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  #1  
Old 11-30-2001, 01:34 AM
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Idle surge on '93 300(2.8), fault codes?

I need some help to solve this problem. My recently acquired '93 300E(2.8) with 110K miles developed an intermittent idle surge problem. Idle fluctuates between 400 rpm and 1500 rpm. It also has an intermittent cold starting problem, which may or may not be related. Once or twice a week it would not start unless I touch the accelerator before cranking. Then it starts and runs just fine.
I did a search on fault code retrievals, made my little code reader light, however the Diagnostic Module is different on this car. It is rectangular unit with 16 holes but only hole 1, 6, 7, 8, 10, 14 and 16 has connectors in them.
I am guessing 1 is ground. Can anyone tell me where should I plug the other lead from the diagnostic light to retrieve the fault codes? If it turns out to be the MAF is there a way to repair it (since Partshop sells remanufactured units)?
The surge problem only occurs once the car is fully warmed up, in park, neutral or in drive as well. Smoothens out after driving the vehicle or pressing on the accelerator.
Any help is greatly appreciated. I do have the chart for the fault codes.
Thanks,

Btw. if anyone has an MB paperback manual for the 104 engine as well as an Electronic Troubleshooting manual for the 124 chassis, '92 AND UP I wil be glad to purchase them .

Alex


Last edited by dacia; 11-30-2001 at 01:42 AM.
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  #2  
Old 11-30-2001, 04:28 AM
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The first thing I would check is the fuel accumulator. It's right next to the fuel pumps.
Remove the fuel pump cover and start the engine, let it idle for a while. Shut of engine, loosen small rubber hose (clamp) on accumulator and check if any fuel comes out of the accumulator. If it does, replace it.

Vin
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  #3  
Old 11-30-2001, 08:03 AM
pfphipps
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If you have the square connector, does it have a small pushbutton switch and an LED on it? I think it does and you can check the codes without anything else. If it does, turn the ignition on but do not start the car. Push the button and hold it for a couple of seconds and release. Any codes will flash back at you on the LED. No codes will give one short flash.
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Old 11-30-2001, 08:29 AM
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The problem you are having is related to the ISC/CC computer & throttle actuator. Diagnosis should be done with a scan tool & many times the problem comes up with control module fault when the problem is really the throttle actuator.
OF course start by cleaning the throttle housing & butterfly.

EDIT! note; EFI cars like this one doesn't have a fuel accumulator.
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  #5  
Old 11-30-2001, 09:01 AM
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That's right, they only have a fuel pressure regulator. What the hell was I thinking? I guess that's what happens when you try to reply to posts half asleep. For same reason I had 91 300E 103 engine stuck in my head when replaying. Sorry about that.

I would definitely look into the throttle actuator $$$, as MB DOC already suggested. I did a 119 with a similar problem (surging) a few months ago. A $900 actuator solved the problem.

Ok, I am definetly getting off the computer and going to sleep now. It's 12:20am here.

Vin
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  #6  
Old 11-30-2001, 09:48 AM
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Quote:
Originally posted by pfphipps
[B]If you have the square connector, does it have a small pushbutton switch and an LED on it? I think it does and you can check the codes without anything else. If it does, turn the ignition on but do not start the car. Push the button and hold it for a couple of seconds and release. Any codes will flash back at you on the LED. No codes will give one short flash. [/
B]
The built-in led/sw only brings up emmission codes and will trigger the check eng light.
The other codes are read with your tool on the other sockets. ISC/CC will be socket 14.
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  #7  
Old 11-30-2001, 07:46 PM
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Thanks guys, I will look around tomorrow and probably take it to my trusted mechanic on Monday morning since I do not have a scan tool. I beleive only the California versions have the pushbutton led however.
I am in the great white north.

Thanks again,

Alex

How difficult is it to clean the throttle housing and the butterfly? Can someone desrcibe the procedure, parts to remove and the chemical or solvent to use?
I am not familiar with the 104 engine just jet. I have done this on the 103 engine. Is it a similar job?

Last edited by dacia; 11-30-2001 at 07:53 PM.
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  #8  
Old 11-30-2001, 08:26 PM
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also, only the california cars have a check engine light on our cars according to the manual. mine doesn't as far as i can tell.
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  #9  
Old 11-30-2001, 10:58 PM
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Mine does not have the 'check engine' light either. Neither does it have factory installed alarm system or leather seats.
But I still like it.
Now if I can only clean the throttle housing....

Alex
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  #10  
Old 12-01-2001, 07:51 AM
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Alex,

You sure about the alarm? I thought that was standard. I always wondered what the "dummy switch" on the dash was until the alarm went off one day when the door cylinder microswitch acted up. You don't see the "armed" blinker until you lock the car with the key from the outside

I'm sure you can manage that throttle cleaning. I keep track of all the 300e 2.8 reports as there are subtle differences from the 3.2

Cheers
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1993 300e-2.8
- gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"
http://banners.wunderground.com/bann...L/Key_West.gif
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  #11  
Old 12-01-2001, 12:09 PM
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Yeah, I am sure about the non- existent alarm system.
I was also under the impression that all Benzes come with one. This car looks like it was almost made for the European market. Cloth seats, no power telescopic steering wheel, no memory for the power seats ,no 'dummy switch' on the dash. All the other features are present however. Dual power heated mirrors, power seats, power antenna, central lock etc.

Alex
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  #12  
Old 12-01-2001, 12:37 PM
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I failed to mention in my previous post that there is a very pronounced rotten egg smell around the car when the idle surge is occuring. I beleive this is coming from the catalyc converter and is the sign of very rich mixture.
So the problem I am experiencing may not be related to the throttle actuator. Wishful thinking, I know.


Alex
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  #13  
Old 12-01-2001, 01:33 PM
pfphipps
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Your car may have an factory alarm but it is not what most people expect. No flashing lights or horn beep when activated or anything like that. And there is no switch or flashing light inside the car (although it is shown and described differently in the owner's manual--my switch position is a black blank plate). This is how the alarm works in my car from experience, not from the book: When the car is locked, if a door or something is opened without the key unlocking the car, it will honk the horn and the outside lights will flash. An easy way to see it to lock the car with the hood open, then put it down but not quite latched. If you open the hood again, the horn will beep until you unlock the car with the key (guess how I found that out!). I was under the impression that it was on all USA 300E2.8s. It was listed as standard equipment on the window sticker when my car was new.

If the car has a check engine light, it is at the extreme right of the lights at the bottom of the instrument cluster. The lettering can be read with the key off and should show up yellow when the key is first turned on. I bought my 1993 300E2.8 new in Albuquerque in December 1992, it has never been to Califonia but I suppose it could be a "California" model even though there is no reference to that on the stickers on the car.

As far as the idling problem, I had a similar problem about a year ago. It turned on the check engine light and the code given was the right one--the hot film air flow sensor. It is an extremely simple repair but the sensor costs about $250. I replaced it and it has been great ever since. It would run almost normal at anything other than an idle. It would idle at about 500 rpm, the gradually increase to maybe 1200 to 1500 rpm in about 3 or 4 seconds, stay there a few seconds and then drop to a very low rpm. After a cycle or two of this, it would die. Just a little crack of the accelerator and it would be almost normal at around 900 rpm. Normal driving at highway speeds, normal fuel consumption as well.

Cloth seats were not an option in the USA in 1993 that I know of. It was MB tex standard and leather as an option. Power seats with no memory were standard on the USA 300E2.8 but there may have been an option for that. Mine has no steering wheel adjust and but the power adjust may have been an option along with the power seat memory since the memory also adjusts the steering wheel.
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  #14  
Old 12-01-2001, 05:56 PM
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pfphipps,

original date of purchase on my car was Sept., '93. on that switch plate mine has a light that flashes when armed. i never noticed it until that episode i had when the alarm went off when i started the car. then i realized there was a light there. as to the check engine light, the rightmost light on my cluster is the SRS light. the position next to it has no light and no lettering that i can make out. interesting differences which could have been due to updates during the year.

i also have headlight wipers and sunroof which i thought were options but the combination doesn't make any sense. i think i might have the original window sticker which i'll have to track down.
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1993 300e-2.8
- gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"
http://banners.wunderground.com/bann...L/Key_West.gif

Last edited by jsmith; 12-02-2001 at 11:39 AM.
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  #15  
Old 12-02-2001, 10:59 AM
pfphipps
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I want to make a correction. After reading the last post, I went down in the dark and looked at the locked car, that is , with the alarm on. It has a little flashing light in what I always thought was just a flat black plate. Impossible to see in the daytime and pretty dim at night. To think I have had the car for nine years and never saw it! I guess I am usually not in the car when it locked with the key.

My car has a sunroof. If I remember, it was a no cost option. You could get them without a sunroof at the same price. I do not know if headlight wipers were an option but I assume they could be. I guess yours might have been added later but if I remember when I looked years ago, installing the wipers was not too bad but the wiring had to be added and the switch installed. Decided it was not that big a problem in the New Mexico desert.

As far as options, doesn't the plate under the hood tell all of the options on a particular car? The only thing is to get the decoding of what the number mean. I know some of them but certainly not all.

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