HELP!!! I am still having a problem with my tranny running down with the motor rpms when I come to a stop. I had posted this a while ago, before winter I think and now that it's nice out again I have tried to fix this problem again. The car runs out great, starts great when cold, idles great, blah, blah, blah. The problem is when you are driving and need to slow down or stop, when you take your foot off the gas and put it on the brake the revs come down to 1500rpm and stays there, it only comes down while you are braking, coming down with the speed of the car until you stop, then it drops right to idle. It feels like it's fighting you until the car stops and then goes to idle. It doesn't die or anything, just idles. I need to fix this, the car is fun and drivable and everything but this just ain't right and probably ain't safe.....
I have tried the idle learn procedure several times and can't seem to get it to work right. I had it once right after the swap was completed but it went away two days later and I can't get it back. My scan tool says all the sensors are working correctly, I get good temperature, good oil pressure, good idle(625rpm according to my scanner). The ecm goes into "closed loop", knows what the rpms are, knows that the water temp is, knows what the sensors read, knows when car is in park or "O"drive, knows when 3rd shift happens, knows when 4th shift happens, knows the correct mph.
I think maybe my starter draws too many volts/amps when the motor is hot. After I idle the car in one spot for a while( 20 minutes or more)and shut it off the starter strains to restart and takes too much voltage from the battery and I think the the ecm forgets with the voltage loss. Sound logical??? I know I probably need a new starter or a heat deflector cause the oil cooler is right below the starter and it could also be heating it up too much.
This is the idle learn procedure that Rockcrawl has said to use for the 4.9/4T60E swap. I have some questions for those that got it to work right... At a). is the car running or just the key in the on position??? At b). the motor doesn't idle for very long at 525 rpm, is this a nesscesity??? At c). again, is the motor running cause this revs it up very high??? At d). is this a motor start or just turn the key to on position???
Make sure the throttle plates and bores are clean before you start. Also make sure you don't have any vacuum leaks. Jumper ALDL A and B to enter the set timing mode. Verify timing at 10* BTDC and remove jumper. a).Disable the alternator by grounding the small brown wire, there should be a green connector inline if it's anything like a Cadillac harness. Disconnect the ISC motor where the main harness attaches to the sub harness. Attach two jumper wires to the blue wires of the sub harness. Connect one jumper to ground and the other to bat positive momentarily until the ISC is fully retracted. If it extends, reverse the polarity to make it retract. When it is fully retracted, the throttle lever should be resting on the minimum idle screw. If the throttle lever is touching the ISC plunger at full retraction, use a pliers to turn the plunger in until it's not touching. b).Use the minimum idle screw (recessed torx) to set the idle to 525 rpm. With the throttle lever resting on the minimum idle screw, set the TPS to .50 volts. c).Now you can extend the ISC by reversing the polarity of the jumpers. At full ISC extension, the TPS should read between 1.15 and 1.20 volts. Adjust the ISC plunger in or out with a pliers to obtain the correct TPS voltage. Retract the ISC. Reconnect the ISC to the main harness. Turn the key off and wait 20 seconds to allow the ECM to perform a TPS learn. d).Cycle the ignition on and off once more. It takes two cycles for a sucessful TPS learn. Perform and idle learn. Run engine until coolant temp is greater than 176*. Allow engine to idle in park for ten minutes. With brake applied, allow engine to idle in drive for at least three minutes. The ECM will command a 600 rpm idle. If it's not idling at 600 +/- 50 rpm after doing this procedure there is something wrong.
a) doesn't matter. b) If it will not idle at 525 RPM with the ISC retracted then you have a problem. c) engine not running. d) key on, engine off. e) email me with your rear tire size so I can double check your file for accuracy.
I found this on the caddy forum: "Before jumping to the conclusion that it is the TPS I would double check that the closed throttle switch is working correctly. What you are describing is classic symptoms of the closed throttle switch not "making" when the throttle is closed so the idle speed control does not know that you have released the throttle....so it holds the throttle open and fixed at the point the plunger extended to in anticipation of you closing the throttle. After you come to a stop the zero MPH flag sets and overrides the throttle switch requirement and goes to RPM control so the idle comes down to normal."
OK, searched Cadillacforums.com and found a reference to my problem. They trace it down to a throttle closed switch with is located inside the ISC plunger box assembly on the throttle body. I think I have a spare one. I'll swap it out and see if my problem goes away. I did have it working at one time...then it went away. Maybe it went bad after I got it running, afterall it did sit in the junkyard for two years before I got it.
I replaced the ISC with my spare and it responds where the other one wouldn't. The respond I'm talking about is when the car is running and you move the thottle off of the idle positon and the plunger follows you should be able to push the plunger back down. My first one I couldn't.
I did the idle learn process again and still have the same problem so now I have two more questions...
I haven't crossed ALDL A+B to check timing since the first time I did this. It was right so I figured I don't have to check it anymore.
1).Is this a neccessity to check timing when you do the idle learn???
2).When do I unground the alternator. Before the ten minute park idle/three minute drive idle or after when I'm all through???
Dragon1/Brian
Anybody want to come over and do this for me????
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03:11 PM
rockcrawl Member
Posts: 2528 From: Lehigh Valley, PA Registered: Jul 2000
Still don't work right... So why do I even need the ISC for??? All I can see that it does is set the startup high idle for warmup. This is not going to be a winter car so I really don't need a warmup period. I unpluged it yesterday and drove around a little and the car seems fine and responds the way it should...when you let up on the gas it goes to idle like it should. It won't do this with the ISC plugged in. Does it affect emissions in anyway where I won't be able to pass the test. I don't have a visual test just the sniffer test.
I checked your file, the chip is set up right. Several years ago I had a coupe with a 4.5 PFI. I ran it for a month or so without the ISC, and even on a warm day it wouldn't stay running when the engine was cold. If I'd turn up the idle set screw so that it would run cold, it would be too high when warm.
Hi Rockcrawl, you may want to check your email because I have sent you a couple with no reply. Could be having a problem with something. Also have tried PM you.
I know it works cause right after the swap I had it working. I have tried a differant used ISC, I get the same thing. I broke down and bought a new ISC and guess what, still the same thing.
Ground the alternator, unhook the ISC, electrically move it in, set idle at 525rpm, turn off car, unground alternator, turn key on, check the TPS .5 volts...electrically move the ISC all the way out, check the TPS, I get 1.2 volts, turn off key, plug the ISC back in, wait 20 seconds or more, turn key to on, turn key to off, start car, idle for ten minutes, temp reaches 203 degrees, idle in drive with foot on brake for three minutes. should be good to go...wrong!!! sail on, sail on, sail on.
Help me please, this is the only thing stopping me from having a perfect running 4.9 swap... except the tach, which reads +300 rpm, but I don't care about that for now.
Dragon1/Brian
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10:40 PM
May 23rd, 2004
collinwestphal Member
Posts: 698 From: Waukesha, WI, USA Registered: Jun 2003
Yeah, goes onto closed loop no problem, scanner also says all the sensors and switches are working. The ecm knows when the brake is stepped on, it knows when tranny shifts to 3rd. and then to 4th. Knows the correct rpm, O2 sensor works, temp is good, speedo is accurate, Car runs great, just has that sail on problem...
I found this in the technical archive from 2000, Will this work with the Caddy ecm too??? Maybe I need to do this also....
Dragon1/Brian
As for the "learning" mode to reset the learning mode on ANY GM ECM you must first "drive car until operating temperature, Then disconnect battery for 10 seconds, To "teach" the vehicle, proceed to drive at part throttle with moderate acceleration and idle conditions until normal performance returns" This is directly out of the Service Manual word for word.
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11:54 AM
ED's85GT Member
Posts: 1054 From: Statesville, NC. Registered: Feb 2002
To "teach" the vehicle, proceed to drive at part throttle with moderate acceleration and idle conditions until normal performance returns" This is directly out of the Service Manual word for word.
Brian, I swapped T/B (including ISC) because of a low MPG issue, my car did the same thing you are experiencing(sp) That awful engine "push" when slowing down. My problem slowly went away on it's own over a period of about 3 days. My car is a daily driver (about 24 miles per day)
Try driving it for a couple of days (if you haven't already done so) and see what happens.
Ed
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05:21 PM
jstricker Member
Posts: 12956 From: Russell, KS USA Registered: Apr 2002
Maybe it's a typo, but in your description you only cycled the key/power to the ECM once. From your initial post with Rockcrawls instructions:
"Turn the key off and wait 20 seconds to allow the ECM to perform a TPS learn. d).Cycle the ignition on and off once more. It takes two cycles for a sucessful TPS learn."
Are you cycling once or twice?
John Stricker
quote
Originally posted by Dragon1:
HELP!!!!!! WHY CAN'T I DO THIS RIGHT.........
I know it works cause right after the swap I had it working. I have tried a differant used ISC, I get the same thing. I broke down and bought a new ISC and guess what, still the same thing.
Ground the alternator, unhook the ISC, electrically move it in, set idle at 525rpm, turn off car, unground alternator, turn key on, check the TPS .5 volts...electrically move the ISC all the way out, check the TPS, I get 1.2 volts, turn off key, plug the ISC back in, wait 20 seconds or more, turn key to on, turn key to off, start car, idle for ten minutes, temp reaches 203 degrees, idle in drive with foot on brake for three minutes. should be good to go...wrong!!! sail on, sail on, sail on.
Help me please, this is the only thing stopping me from having a perfect running 4.9 swap... except the tach, which reads +300 rpm, but I don't care about that for now.
I cycled the key twice, I'm just aggrevated I want this to work so bad...
After I drove home from work today the car was at operating temp, I undid the battery and waited 10 to 20 seconds, redid the battery and went for a 40 mile drive on the freeway. It seems to be better, while I'm driving if I rev it up it comes down to 1500 rpm, but it also stays there while I am stopping and when I come to a stop, it drops to idle. I am driving it every day now 30 mile round trip to work and back, freeway to work and streets on the way home, I'll give it a couple days to a week and hope it fixes itself.
Dragon1/Brian
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08:48 PM
Aug 22nd, 2004
Cplensdorf Member
Posts: 663 From: Grass Lake , MI Registered: Nov 2000
Were you able to solve this problem??? I took my new 4.9 swap for its first real drive yesterday (100 miles) and it "acquired" the same symptoms you express...this was not the case on the first few drives that I took...It really is a pain in the butt to have to fight the car to make it stop.....let me know if you found anything.
Never did figure it out. I've never been a big trouble-shooter. I can put part "A" onto part "B" but if it don't work..... I've just been driving it like it is....city gas milage sucks but highway is great, 25-27mpg.
Could it be the TCC Solenoid guys? My old Lumina (4T60E) would shift straight into over drive on occasion and when coming to a stop from highway speeds it would stay locked up and I would have to fight it to a stop.
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10:04 PM
Aug 24th, 2004
Cplensdorf Member
Posts: 663 From: Grass Lake , MI Registered: Nov 2000
Guys' I have the same problem on my 4.9 with an Allante Intake on it However I am using a manual tranny! So I don't think the problem is the tranny. I had my 4.9 with the standard intake working just fine before I converted to the Allante. I would recommend that you make sure the car will idle at 525 rpm, before you start adjusting the TPS and IAC. I need to take my Throttle body apart and clean it as I can get it to idel at 525 rpm. Good thread I hope to learn from this one.
Joe Sokol 85 SE 5 Speed 2.8 V6 88 Formula/GT 5 Speed 4.9 Caddy Allante intake
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12:23 AM
Cplensdorf Member
Posts: 663 From: Grass Lake , MI Registered: Nov 2000
There was supposedly a Service Bulletin that came on from GM in 94 that addresses this very same thing..car goes 50 miles an hour without foot on accelerator...they provide idle learn procedure instructions and a comment that this will not CURE the problem, that only several weeks of driving will actually set the idle correctly...I am trying to obtain the actual Service Bulletin....anyone got it??
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11:28 AM
ED's85GT Member
Posts: 1054 From: Statesville, NC. Registered: Feb 2002
There was supposedly a Service Bulletin that came on from GM in 94 that addresses this very same thing..car goes 50 miles an hour without foot on accelerator...they provide idle learn procedure instructions and a comment that this will not CURE the problem, that only several weeks of driving will actually set the idle correctly...I am trying to obtain the actual Service Bulletin....anyone got it??
If you can find it, can you post it here/e-mail it to me?
Ed
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04:34 PM
ED's85GT Member
Posts: 1054 From: Statesville, NC. Registered: Feb 2002
SUBJECT: SLOW DECELERATION WITH CLOSED THROTTLE ABOVE 5 MPH (READJUST AIR RATE)
MODELS: 1990-93 CADILLAC DEVILLES, ELDORADOS, FLEETWOODS, SEVILLES, AND SIXTY SPECIALS (EQUIPPED WITH 4.5L OR 4.9L ENGINES)
THIS BULLETIN IS BEING REVISED TO CORRECT THE WARRANTY STATEMENT, AND CANCELS AND SUPERSEDES BULLETIN 316006 PUBLISHED OCTOBER, 1993.
Some owners may comment about slow deceleration with closed throttle above 5 mph. This may be particularly noticeable after performing bulletin T-93-44 (Corporate bulletin 016540R) even though all engine adjustments have been set according to published service information.
To correct this condition readjust the minimum air rate to between 400 and 450 rpm, the TP Sensor setting to .55 volts, and reset TP Sensor/idle learns using the procedures listed in the appropriate Service Information Manual.
This is awesome...positive points given!!!!!!!! I stayed home from work today and did the idle learn procedure again with this info and the car runs fantastic, no more fighting, no more jumping until you reach five mph while slowing down. Just awesome. Where you set the idle to 525rpm in the procedure set it to 400 to 450rpm(I set mine to 400rpm.) Set the TPS sensor to read 5.5 volts at this rpm. Then kill the motor, do this by smothering the throttle body, the key has to stay on. Move out the IAC plunger by crossing the plug like you did to move it in and screw in the plunger until it reads 1.15 to 1.2 volts(I did mine to 1.16 volts.). Turn off the key, wait 20 seconds turn on key,don't start car now,just turn key to on, now turn it off again. Start car and idle until temp comes up to 176degs. then idle in park for ten minutes, put foot on brake, put car in drive and idle for three more minutes. Turn off the car. Unhook the positive battery cable for 10 to 15 seconds to initiate the idle learn and go for a ride. I instantly had the sail on condition fixed and the car comes to a stop with no fighting whatsoever.
Thank you to 87fastback for the info and the solution to my problem, hopefully it works for everyone else..... Thank you to Cplensdorf for bringing back this post...
Dragon1/Brian
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09:59 PM
Aug 27th, 2004
87fastback Member
Posts: 232 From: Fairhope, AL USA Registered: Nov 2001
