Hello all, I’ve been reading and reading and reading….. I see a lot of great information and things that have made perfect sense and some not so perfect. Of course my interpretation of some things is we will leave at limited. Okay, so based on that gibberish you can probably assert I haven’t figured out the problem I am having.
I have just purchased my 1st Camaro, hotrod, or gas guzzler however you view it. I was towed home in it about 4 weeks ago and it was AWESOME! As time goes by and the more money I am pouring into it the uglier my wife is getting. At first it was like “ok honey” now it’s “when are you going to sell it dear?” So I have to get this baby going or loose it forever.
Here’s the history: 94’ Chevy Camaro, LT1(P), 6 speed, Tee-tops. I work with the previous owner. The water pump went out on it and he tried to fix it. Emphasis on tried! While he was working on it he came upon some bad personal fortune and had to come up with money quickly…. Lawyer type quick. Anyway I feel I got it for a steal at $1k. It has 167k miles and was running perfectly before “he” attempted the water pump fix. He did tell me it wouldn’t start now but he figured he had gotten the plug wires wrong or something. Well at that price I figured wth I’m willing to stick my neck out a bit.
SO: After fixing the water leak tried to crank it, it would do nothing but spin over.
I pulled the IGN CTRL MODULE and had it tested, it checked bad so I replaced it. Still wouldn't fire. I ohm'd the coil it ohm'd well over 9K so I replaced it, still wouldn't fire. Changed the distributer cap, rotor and plugs, still wouldn't fire. Found excellent video on YouTube about the Opti-spark. DVOM'd it and according to what I’ve read it was supposed to have had 4 VAC while being started. I had zero voltage so I changed the opti-spark. It's the old style with the splined shaft which has a master spline... so I am sure I haven't changed the timing.
This time however upon trying to start the vehicle it does fire and start after many revolutions. And every start after is the same way, it takes approximately 20 seconds of cranking to get it to start. Once it starts it idles very rough and will only clear up or level out when foot is applied to the pedal. From here you can push the pedal all the way to the floor (hoping to increase the rpms) but nothing happens, it's as though you’re not touching it at all. When you release your foot from it the engine stumbles and dies.
I purchased a GM code reader, which when plugged in is supposed to flash the Computer codes, but when I plug it in and turn the IGN on, none of the lights flash, the fans come on and I hear some clicking (in the ENG compartment) but never get the ENG ck light to flash anything. According to the directions it should at least flash code 12, but never does even after leaving the key on for almost 5 minutes. The only two lights that remain on are the “skip shift” and “check gauges” lights.
So I have read up on how to check the TPS, I have ohm'd it and on the 20K range it shows 7.65, when you rotate the TPS the numbers decline all the way to 1.5 and it appears to be smooth and not erratic. I checked the power wire for 5 VDC and it has 5 VDC, I checked the ground wire and it is also good.
At this point I am at a loss. I certainly would be open to suggestions, or any information that would put me in the right direction. I read somewhere on this site that their opti-spark had been assembled incorrectly. But they never indicated exactly how they came to that conclusion. I have verified my plug wiring but after reading about having the #1 plug wire incorrectly installed that will be the 1st thing I recheck in the AM to include every wire.
Anyway guys, I really could use some wisdom on this. I would love to actually drive it! =)

 

hows your fuel pressure?

 

The worst thing on the 94 is that the optispark is vulnerable to moisture fouling it up - that is something they changed a year later. The opti also had a different drive which can get confused when reassembling it, but it doesn't sound like that was apart since they just did the waterpump. To your knowledge, did it get all wet?

 

You can't scan a 94 with a device that shorts the ALDL pins, and flashes the codes on the SES light. 93 was the last year that would work. Yes, the $30 Actron says it works on a 94, but it WILL NOT. You need a real OBD-I scanner, or free scanning software and a cable.

The fatal code is DTC 16 for loss of the low resolution pulse signal from the Opti. That shuts the fuel system down. But it does not turn on the SES light.

While the splined shaft on the Opti is keyed, and in theory can only be assembled one way, it is frequently misaligned. Everyone who has a problem insists it will only go on one way, and that they assembled it correctly. And almost all of them find out they were wrong.

To check the TPS sensor, you verify 5V on the reference wire (gray wire to black), which you did, But you don't "ohm" the signal wire (blue wire to black). You simply measure the voltage. Closed throttle voltage should be between 0.20-0.90V. Then slowly rotate the blades open, and the signal voltage should increase smoothly - no spikes or dropouts - to about 4.0V higher than the closed throttle voltage.

 

Okay, I would have sworn you could not "mis-time" since there is a master spline, but stranger things have happened. sooo.... I will tear it all back down in the AM. Would it be safe to do this?

Set the #1 piston to TDC, point the opti at the #1 plug wire and engage the shaft and splines. In theory this will ensure the timing is set properly?

teamstream ---> could you elaborate on how to check the fuel pressure on this vehicle? I can probably loan a tool a fuel pressure kit and check, where do I tie into the system?

Kevin Blown 95 TA ---> no he didn't remove the opti, but I have. And yes he had to have soaked it.

So in am, check correct plug wire routing and if that checks out I will check the tps voltages as indicated above then if that is good I will pull the opti back off and try to ensure correct timing.

Thanks guys.

 

Is this with engine running? And should I be on AC or DC voltage?

 

DC voltage.

Before removing the opti, I would again check the plug wires. Carefully check the indexing of the opti if you get to that stage. You can attempt to start the engine before you put the water pump back on (reconnect your MAF). It won't hurt anything if you let it run for a short time.

 

Okay, the TPS reads .56 vdc to 4.48 vdc, smoothly. I have re-checked the plug wires and they are correctly installed. So at this point I will pull the opti.

According to you picture I have it indexed spot on. The only reason I was going to pull it down again is:

 

The TPS would be causing the problems you describe.

 

STOP the press's! Injuneer you hit a home run!

Okay, I pulled the opti, I wasn't quite 180 out but about 100 degrees.. I lined up the splines and it installed just fine, I removed it rotated about 3 or 4 and guess what... it installed,, I removed it rotated another 3 to 5 splines and it installed! The same is true on the block side it can and will install incorrectly, surprisingly easy!!

SO WHAT IS THE FRIGGIN USE OF A MASTER SPLINE ON THIS APPLICATION!!!!!!

I am headed back out now to VERY CAREFULLY line up the master splines and ensure they are correctly engaged. Hopefully this will fix the issue, fingers crossed.

Again thank people!!!! I really appreciate your time and dedication to these forums. I would have NEVER thought I could have mis-aligned the timing.

 

Any research about the indexing the spline drive opti should have netted you the information that Injuneer posted. People get them on wrong all the time. Apparently, the point of the notch is to tell you where to locate it for correct installation.

The same thing goes for the pin drive opti. It has a special slot for proper indexing, but you can install it wrong, too.

 

Well I am a believer! I believe you can mis-time the opti even with a master spline, AND I BELIEVE IN THESE FORUMS AND IT'S MEMBERS!!!

You guys have been awesome and I want to thank you all!

If you read thru my 1st post you know this is my 1st Z28 (hot-rod), and now after driving it any thought given earlier to turn this (sell) is now gone! I love this CAR!!! lol

Thank you.