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Discussion Starter #1
Hi I have an unusual problem with my 86 560sel, about a week ago I went to pull out of the driveway and stepped on the gas pedal like normal but it didn't do anything for about a half second then took of like normal. I drove it a couple days and no other problems. Today I went to the store and it happened again but this time it did not return to normal as fast. For the first few minutes it would do nothing when I stepped on the gas, it would just sit at an idle purring like a kitten no cutting out sputtering nothing. Then it started to rev up a little to 1000 rpm's (keep in mind I was pushing and releasing the pedal the whole time to try to rev it up in nutral) . This went on for about 5 min's or so then it start to rev higher and higher each time I hit the gas. Finally after 20min's it would rev higher ( 5000+ rpm's) so I left for the store. Durring the drive it felt slugish at first then got better as time went on. If I push the gas to the floor it will downshift like normal but it just doesn't have the power it used to have.
Has anyone had this experince?

Thanks

David
 

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Discussion Starter #2
I will check that. One other thing I noticed is the econo gauge didn't move when it was acting up but returned to normal afterwards

Thanks
David
 

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1991 500SEC 55K mi. 1987 560SEC Now 153K mi. 2020
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Hi David,

Longshot Idea of the day:
It probably isn't this, as I understand the option is fairly rare, but is your car fitted with ASR (Acceleration Slip Regulation) perhaps? I can imagine some strange symptoms if that system 'went on the blink'.

Your description of the Economy Gauge operation almost suggests the throttle plate itself isn't responding when the 'loud pedal' is pressed - which would be virtually impossible with the mechanical throttle linkage setup on my 560. Nor can I see an intermittent problem occurring with the mechanical linkage. As you step on the gas > the throttle plate opens > allowing more air into the intake 'plenum' area > the Economy (vacuum) gauge needle responds to the reduction of negative air pressure. Dead Simple.

I really must be barking up the wrong tree........

Has anyone had a sticking/binding Airflow Sensor Plate in the Fuel distributor? That is upstream of the throttle plate.......... Could that explain the odd symptoms??

I guess I'm really hung up on that Economy Gauge and how intermittent the symptoms appear!

Baffled in Boston, MBL
 

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Discussion Starter #4
The linkage was my first thought also but everything looks fine. No my 560 doesn't have the ASR option so no worries there. I was not aware of anything upstream of the throttle body so it looks like I need to take it apart and check things out.

Has anybody taken one apart? Is there anything I should watch out for?

Thanks

David
 

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I have heard of the plate sticking, when I was having a similar problem w/ my 560SEL I was told many times that I should make Sure that the plate/housing and pivot are clean. It was as I had just redone the heads and injection system... On my car it turned out to be a KE control unit that was on it's way out.

I'm doubtful that it's your control unit as this seems this problem is happening all the time. I would unplug your EHA to start, see what that does for you. Could be your pumps on the way out...how do they sound? Could even be a filter that's Very clogged..perhaps you picked up a tank of Dirty gas.


Jonathan
 

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1991 500SEC 55K mi. 1987 560SEC Now 153K mi. 2020
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Hi jhodg5ck,

As the engine is running and if either the pumps were failing, filter clogging or dirty gas present.... given that .... Wouldn't the economy gauge register a change in manifold pressure as the throttle plate is opened?

I'm still chewing on the Economy gauge intermittent operation - not working when the engine is having problems & OK with the engine acting normally.

[?] MBL
 

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Well, I mentioned he should start w/ the sticking throttle plate.. If that's not moving the engine won't generate vacuum. I'm just pondering ideas after that.

Jonathan
 

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Discussion Starter #8
Well wouldn't you know today it hasn't messed up at all. I did however take the breather off and check everything out and nothing was sticking, binding or out of place so I guess I will have to wait til it does it again.

BTW is it normal to have a very strong gas odor when you push the plate open under the breather?
I thought I was going to pass out when I pushed it down.

Thanks

David
 

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1991 500SEC 55K mi. 1987 560SEC Now 153K mi. 2020
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Hi luvmysd,

I would expect if one was to push the airflow sensor plate downwards and if there was sufficient fuel pressure present..(rest pressure).. that the injectors would open, releasing that fuel into the intake 'plenum' area..

I'm sure you'd smell raw gas bigtime!

How's it going with that baby, anyway?

MBL
 

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Discussion Starter #10
Well its been doing great but I have been working a lot lately and haven't driven it much. I hate to say this but I wish it would do it all the time so I could figure out whats wrong with it.

Thanks

David
 

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Hi

I have an unusual problem with my (93) 2.0 190e auto, I just had the head gasket done, a week before the gasket was fixed i noticed when i pullout of the drive way and stepped on the gas pedal like normal it didn't do anything for about a half second then took of like normal. Today I went for a drive and it happened again but this time it did not return to normal as fast. For the first few secounds it would do nothing when I stepped on the gas, it would rev up 2500 when changing to the next gear but move slugishly .

Please Help!!!
 

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1985 500SEC, 1991 190E 2.6.
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Well its been doing great but I have been working a lot lately and haven't driven it much. I hate to say this but I wish it would do it all the time so I could figure out whats wrong with it.

Thanks

David
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