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  #1  
Old 01-13-2003, 10:55 AM
azhari
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190e : Decel Switch???

Holy crap!!!

Stalled 4 times altogether yesterday and once this morning while slowing down to take a left turn. Others were "stop light stalls".

OVP and FPR changed last month.

Is the decel switch the micro switch that is in the engine bay attached to the accelerator cable?

Does it have anything to do with idling the engine when the accelerator is released?

And I thought I had it nailed...

Judging by the number of posts, this is going to be a longggggggg day.........

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  #2  
Old 01-13-2003, 11:41 AM
it leaks, its german
 
Join Date: Mar 2002
Location: raleigh nc
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The switch is on the linkage behind the fuel dist. it signals the cis-e that the throttle is closed, it'll make for some weird happenings if bad, stalling, surging idle, high idle and so on. Not real consistently the same thing on all cars.



Joe
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  #3  
Old 01-13-2003, 08:48 PM
azhari
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Hi Joe

Sounds like a cheap possibility.

Mine looks beat-up and due for a change so I'll try this.

There is mention of "sticking throttle plates" in other posts that would also lead to stalling. Is this correct?

But if the car re-starts immediately after stalling, would this diagnosis be applicable?

Tks for your help.

Azhari
Singapore
Babybenz 190e 1.8
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  #4  
Old 01-14-2003, 05:37 AM
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Join Date: Jan 2002
Location: England
Posts: 1,841
Don't be too hopeful, it is unlikely to cause stop-light stalls
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190E's:
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black 2nd owner
http://www.maylane.demon.co.uk/190esmall.jpghttp://www.maylane.demon.co.uk/190esmall2.jpg
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  #5  
Old 01-14-2003, 11:11 AM
azhari
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Thanks for being a party pooper

Well, it's good to know anyway...

My idling is around 800rpm w/o compressor.Could this be the cause?

Another hopeful question...

The suspense is killing me!!!

Azhari
Singapore
Babybenz 190e 1.8
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  #6  
Old 01-14-2003, 03:49 PM
Dan Rotigel
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hmmm

I have a manual 16valve, so i'm not sure if this will help. I disconnected the switch for two months while waiting for parts/time, it caused a dip in idle after taking your foot off the gas, but then the idle would come back up to 900 or so (regular for mine is 1100). Worse in cold weather, but it wouldn't just _die_ at stop lights.

Dan
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  #7  
Old 01-14-2003, 09:41 PM
azhari
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Dan

There you go...

Just this morning, I was paying more attention to the idling when coming to a stop and it does dip before coming back up. The thing is my tach is out so I don't know the numbers but I felt the dips.

Now if this happens w/o the switch connected on your car, it would mean that mine may not be working at all, wouldn't it? I could test the switch with a multimeter and see how it goes.

I'd just like to be sure. Are you saying that with the switch connected (and in working condition) in your car, there would not be a dip in the rpm comin g to a stop after releasing the accelerator pedal?

Appreciate your help.



Azhari
Singapore
Babybenz 190e 1.8
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  #8  
Old 01-14-2003, 09:45 PM
azhari
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Dan

The reason i'm interested is becoz sometimes, when it dips, it seems like it's going to stall but comes back up.

Other times, the rpm falls and doesn't come back up, resulting in a stall.



Azhari
Singapore
Babybenz 190e 1.8
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  #9  
Old 01-15-2003, 01:05 PM
Dan Rotigel
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dip-d-do-da-day

I'll do my best to think this through. When my foot comes off the accelerator and my car coasts to a stop at a stop sign, and my switch is disconnected, the rpms will dip to the point where the engine shakes a bit (maybe as low as 600 rpm) and then comes back up to around 900.

When my foot comes off the accelerator pedal and the switch is connected, the idle does not dip, it just stays at 1100.

If your car has the same symptoms as mine does with the switch disconnected, plus an occasional stall, I would say there is a pretty good chance that your switch is FUBAR'D.

To be absolutely sure, disconnect the switch and run around a bit. Its a 20 dollar part, which, for me, falls in to the 'throw parts at the problem' catagory. Also, make sure your throttle linkage is tight, because if it isn't, it may not be pushing the switch down.

Dan
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  #10  
Old 01-15-2003, 01:26 PM
190dee's Avatar
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Location: Finland
Posts: 160
Hmmm...I not 100% sure about this but if I recall right the decel switch will only affect your ecu to cut of fuel when engine rpm are above certain amount of rpm. Then when rpm drops below this rpms it will pressurize system for normal use again.

My point is...wheater the switch is working or not it shouldn't affect idle. But I hope someone with more knowledge back this up...I am not sure.
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  #11  
Old 01-16-2003, 11:01 AM
azhari
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190dee

Tks for yr thoughts.

The switch is an open/close affair which sends the signal to the ECU, for what, i have no idea...

But the Haynes manual calls it an idle switch...hmmm...

Anyway, Babybenz hasn't stalled in 2 days and coincidentally, it hasn't rained for the same number of days (it is now raining a lot down here).

If it is an indication of moisture in the Fuel Pump Relay, i'll be damned!!! Coz I changed my OVP and FPR abt 2 months ago!!!

Furthermore, i think it is the newer one which is sealed so i doubt if this is the problem, but i'm also not 100% sure...should check it...

I am definitely going to throw the switch for good measure as it looks pretty beat-up anyway.

Anyone knows what the decel or so-called "idle" switch does, and what happens if it conks out?

Geronimooooooooo!!!

Azhari
Singapore
Babybenz 190e 1.8
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  #12  
Old 01-16-2003, 03:40 PM
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Join Date: Oct 2002
Location: Toronto, Canada
Posts: 700
Correct me if I'm wrong here, but does it not state in the service manual that engaging the decel switch when the engine is not ideling would cause it to surge since you are not giving it fuel?

Maybe the switch is busted and stuck on one setting, you did say it is beat up.

I know that when I bought my car, the fulcrum lever never even reached the decel switch and the car never died, but if it is engaged all the time, you might not be able to get the car out of idle, maybe there is more to it then just that.

xp
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  #13  
Old 01-17-2003, 05:16 AM
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Location: England
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If you have an auto it's easy to test the switch (these steps apply to my '86 190E and a '91 230CE I have tested with, so I assume it's the case for all cars:

Drive at 30mph in '3', and shift from '3' to '2' with your foot off the accelerator. If it bangs down into 2nd gear with a jolt, your switch is working OK for zero throttle. If you do the same thing with even a tiny bit of throttle, it should slip quite a bit, letting you rev the engine fairly freely, and not instantly engage 2nd gear.

If you can get these 2 different behaviours, the switch is fine.
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190E's:
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black 2nd owner
http://www.maylane.demon.co.uk/190esmall.jpghttp://www.maylane.demon.co.uk/190esmall2.jpg
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  #14  
Old 01-17-2003, 08:52 AM
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Join Date: Sep 2002
Location: NE
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I had a bike which did a similar thing. Thing would run like a top until I came to a light and then it would stall when I dropped to nuetral and closed the throttle. turned out it was a vacuum leak, check your hoses.

cdt
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  #15  
Old 01-17-2003, 09:17 AM
azhari
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Pentoman...u de man!

So that's what the switch is for, eh?

Well, guess mine ain't broken.

At 60km/h, dropped to 3 and let off throttle.Bang, she down shifts. At 40km/h, dropped to 2 and let off throttle, same results.

If I downshift with throttle, she doesn't drop gear till i let off.

Is this what the switch is for, really?

Azhari
Singapore
Babybenz 1991 190e 1.8

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