We just installed a new GMPP Opti unit in our 1996 Z28 and the car won't start. Prior to the install, the car ran well, but had a no-start-when-wet problem and then recently developed a 'misfire in cylinder 6' issue.
As part of the Opti swap, we replaced the plugs with factory AC Delco units and carefully installed new stock wires. The new GMPP Opti installed directly in place of the suspicious Accel Opti.
Our work was meticulous and took some time, and the no-start condition has us feeling frustrated.
The engine spins freely and doesn't even sputter. We can hear the fuel pump prime as expected, and smell fuel under the hood, so my preliminary guess is that we have no spark.
Where do we start with troubleshooting this problem?

Thank you,
Rick & Kristi

 

I would check the fuel presure because it is so easy to do. I would then check the connections and check for spark. There are many posts and step by step instructions on here. Goodluck

 

So do you or don't you have spark? Check that first. If no spark then check the connection from the ECM to the opti. If the computer doesn't get a signal from the opti, it won't start and it won't throw any codes.

 

Anything is possible and the new GM Opti "could be" defective, it sounds like you've done a quality install. The optical module within the distributor generates two pulses (high & low-resolution) that are sent back to the PCM.

If the high-resolution pulse is missing the engine "can" be started, but with some "extensive cranking." Once started with the high-resolution pulse missing, a DTC code #P0372 should be generated.

With the low-resolution pulse missing (I believe), it won't start at all (no timing reference). Then you'll need a Scanmaster type tool to diagnose the problem.

I just had the optical module go bad in my MSD Opti that was only about three months old.

WD

 

Let us know what you come up with. I have the same problem.

 

The quick 'n dirty way to check

Spark
Pull a plug wire, stick a long screwdriver into the boot so it hits the contact, hold the screwdriver(don't get zapped) against the header with a little gap between the screwdriver and header, then have an assistant give the key a crank. Do a plug wire on both sides.
If you see spark, try the cheap fuel test. No spark means you're pulling the opti off and taking a peek inside it to see what's up.

Fuel
Shoot some ether into the intake, have assistant crank it. If you have spark, the ether should fire or try to start.

 

I've personally forgotten to hook up the connection from the ECM to the opti more times than I would like to admit.

Get in the car, try to start it, WTF

Forgot the opti

 

I hate to say it,my good buddy has gone through AT LEAST 8 OPTI'S.......EVEN BRAND NEW OUT OF THE BOX,sold by the speedshops.....but the good news is he put the MSD and all seems well..I am so affraid if something happens to my 96...I'm going MSD...but in your case I hope it's something easy

 

When we installed the new Opti, it appeared that the unit could be installed and indexed in only one position. The pin on the end of the camshaft engaged a slot on the back of the Opti drive.
Is this correct? Or is is possible to install the Opti out of phase?

 

Once the cam dowel is "correctly engaged" in the Opti hub slot (on 95-97s), the distributor will "easily" slide back flat on the timing chain cover with mimimal hand pressure. If it isn't engaged correct, if won't fit flat (without a gap).

WD

 

We verified proper injector pulse using a Noid lite, and we confirmed we have spark at the #1 plug.
Upon cranking, the engine actually 'runs', although it seems like only 100 RPM or so. It appears as if the starter spins the motor faster than its current idle speed. The engine is completely unresponsive to the throttle, and the engine will run for about 5 seconds.
Our Interceptor scan gauge shows one DTC - 1351 Ignition Coil Control Circuit High Voltage.

Help!

 

WOW....I'm going through the Exact thing you are right now. When I crank it, I notice I get like 100-200 rpms but no start still. I dont have a scanner so I can't check for codes. I know I installed my brand new opti right, I took it off and on 3 times. Let me know what you come up with, I was thinking of flashing my pcm

 

While it should only go together one way, it is possible to put the pin in the wrong slot. There have been a number of people who have sworn they put it together correctly, only to find out they made a mistake.

http://shbox.com/1/opti_back.jpg

 

I've never got the hub engaged incorrectly and I've replaced an Opti many times (too many times actually). However as I said above, I don't believe the distributor will slide flush with simple hand pressure if the dowel pin is not in the correct hub slot.

If it is wrong, I guess you could "force" it down with the three distributor bolts. Ouch!

WD

 

Any suggestions as to what we should try next?
We appreciate the help,
Rick & Kristi