I don't want to be long winded but want to give the complete story.

It all started 4 months ago with my 94. I was driving one day and it just stalled. Started back up, drove for about a mile and stalled. It kept on doing this all the way home. Check engine light was on. Checked the codes and got 16, 36 & 42. Changed the coil and ICM. It still stalled but I no longer got code 16 and I got code 42 as soon as it started up and the 36 when it stalled. Had the old ICM tested and it was fine so put it back in. Had the PCM tested and it passed. Changed the Opti wiring harness and put in new plugs and wires. Ran like crap but didn't stall and no codes. Check the plug wires and one was crossed. In the process of removing the belt tensioner to check the plug wires I broke the 16 year old plastic end on the coolant temp sensor. Then the brain fart. Drained the radiator but not the block. Guess what happened next!! I had packed a towel under the water pump before pulling the sensor but it got soaked. I put everything back together and the car fired up and ran perfect. I took it for a short drive and everything was great. One week later after doing the brakes I took it for a drive. Ran perfect for about 7 miles. While sitting at a stop light it started to surge and sputter then died. Would not restart. Had to get towed home. After cooling down it will now start right up but dies after a few seconds. Check engine light does not come on now and no codes.

I have posted this problem before and have received lots of input from you guys. It has all been very helpful. I am not a mechanic, just a weekend warrior.

Normally I would think that I have a fuel delivery issue except for the surging part. Or did my opti get wet and is dying?

 

At least yours is acting up all the time.
My 92 has to be hot, driven (commute or on track) and then it acts like it doesn't want to run. After 5 ICM's I'm not convinced its ICM related.

For yours I'd drain the coolant, pull the water pump, pull the opti, open it up and see what you have going on.
Now comes the hard part - check all the wires and see if any have the insulation worn off.

Also, even though your new ICM checked OK it coul be bad.

 

Sounds like the Opti is unhappy.

Codes 16 and 36 are Opti codes.

Code 42 is Electronic Spark Timing circuit.

The gasket on the opti cap tends to get dry and crumbly (leaky). You might have water in it.

 

I'd try a different computer. Yours could be good cold and intermittent hot.

 

BTW, I snapped the end off my CTS too. I've been driving it like that for 3 years.

I have the piece that broke off. I keep telling myself to glue it back on but I never listen.

 

I had ordered a new one from a Chevy dealer. Waited over a month and never got it. Took mine to NAPA. They sent it in for a rebuild. Rebuild place sent it back saying nothing was wrong with it.

 

I have a 4 month old project sitting in my driveway too. Superram install gone bad.


May 25th, 2010. Remove AS&M Runners & Plenum. Wait two days to get SuperRam.

Pull ****ty intake base and replace with ported Big Mouth.
Pull valve covers realizing super ram runner bolts can not be installed with them on.
Discover that drivers side valve cover requires wiper motor to be removed.
Decide since valve covers are off and look like crap, paint them.
Remove wiper motor.
Install Super ram runners.
Install Valve covers.
Install Holley AFPR.
Install plenum.
Realize that the fuel rail purchased with the SuperRam have different size inlet/outlet connectors.
Remove Plenum.
Remove runners.
Swap injectors and Holley AFPR back to old fuel rail.
Install fuel rail.
Install runners.
Install plenum.
Start car.
Runs like crap.
Discover vacuum leak.
Remove plenum, fix vacuum leak.
Reinstall plenum.
Discover AFPR is leaking gas into vacuum line.
Remove Plenum.
Investigate AFPR, decide to install old FPR.
Reinstall Plenum.
Car runs. Barely.
ECM takes a ****, throwing 7 codes at once.
Replace ECM.
ECM Shows knock sensor code.
Replace knock sensor. Snap off old knock sensor in block. Remove drain plug from other side of block and install knock sensor over there.
Low fuel pressure at rail.
Replace fuel pump.
Drop one of fuel pump assembly screws.
Remove spare tire and find fuel pump assembly screw in spare tire holder.
Reinstall spare tire holder.
Install screw making sure not to drop it.
Fuel pressure still low.
Block off return line. Fuel pressure holds at 60 PSI with line blocked off.
Release return line. Fuel pressure plummets to 30 PSI.
Decide that 30 PSI isn't enough for good performance. (Car runs sluggishly)
Pull plenum.
Remove FPR discovering that it was again leaking fuel into the plenum.
Reinstall Holley AFPR because the diaphragm looks ten times better than the stock FPR.
Holley AFPR leaks.
Fuel pressure holds when return line is blocked off, Holley AFPR squirts gas out of vacuum port.

Present. August 9th, 2010.

 

Pwnage1337

You my friend have a lot of patience. Wow

 

Maybe too much patience? Not sure.

I forgot to throw in there remove rocker arms and end up redoing the entire engine's valve lash.

And new Holley AFPR (512-501) on the way. Should be here Wednesday. This never ends

 

Did I read it wrong or did you not replace actual opti? If not, there you go.

 

I have not touched the Opti. I suspected the Opti from the begining but didn't know for sure. I was trying to prevent throwing money at it. Looks like I might have to now.

 

 

I checked the fuel pressure and it is about perfect. Left it running for awhile. It sounded like it was skipping a little bit. Not as smooth as usual. Let it warm up. Fans came on at 228. Cooled down to around 212 I think. Ran a little longer then stalled. Would not start back up. Fuel pressure was fine through the whole thing. No check engine light but checked for codes. Got 16, 36 & 42.

Opti Spark is now ordered. Bought a new water pump, Thermostat and knock sensor.

 

Same issues All Holley. Trashed that AFPR with a another make [ friend donated it ] and all issues disappeared.

TJM

 

You can find those sensor pigtail connectors at NAPA Auto Parts stores. I broke one off once when I was swapping out my 02 sensors, but NAPA hooked me up with a new one.

 

I'd swap out the plugs and wires for new ones, too, while you're in there. For plugs, LT1's like NGK TR-55 Double Platinum. I like the 7 mm wires made by Taylor, Belden, or AC/Delco.

You should go ahead and order the O.E.M. spark plug wire looms and holders, too, since the old ones are brittle and will crack between your fingers as you go to remove them. Order them online from Mid-America Motorworks (MAM).

 

Your symptoms are almost exactly the same as what happened to my 94. The codes you are getting point to the opti. Replaced mine with an MSD as well as a new water pump 7,000 miles and a little over a year ago. Have not had any problems or codes since.

 

Plugs and wire are already done. Used Taylor 8mm wires. I drilled the looms out a little to get the wires to fit. Not of the looms broke.

 

What about the two-wire holders that snap together? Suerely one (or more of them broke.

Every one of mine broke when I went to replace them.

 

While you're waiting on your new Opti why don't you disassemble the old one and see if it's got crud in it or not. There's not many parts in there and I have, on many occasions, cleaned the optical sensor and the slotted wheel and all was good. Clean the sensor by using some alcohol and a lint free cloth. Just dampen the cloth and run it through the slot on the sensor. Make sure there's no moisture in the housing either.

Electronic components (optical sensor) usually just quit and they don't like to be intermittant. I'm betting on some dirt, moisture (turnin to steam possibly when hot) or some rusty places on your slotted wheel. Since yours is just a fancy paperweight right now you have nothing to lose.