Well,
Nothing special..just a Motor Head kid from the '50s who started working on Old Benz's starting around early '60s. I was the Kid in a small New England town that was referred to by the neighbors as that guy who " Works on those damn GERMAN cars " ...
That was the era of the Ford/Chevy Rivalry days and most did not pay much attention to a Benz...
I had worked at repair shops in and out of the '60s and finally owned a couple of small shops the 70/s/80's..
Also Collected several chassis, including several 113 chassis cars and they are probably my Tech Speciality. Had several of them thru the years and worked on so many that I became fairly well versed on all models.
My favorite of that bunch is the 250SL..and I still own a 1967 Early Euro version which has been with me forever.
So, I am basically still just a veteran Benzhead , still tinker , have a few Tech friends that share info and hang with , still drive Benzs, and I have somehow kept up technically... probably just my progressive nature and curiosity in all things Benz...
The Forum is just a way for me to spread what I learned or forgot to the next generation of Benzers.. I do write on several other sites , [ not all Benz related/other Hobbies] ....but this is my favorite Benz one.
I work on-line many hours , so it is easy for me to sneek over here in between my work.
There are several members here that are Pro Techs and Shop Owners and they deserve the credit for this fine group..
That's about it......

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A Dalton

I might add that Arthur has been posting here a LONG time, on this site before 2000 when I first came on-line. Over the years, I have floated in and out as I spend more time on other sites but I always come back when I have a "hard" problem. This is by far the best Mercedes technical site. Thanks in part to Arthur, MBDoc, stevebfl and several of the other very knowledgeable folks who spend their time here.

Now to continue the saga. I replaced the plug wires and stubs and installed a new set of Bosch copper plugs. Nothing significant changed.

I did notice one more interesting symptom; the engine will not rev above 4000 RPM (in neutral). The computer starts cutting out either fuel or spark.

My parts guy mentioned that the mass air sensor on these cars is a commonly replaced item. I would think that a bad air sensor would trip a code.

Just to verify; I checked the pin #8 for codes with the ignition on but the engine not running. The check engine light is still not on (but the bulb is good, lights with key on but the engine not running).

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Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

<>

That is Normal 4K rpm cut-out in N or P . That is the torque converter load protection safety feature. If you tried N while the car was moving a few MPH, you will notice that feature would be disabled.

>>My parts guy mentioned that the mass air sensor on these cars is a commonly replaced item. I would think that a bad air sensor would trip a code.
>>

Possible, but before changing it , I would get some MAF cleaner and try that.
You really need a scope or adaptation #s to properly diagnose the MAF

Do a search on MAF cleaning and I will post some other info shortly.
I would also pull the vac line OFF the purge valve and run the car with that line plugged to be sure it is not causing an internal vac leak..just disregard any purge code in the meantime..

PS --Jim,
I saw you are now are on Utube with some 113 suspension tutorials..very cool.. maybe I can be your Agent....
Here is another video that explains the basics of MAF management that is cool too..I like this guys style .... [This uses later style wide band 02 sensors rather than the one in your car, and may be a little Technical for the diy guy , but still some good info for the curious]
Check it out..............

http://www.picotech.com/auto/automotive-oscilloscope-guide/lambda-sensors.html

Arthur ..... The video was of my suspension presentation at the Pagoda Gathering in Blacklick. There is another Blacklick presentation video on Pagoda drivability modifications on you-tube. I have also done six videos that are for sale in the 190SL Group store. Fun stuff and a good revenue producer for the club.

I checked the EGR with a vacuum pump and it does not leak vacuum. I plugged the line and drove the car without change.

I watched the MAF video, very interesting and a good sales pitch for a two channel laptop interface.

I searched cleaning the MAF sensor and it looks straight forward; remove it and the gently spray the flat plain sensor with a MAF cleaner and then replace it. I happen to have the torx with a center hole for the screws (I needed one to replace the MAF on my Porsche). So I will head out for some "MAF cleaner".

I tried to find a "purge" valve but the best I could see is a "Regeneration switchover valve" but I couldn't locate the actual valve. It controls vacuum to the "activated charcoal filter, which I also could not locate.

__________________
Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

Arthur .... Since you caught me modifying a previous posting, I'll just post another post.

I found the purge valve on the driver's side fender with a vibration mount and two large black tubes. I disconnected and plugged the tube; no effect.

__________________
Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

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Purge is Regeneration.. Same guy , different name.

OK..on that chassis:
Behind the driver headlamp is the ABS pump..and behind that pump is a little valve that says "MOT" on top of it. That is it and there is a vac line [ fairly good sized] feeding that to the intake. The other vac line goes to the canister.
That valve is suppose to pulse rapidly [ 5-20htz ] to allow canister fumes to re-enter the engine [ regeneration]...but they do it in pulses so the engine does not see this as a large gulp of air, [ they meter it ], as to not effect the idle and A/F mixture control system. What can happen on these is they get crap in them and they intermittantly stick open and the engine sees this as a vac leak, resulting in intermittant rough idle. So, if you just disconnect/plug it and the engine acts nicely to that change, you can assume the valve was at fault and you do not have to do all kinds of Purge control test. It is fairly common and this is just a shot/stab at your condition before condemning the MAF, as any unmetered intake air will cause your complaint and I hate to see a MAF changeout before checking some of the other simples...
Worth a try. Just diss the purge code youare going to create.

OK
You are ahead of me on that one too.. my problem is I am a 2 finger typer and it takes you less time to search in the archieves as it does for me to get this keyboard crankin'.....

You are using the search feature , ain't ya ????

Ok
Look everywhere for vac leaks and check for codes again.
Might want to unplug the MAF while at idle and see if any change too.

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A Dalton

Arthur ... Yes ... I search everything to verify that I am doing things correctly. I found "Purge" in numerous places but none corresponding to a location or other terminology.

Well, I got a can of CRC MAF cleaner, removed the sensor and sprayed it down according to the directions. Again, no change.

I took your advice and checked the codes again. This time I got a code 23 on plug #8 that I believe indicates a misfire on coil #2 for cylinder 3/4.

I listened to the injectors click with a mechanic's stethoscope and they all sound the same with a nice audible click.

When I was changing the plugs, I checked the resistance of the coils; all were about 0.6 ohms. This seamed low but it was consistent across all three coils.

__________________
Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

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Ok ...I like that.....

Now, clear the codes . swap that coil and connector to another location and watch to see if the code follows that coil/connector to the new location.........or, do you have a DSO ??????

for the background info. You sound like the kind of guy I'd like to have for a neighbor.

Arthur ..... Bingo! I swapped coil #1 with coil #2 and the problem moved to a malfunction code #22; indicating a misfire of cylinders #2 oand #5 which says that the coil that I moved from position #2 to position #1 is bad.

So, I'll make another parts run tomorrow morning for a coil.

By the way, I forgot to connect the MAF sensor wire after swapping the coils. The engine ran worse and it showed a malfunction code #4 (Duh). After clearing that code and another test drive is when I got the code #22.

__________________
Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

[QUOTE=Jim Villers;1824368]Arthur ..... Bingo! I swapped coil #1 with coil #2 and the problem moved to a malfunction code #22; indicating a misfire of cylinders #2 oand #5 which says that the coil that I moved from position #2 to position #1 is bad.

So, I'll make another parts run tomorrow morning for a coil.

Cool ... I think that could well fit your problem..
These early 104 HFM/SFI had coil problems and the ones that ususally were troublesome were the ones with the Blue sticker on them..most have been changed by now.

Hope that works out.

One can see where a Scope is a nice tool for these full Electronic systems...
I sometimes see those Sun LS2000 DSO's on ebay for short money now [$250]

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A Dalton

Arthur .... A scope would be nice. I tried testing the coil with my inductive timing light. I should have done this before but I kept putting the cover on before I reinstalled the air duct and then it was too late.

The results were not what I was expecting. With the pickup over the plug wire from the coils, the "bad" coil flashed but appeared to flash at about half the rate of the other coils and not consistent. I had expected that the bad coil would not flash at all. I can't imagine why a "bad" coil would flash at a different rate; either it should flash or not. I thought that the high voltage plug wires would come from the same point within the coil. Could the computer be not firing the coil because of something else?

Anyway, I'll get a new coil tomorrow and hope that an "Eureka moment" occurs in the driveway.

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Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"

It is common to have an intermittant coil problem , and usually that would be on the secondary windings side [ but not always]. The ECU actually triggers the primary and spark occures when a pre-determined current is reached, [ spark circuit Ramp] so one could also have a bad trigger threshold in the ECU. That is why I had you try another location for the coil. If the code follows the coil , you can assusme the coil /connector is bad ..if it did not , it would point to that trigger Transistor circuit in the ECU..[ which does happen] or a bad plug/injector/etc at that same cylinder....this swapping stuff around to make a diagnosis is commonplace if one does not have the proper diagnostic equipment and even a good shop will use these quicky test...
The oddity of the Waste Spark system this chassis uses is that the 2 plugs are wired in Series with one coil, meaning the flow goes from coil to electrode of first plug , fires to ground and then on the second plug it goes from ground to electrode for fire and back to the single coils secondary winding to complete the circuit...so, that is quite a path and a couple of plug gaps to overcome..Of course , the second plug offers no load demand [ b/c it has no compression/fuel mix], so it has an easy jump, but even still, there is that contention... knowing this , one can see why the coil to plug connectors are so important, as they can effect both plugs firing as they are always in the circuit, regardless of which cylinder is under compression load................. [ any weak link/connection in a Series circuit shuts down the complete circuit].
I also believe that this plug firing arrangement is the reason these models do not take a likeing to Plats with their ultra-thin electrodes..[ but that is just my guess and may not be a viable reason, even tho its seems to make sense]
The later coil over plug versions use coils on each plug.
I used to be able to just see the electrons path until I got a lethal dose of that Kriptonite stuff...now I have to use a DSO....The Scope allows you to see the signals and wave patterns just as the ECU sees and reads them..so that narrows it right down simple.
Give me a schematic, a jumper , and a test lamp and I am all set to go at it
on the older cars , but these High Techers need equipment to really get it down w/o some guessing, as you could see on that Video..............

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A Dalton

Arthur ..... Eureka arrived. The magic of the correct part was instantaneous and the car was back to its old normal self.

It shows again that the diagnosis is more important than the mechanic. Swapping out the coil was a 5 minute job; finding the correct part took several days.

Thanks again for all of you assistance.

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Jim Villers
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"