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1986 420SEL
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34 Posts
Discussion Starter #1
Okay, so couldn't help myself and bought my second 420SEL. It's a '91 with 108,000, white with grey and she's beautiful. Juan Gonzalez bought her when he signed with the Rangers, so he tricked her out with all the AMG extras.

She had lots of power, ran great, but idled a bit high so had her checked out and found small leak and so replaced manifold gaskets by mechanic recommended on the forum. Also replaced rear axle, did tune up, replaced all fluids and filters, hoses, wires and plugs, new O2 sensor, fuel injector seal, fuel accumulator.

Got her back and now I have a dead zone in the gas pedal of about two inches and she's dying on me when I take off from an intersection stop. I've searched the forums, but since I've just had all this work done I'm wondering if somethings been overlooked or not replaced correctly.

The mechanic is now mentioning could possibly be fuel pump and throttle linkage piece that sits just under the air filter and looks like a small shock absorber. Before we go back into the shop, I thought I'd ask for some help and opinions from you all. Thanks for any help because I'm starting to have sleepless nights here. Rebecca.
 

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Might be a vacuume line off. Take it back and ask to have a mechanic ride with you so he sees what you're yalking about.

You could open the hood and have a look see. ....listen for a sucking sound
 

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1986 420SEL
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34 Posts
Discussion Starter #3
Thanks, Manyhobies.

Maybe the vacuum line could be the cause of the dying on takeoff. Any ideas on the dead zone in gas pedal?

I think these cars have become my only hobby, and an expensive one at that.

Rebecca
 

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'88 560sec (180k mi.), '82 380sec (236k mi.), '86 560sec (?miles)
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273 Posts
Who did the work? Was it a legit shop? You said that a small leak was found, im guessing at the mainfold...? I hope that ALL the gaskets were replaced NEW and all the rubber bits by the throttle body were replaced. How does your economy gauge look now? Pegged?

As far as the dead spot in the pedal, first thing that comes to mind is the air flow sensor, which is on the side of the fuel distributor. You need a voltmeter to adjust it properly. I dont know the specs off-hand, but if that thing was messed with at all or moved then you need to re-adjust.
 

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Depends on the day!
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13,337 Posts
Also, I hope this shop re adusted the CO, if the mixture is Way out you'll have dead spots in the pedal.

The air flow plate potentiometer is a possibility, but I'd hope it's not as the part is no longer available separately from the whole housing which means $$$$$. If it didn't do this before I'd be surprised.

bring it back, if the guy has a clue he should be able to nail it down fairly quickly.

Jonathan
 

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ML500, special edition, CLK550..
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183 Posts
Might be a vacuume line off. Take it back and ask to have a mechanic ride with you so he sees what you're yalking about.

You could open the hood and have a look see. ....listen for a sucking sound
X2...99% of those vacuum lines can be bought at any auto parts store in bulk/cheap..
 
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