Bubbajones_ya

I posted this issue in the TBI section but figured I'd ask here just in case it's more of an electronic issue. I'm having an issue with my 1991 305 TBI Camaro, and when the issue happens, fuse #9 blows as well.

The camaro runs perfect while the issue isn't happening, but as soon as it does, I get several symptoms.

- Fuse #9 blows (so I lose my gauge cluster because it's all digital)
- The car stumbles intermittently as if it's losing spark randomly. The whole time it drives like this, fuse #9 will keep blowing
- The car starts to overheat.

I didn't realize the overheating issue was as bad as it was until today. I've notice previously it seemed to be hotter when I would be able to throw in a new fuse without it blowing after the issue happened and read the gauge, but thought it was the gauge acting up. When I checked it today after driving about 4 miles after the fuse blew, my infrared gun red 260 at the manifold and coolant was spewing out of the radiator cap.

This issue started happening right when I added Lucas octane boost to my tank. I didn't drive the car until I got rid of the whole tank of gas. As soon as I got rid of that tank and added new gas, the issue went away. However, it came back a few days later and has been like this for about a week now.

I don't know if the octane booster was a bad batch and somehow very conductive that it caused a short in the fuel tank sending unit or something, or maybe the coincidence of it occurring and disappearing with the addition and removal of the booster is a very rare coincidence.

The few guesses I'm having are maybe:

- Something is intermittently causing the car to run very lean, causing drive-ability issues, blowing the fuse (somehow) and causing overheating.

It seems to overheat very quickly when the issue happens, and I believe both radiator fans are still working when this happens (one is controlled by an aftermarket controller so it's not related to the main wiring of the camaro). I do have the AC on so the fans should default on as well.\

I can't really see any way for the car to get this hot randomly if both fans are working unless its running lean.



Any help and advice would be greatly appreciated!!!!

I would hate to do this, but I may have to pull the fuel tank and engine if this keeps happening.... I have two vehicles, but my Bronco is down getting the injectors rebuilt and my camaro was supposed to be my reliable backup... I always could try and throw my Bronco's 302 (since I now have a 7.3 in the bronco) if the camaro if my 305 got damaged today...

Bubbajones_ya

I just checked the exhaust header temps after the car cooled down. The circuit breaker I put in place of fuse 9 keeps blowing (when the key is turned on).

After about a minute, the middle two tubes on both the driver and passenger side headers about about 300 degrees, while the outer two tubes are a little under 200.

Could this be a lean fueling issue with the TBI system or potentially damage to something else? If it is lean fueling, I'm guessing the only thing that can intermittently do that is something messed up with my computer (it has the EBL system so maybe something between the computer and EBL got damaged?)