190E idle problem

[modifiede36m3]

Hi All
I have a 1991 190E 2.0 Spotline. I have a problem with the idleing. It sometimes can be high upto 1500 yet other times is very very low, so low that is stalls. It is more often low than high rpm. Any Ideas anyone?

Thanks in advance
Steve

 

[mike65]

Proberly the air idle valve (aka aux air valve). There is a warm idle adjuster screw valve which you can tweak with a screwdriver. Its under the airbox on the drivers side roughly between spark plugs 2 and 3.

Mike.

 

[modifiede36m3]

help

Thanks
I will give it a go. The car only does it when it is warm never when cold. which way should I adjust the screw? Clockwise or anti-clockwise?

Steve

 

[G3maw]

If the previous adjustment mentioned doesn't work, get hold of a 3mm allen key and tweak the mixture control which is situated underneath a removable plug in a narrow tube which is situated inside and towards the centre of the air cleaner - remove top of air cleaner to remove the plug, test your allen key for movement, you press down on the key to engage the adjuster underneath and this may need freeing off with a squirt of Plus-Gas/WD40 etc. When you are satisfied that the adjuster is freely moving, replace the air cleaner top and go for a run to warm the engine up and ONLY THEN turn the adjuster clockwise to richen the mixture or anti-clockwise to weaken it. The Haynes manual advises that you should only do this operation with the aid of an exhaust gas analyser but if you get it running right i.e nice and even and not lumpy, then you won't be far off. If this doesn't work, check the air flow flap in the top of the throttle body ( with the air cleaner removed) for a build up of gunge causing the flap to stick and seat unevenly.

 

[mike65]

Re: help

Thanks
I will give it a go. The car only does it when it is warm never when cold. which way should I adjust the screw? Clockwise or anti-clockwise?

Steve

Turn the screw clockwise to drop revs, anti-clockwise to raise revs.

I think! You'll hear the difference quick enough.

Mike.

 

[modifiede36m3]

help

Hi
I have been told that it could be the idle control valve that they sometimes stick. is this correct?

Steve

 

[mike65]

Thats why I mentioned it before the warm idle screw valve, they do give up the ghost eventually. The electrical contacts which tell the ECU what to do stop working. I'd try to locate a second-hand one before buying new as I think they aint cheap just found a price at http://www.kmsparts.com for 89 quids, and at eurocarparts

IDLE CONTROL VALVE Manufacturer BOSCH AIR SLIDE VALVE UPTO ENG 102962 £42.07

Thats not bad if its the right part.

Mike.

 

[modifiede36m3]

help

Hi
I have been told that if i disconect the electrics from the idle control valve the revs should go up if the vave is working correctly. I do this and the revs do increses. The bottom hose that connects to the valve is seems very lose from the valve and from the engine. Should I replace this small hose?

Steve

 

[mike65]

If there is a leak of air into the idle valve it gets a wrong reading and so the revs are wrong, so the pipe may need replacing but it might just need a better set of fixing clips! Get some jubilee clips and see if that helps (I suspect there's not much room to use a screwdriver though). If that dont work and the pipe looks like its become mishappen at the ends or cracked
then replace.

Mike.

ps if anyone else has any sugestions feel free!