Aklinker

I acquired a 94 camaro with the LT1 5.7L engine in it. It had been sitting for about 7 years. Got it home and started replacing things it's needed like new spark plugs, plug cables, water pump. The car started and ran but seemed kind of sluggish and had some little back fire in it once and awhile. I noticed at an idle after about 15 mins the cat was getting cherry red. A friend told me the cat was probably plugged and just to gut it out and see if that helped the running problem. I plan to put a new cat and y pipes on it but for a test just to see if it would run better after I gutted the cat I tried starting the car and now it won't even start. Back fires some and kind of tries to fire. My question is that do I just need to go ahead and put new y pipes and cat back on and it should fire due to it not having enough back pressure with the cat gutted????? Any help would be nice. I want this car on the road.

Injuneer

If your 1994 actually has an LS1 engine transplanted into it, you would be better off posting on the "LS1 Based Engine Tech" forum.

If your 1994 has the original LT1 engine, this is the correct forum.

Please clarify.

Aklinker

Sorry about that but yes it's a 94 that came stock with the lt1 in it.

Injuneer

Cat would start glowing if the engine was running excessively rich, with the AIR pump running or a few cylinders misfiring. That would pour wet fuel on the cat, and when the oxygen hits it it burns, generating a lot of heat. Could have been hot enough to melt the converter's substrate, plugging the exhaust.

However, once you broke the substrate out of the cat housing, it should start. The engine does not need "back pressure" to start.

Have you drained the old fuel out and added fresh fuel? Have the injectors been cleaned? Have the O2 sensors been replaced?

For starters, check the fuel pressure, and scan the PCM for codes.

https://www.camaroz28.com/forums/com...95-lt1-874306/

Aklinker

Old fuel was drained and replaced fuel filter. Probably wouldn't hurt to replace it again after having it running for a bit, who knows what's been growing in the tank. As for O2 sensors I have not replaced them and also haven't taken the injectors off to clean them. I will take your advice and try that scan program once I get the cable. Thanks for the link for that program and for your input.
I'll report back with info as soon as I find anything new out!!