Brent94Z

Hey Guys!

Long story short...

My 94Z convertible broke down a while back. Figured it was the opti because it just DIED and had no spark. Bought a Delteq system because I thought I'd get lucky and maybe not have to change the opti. Wrong. Opti actually broke in pieces internally. So, installed Delteq and a used opti I got from a friend. Shouldn't have done that because car idled erratically and would detonate something fierce under load above 3k rpm. Took it apart and that opti had some rust on the opti disk. Yikes. Bought new opti but got half of it from AutoZone and the other half from Discount... neither had the "complete" opti so had to do this. Installed this opti and now the car won't even start. ARRGHH!!! It acts like it wants to in that the first time I cranked it over it backfired and sputtered a bit. Now, all I can get is an every so often light/minimal backfire out of it.

I know the Delteq requires a few revolutions to "get its brains" and on the first opti I backfired something fierce the first couple times I tried to start it but then got sync'd and ran OK (the Delteq diagnostics show good). Now, I've cranked it probably 30 times and it is getting fuel and must be getting spark because it has a "weak" backfire once in a while but the damn thing will not start.

What I'm wondering is have any of you experienced something similar? My buddy (a very good mechanic) installed the opti (94 version) but he had never done a 94 before... only a 96+ which he has done several times. He seemed confident that he knew how it went together (remember, I bought this not assembled) but could there be something that was missed to cause the symptoms above?

I'm thinking it has to be the opti because the thing at least started and ran before we stuck the new one on! If nobody has any ideas my next step is to just get a new one from GM and try it. But, I'd rather not spend the extra money because this opti was like $450 (yes, I know... too expensive but I was in a hurry and wanted one quickly) and I don't think they'll take it back since it is now "used" even though the damn thing appears to not work!

Thanks for any advice!

Guest47904

Brent, don't buy anything until you check the old one out first.

Double check the wires are in the correct location on the cap.
Use this diagram.
http://shbox.com/1/opti.jpg Thanks Rob for the diagram
If all that looks good, check to be sure the opti is installed correctly by placing a cylinder at TDC. On a vehicle I have no history with, I use a back cylinder.

Once that cylinder is at TDC, remove the cap from the opti and notice where the contact inside the cap is for the cylinder that you put at TDC. Pay attention to where the contact is when the cap is in place. Now look to see that the rotor is pointing to the location of where the cap contact would be.

Injuneer

Its very easy to get the splined shaft misaligned. Look at Shoebox's photos and make sure you have the "missing tooth" in the correct location. One tooth off and it runs bad, several teeth off and no start.

http://shbox.com/1/93-94_opti.jpg

97FormulaWS-6

I was thinking the same thing... I'm thinking he got the cam drive pin into the wrong location... Very easy to do; I did it the first time I swapped my opti, and that's how my car acted.

Sputter, backfire, and just didn't run... pulled the opti out, and sure enough, I got the camshaft pin into one of the reliefs, and not into its groove.

My bad.. I didn't know those were tooth style.

kingman109

ditto - did that after a cam install - months later and after replacing half the engine we noticed it- car would crank and crank- and would cough like it was about to actually start but wouldnt.. prior it was misfiring awful under 2.5k and would stall. Also prob will want to replace your plugs if youve been trying to start a lot- mine all fouled- and took a while to figure that out too

good luck brent

urbaNHunter44

I've done that one as well.. actually about 3 times before I got it right!

Injuneer

His 94 has the splined shaft, so it even easier to screw up than the dowl pin drive on the 95-97 cars.

urbaNHunter44

Yup, I did my old '94. Jesus you'd never think it was so hard to line up that little shaft haha

BlackScreaminMachine

I did the same thing the 1st time I put the 383 in. If it doesnt go on smooth and you have to force it, its off. I managed to put my opti in wrong.

Useually I find out how it fits into the cam sprocket, dab some white paint to get a reference. then take the splined coupling out and match it to the opti, then try to put it back on the car. More or less after some trial and error, it will just click in.

indieaz

I've installed it wrong myself - the spline was off right about 180* hehe. Actualyl it was my friend who did it - at any rate it's really easy to get he spline misaligned. It's not really notched as well as it should be making improper alignment relatively easy.

94arcticwhiteM6

you guys arent helping my confidence level here. i know its something im going to have to tackle and im not looking forward to it.

Injuneer

It shouldn't be all that difficult. Its simply a matter of matching up the bump on the splined shaft to the missing tooth on the cam sprocket. In theory, it can only fit together one way. So people assume if the shaft slides in the sprocket, it must be right. In fact, with a little excess pressure, you can force the two pieces together incorrectly.

Loadre

If indeed you misaligned it and tried to run it like that, you not only are out of timing, but you're also putting a HELL of a lot of stress on the bearing of the opti. I don't know how everyone is getting theirs misaligned. If you line it up right the opti will slide right against the timing cover like butter, anything less than that and pull it off to recheck.

urbaNHunter44

I trashed one by misaligning it. Just stripped out the back of it.

How I finally did it, was I put the opti down there with the cap loose, so that I could spin the rotor inside with my finger. After having lined them up visually before I put it down there, I moved the rotor back and forth about a half an inch (all I could really be off after having done it by sight) until it slid in extremely easily. You should not have to force it AT ALL. Then I just tightened the cap and it ran perfect.

Make sure to silicone that cap good too, I did that and never had any problems with rain water or car washes afterward.

Brent94Z

Thanks very much guys for the info and suggestions. It is much appreciated!

I just got off the phone with my mechanic buddy and asked him many of the above items. I asked him about the splined shaft/missing tooth and he said he is fully aware of this and knows he got it on correctly because of how easy/smooth it went on.

I suggested that maybe I got a bad opti and he didn't think it would backfire like it does with a bad new opti.

I'm going to call Delteq and see if maybe the gizmo box somehow "memorizes" something that could be messing me up (even though I've disconnected the battery to clear things out). I doubt this is it because I know the Delteq takes a couple attempt to sync up but shouldn't take 30!

I think the next thing I'll try is to just run a set of wires to the opti and see if it runs without the Delteq in the picture. Maybe the Delteq "went bad" out of the blue (unlikely) so I'll rule this out before taking the opti out again.

On a side note, I thought was odd because I had never heard people mention this before, but I talked above how I got the two pieces from different stores. Well, we ended up having to take apart my old opti to "rob" it of the spacer ring between the cap and the other half of the opti. I thought this was a bit strange I didn't get everything I needed NEW and had to steal the spacer from the middle of the old one??? Has anybody heard of this before? Wonder if it's possible if one of the pieces is an incorrect part and messing things up? Doubtful but I don't know a ton about these things so trying to cover all angles

Thanks again for the help and suggestions guys! If you have something else for me to look at/try please do mention it!