93 300ce
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Newbie
Joined: Feb 2011
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300ce
93 300ce
The engine in my 300ce runs smooth and pulls strong. The transmission shifts great, smooth. Idles in neutral at about 700 rpm steadily. Recently when I stop at red light or come to near stop the rpms bounce up a couple of hundred rpms then drop down and repeat till I accelerate. While stopped the rpms will steady out at about 700 if I shift in to neutral. Put it in drive and the rpms surge till I accelerate .
Any idea how to cure this?
Thanks
Will
Any idea how to cure this?
Thanks
Will
Junior Member
Joined: May 2017
Posts: 25
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1987 MERCEDES 300E
I have been experiencing a similar issue with my 1987 300E. There are a multitude of items to test to in order to narrow the issue down. Yours being a 1993 model year, I believe there is a code reader available for that year model. You should have a diagnostic port next to the battery to plug a code reader in to the retrieve any possible codes.
Junior Member
Joined: Jun 2016
Posts: 19
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1996 S600
I just had almost identical issue with mu 95’e420 and it was TB. After the car warms up, idle would bounce up and down in D or R, but not in N. I changed the TB and it got fixed.
I just realized how old the post is... but I guess its ok, someone else migh use the info...it drove me crazy!
I just realized how old the post is... but I guess its ok, someone else migh use the info...it drove me crazy!
Junior Member
Joined: May 2017
Posts: 25
Likes: 0
1987 MERCEDES 300E
I just had almost identical issue with mu 95’e420 and it was TB. After the car warms up, idle would bounce up and down in D or R, but not in N. I changed the TB and it got fixed.
I just realized how old the post is... but I guess its ok, someone else migh use the info...it drove me crazy!
I just realized how old the post is... but I guess its ok, someone else migh use the info...it drove me crazy!
Junior Member
Joined: Jun 2016
Posts: 19
Likes: 0
1996 S600
I agree but the thing I hate the most is when people post a problem but never care to finish it up and tell what solved it. I remember with my issue I found multiple post with similar problem but just one followed through and wrote what fixed the problem. So I figured I can still leave the comment and someone else might find it useful.
I know how you feel, I did almost the same thing with mine…Put the new TB but than idle was just very high and it drove me nuts…Long story short the TB linkage was loose on the back end, near the firewall, and it was causing TB to be slightly open. I just had to pop it back in place which was hard since its hidden in the back and not easily accessible.
I know how you feel, I did almost the same thing with mine…Put the new TB but than idle was just very high and it drove me nuts…Long story short the TB linkage was loose on the back end, near the firewall, and it was causing TB to be slightly open. I just had to pop it back in place which was hard since its hidden in the back and not easily accessible.
Newbie
Joined: Apr 2018
Posts: 2
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1993 300CE
1993 300CE
I agree but the thing I hate the most is when people post a problem but never care to finish it up and tell what solved it. I remember with my issue I found multiple post with similar problem but just one followed through and wrote what fixed the problem. So I figured I can still leave the comment and someone else might find it useful.
I know how you feel, I did almost the same thing with mine…Put the new TB but than idle was just very high and it drove me nuts…Long story short the TB linkage was loose on the back end, near the firewall, and it was causing TB to be slightly open. I just had to pop it back in place which was hard since its hidden in the back and not easily accessible.
I know how you feel, I did almost the same thing with mine…Put the new TB but than idle was just very high and it drove me nuts…Long story short the TB linkage was loose on the back end, near the firewall, and it was causing TB to be slightly open. I just had to pop it back in place which was hard since its hidden in the back and not easily accessible.
My OBD1 Diagnostic code reader is supposed to arrive Saturday. I will see what I get for codes and post findings. The car does have an issue with oil gauge showing a reading. It stays at 0. ASR and oil gauge not working could be wiring harness but that is an expensive item to buy then not have the problem fixed. Was $20 for the diagnostic reader. Could be money well spent if it saves me unnecessary replacement of parts. Hard to find good engine and wiring diagrams for my model. Not many mechanics work on Mercedes and for price, with no guarantee of work, I will learn how to do some of it myself. Apparentently the employees at the Mercedes dealership don’t have any experience with older models and not capable of anything more than routine service. The service advisor couldn’t even figure out how to start it. He didn’t turn key fully. Tried twice. Came back and said something wrong cuz car won’t start. Lol! Not place I want to give hard earned money to, who know less about car than I do. It truly gonna be an act of love to bring this little beauty back to full health. Of all things, wiring!!!! UGH!! When we got it, the hood liner was mostly deteriorated and crispy. Replace hood liner myself. Just figured age was cause of such dry rot, but maybe could’ve been caused by overheating, if sensors are malfunctioning. Now as weather warms up, I will have better idea if fans are operating properly.
