kcd1184 Posted November 23, 2006 Report Share Posted November 23, 2006 Been putting alot of miles on my 94 Eldo these last three months. 150 to 200 miles a day. Milage is at 139,000. I am recently noticing that when I stop at a light or whatever, the motor seems to surge up and then back down again. It goes up about to 800/900 rpms for about 4 seconds and then drops back down. This happens every 10 seconds or so till I start driving again. Runs fine otherwise. Any ideas where to start? Happy Thanksgiving everybody! Kent Link to comment Share on other sites More sharing options...
Cadillac Jim Posted November 23, 2006 Report Share Posted November 23, 2006 First, pull the codes and post them here. You might also look at the throttle linkage near the throttle body. When you get home, stop in Park and see if it is doing it. If so, pop the hood and look at the throttle linkage and see if you can spot the idle speed stepping motor putting the idle up and down. You might see something that needs a little WD-40. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
kcd1184 Posted November 23, 2006 Author Report Share Posted November 23, 2006 First, pull the codes and post them here. You might also look at the throttle linkage near the throttle body. When you get home, stop in Park and see if it is doing it. If so, pop the hood and look at the throttle linkage and see if you can spot the idle speed stepping motor putting the idle up and down. You might see something that needs a little WD-40. Codes P039,P056, and S060(all in the history mode at the moment) shouldn't have any bearing on the surging, I think. I will try checking it in Park after the next run. I'm not sure if it does the surging when I do short trips, something I will check out also. Thanks for the reply. Kent Link to comment Share on other sites More sharing options...
MAC Posted November 23, 2006 Report Share Posted November 23, 2006 I had a similar problem and it turned out that the Idle Speed Control unit was not functioning correctly. After taking it off I opened it and saw that there was no grease since it had dried out over the years. So I cleaned the moving parts and lubricated all the areas (moving parts, etc.) that were greased originally with high temp grease and used 600-grit wet or dry sandpaper to clean the points. It corrected the surge problem. Thanks to Barry94's post on this topic I had good a understanding of what to do. Link to comment Share on other sites More sharing options...
Ranger Posted November 23, 2006 Report Share Posted November 23, 2006 Kent, Check to see if the ISC motor plunger is flutuating at idle as Jim suggested. If so, that's your problem. If not, look for a vacuum leak. Link to comment Share on other sites More sharing options...
Cadillac Jim Posted November 23, 2006 Report Share Posted November 23, 2006 MAC and Ranger have more direct experience with the ISC since I've never actually had that problem myself The ISC diangosis and fix should be done first because that is the most likely cause of your problem. If the ISC is OK, or the problem persists after fixing it and cleaning the throttle body, you might look at the codes again. S060 .............................................. Left Front Position Sensor Fault (check the wiring to the sensor) P039 (E039) ..... Torque Coverter Clutch/Viscous Converter Clutch Engagement Problem P056 (E056) ........................................ Transmission Input Speed Sensor The two tranny codes could mean that there is something there that might feel like an engine idle speed surge. If it doesn't do it in Park or Neutral, you might check the transmission fluid level. When is the last time you had the transmission serviced? If it's been a really long time, there might be something sticking in there that would benefit from a transmission service (not a fluid flush). You might also check the wires to the transmission. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
mmarinov Posted November 23, 2006 Report Share Posted November 23, 2006 Been putting alot of miles on my 94 Eldo these last three months. 150 to 200 miles a day. Milage is at 139,000. I am recently noticing that when I stop at a light or whatever, the motor seems to surge up and then back down again. It goes up about to 800/900 rpms for about 4 seconds and then drops back down. This happens every 10 seconds or so till I start driving again. Runs fine otherwise. Any ideas where to start? Happy Thanksgiving everybody! Kent Kent: I experienced that recently on my '94 Eldo as well. For me, it was more like I had to keep my foot on the brake a little more every 5-10 seconds or it would want to move some. Also, acceleration at WOT was good up until 4,500 RPM or so and then it started running pretty roughly. Since I had 100K+ on OEM spark plugs and wires, I changed them and that fixed it right up. Highly recommended if you have not already had this done. Mark <!--fonto:Arial--><span style="font-family:Arial"><!--/fonto-->2007 DTS Performance - 50K <!--fontc--></span><!--/fontc--> As a matter of fact, I <i>am</i> driving 70 MPH in a phone booth. Link to comment Share on other sites More sharing options...
MAC Posted November 23, 2006 Report Share Posted November 23, 2006 No doubt a number of things can cause surging problems. Regarding new wires and plugs, I just want to add that I still have the original wires at almost 215K miles. Maybe it's time that I replace them but in my case the surging problems were not caused by faulty wire(s) or plugs. Perhaps you can troubleshoot the problem by disconnecting the Idle Speed Control unit. I would think that if it were causing the problem disconnecting it would prevent surging. On the other hand, it may just be best to remove it and clean it and keep it connected and see if it solves the problem. Link to comment Share on other sites More sharing options...
kcd1184 Posted November 25, 2006 Author Report Share Posted November 25, 2006 Getting going on Idle speed control and just removed air intake hose. Throttle body butterfly is open about a 1/4 inch . Is that normal? Don' know if I should continue until I get an answer. I'm wondering if that is part of the problem, and if it is supposed to be closed tight, how to fix it. Kent Link to comment Share on other sites More sharing options...
Ranger Posted November 26, 2006 Report Share Posted November 26, 2006 Kent, On a car with the ISC motor (as opposed to the ISC valve) the throttle plate does have to be open a bit to idle. Not sure how much though. Since you are in there already, clean the TB and see if that helps. Also, does the ISC motor ratchet after shut down? Link to comment Share on other sites More sharing options...
kcd1184 Posted November 26, 2006 Author Report Share Posted November 26, 2006 I removed the idle speed control unit (no room to work) and took it apart , cleaned some dried grease out,used some 600 grit wet/dry on the points, put a little grease back on the gears and after a befuddled moment or two of remembering how it came apart, put it back together and reinstalled. When I returned to the car to reinstall, the butterfly was closed. ??? Go figure. Started OK and drove it to get pizza. 10 miles. Not really enough to warm up good but ran fine except idle is too high now. Looked in my Helms manual for the TPS Sensor/ Idle Learn Proceedure. Don't really understand the proceedure fully and what diagnostics am I suppose to enter? And even if I knew what to do, would I have to do it twice , once with the air on and once with the air off. Can anyone help simplify this for me? Link to comment Share on other sites More sharing options...
Ranger Posted November 26, 2006 Report Share Posted November 26, 2006 With the engine at idle, press on the plunger til it bottoms out, then pull the plug. RPM should drop to about 450 or maybe even die. Now adjust the plunger to a .030 gap with the throttle linkage. Plug the ISC motor back in and your ready to go. No need to do an idle learn. My understanding is that it will learn on its own after a few drives. Did you clean the TB while you were in there? Link to comment Share on other sites More sharing options...
kcd1184 Posted November 26, 2006 Author Report Share Posted November 26, 2006 With the engine at idle, press on the plunger til it bottoms out, then pull the plug. RPM should drop to about 450 or maybe even die. Now adjust the plunger to a .030 gap with the throttle linkage. Plug the ISC motor back in and your ready to go. No need to do an idle learn. My understanding is that it will learn on its own after a few drives. Did you clean the TB while you were in there? Hi Larry I sprayed the body a little, it really wasn't too bad. I BLASTED a few parts and that was all I did. Getting those three little nuts off is a medical proceedure. I thought I had the bottom one figured out till it dropped off the magnet. One of the members said they are stainless but I forgot. Anyhow I don't know how you would get the bottom one back on (used a steel nut) without a magnet anyhow. Is the plunger you are talking about the bolt head that comes out of the ISC motor and hits the throttle body moving piece? Link to comment Share on other sites More sharing options...
Ranger Posted November 26, 2006 Report Share Posted November 26, 2006 Yes, just turn it to adjust. I suppose you are working tomorrow. I could give you a hand with that bottom screw. I just use the braile method. I've done 2 or 3 like that already. Link to comment Share on other sites More sharing options...
kcd1184 Posted November 27, 2006 Author Report Share Posted November 27, 2006 Yes, just turn it to adjust. I suppose you are working tomorrow. I could give you a hand with that bottom screw. I just use the braile method. I've done 2 or 3 like that already. Couldn't get the plunger to move, and disconnecting the plug didn't seem to have much effect. Not much rpm loss unplugging, but it raised rpm when reattached. Tried 4 or 5 out and ins. Got mad and took the unit back out. Not sure the gears had to be back in a certain position. Spun the main gear down(or up) for maximum adjustment and also intentionally found out that the bolt will turn in or out. Greased the gears a little more and reinstalled again. Should have been a surgeon.(still wasn't fun,glad I had a magnet for installing AND retrieving)) For some reason the rpms are lower now than after the first attempt. I have driven the Eldo some, but tomorrow will tell. Back to Chicago. Kent Link to comment Share on other sites More sharing options...
Ranger Posted November 27, 2006 Report Share Posted November 27, 2006 My guess is that if it will not retract with pressure on the plunger, something is wrong with it. Try the adjustment now after the regreasing. Link to comment Share on other sites More sharing options...
MAC Posted November 27, 2006 Report Share Posted November 27, 2006 The ISC plunger may be extended and retracted with the WARMER and COOLER buttons on the Climate Control Center (“CCC”) as follows: 1. Engine not running 2. Vehicle speed 0 3. Transaxle in Park or Neutral 4. Throttle Position Switch is closed or throttle angle (PD01) is less than 1.44 degrees. 5. Enter Diagnostic Mode by depressing both the OFF and WARMER buttons at the same time. 6. Wait until diagnostics cycles then when you see ‘PCM?’ depress the HI button on the CCC to select the displayed system for testing. 8. Cycle through the options until you see the PCM OVERRIDE and again depress the HI button on the CCC to select it. 9. Again depress HI button on the CCC until you see PS03 which is the ISC motor. 10. Pause and look at the CCC and see if you can see the ISC motor cycling from ‘--’ for one second and then 50. This will continue until there is an attempt to override by depressing either the WARMER or COOLER button on the CCC. 11. By depressing the WARMER button the plunger will extend as far as it can and ‘99’ will be displayed. By depressing the COOLER button the plunger will retract until the throttle switch opens and ‘00’ will be displayed. Link to comment Share on other sites More sharing options...
epricedright Posted November 28, 2006 Report Share Posted November 28, 2006 Yes, just turn it to adjust. I suppose you are working tomorrow. I could give you a hand with that bottom screw. I just use the braile method. I've done 2 or 3 like that already. Couldn't get the plunger to move, and disconnecting the plug didn't seem to have much effect. Not much rpm loss unplugging, but it raised rpm when reattached. Tried 4 or 5 out and ins. Got mad and took the unit back out. Not sure the gears had to be back in a certain position. Spun the main gear down(or up) for maximum adjustment and also intentionally found out that the bolt will turn in or out. Greased the gears a little more and reinstalled again. Should have been a surgeon.(still wasn't fun,glad I had a magnet for installing AND retrieving)) For some reason the rpms are lower now than after the first attempt. I have driven the Eldo some, but tomorrow will tell. Back to Chicago. Kent I agree with Larry, it should push in with your finger. Unplugging it when it's fully retracted will hold the plunger in it's retracted position, allowing you to adjust the gap between the plunger and the throttle lever. Link to comment Share on other sites More sharing options...
epricedright Posted November 28, 2006 Report Share Posted November 28, 2006 If your car is anything like mine, that bottom screw IS a pain. I took Mike's advice and bought one of these: http://www.sears.com/sr/javasr/product.do?...L&ihtoken=1 Using that flexible 1/4" driver was the only way I could work that screw. Link to comment Share on other sites More sharing options...
kcd1184 Posted November 28, 2006 Author Report Share Posted November 28, 2006 So far so good. Hope I'm not jinxing myself. Two Chicago runs and no engine surge. Haven't done anything since I put it back together. Rpms seem ok. I'm thinking that when I ran the gear down (up?) to the max, it was the same as pushing the plunger in. Then when I started the Eldo back up, the idle setting process took over.(?) Should I still back the plunger off .030? What does that do, and if I'm running good , should I mess with it? Link to comment Share on other sites More sharing options...
adallak Posted November 29, 2006 Report Share Posted November 29, 2006 So far so good. Hope I'm not jinxing myself. Two Chicago runs and no engine surge. Haven't done anything since I put it back together. Rpms seem ok. I'm thinking that when I ran the gear down (up?) to the max, it was the same as pushing the plunger in. Then when I started the Eldo back up, the idle setting process took over.(?) Should I still back the plunger off .030? What does that do, and if I'm running good , should I mess with it? I would leave ISC alone. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Ranger Posted November 29, 2006 Report Share Posted November 29, 2006 I think the .030 gap gives it a base setting to start from. You are probably close if it is idling ok. Link to comment Share on other sites More sharing options...
MAC Posted November 29, 2006 Report Share Posted November 29, 2006 I would leave ISC alone. I agree. After I cleaned and lubed my Eldorado's ISC I didn't need to adjust anything. It's still working fine. Link to comment Share on other sites More sharing options...
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