another idle problem....
 

my car is a 1986 230E (mannual trans) and although my idle problem may not be described as rough, i certainly know that something is wrong with it since I heard from another post that your idle should always stay as is except during start-up when it goes up a bit to about 10-11 then immediately goes down to about 8-9. My M102 engine idles generally fine, does the start-up idle and normally does not move and inch (except of course when revving). However when the airconditioning system cuts in (compressor and aux fun running) my idle goes down to about 5-6 (engines vibrates almost to a point of stopping) then returns to 8-9 and stays there even when it cuts off. My technician has diagnosed, adjusted/checked a lot of things and finally told me that based on his expereince in repairing MBs, the M102 engine is normally like that being smaller than it's brothers (M103 and M104). I really trust him with a lot of things about my car but no one is perfect and i hope he's wrong about this one.

I know i have an adjustable idle control valve which i replaced last September 2002 due to rough and constantly high idle. Could this be the culprit? Can I just adjust it so that it can better compensate whenever the aircon cuts in?

Added input: My airconditioning system is not an original MB due to our tropical climate. It has been converted and is using a japanese system and it remained satisfactory so far in terms of output compared to the original which is cold but not as cold.

Really need your help on this one.

anyone?????????

none???? unless this is normal would appreciate receiving an advise.

on the 103 there is tsb re idle with a/c on/off. this was
corrected by my mb dealership sometime ago free of
charge (89 300e). i was told that the rpm will dip
when you switch the a/c on, but will rise up to normal
level (600 - 700) immediately afterwards.

would suggest for you to visit your local dealership,
also reexamine your ac compressor for electrical draw.
is universal motors still around?

thanks. joel. But what is a tsb?
yes, universal motors is still around.

technical service bulletin issued by car manufacturers
to correct technical issues that may arise from time to time.
your mb dealer should be aware of this.

maraming salamat.

Joel,

just a thought, what was exactly done to your ac to correct idle.

thanks again.

124addict

nothing was done to my ac. the dealer just did the
corrective measure in relation to my regular maintenance
schedule.

click on this for the tsb on your car,
http://www.alldata.com/TSB/8935_mo.html.

before throwing money onto your car, try the usual suspects.
when did you last replace your fuel filter? also, pour some
fuel injection cleaner - techron works, and drive long and hard.
the winding roads to Olongapo or Baguio would clear
up carbon deposits for sure!

Recently replaced fuel filters, changed spark plugs, changed oil, applied fuel line/injector cleaners, and went to Subic for a much needed italian tune-up, but the problem persist anyway. Coming from you, I'm looking at a possible power draw from the compressor but have not really had anyone check it yet.

I'm tempted to adjust the idle control valve (DIY) as it has a dial but I don't know if this will work and i'm afraid that this might complicate the matter unless someone can enlighten me on the matter.

Thanks for the patience.