CCC system and E4MC Questions....

[Canon_Mutant]

It matters to have the ecm in diagnostic mode. What is it A-B on the OBD1 guys? Don't have a manual handy. Diag mode, KOEO, and you should get 25 secs of Solenoid clicks activity. Be really surprised the thing runs hardly at all with no solenoid control at all but stuck full rich rather than full lean, maybe it would run?

 

[wnagel]

If the carb run rich , a high problem is the mcs , when the mcs is off the default position is "rich"

 

[Clone TIE Pilot]

The off position for the M/C solenoid is rich, the on position is lean. So if the solenoid fails, it default to rich.

 

[oxide80]

Thanks for chiming in on my question, so I ran a jumper 12v power and ground straight from the battery to the MCS solenoid and still no clicking. I unplugged the MCS and ran it with no changes with the drivability I mentioned in my posts.

I checked the canister purge valve at the carb and no leaks as Airboatgreg suggested.

All security plugs are missing, so im assuming its been off and tampered with at some point in its life. Reman solenoids seem to be under $30, cant hurt to toss one in i guess.

Any suggestions on things to check before to dismantle the top of the carb? Like the rich/lean metering screws or other possible causes? Special tools beyond the torq screws and small punch for the acc pump lever?

 

[1985olds442]

I just got home, went and checked.... both security plugs have been removed from a/f mixture screws... so someone has been into this thing. tomorrow im going to check the canister purge valve and check the soleniod to see if it clicks with battery power/ground.

I had a similar problem after I did a carb rebuild. Solenoid had power, but It would click for a bit when the engine was cold and then stop. It turned out that the new solenoid plunger wasn't quite the same as the original, and it would get stuck on the lean/rich stop. I put the old one back in and problem gone.

 

[oxide80]

Soleniod is not clicking. I jumped straight from the battery. I have 25.8ohms resistance through it. Dwell seemed to be with in tollorance too. I have one more place to call before I do the rebuild myself.

 

[1985olds442]

Soleniod is not clicking. I jumped straight from the battery. I have 25.8ohms resistance through it. Dwell seemed to be with in tollorance too. I have one more place to call before I do the rebuild myself.

If the plunger is stuck, you won't hear a click. I jumpered mine and heard nothing when I was having my issue. The click you hear on a working system is the plunger bottoming out on the solenoid. It's just a thought, but if someone's been in the carb they may have replaced the plunger with an aftermarket one. I took meticulous measurements of the new and old plunger with a caliper and the difference in the opening of the plunger was 0.1 mm, but it was enough to make it get stuck.

It seems like the computer is sending a signal since you have dwell and the resistance seems ok, so my guess is the solenoid is ok.