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Normal Idle?

4K views 14 replies 8 participants last post by  Savannahbenz 
#1 · (Edited)
At what should the idle be,warmed up,in park,in gear, also with a/c on?
mine the 1990 300SE M103- park its at 700rpm,drive 550rpm,a/c on around 525rpm
did some work on the wife's car,seems to die at red light,idle to low
just replaced OVP,dist cap,wires good,tested and cleaned ICV,opens and closes like it should, did a propane test to the vacuum system,passed,cleaned fuel screen at fuel distributor ,duty cycle at 50%
car starts and drives,but feels to me like its lacking power,fuel pump and filter has 30k on them
I give it gas while driving and hesitates then takes off?
only thing left to do is adjust eha to distributor,its a used one from ebay, this low Idle stalling started after the eha was installed
what are your thoughts? Thanks
 

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#2 ·
NOOOOOOOOOOOOOooooooooooooooooooooo ooooooooo !!!!!

No more used EHA's from eBay JOHN I thought you had learnt your lesson !!!!!


Injectors ??? all spitting the way they should ?
 
#3 ·
Eha is about 6 months old and car ran fine for a while,but lately developed a low idle condition? and lacking power on take off? guess I could switch out eha from another one of my cars to rule it out.
here's a tid bit of past history with this car,last 3 times I brought it in for emission testing for DMV registration (every other year) really hard to get it to pass,one time had to really get the car warm to pass,next time the tech had problems to,so he took off in the car then came back and it passed,don't know what he did? he was gone for 5 min,last time it wouldn't pass so gave it to Rick my neighbor who's a mechanic,he came back said it didn't pass! he told me to change the plugs,I did he took it back and it passed!? car kinda feels like cat converter is plugged up.
maybe I'm going crazy again! but the 2 3ooe's kick this cars ass big time
My wife says there's nothing wrong with the car ,I'm just being picky!
so why stalls,low power band,low Idle!
 
#4 ·
John

DO NOT try and adjust the EHA. They are as sensitive as nitroglycerin. You don't have the specialized tools or training to have any success in doing so. Just adjust the A/F ratio and be done with it. Normal idle, regardless of a/c, drive etc should be 600-650. The ECU compensates for load on the motor.

Jim

Sent from my DROID2 using AutoGuide.Com Free App
 
#6 ·
John
You might well be onto something worth investigating in the cat convertor.
The fact you mention it passing/failing/passing/failing could well indicate the cat is clogged up. Prior to changing the cat on my CE, I had somewhat erratic idle and some start issues.

These appear to have been resolved by either
(a) the replacement cat and/or
(b) removal and refitting of the OVP (my ebay new one was crap)
(c) running 4-5 tanks including injector cleaner though the system

These are the ONLY 3 things I have undertaken in the last 6 months and performance has improved as has the idle.

Ray
 
#7 ·
Thanks Ray! will try the injector cleaner,this car used to be a rocket ship to me,but after driving the w124's that are much smaller and lighter with the same engine,it feel's like a slug! what are the signs of a plugged Cat?
once heard if you take a rubber mallet to it and hear stuff rattling around its toast,emission failings point to a bad Cat most of the times round here, just went to the store to get some liquid courage and car ran great! it seems to be a on and off condition
pics of tach 1st in park , 2nd in drive a/c on....Oh and George thinks I'm crazzzzy to!!!:D
 

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#9 ·
That is exactly what I get on my 91 300te today. (Just officially broke 325K)
Good power, wot responsive, stop idle in drive just what you show in pic.
200 mile road test today, highway, simulate town traffic (only two stoplights here).
So far so good.
New fuel filter cured my surging problem and intake pop when revving.
Still have cold start die unless I press accelerator slightly (or hold down airflow plate as my wife says "I just want it to work!" Guess she won't go for that every morning.)

What is your rpm at 75mph?

Is it stalling or surging idle (this one dies at first start cold, but fine after)

(On the road again, thanks mega info on this board and others. Still have to figure out the initial start sympton and why, unplugging IAC my idle goes down!
Dam Deer!)
 

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#11 · (Edited)
Those idle numbers are the same as my 1991 300CE-24 with the M104. One thing I didn't see was the cold start up, that is about 1200 rpm and gradually decreases as it gets closer to 80 degrees. Sometimes it sputters a bit on cold start up, then goes to the 1200 rpm smooth idle after a few seconds. Doesn't always hit with a bang the first time, but never fails to start. Very responsive off idle at a dead stop. On a side note, these idle numbers are the same on my 2004 SLK320.
 
#13 · (Edited)
The TE idles at around 650 rpm regardless of whether it's in drive, neutral or with the a/c on. However, on the odd occasion when pulling up the revs will drop below 500 and it threatens to stall. Actually did once but that was 2 years ago:confused:.

The pump was rumbling so I changed the filter yesterday and the fuel on the inlet side was black and I had to really shake it to empty the outlet side. There is now a noticeable improvement in starting and idling.

I would definitely change the filter first.
 
#14 · (Edited)
Have you volume tested? (For fuel filter)
Per ps2cho w124-zone.com/articles.php?article_id=48
Real simple- air filter off, remove outlet connection on regulator, attach hose (I used clear hardware store plastic), plastic container to measure 1l in 40sec minimum.)
Battery out.
I have a MAF so unlocked it (tight but has to go all the way around to release).

Made a jumper with2 male snap or banana male plugs. (Got a light switch, put that in the jumper, otherwise the pumps go on when battery is connected. Ask me how I know.
Plugged in between 1 and 2 (front two connections).
Below 1l/40 sec with old fuel filter. Now 1L in 28 sec.

Also- isn;t the Idle air control valve supposed to compensate for load like turning with power steering?
Two write ups I.ve used.
 

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