poopdeville Posted November 4, 2004 Report Share Posted November 4, 2004 Hey all that helped with my old girl's recent misbehaviour. I replaced the ICM, I cleaned out the EGR tubes (and the rest of the Throttle body) and she still has the same bad attitude. My local mechanic (not GM but services about 10 of this vintage) checked/scanned the car and all reads ok. Bo engine light and no codes but it won't idle down without an additional spring added to assist in the return to idle. Whaddaya think? I am waiting for experts to assist me again here with ideas. thanks in advance Mike P Link to comment Share on other sites More sharing options...
adallak Posted November 4, 2004 Report Share Posted November 4, 2004 What is the "fast idle" exactly? How many RPM say, in 10 seconds after crancing? The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
poopdeville Posted November 4, 2004 Author Report Share Posted November 4, 2004 It will idle down now because of the new additional return spring but when you put your foot down on the pedal to accelerate from a stop, then reach the limit (say 40 mph) you release the pedal to slow down to 35 mph and it keeps going along at 40 as if the cruise was on... no pressure on the pedal, no deceleration. This is REALLY hard on the brakes... lol... The original throttle body spring is really strong, the additional one just seems to give a bit of extra help to force the ICM to retract and allow an idle. I am thinking the Throttle body is in need of removal and rebuild or something... The fast idle in park used to be about 2000 - 2200 RPM and about 100 less in drive... bfore the additional spring was added in order to force the ICM to retract. Mike P Link to comment Share on other sites More sharing options...
adallak Posted November 4, 2004 Report Share Posted November 4, 2004 Did you disconnect the battery for a couple of minutes after you installed the new ISC motoe? How about TPS learn, idle learn procedures? All are done and still 200 RPM? The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
poopdeville Posted November 4, 2004 Author Report Share Posted November 4, 2004 Yes sir, I did the idle learn thing for sure... 10 minutes in park and 3 in drive... I am going to do it again tomorrow in the daylight (and hopefully less rain coming down) and see if it helps with the new additional spring. It almost seems like something is preventing the ECM or whatever, from realising and recognising a coasting deceleration. The car just keeps on going at the RPM you left it at when you removed your foot from the pedal unless you force it to slow with braking. I really wish I could watch the cables and throttle movement while I was driving in order to see if there is a bind or a jamming of the plates or ?... as I am sure you can imagine, this would be very difficult to do without removing the hood and asking my lady to drive the car while I straddled the engine compartment (with a helmet on of course) and driving down the road at 40 mph... lol I am losing my mind I think with this... Mike P Link to comment Share on other sites More sharing options...
adallak Posted November 4, 2004 Report Share Posted November 4, 2004 Despite I do lots of "improvements" on my own I do not think an additional spring is a good idea. Sounds like there is a mechanical retriction. Are you sure your blades move freely when you apply the pedal with the motor shot down? Besides you can completely retract the ISC motor plunger entering the overdrive 003 and depressing Cooler and then disconnecting ISC motor connector. It would allow you to watch the throttle blades at all possible angles including so called minimum air. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
poopdeville Posted November 5, 2004 Author Report Share Posted November 5, 2004 WOW! You lost me with the 003 cooler overdrive thing... I need detailed instructions my friend... I am old and slow but have a great memory... for now Please elaborate for me and thank you Mike P Link to comment Share on other sites More sharing options...
adallak Posted November 5, 2004 Report Share Posted November 5, 2004 Mine is 4.9 I am not sure the procedures described in my service manual may be applied to 4.5. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
poopdeville Posted November 5, 2004 Author Report Share Posted November 5, 2004 Thank you very much for your direction bobynski... I will attempt to follow your diagnosis and test procedures to the letter and report back on some issues I do not yet have an answer for yet. I do know a few things at this point though. 1) The Idle motor I put in was new, an Echlin brand purchased at NAPA. 2) The cruise cable has lots of slack and does not interfere with the assembly moving and rolling through it's travel. 3) I put the spring on because when at "idle" the motor would not fully retract (resulting in an "idle" of about 1500 rpm in park or in drive) without a little "help". By this I mean a really soft touch to the throttle arm that rests on the plunger pad of the ISC motor. Once the spring was added, this little "touch" is not needed to result in the plunger retracting all the way in and resulting in an acceptable idle. The remaining issue at this point is that while moving along in drive, when I release the pedal to coast and decelerate, the engine does not respond and decelerate. As you suggested, it may be binding (the linkage/plates/? somewhere inside or outside the TB or?) as the new ISC motor seems to be behaving properly in that it does what you have described that it should do. I have not done the "un-plug the ISCM" as you described though... yet. 4) The other item we checked was the coolant sensor because if it isn't working right, it will tell the computer the engine is cold and provide a "fast idle: to warm it up. This test showed the engine coolant at 200 C. I was told this is acceptable and not the source of the problem. I did this test because I put a new heater core in last weekend due to the original giving up and leaking. The cooling/heating system is working ok now. Today I will do the "learn" again as last time I did it, I did not have the spring to help it totally idle down. Maybe I have inadvertently programmed the system to react the way it is. I will start again with this and report back to you all this evening with the results. My morning drive to work will result in more brake wear (50 miles in freeway traffic) and then I can disconnect and start over for the ride home. Thanks again and stay tuned for the latest news! lol. Mike P Link to comment Share on other sites More sharing options...
adallak Posted November 5, 2004 Report Share Posted November 5, 2004 ....it should retract and keep retracting until it stops. When it stops, disconnect the wire connector to the ISC motor to "freeze" it in the fully retracted position. here is what you need to disconnect - The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
GOOB Posted November 5, 2004 Report Share Posted November 5, 2004 EXACT same thing I was experiencing a few weeks ago. I thought I had narrowed mine down to the TPS. Changed that and hadn't really experienced anything similar until the last few days. Idle at start was around 2200 rpms this morning. A simple tap on the accelarator "unstuck" whatever was causing the problem and the rpms dropped backdown to normal. I think I need to print out Guru's instructions and test my ISC motor as well. Very detailed instructions Guru (as usual) thanx Link to comment Share on other sites More sharing options...
adallak Posted November 5, 2004 Report Share Posted November 5, 2004 I do not know if it is normal but my RPM is about 2000-2200 at crank, then it drops to some 900-1100 depending on ambient temperature in a few seconds as the ISC motor's plunger retracts. It will go down to 650 as the engine warms up to some 180 degrees in a few minutes. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
poopdeville Posted November 5, 2004 Author Report Share Posted November 5, 2004 Hey there all, I am home from work and unfortunately I did not get the time to re-learn my old girl's idle position... yet. Goob and addalac, thanks for your insight as well. To be more specific and/or to explain the start-up idle sequence thing... WHEN I crank the car and she goes, yes, the initial start sequence will climb to a fast idle of 1500-2000 rpm for about 2 seconds and then drop down... when it is warm. When the engine is cold, the idle will climb to about 2000 at start-up and drop to 1500 (in a couple of seconds... slowly) and down slowly once the engine warms up, to about 600 or so. ALL of the above is happening now SINCE I put the extra return spring on the throttle arm. PRIOR to the addition of the spring, the idle would go no lower than 1500 or so... EVER. New ISC Motor, super TB clean etc., no change, no codes, no engine light. The deceleration sequence is controlled by the driver releasing his/her foot from the pedal and the engine should drop a few hundred or so RPM and the car coast while slowly decelerating. Mine does not do this. IF you release the pedal, it will drop in RPM to about 1500 and stay there all day unless you pull the car down by braking. Once stopped (and still revving 1500 RPM), in a second or 2 the ISC motor with the new spring will pull the idle down a bit more to about 600 or so. I want to remove the extra spring and I need to figure out whether something electronic is messed up (maybe the entire ECM circuit that controls the ISCM or ?) or whether it is mechanical (ie Throttle body is binding somewhere) but I don't know where to start looking when the most basic function of deceleration (removing the foot and coasting) isn't working. Mike P PS. Goob, mine used to return to 'normal' (doing what you did) a while ago but now it won't. It has gone from intermittent to full time and the kick is useless for mine at this point. PSS: Specific to bbobynski: Thanks for your detail and help... It did something wierd today, since the additional spring went on... does this mean anything?... here goes... When the engine is cold (first start this morning and again at 4:30 after work) when I turn the key to 'ON' (no crank yet) the gas pedal jumps in and out with a rattle 4 times. The car starts fine and runs as described but this is new. Mean anything to you or give any hints? Do I need an exorcist for my car? lol... I have always started an electric fuel pump car this way. I turn on the key to ON and let the pump bring the fuel system up to pressure, then I engage the starter. This wierd thing happened today during the 'pressure' sequence. Mike P Link to comment Share on other sites More sharing options...
adallak Posted November 6, 2004 Report Share Posted November 6, 2004 Jumping pedal at start... hmmmm... :cruise control interference? You IS problem's solution may be as easy as the plunger's length adjustment. Just turn it in as deep as say, 1/8 of an inch and try again. You cannot hurt anything this way. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
adallak Posted November 6, 2004 Report Share Posted November 6, 2004 Actually, the ISC motor's plunger could move your gas pedal. Since nobody keeps his foot on the pedal at start nobody notices it. I'll try it tomorrow. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
poopdeville Posted November 6, 2004 Author Report Share Posted November 6, 2004 The ISCM plunger is screwed in all the way... my buddy the Caddy fixer also added a couple of washers between the mount and the ISCM to pull it further away even more... same results. I really do not think it is the ISCM in any way. I must be binding somewhere or getting a wrong signal electronically from something. I will remove all our experimental additions as soon as I get it to respond the way it did last month... perfectly. The cruise cable is slack with lots of play in it, there is nothing visible that is hindering the return. I just dunno where to look beyond the obvious. Thanks add... Mike P Link to comment Share on other sites More sharing options...
GOOB Posted November 6, 2004 Report Share Posted November 6, 2004 My gas pedal was doing the same thing (before the TPS change) except it was happening after I had been doing some hard freeway driving. When I would pull up in the driveway and shut the car off, my gas pedal would jump (accompanied by a very noticeable "thumping" noise. I was told (I think by Guru) that this was my ISC attempting to prep for the next start (or something like that). I am really starting to lean towards changing that darn ISC motor. Link to comment Share on other sites More sharing options...
poopdeville Posted November 6, 2004 Author Report Share Posted November 6, 2004 Yo duh... misread your post... I can actually "HEAR" the gas pedal popping in and out... really strange!!! Thanks! Mike P Link to comment Share on other sites More sharing options...
poopdeville Posted November 6, 2004 Author Report Share Posted November 6, 2004 Hey there GOOB, did your TPS malfunction give you a code of any sort or just mess up and leave you (like me) with a blank look in your face? lol... I am thinking of a TPS now... lol... Mike P Link to comment Share on other sites More sharing options...
adallak Posted November 6, 2004 Report Share Posted November 6, 2004 poopdeville, I would bring ISC motor area to its virgin shape and patiently check out all the mechanical stuff starting from the pedal down to the lever and throttle blades. Did you try to lubricate the pedal? Does the pedal moves freely? Do the throttle blades move coherently when ISC motor disabled (key is off)? Do you have a manual? (even Chilton would shed some light on ISC motor adjustments). The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
GOOB Posted November 6, 2004 Report Share Posted November 6, 2004 I got a intermittent TPS code (forgot what the number is) a couple of times. But like I said earlier, I don't think that COMPLETELY fixed my problems. Just recently, mine is starting to act like it wants to "hang-up" again when I get of the gas. When I let up, it pauses for a second or two before decelerating. This just started happening again 2 days ago...after having the new TPS in for about 3 weeks. I definitely feel your pain. I actually had to lock up my emergency brake a couple of times because my ABS was not stopping the car because it was idling so high!!! Link to comment Share on other sites More sharing options...
poopdeville Posted November 6, 2004 Author Report Share Posted November 6, 2004 hey Goob, MY BEAUTIFUL WHITEWALLS TURNED BLACKWALL COLOR!!!! OMG!!!! What a bad look it was on the front... gotta fix this @#$@$ thing yet. Mike P PS. Thanks aAdd... I will take all the crap off tomorrow and do as you say... start at the pedal and follow it out... It seems to be moving ok without binding when I turn the assembly but I haven't done as Guru said and pulled it all the way in and done the unplug. Tomorrow will be a day of tickiling her under the hood. HOPEFULLY I will find her dismay and restore her to the thing of beauty she is. I will let you know. Mike P Link to comment Share on other sites More sharing options...
DFBonnett Posted November 6, 2004 Report Share Posted November 6, 2004 Disconnect the Idle speed control motor AT THE ISC MOTOR...not the connector someone put an arrow to..... Guru, I've been trying to isolate a transient idle problem for some time and believe it may be ISC related. In order to help me to better understand how the ISC motor interfaces with the rest of the system, can you clarify why it is necessary to remove the connector at the motor rather than at the connector noted by the arrow? I have been disconnecting at the more accessible connector noted by the arrow and perhaps this is related to my lack of success. I don't recall this being dealt with previously in any post. TIA DFB Link to comment Share on other sites More sharing options...
adallak Posted November 6, 2004 Report Share Posted November 6, 2004 Disconnect the Idle speed control motor AT THE ISC MOTOR...not the connector someone put an arrow to..... That's what the FSM says. The connector I showed is the only ISC motor related connector mentioned in the manual and clearly shown in pictures. The accecibility sems to be the only reason to have this jumper with extra connector. Would you please clarify this, Guru? I was watching the icons while in diagnostics and the only icon which reacted coherently with pedal movements was not OFF but LO. OFF icon was on all the time no matter was the lever contacting the plunger or not. Besides, I depressed the plunger to retract it as Guru suggested. It retracted but not all the way. When I released the lever it leaned on the minimum air screw but the plunger definitely contacted the lever. The only way to retruct the plunger completely was the way described in the FSM by entering diagnistics override 003 mode and depressing COOLER button. These are bare experimental data. I am not going to do any conclusion or suggestion since am sure Guru knows what he is talking about, and I might be dead wrong. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
adallak Posted November 7, 2004 Report Share Posted November 7, 2004 Guru, thanks for comments. I suspected there might be differences between year models but posted my results since someone migh find them helpful some day. Let's see what poopdeville will report. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
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