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2001 SLS
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27 Posts
Discussion Starter #1
Hello,
First posted message :bigroll:. I have a 2000 SLS with 92k miles. The engine has a very slight rumble at idle. This happens cold or hot and is constant. You can barely feel it inside the car every 5 seconds or so. This cannot be felt while driving at all and the car feels very strong. The car does not hesitate ant any RPM and the tach does not move at all when idleing.

-Performed many WOT's according to some posts - didn't smoke much at all if any
-No oil or coolant leaks (no loss in coolant whatsoever)
-Changed spark plugs (Made no difference)
-The front COP is new due to #4 Cylinder misfire (Idle was the same before this happened)
-Cleaned the TB (No change)
-Put some Seafoam in the brake booster according to the instructions (Wow lots of smoke, only white thought not black) Accelerates faster now :thumbsup:
-Pulled codes (only a RIM B1009)

Is this just how these engines are or should I be worried? Thanks in advance.
 

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White Diamond '03 DHS (with DTS floor shift)
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Put some Seafoam in the brake booster according to the instructions (Wow lots of smoke, only white thought not black)
Maybe fouled a plug.
 

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2001 SLS
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27 Posts
Discussion Starter #3 (Edited)
Thanks for the quick response, I am new to owning a Cadillac and have learned most of the troubleshooting from you guys :). I forgot to mention that when the front COP went bad ,I replace it and all the plugs. I have since then, rechecked them and they all look good. Is there a way to check if the engines history of misfires?
 

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1998 Seville SLS
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56 Posts
Thanks for the quick response, I am new to owning a Cadillac and have learned most of the troubleshooting from you guys :). I forgot to mention that when the front COP went bad ,I replace it and all the plugs. I have since then, rechecked them and they all look good. Is there a way to check if the engines history of misfires?
Pull the codes, I think there is one for a misfire.
 

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1999 Seville STS
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37 Posts
I had the same kind of rough idle you described - shaking every 5 seconds while tach needle showed no variation. In addition, my car (1999 Seville STS) stalled occasionally while waiting in the lights, albeit only very, very occasionally and at exactly the right temperature. The stalling problem is why I changed crank position sensors. Fixed the stalling issue, and as a bonus, it smoothed out the idle considerably!

Before that I also had plugs and wires changed - this did nothing to the idle problem.

Another potential cause that comes to mind is a broken engine mount. Quite a common problem with last gen Sevilles.
 

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2001 SLS
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27 Posts
Discussion Starter #6
-Pulled codes (only a RIM B1009, does anyone know if this affect anything?)

How can I check for a broken motor mount? The engine doesn't seem to jump when put in or out of gear.

Can I change the crank position sensors myself? Anyone have pictures of their location? Are they costly?
 

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2001 SLS
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27 Posts
Discussion Starter #9
I see that an B1009 is an eeprom checksum error, but cannot find what it effects on the car. Does anyone know?
Any help on checking a motor mount?
 

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2001 SLS
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Discussion Starter #10
I had the same kind of rough idle you described - shaking every 5 seconds while tach needle showed no variation. In addition, my car (1999 Seville STS) stalled occasionally while waiting in the lights, albeit only very, very occasionally and at exactly the right temperature. The stalling problem is why I changed crank position sensors. Fixed the stalling issue, and as a bonus, it smoothed out the idle considerably!

Before that I also had plugs and wires changed - this did nothing to the idle problem.

Another potential cause that comes to mind is a broken engine mount. Quite a common problem with last gen Sevilles.
Seems just like my problem, I only had the car stall one time. Changed out my Crank Position Sensors yesterday . It smoothed out the idle, but I still seems to get a slight shudder every 5 to 10 seconds. Also I noticed that it seems to idle smoother when the A/C is on :confused: It would seem that fixing a broken motor mount (if I had one) would only better isolate the engine from the chasis, but it wouldn't stop the engine from a rough idle. Did you ever solve your problem? Do you think its possible for a misfire that the computer wouldn't pick up. If I don't have a SES light coming on, is it worth hooking up a scanner to the car? Would anything show there that wouldn't show up when pulling codes?
 

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Seville SLS 2000
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9 Posts
My SLS has the same problem. Cadillac dealership has changed crank sensor but no difference. Now, they said the fuel pump is not up to full pressure. It's only at 35psi which should be 45 psi. They also said that engine is running lean. On tuesday a new fuel pump for a total of about $600 will be installed. Hopefully this will take car of the problem. Any other suggestions?
 

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White Diamond '03 DHS (with DTS floor shift)
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35 psi IS low. Running lean and rough idle may be a vacuum leak. Do a search for "plenum". Seems to be a common leak point on 2000+.
 

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The Northstar Tuner
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2,759 Posts
Please just take this will little thought.
This car would have this condition from day 1
If the Timing chain gears or guide wear it can throw off the cam timing and cause a rough idle. This condition would have progressively come in.
.

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Subject:
4.6L LD8 , L37 and 4.0L , L47 Engine Rough Idle - kw body calibration camshaft code DTC EGR intake leak lean manifold MIL miss misfire PCM #PI01748A - (02/20/2004)

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Condition/Concern:
Some 2000 and early built 2001 model year Cadillac Deville, Eldorado, Seville with 4.6L (LD8, L37) engines or 2001 Oldsmobile Aurora with 4.0L (L47) engine, may exhibit a condition of rough idle with no PCM DTC and no driveability complaints

Recommendation/Instructions:
The camshafts must be replaced (part numbers are listed below) on all 2000 vehicles with 4.6L (LD8) (L37) Engines and the early built 2001 vehicles (see broadcast codes listed below) with 4.0L (L47) OR 4.6L (LD8) (L37) Engines. For a 2001 vehicle, you must verify that it has the early cam profile by reading the 3 alpha characters of the broadcast code listed on the tag attached to the passengers side of the engine's rear cam cover. The Broadcast Codes for early 2001 engines are:

Seville, Deville Applications:

ENGINE VIN CODE Y KMA

ENGINE VIN CODE 9 KKA

.

Eldorado Applications:

ENGINE VIN CODE Y KCA

ENGINE VIN CODE 9 KBA

.

Aurora Application:

ENGINE VIN CODE C KYA

.

Camshaft Service Part Numbers:

.

4.6L (LD8) VIN CODE Y AND 4.0L (L47) VIN CODE C CAMSHAFT SERVICE PART NUMBERS;

12570331 RH EXH

12570332 LH INT

12570333 RH INT

12570334 LH EXH

.

4.6 (L37) VIN CODE 9 CAMSHAFT SERVICE PART NUMBERS;

12570335 RH INT

12570336 LH INT

12570337 RH EXH

12570338 LH EXH

NOTE: the Camshaft Service Part Number information can also be found on page 7 of the July 2001 GM Tech Link Volume, No. 7

http://216.182.211.32/techlink/images/issues/arcv_pdf/7_01_e.pdf



Once all 4 camshafts have been installed, the calibration must be updated. The dealer must contact TECHLINE and tell them that the camshafts on the vehicle have been replaced, and they will give the Dealer a VCI number to install the correct calibration. Techline must be contacted each time so that they have a record of when a camshaft change occurred on each vehicle. This will ensure that future calibration for that vehicle will be correct.

.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

Models:
(00 01 CADILLAC DEVILLE, SEVILLE, KB, ELDORADO, EB, 4.6L (LD8 , L37) ENGINE) and 01 OLDSMOBILE AURORA 4.0L (L47) ENGINE)

.
 

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The Northstar Tuner
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He doesn't have a code like that.

treddekopp,
You said that you cleaned the TB, but did you also clean out the IAC (Idle Air Control) tubing?
KW stands for KeyWord. This is use like a tag for searching.

Searching any of these words (body, calibration, camshaft, code DTC EGR, intake, leak, lean, manifold, MIL, miss, misfire, PCM) will send you to this PI.
.
As you can see in the Condition/Concern part of the PI. The Customer may exhibit a condition of rough idle with no PCM DTC and no driveability complaints
.
.
So what code are you talking about?


more info that I listed
Clipboard02.jpg
 

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2001 SLS
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27 Posts
Discussion Starter #16
He doesn't have a code like that.

treddekopp,
You said that you cleaned the TB, but did you also clean out the IAC (Idle Air Control) tubing?
No didn't clean that. Not sure which tubes to clean out :confused:. Can you tell me where the IAC tubing is? Thanks in advance
 

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White Diamond '03 DHS (with DTS floor shift)
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The IAC valve is mounted on the side of the TB. Don't mistake it for the TPS, which is inline with the throttle plate pivot. There is no tubing. There is an air bypass circuit in the TB that the IAC valve controls. The air simply bypasses the closed throttle plate to allow the engine to idle and the valve controls how much air is bypassed. Just pull the IAC valve and blow out the air channel with compressed air.
 

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2001 SLS
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27 Posts
Discussion Starter #18
Thanks for the insight on the IAC Valve, I might have solved the problem :thumbsup:. I checked under the hood and saw a couple of hoses going to the throttle body. There are some really tiny ones and a couple of bigger ones. I removed the engine cover, and the brake booster line to get to what I think is the IAC. There is a vacuum hose that connects to the front of the engine valve cover via a hard tube. Anyway, to get to the point, the 90 degree connector was brittle and cracked in multiple places, I removed it, cleaned it up and wrapped electrical tape around the connector (only temporary until I get the part). Does anyone know what that part is called, I tried to get it at my Autozone and they said it must be a dealer item only? I still get a suddle shake every now and then, but the car seems to Idle much, much smoother. Can anyone verify that I was working on the hose that leads to the IAC valve? Can the IAC valve itself be cleaned?:confused: . Thank you all for your insight, I am getting closer :yup:
 

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White Diamond '03 DHS (with DTS floor shift)
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The IAC valve is electronically controlled, not vacuum. Yes, you should be able to pull it off and clean the pintle valve and seat. The vacuum line in question is for crankcase ventilation. It draws air (crankcase gases) from the crankcase through the TB & manifold to burn them. I believe it replaces the PCV valve. A crack in that line will cause a vacuum leak and idle problems. As for other ideas, clean the EGR valve (if not already done).
 

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2001 SLS
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Discussion Starter #20
The IAC valve is electronically controlled, not vacuum. Yes, you should be able to pull it off and clean the pintle valve and seat. The vacuum line in question is for crankcase ventilation. It draws air (crankcase gases) from the crankcase through the TB & manifold to burn them. I believe it replaces the PCV valve. A crack in that line will cause a vacuum leak and idle problems. As for other ideas, clean the EGR valve (if not already done).
I still have a PCV Valve, that is connected to the back valve cover on the engine. In a previous quote, you said that the IAC valce has tubing going to it, what tubing are you speaking of? I looked at it again last night and I am still not sure what part is the IAC. I tried to remove the EGR valve last month but the metal guard around it was giving me hell to remove it, so I gave up. I will try the EGR again next.
 
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