Hey All,

After winter storage, I developed a slight missfire (96 LT1). I took it up to Autozone for a quick scan and forgot which cylinder was giving me trouble ('cause I'm a dummy) I bought NGK G-power plugs and a set of 8mm Taylor Spiro Wires.

I started the passenger side first - I ran out of time so I left the Driver side for today. After finishing up the Passenger side, I started her up, felt a heavier miss and noticed white smoke coming from the Driver side exhaust pipe. SES light was blinking. I quickly pulled the car into the garage and shut her off.

Today, I completed the driver side plugs and wires and double checked all of the passenger side connections. There is still a heavier miss at idle (engine just feels rough), and if I give it a little bit of gas, the engine runs rougher, as I expected. White smoke persists through the drivers side exhaust pipe and there is a faint smell of gasoline in the smoke. SES light is lit.

I left the car on for approximately 10 minutes incase the ECM had to learn the new wires & Plugs, but that didn't seem to help.

All wire connections were lubed lightly with Dielectric grease - All gaps were checked prior to spark plug instalation. Old Spark plugs look original and have normal wear - a slight bit oily.

I'm nervous to drive to get it scanned under the above conditions. What do you think it could be?

Thanks!

 

How long did you have it stored for winter? It's June!

Have you checked the timimg? Could be that your cat is clogged too!

 

I had it stored from November to April. Threw some tires on it in May and tackled this project in June. I noticed some rumble in April. Its never stalled and I've got a fresh tank of gas and some injector cleaner mixed in.

I haven't checked timing - I know theres a wealth of information on timing here in the forums. I will look in to that.

How should I clean the cats? I wish I could delete them all together!

 

You can't set the timing on an 96 LT1. It is set by the computer. You can read the DTC codes w/o driving it. I am not sure how to do it on your 96, I know on my 93 but it might be different, someone will chime in soon and let us know. That is the best place to start. The white smoke makes me think it's oil related. You can't "clean" the cats either, but they could be plugged and not functioning, that would throw a code on your 96 because they have an 02 before and after the cat to make sure they are working properly (I think). Hope you can get this solved, nothing worse than having great spring weather and wanting to drive your car and it won't run.

 

Without knowing which code is being set, how many miles on the car and the past maintenance; it could be a number of things. However cylinder misfire and heavy gasoline smell may spell a bad pre-cat Oxygen sensor on the drivers side. See if someone with a scanner can come over or try to purchase a scanner on sale. I bought an Actron for half price at closeout a few years ago - one of the best investments I ever made for a tool.

 

And I forgot to add, try not to drive the car - if raw gasoline is getting to one or both of the cats it can wreak havoc and take out the cat. If it is the oxygen sensor replace both sides as the other one is probably not far behind. Good luck.

 

White smoke, and a heavy miss, says headgasket to me, or worse. Did it have a chance to freeze over the winter? If so it may have cracked the block, which would explain why it happened all of a sudden. h

 

I'll bet you have two plug wires swapped. These cars will run amazingly well on 6 cylinders (been there, done that).

Pull the codes yourself:

http://forums.corvetteforum.com/c4-t...n-96-cars.html
http://corvettephotographs.com/c4vettes/codes.htm

What they mean:

http://forums.corvetteforum.com/1576116036-post35.html

 

You can be so careful and still screw this up, believe me.

 

Can't pull PCM codes on a '96 due to OBD II. Only CCM codes, some ABS codes, Ride Control, etc.

OBD II codes are 4 digits plus the letter (ie P for Powertrain) while the digital speedo can only show 3 digits. This is why you can't display them.

 

Thanks Cliff! 6 gloom and doom responses before common sense arrives on the scene. I don't know what makes it so easy to switch a couple of plug wires when changing them out but it sure happens and it is the first thing to check after having the wires off. Heck, I memorized the SBC firing order when I was 12 and I still manage to reverse a couple of wires from time to time.

mszietlow needs to recheck their work and clean out the leaves and trash between the A/C condenser and the radiator (nothing to do with the miss, just a oddball maintenance item that is overlooked until the car starts running hot.)

By the way, OBD II will flash the Check Engine light when misfire is detected. The PCM will set a code of P0301 - P0308, with the last digit indicating which cylinder was misfiring. I don't know about the Vette, but V6 Camaros will turn the CEL back off after a couple of start cycles without a misfire. (The code is still stored in memory.)

You can get a basic code reader on flea-Bay for under $25 and it is small enough to fit in the tray over the jack. It beats running to AZ ll the time and having to listen to half baked troubleshooting from a red shirt. (Yeah, it's like Star Trek. The Noobies wear red shirts, the assistant managers wear gray).

 

See this link:

http://forums.corvetteforum.com/c4-t...n-96-cars.html

 

But they changed it...

I remember the firing order being molded into the intake manifold. Not sure what year that was. I had a '57 Chevy, '69 Camaro, '71 Corvette. I'm pretty sure it was one or more of those.

They swapped two cylinders. I don't remember which ones. 5 & 7?

 

The firing order was 18436572, and everyone swapped 5, and 7 at least once. They were next to each other on the cap, and the block. h

 

try re-plugging the wires in at the opti, carefully...if you're then positive they are correct and still have the white smoke, you got coolant in the cylinders somehow, either cracked block (rare if you stored the car inside a garage) or blown head gasket (more common on these LT cars than others.

 

The link is how to pull CCM codes. The PCM codes on a '96 cannot be retrieved using this method.

 

This thread is starting to resemble a circular argument.

Mszietlow - get an OBDII scanner. They are relatively cheap nowadays and the money you spend is paid back the first time you use it. I paid $99.00 for mine on closeout about 5-6 years ago and it has saved me a great deal of time and money. 96GS#007 is right on the money (no pun intended).
Until you pull the codes, you are wasting your time and by extension, everyone elses' time. And if you don't have it already, get a factory service manual - that will be invaluable for you or your mechanic of choice.

As for the smoke, could be raw gas or coolant. More importantly, pull the codes first.

 

Thanks for all the input - INVALUABLE info from you ALL.

I've got a scanner on the way - should be here just in time for the weekend and some sunny weather here in Cleveland. I'll let you know what I find!

 

BINGO

Rechecked the Plug Wires.


2 were swapped.

On to the next project!

Thanks everyone!

 

Glad you found it. Sometimes it's the simple things that do us in.