wanobi Posted August 29, 2006 Report Share Posted August 29, 2006 Hello, I've read many posts and pretty much am posting to confirm my feeling. I've ran the diagnostics and all sensors and reading come back good, exept for when it is cold. The car will start to idle down then jump back up and do this for a little while. The diag shows the tps voltages swing when this is happening, but I'm not depressing the gas pedal. My thoughts are leaning towards a defective ICS or its starting to go bad. Link to comment Share on other sites More sharing options...
epricedright Posted August 29, 2006 Report Share Posted August 29, 2006 Hello, I've read many posts and pretty much am posting to confirm my feeling. I've ran the diagnostics and all sensors and reading come back good, exept for when it is cold. The car will start to idle down then jump back up and do this for a little while. The diag shows the tps voltages swing when this is happening, but I'm not depressing the gas pedal. My thoughts are leaning towards a defective ICS or its starting to go bad. Do you mean ISC...Idle Speed Controller? Does it make repeated ratcheting sounds after shut down? Link to comment Share on other sites More sharing options...
wanobi Posted August 29, 2006 Author Report Share Posted August 29, 2006 Hello, I've read many posts and pretty much am posting to confirm my feeling. I've ran the diagnostics and all sensors and reading come back good, exept for when it is cold. The car will start to idle down then jump back up and do this for a little while. The diag shows the tps voltages swing when this is happening, but I'm not depressing the gas pedal. My thoughts are leaning towards a defective ICS or its starting to go bad. Do you mean ISC...Idle Speed Controller? Does it make repeated ratcheting sounds after shut down? Oops, yes ISC is what I meant. every once in awhile I can hear it from inside the car. While it's trying to "idle down" when first started I can hear it kinda clicking, if I'm standing outside of the car. Link to comment Share on other sites More sharing options...
adallak Posted August 29, 2006 Report Share Posted August 29, 2006 If it is original ISC motor and it makes noises you did not hear before - just replace it. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted August 29, 2006 Report Share Posted August 29, 2006 It probably is your ISC. Before cleaning or replacing it, disconnect your negative battery cable and clean your throttle body thoroughly. See previous threads on how to clean your TB. Disconnecting the neg cable for 10 minutes will reset the idle for a clean TB. Someone posted instructions on how to dissassemle your ISC and clean the contacts inside, if that's something you want to try. Link to comment Share on other sites More sharing options...
Patrick7997 Posted August 29, 2006 Report Share Posted August 29, 2006 I agree, ISC... my 92 Eldorado 4.9 did the same thing..... Link to comment Share on other sites More sharing options...
wanobi Posted August 30, 2006 Author Report Share Posted August 30, 2006 I agree, ISC... my 92 Eldorado 4.9 did the same thing..... picked up new isc today. hopefully will get it replaced tomorrow or thursday, providing work doesn't get too hectic. Link to comment Share on other sites More sharing options...
wanobi Posted August 31, 2006 Author Report Share Posted August 31, 2006 Ok got the ISC replaced, didnt get to do the idle learn procedure due to loss of light, but after replacing ISC I did disconnect neg cable from battery for 1 min. reconnected, turned key to run position to allow ISC to reposition itself, turned key off, then started car. It shot to 2.5k then came down pretty quick ( faster than before ) leveled off around 900, got on the road and drove around for about 15-20 mins..stopping at stop signs and varying speeds. About 5-7 mins when I would stop it would idle down to about 550-600. Every once in awhile it would do the little rev up thing as before but that could be from not doing the idle learn correctly or at all. The cold start in the morning will be the real test. Link to comment Share on other sites More sharing options...
Ranger Posted August 31, 2006 Report Share Posted August 31, 2006 Did you adjust the ISC motor after the install? If not, with the key on, press on the plunger til it retracts. When it bottoms out, pull the plug. Now adjust it to a .030 gap by screwing the plunger in or out as necassary. Now plug it back in. Link to comment Share on other sites More sharing options...
wanobi Posted August 31, 2006 Author Report Share Posted August 31, 2006 Did you adjust the ISC motor after the install? If not, with the key on, press on the plunger til it retracts. When it bottoms out, pull the plug. Now adjust it to a .030 gap by screwing the plunger in or out as necassary. Now plug it back in. When I first turned the key to on, the plunger extended quit abit. Now as far as adjusting the gap of the plunger I got a little confused. The screw threads into the plunger and the plunger slides in/out of the assembly. The screw is about 1/4 in from the end of the plunger. Link to comment Share on other sites More sharing options...
adallak Posted August 31, 2006 Report Share Posted August 31, 2006 Ok got the ISC replaced, didnt get to do the idle learn procedure due to loss of light, but after replacing ISC I did disconnect neg cable from battery for 1 min. reconnected, turned key to run position to allow ISC to reposition itself, turned key off, then started car. It shot to 2.5k then came down pretty quick ( faster than before ) leveled off around 900, got on the road and drove around for about 15-20 mins..stopping at stop signs and varying speeds. About 5-7 mins when I would stop it would idle down to about 550-600. Every once in awhile it would do the little rev up thing as before but that could be from not doing the idle learn correctly or at all. The cold start in the morning will be the real test. Looks normal to me. It cannot come to 550-600 in the morning until the engine reaches the opeartional temperature (180F plus). Do not worry about idle learn. The ECM will learn when you start driving (after say, some 5-10 miles or so). The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
wanobi Posted August 31, 2006 Author Report Share Posted August 31, 2006 Ok got the ISC replaced, didnt get to do the idle learn procedure due to loss of light, but after replacing ISC I did disconnect neg cable from battery for 1 min. reconnected, turned key to run position to allow ISC to reposition itself, turned key off, then started car. It shot to 2.5k then came down pretty quick ( faster than before ) leveled off around 900, got on the road and drove around for about 15-20 mins..stopping at stop signs and varying speeds. About 5-7 mins when I would stop it would idle down to about 550-600. Every once in awhile it would do the little rev up thing as before but that could be from not doing the idle learn correctly or at all. The cold start in the morning will be the real test. Looks normal to me. It cannot come to 550-600 in the morning until the engine reaches the opeartional temperature (180F plus). Do not worry about idle learn. The ECM will learn when you start driving (after say, some 5-10 miles or so). What about the adjusting the plunger to the .030? Do I still need to do this or will it work itself out after driving it a bit? And if so is my description of what needs to measure .030 accurate ( the distance of the plunger from the assembly, not the screw from the assembly ) Link to comment Share on other sites More sharing options...
adallak Posted August 31, 2006 Report Share Posted August 31, 2006 Ok got the ISC replaced, didnt get to do the idle learn procedure due to loss of light, but after replacing ISC I did disconnect neg cable from battery for 1 min. reconnected, turned key to run position to allow ISC to reposition itself, turned key off, then started car. It shot to 2.5k then came down pretty quick ( faster than before ) leveled off around 900, got on the road and drove around for about 15-20 mins..stopping at stop signs and varying speeds. About 5-7 mins when I would stop it would idle down to about 550-600. Every once in awhile it would do the little rev up thing as before but that could be from not doing the idle learn correctly or at all. The cold start in the morning will be the real test. Looks normal to me. It cannot come to 550-600 in the morning until the engine reaches the opeartional temperature (180F plus). Do not worry about idle learn. The ECM will learn when you start driving (after say, some 5-10 miles or so). What about the adjusting the plunger to the .030? Do I still need to do this or will it work itself out after driving it a bit? And if so is my description of what needs to measure .030 accurate ( the distance of the plunger from the assembly, not the screw from the assembly ) No, it will not work itself out. But I am sure you are pretty close to 0.30" between the plunger and the throttle lever. If it is not 0.30", start the engine, lift the throttle lever to increase RPM to some 2000 and press the ISC plunger until it is retracted completely. Disconnect the connector, thereby disabling the ISC motor. Check the gap, adjsut as necessary. Reconnect the ISC motor. Here is a tool for adjustment: The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
adallak Posted August 31, 2006 Report Share Posted August 31, 2006 One penny tool. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted August 31, 2006 Report Share Posted August 31, 2006 This is basically the same as what adallak wrote, except my notes say the gap should be .060 Next cold start, retract the idle speed control motor to full retract. Do this by holding the throttle open slightly while pressing the end of the ISC motor plunger with your finger. It should retract. Keep retracting it until the plunger is fully retracted. Unplug the wire connector to the ISC to freeze the ISC motor in the retracted position. You may need a second set of hands. Slowly release the throttle to idle and see if the engine idles down. It should almost stall if you do this cold. If so, there is no vacuum leak. If it doesn't idle down check to see if the cruise control link is holding the throttle open. The cruise control link should have some slight slop in it even cold. It is at this point that there should be .060" clearance between the plunger and the throttle mechanism. If not, adjust the plunger until the throttle bore is closed AND there is .060" clearance to the plunger. The engine should be idling very low at this point. When you plug the ISC back in, it should contact the linkage to raise the RPM to a normal idle so the engine does not stall. Link to comment Share on other sites More sharing options...
adallak Posted August 31, 2006 Report Share Posted August 31, 2006 This is basically the same as what adallak wrote, except my notes say the gap should be .060 Next cold start, retract the idle speed control motor to full retract. Do this by holding the throttle open slightly while pressing the end of the ISC motor plunger with your finger. It should retract. Keep retracting it until the plunger is fully retracted. Unplug the wire connector to the ISC to freeze the ISC motor in the retracted position. You may need a second set of hands. Slowly release the throttle to idle and see if the engine idles down. It should almost stall if you do this cold. If so, there is no vacuum leak. If it doesn't idle down check to see if the cruise control link is holding the throttle open. The cruise control link should have some slight slop in it even cold. It is at this point that there should be .060" clearance between the plunger and the throttle mechanism. If not, adjust the plunger until the throttle bore is closed AND there is .060" clearance to the plunger. The engine should be idling very low at this point. When you plug the ISC back in, it should contact the linkage to raise the RPM to a normal idle so the engine does not stall. I would do this when engine is at operational temp (180 plus). With ISC retracted AND disabled only minimum air screw controls the idle RPM ( the screw the throttle lever is leaning on). It should be 450-500. Do net get upset if it is 550. It is still ok. When you are done with adjustment cycle the ignition key two times. Good to go. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted August 31, 2006 Report Share Posted August 31, 2006 adallak, I think you're right about the eng temp. I believe those notes were from when I had an idle problem. More of what we already said, these notes are from Kevin: When the ignition is turned off, the ISC will set up for the next start. It should not ratchet. Open the throttle slightly and depress the closed idle switch. The ISC plunger should retract. When the ISC plunger is fully retracted, disconnect the electrical plug from the ISC motor. There should be about .060 clearance between the throttle lever and the isc motor plunger when the plunger is fully retracted and the throttle is at rest. If not, adjust the plunger to obtain .060" clearance. Take the car for a test drive and then recheck the ISC to make sure you have the .060" clearance with the engine idling in park. If the ISC ratchets, turn it out 1/2 turn and road test/examine for clearance. Link to comment Share on other sites More sharing options...
wanobi Posted August 31, 2006 Author Report Share Posted August 31, 2006 adallak, I think you're right about the eng temp. I believe those notes were from when I had an idle problem. More of what we already said, these notes are from Kevin: When the ignition is turned off, the ISC will set up for the next start. It should not ratchet. Open the throttle slightly and depress the closed idle switch. The ISC plunger should retract. When the ISC plunger is fully retracted, disconnect the electrical plug from the ISC motor. There should be about .060 clearance between the throttle lever and the isc motor plunger when the plunger is fully retracted and the throttle is at rest. If not, adjust the plunger to obtain .060" clearance. Take the car for a test drive and then recheck the ISC to make sure you have the .060" clearance with the engine idling in park. If the ISC ratchets, turn it out 1/2 turn and road test/examine for clearance. The .060" that I'm trying to set, it is the distance from the head of the bolt that screws into the ISC and the throttle lever when the throttle blades in the TB are closed, right? .. Please forgive me if I sound like an idiot. My mechanic skills are still weak, but I'm trying to learn. Link to comment Share on other sites More sharing options...
adallak Posted August 31, 2006 Report Share Posted August 31, 2006 adallak, I think you're right about the eng temp. I believe those notes were from when I had an idle problem. More of what we already said, these notes are from Kevin: When the ignition is turned off, the ISC will set up for the next start. It should not ratchet. Open the throttle slightly and depress the closed idle switch. The ISC plunger should retract. When the ISC plunger is fully retracted, disconnect the electrical plug from the ISC motor. There should be about .060 clearance between the throttle lever and the isc motor plunger when the plunger is fully retracted and the throttle is at rest. If not, adjust the plunger to obtain .060" clearance. Take the car for a test drive and then recheck the ISC to make sure you have the .060" clearance with the engine idling in park. If the ISC ratchets, turn it out 1/2 turn and road test/examine for clearance. The .060" that I'm trying to set, it is the distance from the head of the bolt that screws into the ISC and the throttle lever when the throttle blades in the TB are closed, right? .. Please forgive me if I sound like an idiot. My mechanic skills are still weak, but I'm trying to learn. CORRECT. That's the gap between the surface of the plunger head that normally contacts the throttle lever an d the closest point of the throttle lever when the latter rests on th eminimum air screw (the blades in their minimum air position, one that you called "closed'). The Guru insisted on 0.30". You can try 0.60" as well and see how it works. You do not sound like an idiot at all. The beauty of an used Cadillac (any car actually) is that you have a lot to learn! LOL The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted August 31, 2006 Report Share Posted August 31, 2006 adallak, I think you're right about the eng temp. I believe those notes were from when I had an idle problem. More of what we already said, these notes are from Kevin: When the ignition is turned off, the ISC will set up for the next start. It should not ratchet. Open the throttle slightly and depress the closed idle switch. The ISC plunger should retract. When the ISC plunger is fully retracted, disconnect the electrical plug from the ISC motor. There should be about .060 clearance between the throttle lever and the isc motor plunger when the plunger is fully retracted and the throttle is at rest. If not, adjust the plunger to obtain .060" clearance. Take the car for a test drive and then recheck the ISC to make sure you have the .060" clearance with the engine idling in park. If the ISC ratchets, turn it out 1/2 turn and road test/examine for clearance. The .060" that I'm trying to set, it is the distance from the head of the bolt that screws into the ISC and the throttle lever when the throttle blades in the TB are closed, right? .. Please forgive me if I sound like an idiot. My mechanic skills are still weak, but I'm trying to learn. CORRECT. That's the gap between the surface of the plunger head that normally contacts the throttle lever an d the closest point of the throttle lever when the latter rests on th eminimum air screw (the blades in their minimum air position, one that you called "closed'). The Guru insisted on 0.30". You can try 0.60" as well and see how it works. You do not sound like an idiot at all. The beauty of an used Cadillac (any car actually) is that you have a lot to learn! LOL adallak, your recollection of what the guru said could be right about the the gap being .030". I'm not arguing with you, and certainly not the guru. I just copied and pasted notes from when I had problems with my ISC. Some of those notes were from when KHE helped me and he mentioned .060". That's what I set mine to and it worked fine. I wonder what the FSM says? I imagine either .030" or .060" would be fine though. The compressor clutch air gap is .030", I'm positive about that. Link to comment Share on other sites More sharing options...
Ranger Posted August 31, 2006 Report Share Posted August 31, 2006 FWIW, I recall the Guru saying .030 as well. That's why I posted .030. I doubt that it is too critical. Link to comment Share on other sites More sharing options...
adallak Posted August 31, 2006 Report Share Posted August 31, 2006 adallak, I think you're right about the eng temp. I believe those notes were from when I had an idle problem. More of what we already said, these notes are from Kevin: When the ignition is turned off, the ISC will set up for the next start. It should not ratchet. Open the throttle slightly and depress the closed idle switch. The ISC plunger should retract. When the ISC plunger is fully retracted, disconnect the electrical plug from the ISC motor. There should be about .060 clearance between the throttle lever and the isc motor plunger when the plunger is fully retracted and the throttle is at rest. If not, adjust the plunger to obtain .060" clearance. Take the car for a test drive and then recheck the ISC to make sure you have the .060" clearance with the engine idling in park. If the ISC ratchets, turn it out 1/2 turn and road test/examine for clearance. The .060" that I'm trying to set, it is the distance from the head of the bolt that screws into the ISC and the throttle lever when the throttle blades in the TB are closed, right? .. Please forgive me if I sound like an idiot. My mechanic skills are still weak, but I'm trying to learn. CORRECT. That's the gap between the surface of the plunger head that normally contacts the throttle lever an d the closest point of the throttle lever when the latter rests on th eminimum air screw (the blades in their minimum air position, one that you called "closed'). The Guru insisted on 0.30". You can try 0.60" as well and see how it works. You do not sound like an idiot at all. The beauty of an used Cadillac (any car actually) is that you have a lot to learn! LOL adallak, your recollection of what the guru said could be right about the the gap being .030". I'm not arguing with you, and certainly not the guru. I just copied and pasted notes from when I had problems with my ISC. Some of those notes were from when KHE helped me and he mentioned .060". That's what I set mine to and it worked fine. I wonder what the FSM says? I imagine either .030" or .060" would be fine though. The compressor clutch air gap is .030", I'm positive about that. Epricedright, I do not remmber FSM saying anything about the gap. Their procedure is different. One thing I learned about the idle ...whatever you do it still has its own mind! LOL The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
wanobi Posted August 31, 2006 Author Report Share Posted August 31, 2006 GRRRR!! The plunger will NOT fully retract. It was fully retracted when I got it......hmmm maybe if I unscrew the screw I can get it to fully retract. I started the car eased the throttle stop off of the plunger, so I could depress the plunger it moved slightly but not fully retracting. What is wrong? Link to comment Share on other sites More sharing options...
wanobi Posted September 1, 2006 Author Report Share Posted September 1, 2006 GRRRR!! The plunger will NOT fully retract. It was fully retracted when I got it......hmmm maybe if I unscrew the screw I can get it to fully retract. I started the car eased the throttle stop off of the plunger, so I could depress the plunger it moved slightly but not fully retracting. What is wrong? Ok got it to go in...just have to be patient...LOL Link to comment Share on other sites More sharing options...
adallak Posted September 1, 2006 Report Share Posted September 1, 2006 GRRRR!! The plunger will NOT fully retract. It was fully retracted when I got it......hmmm maybe if I unscrew the screw I can get it to fully retract. I started the car eased the throttle stop off of the plunger, so I could depress the plunger it moved slightly but not fully retracting. What is wrong? Fully retracted means it does not move any more. If in that position it touches the throttle lever, screw it in to obtain the necessary gap. I even had to cut the plunger screw off to get it right. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
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