brand new when I made the LTCC conversion. That setup has been on the car for about 3 years and 20K miles with no issues.
I have a new tune for the engine from Keith Wenzel (pcmforless.com) that I have NOT installed. I don't want to introduce anything new until I sort out this issue. I can't imagine a minor tuning change would sort out a problem this big
I just swapped an LT1 for another LT1 (new one has Hot Cam kit and ported heads). The car was running fabulously with the new engine. It has much more power and still a pretty smooth idle, revs high and did not show any issues during the first two trips (about 3 miles each). Then I took it on a longer drive (about 5 miles) and it started cutting out momentarily and bucking. It continued that way until I could drive home (about 2 miles). It ran like crap, but it still ran. I looked all around under the hood and didn't see anything disconnected. So after about 15 minutes, I started it up and it ran great again. I took it for another drive and the same thing happened after a few miles. This time the Check Engine light came on twice briefly, but when I checked codes after I got back, nothing was stored. On the way home, I started smelling something burning that I couldn't identify. By the time I got home, there was smoke in the car. After checking it out, it seems the passenger-side floor got so hot that it started the carpet padding smoldering. I poured some water on the carpet to stop the smoking. Apparently, the converter got REALLY hot! I'm inclinded to think this is an ignition problem, causing excess fuel in the exhaust to overheat the converter. Since I just put in a new engine, I'm thinking maybe I didn't secure a connector all the way or something like that. I should also point out that I have an LTCC coil-per-cylinder conversion and an MSD Opti that was brand new when I made the LTCC conversion. That setup has been on the car for about 3 years and 20K miles with no issues.
I have a new tune for the engine from Keith Wenzel (pcmforless.com) that I have NOT installed. I don't want to introduce anything new until I sort out this issue. I can't imagine a minor tuning change would sort out a problem this big