Ricky 91 vette

hi everyone, i have a 91 l98 with a mild cam, 24 lb buschIII, edelbrock performer heads, and edelbrock hi flow base plate and runners( which were weast of money), and 58 bbk mm, hooker long tubes, one cat, and magnaflow cat back, yesterday i was trying to mess with the coputer tune using ostrich2, for some reason it looks like i didnt load the file corectley into the ostrich, and when i started the car , it was backfiring for couple or three times and then withen a min a white cloud of smoke started coming out of the mufflers, i turned it off right away and put the oem chip back into place and started the car again and its the same smoke and its getting worst, i drove it around town (watching for cops) and i couldnt see nothing behind me from the white smoke!! beside it had no power and felt like one or two cylinders were not firing!!

Ricky 91 vette

i thought i blowed my engine, but i talked to my uncle who is a mechanic and works at a local shop, and he thinks its only timing slipping issue, i know that i have a double timing chain, and its only been like 15k since was installed in the car with the other mods, besides if that would be possible, wouldn't it bend the valves and crack the pistones? right now it fires but it takes me to step on the gas and idles roughley and backfires too when i stepped on it, so i shut it off after a min,,, any ideas?

STL94LT1

It's nearly impossible that your timing chain slipped. How does the oil look?

Ricky 91 vette

I already checked the oil and it looks clean

Midnight 85

Your uncle is a mechanic and he says a slipped timing chain will cause white smoke??? There is only two things that will cause white exhaust smoke, cold weather and water in the combustion area.

joe paco

ever start your vette after a long sleep and see the "white" oil smoke. He says white rather than black fuel smoke.

cause: oil in the combustion chamber.

Joe B.

Don't know if the '91 still uses 'em but I had a '62 Impala with a blown transmission vacuum modulator and the trans fluid being sucked into the intake caused an immense cloud of white smoke.

l98tpi

Head Gasket? Also white(light blue) smoke= oil and black smoke = fuel.

Midnight 85

5abivt

Sounds like Head gasket. preignition of backfiring or detonation whatever white smoke can mean the cylinder pressure caused a head gasket to leak coolant. Hopefully you dont have any mechanical damage like piston ring/lands or the piston itself.

If the timing was off and the air/fuel ignites while the piston is trying to come upwards... think about it. The pressure has to go somewhere. so many possibilities !

Ricky 91 vette

I think it should be black in that case and not white!!

Ricky 91 vette

my o2 sensor is on the driver side header colector and right next to it is my wide band sensor too which been reading very rich like 10.5:1 since this started even when i was driving it in the freeway to see if i could clean up the engine and the exasut in case the cause was only the bad tune, so i thought that if there is oil burning ( either from bad gasket or bad piston or ring) it will be covering the spark plug and thats why it was so rich because a coverd with oil spark plug= no spark, so i pulled the plugs on the driver side and i couldnt find any oil on them, only carbon, lots of carbon, i cleaned them well and put them back, drove it around , it seemed to start leaning a bit on the wide band for like a min and then it richened again, while the cloud was getting bigger and bigger behind me and i could feel that at least couple of cylenders were not firing!!

Ricky 91 vette

yah i agree but dont you think that bad tune and couple backfires are not enough to damage the engine when it run only for a min like that?

Ricky 91 vette

tomorrow im gonna pull the right side plugs and check for oil in them too, and my uncle will stop by to check the timing too and we will see ....

Midnight 85

If you are running rich it will put out black smoke, if you are burning water it will put out white smoke. Before you start it again, pull all the plugs, keep track of which cylinder they came from and look for any that are unusually clean. If you find clean plugs then have someone watch the holes they came out of and crank the engine. If you have a bad head gasket you will have water coming out of the injured cylinders.
If you are describing this correctly you will find the problem. If however the timing has slipped somehow then the computer could be trying to compensate for false readings and make it run rich, BUT, I repeat the smoke is going to be BLACK or dark colored,, not white.
Joe B. also mentioned something that will cause white smoke but there is no modulator on your car.

tlong

Simple pressure test or coolant test for combustion gasses will tell the tale. White smoke is a head gasket probably and is easy to diagnose.

It will kill the O2 sensors fast, and hydro-lock the cylinder possibly yielding a bent rod or ruptured piston. Sorry but Unc is barking up the wrong tree.

kenv

hooked073

You did not say if this stuff was all new and this was the first start sense. If so there are several things that could cause your problems. I agree with most it sounds like cooleant. Go over everything you have done. I am not one to go to worse case sereno but head gaskets are possible but if you add back firing into the equation I would not rule out cracked head or cyl wall. Back firing in a cyl can cause strange things to happen good luck let us know what you find

Ricky 91 vette

well i can smell the gas too from the smoke which is not white white, its kind of blueish white, if it would be a gasket and its burning water, i think the coolant would be like bubbling or boiling but its not, i took off the led of the coolant tank( the black one ) and i kept it running tell it reached 170 degrees(i have 160 thermostat in it) and the coolant was normal, the timing was corect by the way, tomorrow i will pull out the plugs and check for oil in them, and we will see

Ricky 91 vette

by the way, thanks for everyone for all the support and the ideas, i know a good corvette's mechanic, but he is really expensive, and if i know for sure its a gasket, i can pull out the heads and clean them up and put them back again, so that's why im here trying to fix it myself with ur help here