Ugh... Right after I washed it a couple of weeks ago, on the way home, my GTA's ('90, 305 TPI, 700R4) CES light came on for a couple of minutes. When I came to a red light I shut it off and restarted it. The light came back on but went out again about fifteen seconds later. When I checked for codes it spat out a 42 and a 43. Great...

Now yesterday, after about an hour and a half of driving, the CES light came back on. I was close to home so I kept an eye on the gauges and proceeded back. I didn't notice any drivability problems at all. This time when I shut it down and restarted the light didn't come back on like it had the last time. Today I checked for codes and it spat out a 42 and a 43 (didn't clear them last time) and now a code 45.

According to my Haynes manual 42 and 43 are ignition related and 45 is a rich exhaust. The only "probable cause" shared by the three is a defective ECM.

That is where I stand right now. The problem isn't at all repeatable which is the biggest kick in the teeth. Any ideas?

 

Well, if you have an ignition problem, you may no be burning all of the fuel, making for a 'rich exhaust'

I'm not sure what to look for, but I'd check out the ignition. Loose plug wire maybe? Probably something a little more involved than that though...

 

The leads and cap/rotor are new, just before it came out of storage about a month ago. The distributor is a rebuilt unit, with an Accel module, installed along with the leads and cap/rotor before the first of the two CES lights. The plugs are new, installed last Thursday, before the second CES light. The only original part is the coil.

There is a little more to the story. When I brought it out of storage last year (with all original ignition parts), on it's first run, the CES light came on for a few minutes. Again, it disappeared once shut down and restarted. At the time I didn't think to check for codes. This makes exactly three times the CES light has popped up since I've owned the car, twice recently, all behaving the same and very intermittently. Any suggestions?

 

Sounds to me like a pickup coil in the distributor or ignition module that is bolted inside the distibuter base.You mentioned something about washing it.Any moister that might have enter the distibuter which can happen if you used a high pressure washer could have shorted these out.It may stop coding given time to dry but if not my first replacement would be module.If you have the book for your car it tells how to check if module,and coil are bad.Your problem scares most people but if you take the time to check each piece of the ignition system(and there really arent that many)you'll track it down quickly.Just dont let the book lead you away from ignition and get you to testing and doubting emmission sensors(oxygen,knock,MAP)these are not the cause of your problem I gauruntee.

 

I could swap in the stock module but the problem is so intermittent that I may not know for months if it's gone or not. Like I said, the very first CES light came with the original distributor and module, while the recent two have been with a different distributor and aftermarket module.

I thought it was probably moisture related until that last time. There was no moisture in sight and it had been running for well over an hour.

If it pops up again I'll stick the old module in it and hope for the best, but other than that I' not sure what to do.

 

O.K. Even though you're a Leafs fan, we'll try to help out anyway. (Since they're part of the original six, they're still a REAL hockey club, not associated with any greasy waterfowl...)

Check the knock sensor connection for moisture and good contact. Check the EST bypass connector for the same. Ditto the distributor multi-wire connector and coil connections. Since you have a rebuilt distributor, it should have had a new pickup coil and reluctor. It's a good thing to check over just in case. While you're in there, check the HEI switching module connections and ground/mounting screws.

Ignition coils usually don't come and go intermittently. They just go with heating, and maybe get a little better after cooling. It is possible to have a crack in an epoxy filled coil that is allowing water penetration, however.

 

lol Thanks. I was sure I had changed that avatar. Hey, so what if we haven't had a cup in nearly forty years.

Thanks for the advise. I was thinking, could one of the first two codes simply be from when I set the base timing a few weeks prior? I disabled the advance properly and the CES light was on while adjusting the timing (normal, I presume), but I didn't think to clear any codes once I had finished.

Considering the nice big shower I gave the engine bay this evening I'm fairly sure it's not moisture related afterall. I covered the alternator and as much as the distributor as I could (tough to completely cover under the plenum extension) before unloading a can of degreaser but I'm sure the distributor still got wet along with EVERYTHING else when I rinsed. No problems firing up afterwards (while still wet), no codes on the way home.

If only it were more consistent...

 

The cool thing about Packard Electric Division's WeatherPak connectors is that they're a good pin/sleeve contact design, have a pretty positive retaining means for the pins, and have very good seals on the pin and wire entrance sides. The seals do a very good job or keeping moisture out. Unfortunately, if you DO get moisture in a connector, they also hold it in. You may have to disconnect some of the connectors and blow them dry.

 

All I did was clean the connectors with a shot of WD40, and put a little dielectric grease on them before hooking them back up. As expected (being as intermittent as it is), no codes yet. Granted that was only one day to work and back (it's not my daily driver) but I have my fingers crossed. If it pops up I'll be back to complain. lol Thanks for the advise.