I have a buddy of mine who has a 1994 Z28 and just replaced the opti and I beleive he mounted it wrong because it is backfiring through the intake. So the ignition timing has to be off. It is a 1994 so the opti is splined.... that makes it a whole lot more difficult to set unlike the 1995's and up. They only go on one way. Send me your pics and how too's... SHbox.com doesnt have them on 1994's.

 

actually i thought 1995+ are harder to set right. 94s have the dowel that only goes 1 way.

 

+1 on this. Ive been stuck on this for like a week. IDK if the opti is bad or not because I cant seem to get it on right.

 

The 95's have the dowel pin on the cam.... not the 94's.

 

damn, this sucks. i thought i had the one way only opti.

 

Dude. Your avatar is ****** scary!

 

haha. its old though had it for like 3 years on the computer

 

ZEX-Z I am in the exact same boat as your friend. I don't know what the hell is going on.

 

did you guys get new opti's? i had this problem at work, we ordered the summit brand and i had to return 3 of them because they were phased/indexed wrong compared to the stock one i took off, they were all 120* off in the same spot, so there was a mfg. problem...sent them back, did a little bitching, and got a gmpp one for cheaper and it worked mint

 

When cyl 1 is on TDC, where should the rotor be pointing in relationship to a clock? Maybe I just have mine way off or something.

 

so 94 optis can go in two ways if im reading this right ...if so how do u make sure its on right i havent had my car runnin for over a month because i changed my opti and i cant get it to runn

 

to the top. I also can't get my car to run!

 

****** opti's..... Gm....... Damn you! The person who invented the opti will burn for his mistake......

 

94s have a splined coupler, or shaft. Look at it real close, it has a master spline. It can only go in one way unless you force it. I had one come in the shop fucked up, and it turns out the had the splined shaft off and it was jammed in tight.
The 95+ has the dowel on the cam. Those should only go on one way too, but not sure if they can be installed incorrectly. They do have 3 dif "slots", for lack of a better term, that look like the dowel could fit in.

 

i took my opti off again to see if it was on wrong ang i put it back on and slid right on then i tested my spark and spark plugs are gettin spark i dont no why this damn car is runnin so i no what u guys are goin thru..i hate opti's!!!

 

+1...they have a master spline that is meant to go on only one way. It is possible to force them on in the wrong position so look careful, line up the splines, and patiently pop it on. You'll know if its on correctly, it'll slide on nice 'n flush.

I've heard of guys forcing on the dowel type incorrectly also....so nothing's fool-proof.

If you're having massive backfire, first thing I would check is Plug wires and firing order. Most common mistake is switching cyl 5 and cyl 7 plug wires. Most of the time if you only switch two it'll still start and just run and pop horribly.

Surprisingly, I also had the same problem with Summit Opti's. They sent me 2 back to back that were faulty from the factory. They also ended up sending me a GM unit instead, worked perfectly.

 

c'mon guys we need some input of this ...i no i especially need somthing to get my car runnin again..how likly is it for 2 gm opti's to be bad any idea?

 

They can go in any number of ways if you have a big enough hammer.

It seems impossible to install the 1G opti wrong, but there have been a few people over the years who have managed to force it on in the wrong position.

 

have you checked firing order yet? start with the simple stuff, and report back.

 

did you end up getting any money off by bitching?