I just bought a 99 z28 yesterday.made a day out of it and drove a state away to pick it up.very clean low milage car that is well modded.

took it for a test drive and everthing seemed fine.

put it on a trailer and took it home.( a good thing) casue it probably would have cought fire.

once i got it off the trailer,i took it for a 5 minute drive and i noticed some smoke from underneath the car. the drivers side cat is glowing red.
it actually melted a hole in the carpet and floor mat.

kinda sucks cause the interior still looks new. only 10k miles on the car.


i swapped the cats from on side to the other to see it the cat might be bas, but the same thing happened.


car also wants to backfire a little after running for a few minutes.




anyone have this happen before? or know what might be going on?

any info would be appreciated.



thanks!

 

Almost sounds like a timing problem. Though timing isn't exactly adjustable. Cam jumped timing?

 

Im assuming the drivers position glowed red again, not the drivers cat now on the pass side. Could be timing but sounds like its pouring fuel in that bank and the excess is collecting in the cat. Scan it asap and see what that bank is doing. Is it still on a stock tune? Correct spark plugs installed? Besides a backfire, how else does it run?

 

No SES codes? I can't believe this didn't happen during the test drive...

 

yes its still glowing red on the drivers side even after i swapped cats.


the car has been dyno tuned as it it well modded. head,s big cam,etc.



check engine light did come on but not during the test drive.(some bad luck right)


the car idles real nice but once its backfires it did seem to have a little hesitating.



man that cat was glowing red. that cat and about 6 inching of the piping on the backside of the cat.

 

Besides a possible mechanical problem, Im curious what your tune looks like. I would be weary of the dyno tune, seems too often dyno tunes are just WOT tuning and the rest is ignored. First, Id go to oreilly or any shop to scan for codes. Then, find a tuner/speed shop in your area and get a .bin file of your current tune. That should find the problem.

 

im gonna try to find someone to come by and pull the codes for me.
i dont wanna drive it plus it not even registered yet.


the car was sitting for a long while , so i dont know if bad gas would have anything to do with it.

 

thats odd as can be.....I bough my z28 about a month ago it would backfire if i railed on it past 4xxx rpms but also my o2 sensors are bad so slight problem there but the guy i bought it from was runnin 87...i bumped to 91+ and it hasnt done it since evn with the faulty 02's I would do the professional tune by a shop and go from there. Thats my next step as soon as I save some damn money

 

had the codes pulled tonight.

says the bank is running lean ,though it seems to be running rich to me.


any suggestions on where to start?


i was gonna try the o2s first.


are the front and rears the same size?

i only ask cause i still have the rears from when the exaust was changed.

 

pull the plugs, see if there seems to be a problem on just a single cylinder, O2 sensor, fuel injectiors would be next.

 

i ended up changing the o2 sensors today and the plugs.

first time changing plugs on the camaro.(passenger side was a bitch)

the plugs looked pretty bad on the drivers side and had gas residue.


im not sure what fixed it The plugs or the o2s but it seems to being running fine now and no more glowing cat!!


it does seem like the cat is a little close to the floorboard on the drivers side though.

i have flp longtubes with high flow cats.

any suggestions on this??

 

Glad you fixed the problem. Does the cat hit the floorboard when you accelerating? Best way to correct that is with at least one poly engine mount.

 

actually it may hit, i did hear something when accelerating and assumed the exaust was rubbing somewhere since it was really close at a few points.so it might be at the cat.


what is the poly monnt gonna do??

any other suggestions?