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ISC Motor


Klr Ontherd

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Am attempting to change my ISC Motor (following instructions found here and elsewhere) but have run into a snag.

When attempting to adjust the plunger for the .030 gap the screw stops at about half thread. Feels as though it will take a fair amont of torx to get it to turn in any further.

Is this right ?

I cant see anyother way to get the required gap, but dont want to damage a new $180 part.

The plunger is fully retracted and did disconect the motor.

One other thing.

Once the plunger is retracted and the motor disconnected, Is it ok if the engine completely stalls ? Or should it stay at a low, almost stalling RPM ?

Mine completely stalled. So then shut of the ignition.

Hopefullly I can get some help soon. Dont want to be seen by the neighbors pushing my car into the garage. LOL.

BTW.

Is a 93 SLS 4.9 litre.

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Am attempting to change my ISC Motor (following instructions found here and elsewhere) but have run into a snag.

When attempting to adjust the plunger for the .030 gap the screw stops at about half thread. Feels as though it will take a fair amont of torx to get it to turn in any further.

Is this right ?

I cant see anyother way to get the required gap, but dont want to damage a new $180 part.

The plunger is fully retracted and did disconect the motor.

One other thing.

Once the plunger is retracted and the motor disconnected, Is it ok if the engine completely stalls ? Or should it stay at a low, almost stalling RPM ?

Mine completely stalled. So then shut of the ignition.

Hopefullly I can get some help soon. Dont want to be seen by the neighbors pushing my car into the garage. LOL.

BTW.

Is a 93 SLS 4.9 litre.

1. I personally cut the screw to fit, but I did not see yours. Manufacturers sometimes makes ISC motor which need "adjustment".

2. The RPM drops to 450-500 and the engine may stall particularly if it is cold and plugs wires are old. It is normal.

Any other problem?

The saddest thing in life is wasted talent

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I was able to get the screw to go all the way in on the old one. But it took a bit.

The engine was hot and the plugs, wires, cap and rotor are fairly new.

So your saying, if it does stall then dont worry about it and continue with the adjustments ?

BTW

Thank you very much !!

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Not workin out at all!!

I re-did the procedure this morning, but made the gap about .050 this time.

Again idled round 1900. But by applying the brake it brought the idle down to a fluctuating 750-900.

So took it for a drive.

Idled in drive at round 700 and seemed to run ok. Got back and put into park and rpms still fluctuated from 750-900. let it idle for a while and ran the shifter through the gears to see if it would settle. It didnt unless in drive. Shut it off then cleared the codes. Had the EO/PO52 with the service engine soon from last night.

Re-started and RPMs went up to 1900 again but wouldnt come down when applying the brake like before.

Pulled it into the garage. Shut it off. Re-started and went up to almost 3000.

Shut it off again and popped the hood. Noticed the coolant in the overflow was very high. Checked the temp and was at I think 127 celsius (way too high).

Also noticed that the plunger for the ISC Motor is out quite a bit holding the throttle open. Which would explain the high idle. But dont know why it wont retract automaticly. If I remove it from the harness and hold the idle manually at 2500, I can get it to retract by pushing on it.

Should add that the water pump was changed a week ago. Made sure he used the pellets and that it was a new GM pump and not a re-build. Everything seemed fine there. Was watching the temp all last week and was running quite cool.

Also, this morn. When easing of on the throttle after retracting the plunger something clunked/knocked just before it stalled.

Hopin not to have to tow it to the dealer !

Any ideas ??

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I think I know what it is now.

Just have to wait for the part. Has to come from the warehouse so not till tomorrow morn.

I believe its the connector to the ISC Motor.

I discovered that the plastic posts that cover 3 of the 4 pins are cracked at the base.

Looks like they've been like that for a while. Breaks in the plastic dont look clean and new.

And the A pin is actually loose inside the post. Totally disconected by the looks of it. Figure that the pin probably finally gave way while putting in the new motor.

Tried pushing against the throttle lever as you described but the plunger wouldnt retract.

Im assuming that pin being broken could cause that.

Certainly cant be helping anything LOL.

I had noticed in one of your older posts explaining how to set the gap, you had said to make it between .030 and .060. That is why I thought to try it at .050.

When I get the new connector I will re-do all again to .030

Has gotten so's I can do this with my eyes closed. Think I even dreamed about doing it last night LOL.

Thanx

And will let know how it goes.

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Try putting a fairly heavy throttle return spring on temporarily to see if that is the problem (steal the screen door spring for a moment and try that....).

Now there's something I'd NEVER have thought of . . . . <_>

Regards,

Warren :D

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All Done !!!

If I knew how easy it was, I would have done it a long time ago. LMAO

Actually it is quite simple. Specially after the 6th time.

Know that the old ISC was bad, but wasnt expecting the connector to be shot too.

Thats what was hampering everything. Damned connector.

The replacement was only one end so had to splice it. Put everything back together, set the gap, took it round the blocks a few times, all in under 45 mins.

Kinda wonder how long it would have took the dealer to find the connector problem ? Not to mention what the charge would have been ??

Im guessing It would have been quite steep. Probably would have heard all about electrical diagnosis, etc. etc. then been hand a huge bill.

Ive learned one thing for sure through all this.

Anytime I unhook a connector to replace/repair another part, First thing is to inspect the connector !!!

Thanx for the help !!

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