m113k making strange sound when accelerating sounds like a blow off valve hiss
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98 SL500 sport
m113k making strange sound when accelerating sounds like a blow off valve hiss
so my 03 s55 amg is making what sounds like a blow off valve on a turbo hiss when accelerating as car shifts from 1st to 2nd . is this a common issue and im just not searching it correctly to find the answer ? no codes but car is definitely not feeling 100%
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98 SL500 sport
Smoked it and didn't see any significant smoke from anyplace that should be sealed . Where can I get that groomed for the vacuum line or can I just silicone it back into place? The TB butterfly is chattering badly despite the screws being tight I'm also positive I need to change the motor mounts . I'm curious if there is any way to diy repair the existing throttle body or am I forced to replace ,?
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98 SL500 sport
That small rubber grommet on the Evap line from MB is $85 that's ridiculous tell me someone has found an alternative ? I can purchase the line with the grommet used for $47.but prefer to just replace the grommet since I'm replacing the throttle body , map sensor and surge tank gaskets. While I have the TB off is there anything else you would suggest me servicing / replacing or doing ?
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98 SL500 sport
That small rubber grommet on the Evap line from MB is $85 that's ridiculous tell me someone has found an alternative ? I can purchase the line with the grommet used for $47.but prefer to just replace the grommet since I'm replacing the throttle body , map sensor and surge tank gaskets. While I have the TB off is there anything else you would suggest me servicing / replacing or doing ?
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
so I resealed the evap breather line into the super charger, surge tank gaskets , map & IAC sensors and replaced the TB with a new stock unit and the chatter and engine missing at low idle and under low load remains but the strange hissing sound has been isolated ! its my supercharger pulley ! every time there car would shift from 1st into 2nd id hear that sound so I pulled the belt drove the car and no hissing sound ! super charger pulley bearing is toast and the clutch is way out of spec so im replacing . im still stumped on what's causing the misfire feeling at idle im wondering if the new o2 sensor I installed is faulty but not enough to throw any codes or possibly an out of gap spark plug ? I do hav some codes for interior can bus short and some other electrical stuff inside the car but nothing with the engine or trans
maw
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98 SL500 sport
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
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98 SL500 sport
well it keeps getting worse lol by worse I mean expensive !!! my water pump is whining and my AC condenser is covered in oil ! my power steering pump isn't losing fluid when I check the levels so that's a plus but I know I need to replace the accumulators . right now im focused on the water pump I can't shell out $500 for oem pump and really don't want to buy the URO pump despite them upgrading the propeller from plastic to metal is there a similar priced unit to the uro pump that's better quality ?
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98 SL500 sport
Update
Today I'm installing the water pump a new thermostat & temp sensor ! Next I'll be preparing to replace the ABC pump with a rebuilt unit I believe I'm losing fluid from the bottom front side of the ABC pulley but I don't see any fluid loss registering on the dipstick in the reservoir for the ABC system my main concern now is getting the serpentine tensioner pulley removed because the T-50 Torx Bolt that secures the serpentine tensioner is stripped out and I really don't want to take the whole front of the car apart to do this job! So I'm looking to see if I can remove the serpentine tensioner without pulling the pulley?
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98 SL500 sport
so fun update - performed smoke test no leaks via the brake booster line . had a code - rich bank 2 so I replaced all o2 sensors and the codes are gone. long term trims are neck in neck at 5% but this stranger stumble and whooshing sound still happens under load while moving slow . once the car is in motion and has momentum it doesn't happen . I decided to remove secondary cats and resonators installed x pipe . car feels day and night but issue remains . started thinking maybe my cats are clogged so ran 3 bottles of CRC cat cleaner and each time the car feels better . I can't visually find any cracks or signs of an exhaust leak so now im wondering if it is in fact the cats or possible the transmission ? I serviced transmission and it shifts smoothly . when I hear the sound from what I can tell its in that area underneath the car ironically where both the cats and trans are located . I purchased a china xentry pc but of course the multiplexer won't connect and its full of bugs so im waiting on them to send a new disk drive so I can hopefully check the blow off = recirculation flap = lower throttle body to make sure its functioning properly . I do have a launch x431 but don't know how to check for that on the unit . if anyone can guide me on how to calibrate or verify blow off valve that would be greatly appreciated !
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From: Phoenix
222 S-65
OP 'Blow off valve' is the second throttle body. Grab a can of non-flammable brake cleaner and clean up the electrical connectors to both throttle bodies. They live right next to crankcase vapor lines and get to behaving strangely when soaked with a mixture of crankcase vapors and dirt that naturally collects along with.
As for the noise. I'd have to drive it. Engine and transmission mounts fresh?
Replacing all the accumulators is good practice in any 220 with ABC every five years or so. Give it a fresh filter and a rodeo.
ABC leaks? Usually a hose. Remove a leaking hose and have it remade at a hydraulic shop. Any tractor shop or heavy duty shop will do this. Not expensive. Modern materials FTW.
As for the noise. I'd have to drive it. Engine and transmission mounts fresh?
Replacing all the accumulators is good practice in any 220 with ABC every five years or so. Give it a fresh filter and a rodeo.
ABC leaks? Usually a hose. Remove a leaking hose and have it remade at a hydraulic shop. Any tractor shop or heavy duty shop will do this. Not expensive. Modern materials FTW.
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
so fun update - performed smoke test no leaks via the brake booster line . had a code - rich bank 2 so I replaced all o2 sensors and the codes are gone. long term trims are neck in neck at 5% but this stranger stumble and whooshing sound still happens under load while moving slow . once the car is in motion and has momentum it doesn't happen . I decided to remove secondary cats and resonators installed x pipe . car feels day and night but issue remains . started thinking maybe my cats are clogged so ran 3 bottles of CRC cat cleaner and each time the car feels better . I can't visually find any cracks or signs of an exhaust leak so now im wondering if it is in fact the cats or possible the transmission ? I serviced transmission and it shifts smoothly . when I hear the sound from what I can tell its in that area underneath the car ironically where both the cats and trans are located . I purchased a china xentry pc but of course the multiplexer won't connect and its full of bugs so im waiting on them to send a new disk drive so I can hopefully check the blow off = recirculation flap = lower throttle body to make sure its functioning properly . I do have a launch x431 but don't know how to check for that on the unit . if anyone can guide me on how to calibrate or verify blow off valve that would be greatly appreciated !
As for the stumble, make sure the fuel pump and filter are correct for the car. Wouldn't help to swap the filter (passenger side near the rear wheel). Often overlooked. Stumble might be fuel delivery. Also check the plugs. Many people run one step colder plugs on these M113k, especially when they're boosted. I certainly do, and the idle isn't as mirror smooth as stock for this reason, but I don't care because I know (or at least I think I know) what it is. Cost of extra boost as far as I'm concerned. Better than having her lean out under heavy load.
maw
Last edited by maw1124; May 15, 2026 at 01:17 PM.
