Mercedes-Benz Forum banner
1 - 20 of 67 Posts

·
Registered
1993 Mecedes-Benz 190E 2.6L - W201
Joined
·
36 Posts
Discussion Starter · #1 ·
Was driving around and was checking out the bay after I parked it. Been having some idling issues lately and saw this vacuum line loose. I figure Its the reason? It was facing downward behind the large hose and behind the oil filter. I don't know what it is and I don't know where it goes. Please help! Thank you
2696603
 

·
Registered
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
4,559 Posts
Welcome to the forum. Assuming you have an auto transmission (most do) that is most likely the vacuum line that goes to the modulator for the transmission.
 

·
Registered
1993 Mecedes-Benz 190E 2.6L - W201
Joined
·
36 Posts
Discussion Starter · #3 ·
Welcome to the forum. Assuming you have an auto transmission (most do) that is most likely the vacuum line that goes to the modulator for the transmission.
Thank you thank you! Now my next obstacle.

The previous owner had a skid plate welded to the chassis under the engine to protect it from New England potholes, since the car is lowered on H&R Springs w/ Bilstein shocks. It's too low to get under without jacking it and the plate makes it hard to see anything. Would you happen to know where on the trans (yes I have auto) this line would go?

Also, do you think this unplugged could be the culprit behind my high idle increase from 2k ?

Thanks!
 

·
Registered
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
4,559 Posts
I'm not sure if that alone would cause an idle of 2K. It allows unmetered air into the intake which is not a good thing.
Plug the vacuum line and see what happens.
I assume your transmission shifts are a bit messed up though.

I have never heard of welding a steel plate that can not be taken off on a W201. You may have to find a way to remove it.
A lot of work needs access from the bottom including inspecting things, which is why many people even take off the plastic one and toss it.

I have never owned an auto transmission W201, so can not help you with the modulator questions. Sorry...
 

·
Registered
89 190E 2.6 x2, 99 SL500 Sport
Joined
·
1,835 Posts
In order to re-connect that line you're gonna have to drop the transmission to access the modulator. I wouldn't be surprised if your car had a bad vacuum modulator and was sucking ATF into the intake. Mine is disconnected for now, the car will drive fine but shifts will be harsher.
Easiest thing to check for high idle are the idle control valve hoses, the rubber gets hard and they don't seal. Spray carb choke on all the lines and if you see change in idle then you've found the leak.
I would cut that skid plate off asap too-I hope they didn't weld it to the sway bar. They used to have a factory metal skid plate as an option but it's impossible to find now.
 
  • Like
Reactions: thelooneyToon

·
Registered
1993 Mecedes-Benz 190E 2.6L - W201
Joined
·
36 Posts
Discussion Starter · #6 ·
In order to re-connect that line you're gonna have to drop the transmission to access the modulator. I wouldn't be surprised if your car had a bad vacuum modulator and was sucking ATF into the intake. Mine is disconnected for now, the car will drive fine but shifts will be harsher.
Easiest thing to check for high idle are the idle control valve hoses, the rubber gets hard and they don't seal. Spray carb choke on all the lines and if you see change in idle then you've found the leak.
I would cut that skid plate off asap too-I hope they didn't weld it to the sway bar. They used to have a factory metal skid plate as an option but it's impossible to find now.
Bruh, I really don't want to have to take the transmission out lol. I don't have a garage, she's parked on the curb. Say I do find a place to take the trans out, would it be possible to take it out without having to take the engine itself out?

And what is ATF? (My first car, and dream car) still learning as I go!!

Also, I kinda get hung up looking at how hectic the engine bay is. I'm afraid that if I loose anything within the jetronic that I'll forget where things go. What tips do you have for that if any? Again, thank you all
 

·
Registered
89 190E 2.6 x2, 99 SL500 Sport
Joined
·
1,835 Posts
Bruh, I really don't want to have to take the transmission out lol. I don't have a garage, she's parked on the curb. Say I do find a place to take the trans out, would it be possible to take it out without having to take the engine itself out?

And what is ATF? (My first car, and dream car) still learning as I go!!

Also, I kinda get hung up looking at how hectic the engine bay is. I'm afraid that if I loose anything within the jetronic that I'll forget where things go. What tips do you have for that if any? Again, thank you all
So the transmission doesn't actually have to come out to access the modulator. You just have to remove the transmission support, unbolt an exhaust bracket and it will drop a couple inches which gives you access to the modulator on the side of the transmission. All you need are some wheel ramps and a jack. I've done plenty of wrenching out in the street over the years w/ no issues.
ATF=automatic transmission fluid.

W/ the KE-Jetronic, my best advise is to just post your problems here. Make sure to include pics and video helps
Most of the issues I see on these cars are just caused by age-e.g. old cracked rubber hoses, sticky idle control valves, cracked breather hoses etc.
 
  • Like
Reactions: thelooneyToon

·
Registered
1993 Mecedes-Benz 190E 2.6L - W201
Joined
·
36 Posts
Discussion Starter · #8 ·
So the transmission doesn't actually have to come out to access the modulator. You just have to remove the transmission support, unbolt an exhaust bracket and it will drop a couple inches which gives you access to the modulator on the side of the transmission. All you need are some wheel ramps and a jack. I've done plenty of wrenching out in the street over the years w/ no issues.
ATF=automatic transmission fluid.

W/ the KE-Jetronic, my best advise is to just post your problems here. Make sure to include pics and video helps
Most of the issues I see on these cars are just caused by age-e.g. old cracked rubber hoses, sticky idle control valves, cracked breather hoses etc.
If I were to change the jetronic to an itb setup, would I be able to use the same sensors?

I want to clean up the bay as much as I could right now because I have more plans to make this car as fun as I intend over time. A friend told me to check out a smoke test. I checked out the cost to have it done by a shop and I ended up just buying a high rating machine for a good price for future endeavors instead. Think that was a good idea? I also decided that after I cut the plate off, I'll try to find a way to properly bold it on so I'll always be able to take it on and off whenever I need it.
 

·
Registered
89 190E 2.6 x2, 99 SL500 Sport
Joined
·
1,835 Posts
If I were to change the jetronic to an itb setup, would I be able to use the same sensors?

I want to clean up the bay as much as I could right now because I have more plans to make this car as fun as I intend over time. A friend told me to check out a smoke test. I checked out the cost to have it done by a shop and I ended up just buying a high rating machine for a good price for future endeavors instead. Think that was a good idea? I also decided that after I cut the plate off, I'll try to find a way to properly bold it on so I'll always be able to take it on and off whenever I need it.
So I've working on the 201s for a very long time (over 15 yrs) and I can tell you that any sort of performance modification such as ITBs is going to be very expensive. Everything is custom and I couldn't tell you about what sensors will work, what won't etc. Honestly, the KE Jetronic is actually pretty reliable once you've sorted out all the issues. It seems scary at first, but really isn't that bad to sort out.

Also good call on buying a smoke machine. I've bought quite a lot of specialty tools over the years and they've generally paid for themselves. Here in the Bay Area most shops are over $150/hr so buying tools and DIY saves $$$$.
 
  • Like
Reactions: thelooneyToon

·
Registered
1993 Mecedes-Benz 190E 2.6L - W201
Joined
·
36 Posts
Discussion Starter · #10 ·
I'm not sure if that alone would cause an idle of 2K. It allows unmetered air into the intake which is not a good thing.
Plug the vacuum line and see what happens.
I assume your transmission shifts are a bit messed up though.

I have never heard of welding a steel plate that can not be taken off on a W201. You may have to find a way to remove it.
A lot of work needs access from the bottom including inspecting things, which is why many people even take off the plastic one and toss it.

I have never owned an auto transmission W201, so can not help you with the modulator questions. Sorry...
Gm. Yes, my transmission is auto and it does shift a bit hard. I always thought it shift hard because the diff is welded from the previous owner (I still have the original diff).
They really tried to drift with it etc. They never told me that they changed the transmission fluid and I didn't see that it was done in the carfax report (after I cut the plate off, I plan on changing the fluid and oil same time).

Also, I have a manual transmission I got from Germany lol. I bought it due to advertising making me think it was a 5spd forward, but it was actually the 4spd trans 717.412 (I'm not mad, I still feel good about my purchase). Also got the original shifter for it.

I have a dream build in mind, just slowly getting the pieces together.
 

·
Registered
89 190E 2.6 x2, 99 SL500 Sport
Joined
·
1,835 Posts
Sounds like you've got quite a project ahead. Looking forward to seeing how things go w/ your build.
Also, PN187 and SEC560 are going to be the experts on this forum on the manual transmission conversion. They've both done numerous conversions over the years.
 
  • Like
Reactions: thelooneyToon

·
Registered
1993 Mecedes-Benz 190E 2.6L - W201
Joined
·
36 Posts
Discussion Starter · #12 · (Edited)
Sounds like you've got quite a project ahead. Looking forward to seeing how things go w/ your build.
Also, PN187 and SEC560 are going to be the experts on this forum on the manual transmission conversion. They've both done numerous conversions over the years.
I sure do, I just want to go about it at my own pace. I saw a thread somewhere in the forum that someone was able to convert the 4spd to a 5spd. Seeing the process though, with my lack of knowledge lol, I don't think I'll so a rebuild on the trans before I get the engine to idle correctly right now.

It's weird, the idle issue started after I put a different dash cluster in. The old one couldn't track miles anymore and I couldn't figure out how to replace the gears after having bought the gears to change it lol. I just ended up getting another cluster that includes an O2 sensor and fuel economy. After I managed to put it in, I took it for a drive. Worked fine, but when I put it in park the idle shot up to 4k.

Looking at it now, after lubricating the throttle cable, I got it down to 2k just about. Then I took the air filter off and just barely touched down on the throttle sensor plate and it ended up evening out at just over 1k. Let it idle a bit and just gave it a light tap on the gas and it shot up on an increase that didn't stop. Turned off at 3k rpm and went inside to think about it.

I checked online a bunch and found a few channels and videos talking about the sensor plate adjustment. I'm familiar with mm and it was stated that between 1.5 to 3mm is the ideal play amount. That's the last thing I wanna play with for now (The plate has a good amount of give, then again maybe too much?). Then I got lead onto air leaks, went back outside to check the bay out and saw that vacuum line out. Thought it was that so I did what was suggested and had my brother plug it with his finger both on start up and idle on and off separate times. While the engine was running, I had it plugged. The idle went down a bit, but went back up. Out of all times tried, that was the only affect out of the many different tries (The vacuum hose in the picture).

Explained my situation to a friend, he suggested the smoke test. Then I went out to buy one, now I'm currently waiting for it. I have a huge suspicion its an air leak somewhere and or the O2 sensor is wacky?
 

·
Registered
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
4,559 Posts
A few comments, not necessarily in any order:

(1) I have tried 1992, 1990 and my original 1989 clusters in my car. They all worked as expected, though the 1992 was missing the vacuum gauge of course. I currently use the 1990. The reason was the same odometer stopped working on the original '89 and I like the 1990 orange coloring more and it was lower miles. So the later ones appear to be backwards compatible for sure.
(2) Your high idle. I can assure you it is not adjustment related, so do not adjust anything
(3) Have you tested the microswitch and the throttle plate sensors already, those have to be in working order otherwise the ECU does not know it has to regulate idle.
(4) Let us know how the smoke test goes but the idle speeds you are quoting are very high, likely not leak related. As it is plugged in measure the voltage the IACV, let's see if the ECU is even trying to reduce it? I suspect not.
 

·
Registered
1993 Mecedes-Benz 190E 2.6L - W201
Joined
·
36 Posts
Discussion Starter · #14 ·
A few comments, not necessarily in any order:

(1) I have tried 1992, 1990 and my original 1989 clusters in my car. They all worked as expected, though the 1992 was missing the vacuum gauge of course. I currently use the 1990. The reason was the same odometer stopped working on the original '89 and I like the 1990 orange coloring more and it was lower miles. So the later ones appear to be backwards compatible for sure.
(2) Your high idle. I can assure you it is not adjustment related, so do not adjust anything
(3) Have you tested the microswitch and the throttle plate sensors already, those have to be in working order otherwise the ECU does not know it has to regulate idle.
(4) Let us know how the smoke test goes but the idle speeds you are quoting are very high, likely not leak related. As it is plugged in measure the voltage the IACV, let's see if the ECU is even trying to reduce it? I suspect not.
Thank you. Could you please tell me where the IACV is located? When I go home today I'll shoot a small video of what's going on.

I recently bought a GoPro to document my build and I wanna check out the problem with the GoPro.
 

·
Registered
89 190E 2.6 x2, 99 SL500 Sport
Joined
·
1,835 Posts
Ok the gauge cluster thing is very helpful info. Do you know if the cluster came off a 2.3 or 2.6? Reason I ask is that I once drove a 2.6 w/ a 2.3 gauge cluster and the tach was way off. Every time it shifted gears the tach was in the redline area even though it was perfectly fine. Trying swapping the tach from the 1992 into the 1990 cluster.
Get this mixed and then you'll get a proper idle reading. Like Dolucasi said don't go adjusting anything yet.
 

·
Registered
1993 Mecedes-Benz 190E 2.6L - W201
Joined
·
36 Posts
Discussion Starter · #16 ·
Ok the gauge cluster thing is very helpful info. Do you know if the cluster came off a 2.3 or 2.6? Reason I ask is that I once drove a 2.6 w/ a 2.3 gauge cluster and the tach was way off. Every time it shifted gears the tach was in the redline area even though it was perfectly fine. Trying swapping the tach from the 1992 into the 1990 cluster.
Get this mixed and then you'll get a proper idle reading. Like Dolucasi said don't go adjusting anything yet.
Alright I'm going to try that, I just damn hate putting the speed cable on. It's the more tedious thing lol.
The cluster came from an 89' model, but no other info other than that was provided.
 

·
Registered
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
4,559 Posts
Yeah, speedo cable makes this harder. When I did my swaps my entire dash was removed for another reason, so swapping clusters was a piece of cake (other then plugging and unplugging all the connections).

Your 2.6 IACV is between the intake and the power steering pump closer to the intake. The hose comes from the throttle plate and feeds back into the intake near the cylinder head. You will need to insert a couple of thin copper wires into the socket and leave it plugged in. Measure average voltage (DC).

But more importantly make sure the Throttle plate switch (TPS) and the micro-switch is operational first. Micro-switch tells the ECU the driver has his/her foot on the pedal (ever so lightly)
TPS tells the ECU the throttle plate is starting to open. They have different functionalities.
 

·
Registered
1993 Mecedes-Benz 190E 2.6L - W201
Joined
·
36 Posts
Discussion Starter · #18 ·
Yeah, speedo cable makes this harder. When I did my swaps my entire dash was removed for another reason, so swapping clusters was a piece of cake (other then plugging and unplugging all the connections).

Your 2.6 IACV is between the intake and the power steering pump closer to the intake. The hose comes from the throttle plate and feeds back into the intake near the cylinder head. You will need to insert a couple of thin copper wires into the socket and leave it plugged in. Measure average voltage (DC).

But more importantly make sure the Throttle plate switch (TPS) and the micro-switch is operational first. Micro-switch tells the ECU the driver has his/her foot on the pedal (ever so lightly)
TPS tells the ECU the throttle plate is starting to open. They have different functionalities.
Still at work. I wasn't able to work on the engine yester, but today I was able to get my hands on a fluke T5-1000 to borrow. I'm going to check all that was suggested today and see what happens.

I also found this What to do when my M103 is giving me trouble: A beginners guide ~ Artisan (artisanmotor.com). I have a feeling its the potentiometer but I don't want to come to any firm conclusions yet.

I skimmed over some suggestions prior to my first post here and impulsively bought a new potentiometer (its on its way). About the microswitch, would anything mechanical on it need to be lubricated at all or is it majority of the time just an electrical issue with it and needs to be replaced if at fault?
 

·
Registered
1993 Mecedes-Benz 190E 2.6L - W201
Joined
·
36 Posts
Discussion Starter · #19 ·
I heard beeps with the device I borrowed on the idle air control valve, the microswitch, and the EHA, but tested the potentiometer and got nothing. I tried multiple configurations because I didn't know which is positive and negative, and got no beeps. I don't know what to make of that other than maybe I do have to replace it? This is all done with the engine off and battery unplugged. I'm completely new to all of this.

I started the car and the idle went up to 3k from base line at 2k rpm. Before I shut it off I just decided to pull up the air flow plate with my fingers holding onto the middle part of it to see if I can get the idle to go down a bit without actually adjusting anything. It went down, but it went back up when I let go and the rpm went up more. I even depressed the linkage to see if the microswitch would tell the ecu anything, but got nothing. That's what I have done so far.

I tried to upload a video, but it said the file was too large sooo yeah. Also, I wanna know where I can refill the AC refrigerant. It blows hot air, the blower works fine. I was told that if all works good but it blows hot air instead of cool, then it needs a refrigerant refill.

Thank you all again for your input!
 

·
Registered
89 190E2.6- 5-speed Manual - 200K miles, 95 E320 Sportsline-sold, 2001 E320 4matic Wagon-sold
Joined
·
4,559 Posts
You are going in all different directions looneytoon. You need to slow down and check one thing at a time.

(1) Make sure your throttle cable is adjusted properly -
(2) Connect you ohmmeter to the microswitch and check to make sure it is operating correctly. It should switch on/off with the throttle actuator pressed a tiny bit. Disconnect the switch when you do this.
(3) Do the same with your Throttle plate switch.

Report on these results before reporting on other tests.

AFM pot can not be tested the way you are doing it to measure for shorts/switch/beeps.
Do not measure your AFM pot just yet. It's functionality is super limited and hardly ever causes idle issues.

Leave the AC alone for now, you have more serious running issues.
 
1 - 20 of 67 Posts
Top