I have a 97 Z28 with LE stage 2 package, longtubes, ETC. Anyways, I just replaced the wires with msd 8.5, new plugs(NGk TR-55's) and New MSD coil. The car seems to have a very low miss when I start to accelerate then it will take off and go. Also, while cruising at a steady speed and then quickly giving the car half throttle, it will back fire(sounds like up front possiblely through the throttle body) then take off. I pulled all the plugs and they are all burning clean. Also, the car runs very rich, could it be loading up? WOT seems to not have any problems. i also replaced the opti with a used unit that I found off a member. THere are no timing adjustments,right? Thanks for any suggestions,Troy.

 

I know when that happens on a nitrous car with a wet kit, it's fuel puddling in the intake. Looks like you have some extreme rich condition or somehow fuel getting into the intake?? Not sure maybe someone else can chime in.

Brian

 

BTW, I have 58mm bbk throttle body and 38# injectors. Thanks.

 

Any suggestions? Thanks,troy.

 

hey man, sorry to hear about some troubles. maybe try and put the stock coil back on and see if it does it? my friend got an msd coil and he had to put his stock one back on...

 

I'd say put the stock coil back on too, I had some issuses similar to that.

 

I doubt its backfiring through the TB. Did you check the gap on the plugs before they went in? I am not sure why its acting up. When I rode in that car it ran just a smooth as mine. Where is Mason, OH? You might need it scanned to check things. A Dyno tune would be awesome for the H/C package too. Most LT1's run real rich, I know mine does. Also sometimes my car will blow up some gas in the Y-pipe, but thats only occasionally. I have black carbon bumper marks. All I know is its Lou's fault

-Dustin-

 

That car was my buddies before you bought it off him. It ran fine when he had it, everything was brand new....why would replace the wires, plugs, and coil on it? Anyways, I woudl try putting the old coil back on, check and make sure you don't have any plugs crossed, or that none are burnt already. Also if you get the plugs to close to some of the electronics in the engine bay it will cause a miss also as the electronic signals mess with the spark.

Good luck.

 

Why would you do this? I even heard it was a nonvented from a 94?!? Rule of thumb, never replace an opti with a used one. Hell most people wont even do just the cap and rotor.

-Dustin-

 

I replaced the opti because I cleaned the engine and then It started to miss. (I know, thats a big no-no, but it really needed to be cleaned up. I'm very ****). Anyways, I replaced the opti with a good used one, that fixed the miss. I changed the plugs too NGK TR-55's because the ones in it were all carboned up. The car ran great until I washed the engine. The car seems very responsive and no problems until it gets heated up, then it is sluggish when I rev it. If I idel it up to 2000rpm and then rev into it, its fine. I'll put the original coil back on and see what that does. Thanks.

 

The opti is a vented from another 97 Z28. The wires are away from all heat and electronics. The plugs are all gapped at 50-55 ( I just pulled them and re-checked today) . This car also has a terrible vibration at70mph and up. Sounds and feels like the tranny is falling out. Mount is new and tight. Could it be the rear gears vibrating? Thanks,Troy.

 

hehe, i bet you just arent used to 3.73's and a steel driveshaft now my room mate got brand new mounts too and it changed the angle too much it vibrated so bad he couldnt get it above 65. he had to change it back. When you first bought it did you take it above 80 when you left here? if so does it still feel like that or did it change after you put the mounts on? if it changed then put the stock mounts back on or new stock mounts and get an aluminum driveshaft from a 98 and up or the 1LE alumin driveshaft. when i had it it did vibrate above 65 a "little". but my little could be huge to you. i would go with the stock mounts and an aluminum DS if nothing else was changed when you left here. let me know what happens and if you need more help!

 

This car used to run great - hope you get it back to the way Lou had it. Used to walk me on the highway with no problem - should run high 11's low 12's with the right tires.


As for the vibration - if you have an ES tranny mount - make sure that the shim is not installed. FWIW - mine vibrates as well at the same RPM with my ES tranny mount.

 

Car has a poly mount. sAME MOUNT that Lou had in it. The only thing I did was remove the rear training arm relocators.