Backfire Issue
 

I have one for everyone.....has me stumped. I currently have a 97 Z-28 LT1 with 97,000 miles on it. This is my second 4th generation Z. My last was a 95. So I have experienced the pain of replacing the plugs, optispark and all the common issues with them and the ICM. This last weekend I put in two new upstream O2 sensors along with new plugs and replaced some bad vacuum lines on the evap system. Now I have the weirdest problem. When I first start the car and drive it in a straight line it runs great. As soon as I take a right hand corner it starts backfiring like mad and runs like crap after that. Now I did pressure wash the engine while I had the radiator and everything out and flushed the engine block, forgetting to be careful not to get the optispark wet. I am thinking I may have got some water in the optispark, but I am not sure if it would cause the symptoms I am having... my thoughts were if I got water in the optispark, it would just run like crap all the time. Any comments or ideas....

Could be water inside that gets sloshed around when you make a turn, then shorting out on the contacts. Being you have a vented opti, you could remove both vent hoses and run compressed air through the opti, like let it flow continuously for a while. It might help in the long run, but you still could get corrosion on the inside to later mess things up.

Yeah, that's what I was thinking too. It is worse when I make a right hand turn as opposed to a left hand turn, and if you look at the design of it, it makes sense. I just can't believe I forgot about the vent hose on those things. Not good to get them wet. That's what I get. I just went ahead and ordered a new one for it. Just sucks because I had it all torn apart this weekend when I put in the plugs and O2 sensors, i also had the radiator out because I had to reroute the heater hoses. The guy I bought it from thought he was a mechanic, but he was not.

Since this just happened, you could have opened the opti back up and dry/clean it up inside. Did you accidentally leave the vent hoses off?

I tried blowing it out. But it didn't work, I ordered a new one yesterday. I just bought it from a guy who thinks he's a mechanic, but all I am finding out is he was a maroon who butchered the car. I dont even know that it has the correct distributor cap on the opti. Took it apart today and found the top right hole of the opti where the screw is supposed to go, there were zip ties holding it on instead. There are two vacuum lines going to the bottom of the Opti, but only one vent hole. There are butt connectors on the wires going to the crank sensor in the timing chain cover. Every bolt on the transmission pan was loose. the heater hoses were routed completely wrong. I just keep finding more and more crap. I'll piece it back together again slowly, and make sure it is done right.

Well, took off the old Opti and it had alot of water in it.. It was also from an older model because it had no vent hole. Put the new one one and it runs great. Hopefully I will have no more surprises with this car.