Cadillac Owners Forum banner

2002 deville rough idle HELP!

10K views 34 replies 6 participants last post by  2002 DHS 
#1 ·
i was driving on the highway at 80 and noticed the engine sputter for a moment...my exit was 1/2 down the road....i got off and the car completely died...this was all after a 45 min trip...the car sat for hours then i took the same trip home without any problems except for a rough idle when i came to slow down, and when in park...car has 155,000 miles on it so i replaced all the plugs (even the stupid ones along the firewall!) i cleaned the throttle body (took a whole can of cleaner! :( and i took out the AIC i believe its called? the thing that goes into the throttle body that your supposed to only use electrical cleaner on...after all that when parked it idles rough between 650 and 750 reving up and slowing down...i pulled some codes, but have no clue as what they mean...i looked at the sticky but it looked like russian to me :( please HELP! the codes are

IPM B0429 CURRENT
IPM B1004 History
RIM C0658 History
i bought some seafoam and a new fuel filter i am about to go install...oh yeah and i cleaned the MAF...i would appreciate some insight as what to try next? thanks in advance guys:bouncy:
 
#2 ·
AIC i believe its called?
IAC = Idle Air Control

B0429 is the actuator for the rear seat temp control valve (not you problem).
B1004 just means that battery power was probably pulled (not your problem).
C0658 is for the ELC (Electronic Level Control) system (not your problem).

Check the Plenum for a rip. It should set codes, but doesn't always. Do a search for plenum and you'll find LOTS of info and pics.

P.S.
Take the Seafoam back and get a refund.
 
#3 ·
well i changed the fuel filter...looked pretty old and like it def wouldnt have hurt anything by changing it...added some seafoam to gas, and some to the oil...drove it in town to runa couple of errands and no sign of a fix yet...

buuuuuuuuut before i took off, i sprayed some starting fluid kind of underneath the plenum and i got a high idle...so i guess that may be the problem? regardless i just ordered one as i am sure it wouldnt hurt to replace it with the car having 150,000 on it...i wanna try and squeeze another 150 out of it!

bought an 00' DTS 3 years ago from florida w only 60,00 miles...that mofo was spotless! i wouldnt even drive it in the rain! then one day we had a hail storm...i hated to look at the car after that and had to sell her...so this deville is the replacement...its gunna have to last a while til i can afford the new body style!

thanks ranger rick for the reply! with what i said about the high idle, do you thinnk that narrows it down to the plenum?:hmm:
 
#5 ·
lol i was just playin man...you seem to be pretty smart when it comes to these engines...thanks for the help! hope to get mines fixed by this weekend...i cant wait to really be able to clean the hell out of my TB...it looks pretty bad...also will check the starter connections while i have the intake off...could you point me in the direction of getting my damn fuel guage to work properly? seems to fluctuate constantly...only when i start the car can i get a pretty good reading, then as i drive i end up with a full tank of gas by the end of my trip! i wish i really did get free gas as i drove, but thats not the case...actually thats what i thought my problem was all along...when it died on me, it didnt make sense cuz i just put 30 bucks in it!~
 
#6 ·
The fluctuating fuel gauge is probably the sending unit in the tank. Luckily, there is an access panel in the trunk so you do not have to drop the tank. It has been discussed many times so if you do a search you should come up with lots of info on it.
 
#7 ·
alright you were right ranger! the plenum was bad! had about a 2 1/2 inch rip on the bottom side...so i did the plenum change and she still aint right...here is a few things i think it may be? while i had the intake off, my dumb a** decided to unscrew the two screws that were holding in a little round thing...well after i realized it was just a spring behind there i quit and tightened the screws back...is that some type of adustment? also i tried to clean the TB while it was still in its place but noticed that there is a gap between that and another piece of metal? maybe some carbon fell inbetween there and there is not a good seal? so its idleing at about 950 when i start it up then dropping to 700-750 while in Drive...My car used to idle at 1200 when started then drop down to 650 i believe...My SES light is still on also...havent had a chance to take the TB off and clean it, and wont until monday...maybe some gunk got down in there with the gasket and its not seated right? other than me messing up something down the road, the plenum change wasnt hard...
 
#8 ·
The "little round thing" under the plenum is the intake manifold overpressure valve. Any leaks there and you have big fuel mixture problems. Another "little round thing" in the other end of the manifold is a blank rubber plug. Don't mess with it. If you did not carefully remove and install the 3 long plenum bolts - they also secure the TB - you may have more vacuum leaks than when you started. The entire process should be done like a clean surgical procedure............

No need to take the TB off to clean it - remove the intake ducting, block the gas pedal wide open, and scrub away with TB spray cleaner, rags, and a toothbrush.

Did you carefully remove and inspect the IAC motor and plunger (Idle Air Control) ?? Careful - that puppy costs about $200.

Don't put snake oil in that engine !!! DON'T !!!!

The cold start sequence should be 1200 rpm for 15 -30 seconds, down to about 950 for a while, down to 650 idle.

If you did not clear the SES codes, then the system needs 3 start/run cycles during which the relevant code doesn't set, the light then goes out, and the code goes to History, where it remains for another 40 successful cycles after which it self-clears.
 
#9 ·
i carefully pulled out the AIC and cleaned it with electric parts cleaner as it was black...is there an adjustment on the overpressure valve? like did i get it out of wack when i tried to remove the scews? i noticed the spring in there and it seemed as if that thing make it move?
 
#10 ·
maybe my 3 bolts that go through the throttle body are not tight enough? i didnt want to sinch them down and strip out the nuts that are attached to the plenum...they seemed sort of fragile...and i understand that you can clean the TB that way, but my was very dirty on the back side and i tried a toothbrush, but a bristle broke off and it freaked me out so i stopped...i guess i need to take some time and get it all cleaned up and like i said there may be some carbon clumps inbetween the TB where the seal is :( i feel like a horrible cadillac mech right now...
 
#13 ·
yeah i bought this car at 149,000 and it looked like it had NEVER been cleaned...the back side of the flipper is pretty caked on...ill try and take it all apar tomo and get it cleaned up....is there a torque spec on the 3 bolts that hold the TB to the plenum? i dont even have a torque wrench, but can kinda calculate with my brain that too much is too much...like i said i didnt wanna overdo it cuz of the nuts that are attached to the plenum...
 
#14 ·
The 3 throttlebody bolts AND intake manifold bolts are torqued to 89 in/lb, about 7.5 ft/lb.

NEVER guess at torque settings.......... if you are going to do half-decent engine work, invest in the correct tools, otherwise let a professional do the work before you break something. Harsh words, but very true. You have already learned part of the truth......................
 
#15 ·
dang those are harsh words...but they are definitley true! i went to autozone today and the only torque wrench they had for inch pounds started at 120 so i didnt get it obviously...im gunna run to sears here after a bit and see what they have...but as i went to taking off the air tube/dam? i found i didnt plug the MAF in! so i plugged it in, and i have the proper idle at start up 1200, and then it went down to 700 i think thats the proper range isnt it? im going on a 25 minute trip later today and hope all is well now :) and i sure hope the SES light goes off...if it does not, is there something i have to do to reset it?
 
#16 ·
The SES light will go out after 3 ignition cycles with the failure not detected OR you can go into the onboard diagnostics and clear it.

Technically, EVERY nut and bolt on the car has a torque setting. That said (Sub may disagree), I rarely ever use a torque wrench other than on lug nuts.
 
#19 ·
That said (Sub may disagree)

I don't use a torque wrench on everything, either...............but when you're fooling with plastic manifolds and cast throttlebodies I figure it's good politics to advise a relative novice to use torque specs instead of "squeak tight + a quarter turn".
 
#18 ·
took a short drive to the gas station this morning to put in some techron...looked down and the dash was free and clear of that monster light known as the SES! thanks guys for all your help! my next challenge will be the fuel sending unit? so my gas guage takes a chill pill! unless the magic bottle of techron works?
 
#22 ·
---------------------------------
NEVER start by throwing a bunch of parts at a problem -

DIAGNOSE the problem FIRST -
THEN replace what is required - if anything -

STEP ONE - ALWAYS -

check for Diagnostic Trouble Codes -

if you don't know how - go here and read the ENTIRE post -

http://www.cadillacforums.com/forum...ncluding-1985/138257-how-pull-codes-dtcs.html

if you have any codes - post them here -
ALONG WITH THEIR DEFINITIONS -
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top