01 sls rough idle and clunk in rear

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01 sls rough idle and clunk in rear

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01 sls rough idle and clunk in rear - 5/20/2008 12:08:05 PM

2001slswhite

Posts: 7
Joined: 5/20/2008
Status: offline Hello all..

I have a 2001 SLS. ive had it for a year and a half. I do most of work myself but have run into two problems that i can not figure out. First I have a very rough idle and a spark knock. the spark knock is only when engine is warm. It runs fine while driving but at a stop or when in park it bounces from 600-850rpm. the engine does not stop ever. The service engine soon light is on and i pulled the codes and there were 2. they were saying that bank 1 and bank 2 were running lean. checked the mass airflow and checked for vacuum leaks the best that i could. I have been reading that the crank sensors are a common problem but just looking for a bit of advice....

Second, I have a clunk in the rear. I have checked for play and wear marks through out rear suspension but have not found anything. I sounds like it is coming from drivers side. Me and my father looked at it for hours one day and came up empty. we both have done alot of work on cars in the past. the sound seems to come when i hit small bumps. i dont really hear it when i hit big bumps. it sounds like kinda a hollow clunk. I have checked strut mounts, brake hardware and have pryed on everything possible and found no play. also sounds stupid but if i kick the rear tire i can hear a similar nose. the reason i kicked it is that i had it jacked up and wanted to see if that would help duplicate the noise. not because i was mad.haha if u need a better explination just ask and i will do my best.

I thank you for taking time to help.....

Post #: 1

RE: 01 sls rough idle and clunk in rear - 5/21/2008 6:54:51 AM

Stealth

Posts: 3006
Joined: 2/18/2007
Status: offline

quote:

ORIGINAL: 2001slswhite

Hello all..

I have a 2001 SLS. ive had it for a year and a half. I do most of work myself but have run into two problems that i can not figure out. First I have a very rough idle and a spark knock. the spark knock is only when engine is warm. It runs fine while driving but at a stop or when in park it bounces from 600-850rpm. the engine does not stop ever. The service engine soon light is on and i pulled the codes and there were 2. they were saying that bank 1 and bank 2 were running lean. checked the mass airflow and checked for vacuum leaks the best that i could. I have been reading that the crank sensors are a common problem but just looking for a bit of advice....

Second, I have a clunk in the rear. I have checked for play and wear marks through out rear suspension but have not found anything. I sounds like it is coming from drivers side. Me and my father looked at it for hours one day and came up empty. we both have done alot of work on cars in the past. the sound seems to come when i hit small bumps. i dont really hear it when i hit big bumps. it sounds like kinda a hollow clunk. I have checked strut mounts, brake hardware and have pryed on everything possible and found no play. also sounds stupid but if i kick the rear tire i can hear a similar nose. the reason i kicked it is that i had it jacked up and wanted to see if that would help duplicate the noise. not because i was mad.haha if u need a better explination just ask and i will do my best.

I thank you for taking time to help.....

the clunk .. get under the car, grab the exhaust pipe at different points, yank on it .. the #1 clunker.

the CODES? I dont see them .. what are they?
Also, check throotle intake and idle controller.

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Post #: 2

RE: 01 sls rough idle and clunk in rear - 5/21/2008 8:53:33 AM

2001slswhite

Posts: 7
Joined: 5/20/2008
Status: offline hey stealth thank you for taking the time to help... I have already tried making the exhaust duplicate the noise. It is like a phantom noise. sounds like it is coming from the drivers side rear hub. i have gone to the extent of riding in the trunk and backseat with the door open, with my head outside the car. It really soounds like its coming from the hub. i have checked it for play also. wheel bearing seems fine.

And about the codes, there were 2 codes that are all related to banks 1 and 2 being to lean. p0171 and p0174.... hope this helps.. thanks a bunch

(in reply to Stealth)

Post #: 3

RE: 01 sls rough idle and clunk in rear - 5/21/2008 8:57:37 AM

stomper

Posts: 1447
Joined: 6/18/2007
Status: offline
where is the gasoline filler neck on your car?

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Post #: 4

RE: 01 sls rough idle and clunk in rear - 5/21/2008 9:07:53 AM

2001slswhite

Posts: 7
Joined: 5/20/2008
Status: offline on the drivers side.. want to say that i checked that but not positive so i will try it again. I havent looked at in awhile. was just going to wait till it got worse but then i found this site plus it is really starting to bother me. Im going to go outside and check it. any suggestions on the idle.

(in reply to stomper)

Post #: 5

RE: 01 sls rough idle and clunk in rear - 5/21/2008 10:58:54 PM

jerrymac

Posts: 55
Joined: 4/6/2008
Status: offline I use a 'chassis EAR' to check for clicks,clunks,rattles,squeaks,rumbles,etc. It might take
a couple of roadtests to pinpoint the noise, but there hasn't been 1 yet that I didn't find.
Ask your friends,relatives,etc., if they have one you can borrow. They cost about $150.00
so unless you plan on using it alot it might not be worth the cost of buying one.

(in reply to 2001slswhite)

Post #: 6

RE: 01 sls rough idle and clunk in rear - 8/10/2008 2:52:51 PM

obnoxus

Posts: 14
Joined: 12/19/2006
Status: offline Replace the bellows between the throttle body and the intake,,,,, its cracked

(in reply to jerrymac)

Post #: 7

RE: 01 sls rough idle and clunk in rear - 11/18/2008 2:16:07 PM

HockeyPuck

Posts: 2
Joined: 11/18/2008
Status: offline I have a 2001 SLS that was giving me the lean codes bank 1 and 2 and an irratic idle. Found the problem with starting fluid. It had a crack in the rubber boot that connects the intake and the throttle body. I believe they call it the plentum. You have to take the intake off to replace it. Sure enough on the bottom side of it there was a 1 inch crack in it. Runs like new now.

(in reply to obnoxus)

Post #: 8

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