Mercedes SLK World banner

Status
Not open for further replies.
1 - 12 of 12 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
Not clear if there is a connection between the two, but the engine surges around 300 rpm at rate of about once per 2 seconds when feathering the throttle, and seems to have a noticeable loss of power from about half to full throttle. Surges when idling in park about 600 - 1000 rpm for a while and then settles to 700 steady. Check engine light is on and coolant level light comes on intermittently. Odometer is now 105K. Any ideas as to whats going on here?
 

·
Registered
Joined
·
9 Posts
What did the problem turn out to be?


I've got exactly the same symptoms.

Surging while cruising. Like a "tug" every second or so.
Stumbling/surging at idle. 300-1K.

If I turn the engine off and restart, it will have gone away, so the dealership never sees it and can't fix it :mad:

I once got CEL with P0101.
Replaced the MAF, cleaned oil sep in compressor muffler (air intake).
No change.

It doesn't do it everyday. And never when it's at the dealership.

It's disconcerting/annoying on the highway.
When braking to a stop it feels errily/scary when it's tugging you as you come to a stop.
Then at idle, it will stutter to 300 and then surge to 1K, back and forth about once per second.
 

·
Administrator 2009 SLK 55 AMG/Founding Member 2006
Joined
·
97,344 Posts
RicksterSLK,

Welcome to SLKWorld.com: The #1 Mercedes-Benz SLK Forum from Valrico, Florida!

Please update your location/vehicle (model and year) in your profile as it helps the members answer your questions which usually are based on that information if you haven’t already.
‘Usercp’ at the top left of page, then ‘edit your details’ on the left side, ‘additional information’ near the bottom, edit your ‘location’ and ‘vehicle’.

You might want to post an introduction in the ‘New members introduce yourself here’ section, if you haven’t already.

Some tips to make your visit here more enjoyable:
If you haven’t, please use the 'search' feature at the top right of the page for your questions as they have probably been asked before. Remember, ‘Search’ is your friend.
In addition, if you haven’t, please post your question in the appropriate discussion forum for a quicker response and only once. Be patient and a knowledgeable member will address your question.
If you wish to become PM (Private Message) - capable, you need 15 posts. To get those 15 posts quickly, just go to the ‘New members introduce yourself here’ section and welcome enough new members to obtain your needed posts to PM.
Want to post a picture? Start a new thread or make a post, click on the ‘paper clip’ or go to ‘advanced’ and then ‘manage attachments’ then ‘choose file’ then ‘upload’ and ‘submit’!
Want to ‘like’ or thank’ someone’s comments? Use the ‘like’ button to the right or the ‘Thanks’ button, bottom right of any post you like. This saves you having to comment.
New members should be aware that the 'New Posts' link next to the 'Search' link top right of the info bar is a great way to see all of the posts you have missed since you were on the forum last. Remember to click 'mark forums read' under ‘quick links’ when you leave.
Also vote or enter our Ride of the Month competition: http://www.slkworld.com/rotm-submissions-voting/

Thank you
Jeff
Moderator/Founding Member/Ride of the Month Coordinator
 

·
Per ardua ad cineris.
Joined
·
1,039 Posts
What did the problem turn out to be?


I've got exactly the same symptoms.

Surging while cruising. Like a "tug" every second or so.
Stumbling/surging at idle. 300-1K.

If I turn the engine off and restart, it will have gone away, so the dealership never sees it and can't fix it :mad:

I once got CEL with P0101.
Replaced the MAF, cleaned oil sep in compressor muffler (air intake).
No change.

It doesn't do it everyday. And never when it's at the dealership.

It's disconcerting/annoying on the highway.
When braking to a stop it feels errily/scary when it's tugging you as you come to a stop.
Then at idle, it will stutter to 300 and then surge to 1K, back and forth about once per second.
Answer with a question; do these cars have an Exhaust Gas Recirculation Valve? These are used to cool teh exhaust gasses to reduce NOx emissions, and work under part throttle.
Typical effect is to cause a pause in acceleration as you pass 1500 revs, but if controlled erratically, would have the effect you describe.

Seems strange to use hot exhaust gasses to cool the exhaust gas flow; it actually puts inert nitrogen into the inlet manifold, so there is lots of gas but less oxygen to burn, so teh cylinder flame temp is decreased, and hence the NOx generation (which happens at high flame temps) is decreased.
Why is the exhaust gas only nitrogen? Because the right amount of fuel has been put in to burn all the oxygen in the previous cycle!

HTH.
 

·
Registered
Joined
·
9 Posts
sorry for bringing up an old thread... what was the problem and did u find the solution in the end? does it have to do with the charcoal canister thing at the fuel line...?
Almost afraid to respond. It's been working well lately, probably will fail tomorrow:)

For a while, I continued to clean the maf once a month and all the other hoses with spray carb cleaner

One day I disconnected all the hoses with spay carb cleaner, including the short one from valve rockers (?) to intake manifold above the oil scavenger to make sure it was ok.

In the past, my blowing out of the tubes was just sticking the Small spray hose into the hose and giving it a **** until anything running out was clean.
This time I "sealed" the small hose in the hoses by wrapping with a tight corner of a rag. This pressurized and truly blasted the cleaner into/through the hose.

While blowing out all the hoses, I blasted a lot in the hose that goes down to oil dipstick.
Suddenly there was a "splorp" and a glop of oil came out the rocer manifold.
I'm guessing the check valve in the hose to dipstick was clogged -guessing.

If at check valve was clogged, the scavenged oil wouldn't drain. If it was stuck, oil would probably blast back up the hose. Both guesses old cause the probelem

Note that I don't actually see where ths check valve s, or I'd replace it...

I reassembled and haven't had a problem since.

Note. Had to replace that short hose. It was brittle and cracked while disconnecting.
I taped it up, but at next service, they noticed it and replaced it.
 

·
Per ardua ad cineris.
Joined
·
1,039 Posts
Almost afraid to respond. It's been working well lately, probably will fail tomorrow:)

For a while, I continued to clean the maf once a month and all the other hoses with spray carb cleaner

One day I disconnected all the hoses with spay carb cleaner, including the short one from valve rockers (?) to intake manifold above the oil scavenger to make sure it was ok.

In the past, my blowing out of the tubes was just sticking the Small spray hose into the hose and giving it a **** until anything running out was clean.
This time I "sealed" the small hose in the hoses by wrapping with a tight corner of a rag. This pressurized and truly blasted the cleaner into/through the hose.

While blowing out all the hoses, I blasted a lot in the hose that goes down to oil dipstick.
Suddenly there was a "splorp" and a glop of oil came out the rocer manifold.
I'm guessing the check valve in the hose to dipstick was clogged -guessing.

If at check valve was clogged, the scavenged oil wouldn't drain. If it was stuck, oil would probably blast back up the hose. Both guesses old cause the probelem

Note that I don't actually see where ths check valve s, or I'd replace it...

I reassembled and haven't had a problem since.

Note. Had to replace that short hose. It was brittle and cracked while disconnecting.
I taped it up, but at next service, they noticed it and replaced it.
Sounds like the MAF is the primary driver to cause this problem for you; similar for me.
You are now looking at the next stage of the oil scavenger system.
Many threads here, but in brief, the high flow scavenger is the obvious one beside the air filter; when the flow is fast enough, the swirl chanber gets the oil out of the air, and the fresh air goes into the (downstream of the filter) mixed airflow, and the oil drops down to teh sump. it is this tube that it sounds like you have cleared.
The low flow scavenger, with teh check vavle, is buried under the inlet manifold; there are two brass nozzles that allow the low flow to be sucked out of the head oil chambers, and then through the check valve to into teh manifold proper. Being limited to low flow by the nozzles, this often blocks, which results in teh high flow system coping with teh low flows, and having insuficient flow to work the centrifuge, the separation doesn't work, and the MAF gets oily.

As mentioned, many threads; once you get in there, change all the hoses under the manifold, since it's not a trivial task to get there to repeat the process.
 

·
Registered
Joined
·
9 Posts
Clogged maf, p0101

I think my constantly fouling maf (p0101) was caused by a clogged check valve in the drain of the PVC oil scavenger. It drains into the oil dipstick tube.

Pull the large hose off the oil scavenger and flush with carb cleaner.
Plug with a wad of paper Owen and your finger to make it airtight and build up pressure as you spray.

Mine clicked a few times then I cloud clearly hear the sprat going into the oil dipstick.

Clean the maf and hopefully it won't come back.
 

·
Registered
Joined
·
5 Posts
SLK Surge under light throttle

Well, well, well. Seems I am not the only one. We have been struggling for about a year 30 000km to find a solution. The MAF does get some oil on it, but cleaning does not ensure no surge, and an oily MAFdoes not mean it WILL surge. I have even had it surge with MAF disconnected electrically. Forget MAF. I will keep working with diagnostics expert who cannot identify even with laptop connected while driving the vehicle. Current possibility is the upstream sensor but a bit expensive to change just to test. I will post again if any progress is made or a solution found.
This is a R170 200 Kompressor, 2001 with 300 000 plus on the odor.
Good to know I am not alone.
 

·
Registered 1999 SLK230
Joined
·
75 Posts
Having a similar problem with my wife’s 99 SLK230. Started suddenly this week. Surging at idle, SLAM when put into drive or reverse, no gas pedal response.

Just cleaned the throttle body which was pretty clean anyway. Code P1580 Throttle motor wiring.

Next step is to try to find out the interconnect problem. Maybe reset the throttle / pedal positions first.

Anyone know how strong the throttle plate spring should be?? Seems crazy strong to me. Requires *pounds* of finger pressure to open the plate.

Took the assembly apart and the motor and gears spin fine. Just a very strong spring!
 

·
Super Moderator UK SLK 55 AMG 2007
Joined
·
28,112 Posts
Having a similar problem with my wife’s 99 SLK230. Started suddenly this week. Surging at idle, SLAM when put into drive or reverse, no gas pedal response.

Just cleaned the throttle body which was pretty clean anyway. Code P1580 Throttle motor wiring.

Next step is to try to find out the interconnect problem. Maybe reset the throttle / pedal positions first.

Anyone know how strong the throttle plate spring should be?? Seems crazy strong to me. Requires *pounds* of finger pressure to open the plate.

Took the assembly apart and the motor and gears spin fine. Just a very strong spring!
I see you posted your own thread on this:
http://www.slkworld.com/slk-r170-general-discussion/477697-idle-surging-dead-gas-pedal.html

Wise, as this is an old thread.

http://www.slkworld.com/new-members-introduce-yourself-here/233026-posting-old-thread-how-fix.html
 
1 - 12 of 12 Posts
Status
Not open for further replies.
Top