300e Idling problem

[aturner]

I have recently bought a 1987 300e. When you start it up it doesn't idle properly, not sure if this a faulty idling valve, does anyone have any advice

 

[Richard Moakes]

In what way doesn't it idle properly?

1). Revs too high?
2). Revs too low?
3). Lumpy?
4). Stalls?

Could be any number of things, but more info is needed to help.

Cheers,

Richard

 

[aturner]

Richard,

It revs too low, and feels like it may stall

Cheers

Alistair

 

[Richard Moakes]

When warm the idle speeds are as follows:

In drive, it will idle about 550 rpm, in neutral about 750 rpm

When cold it will rev higher, in neutral about 1000rpm until warmed up.

Is it just for the first 15 secs or so or does this go on for a prolonged period?

It could be the idle air valve.... or has the ABS light been on recently?

Cheers,

Richard

 

[aturner]

Richard,

The ABS light has not been on recently. It seems to misfire when idling and does not run faster when cold, and occasionaly stalls when cold.

It feels lumpy and when sitting in traffic it feels like it is misfiring on idle speed only, no problem when travelling normally.

Also my cruise control does not work, any suggestions on what this may be?

Thanks for the advice

Alistair

 

[Richard Moakes]

Right, it sounds to me like your idle air valve is not work properly.

These things are expensive, but in most cases can be brought back to life with a bit of carb cleaner, care and wd40.

It is located underneath the air filter housing, and is silver cylinder with an electrical connection and two approx one inch diameter black rubber hoses connected to it.

Remove it from the car, blast the insides with carb cleaner, carefully prod the slide valve mechanism with a screwdriver and make sure it is free moving. Then lube it up with WD40 and refit.

Failing that, contact someone like Mercman for a second hand unit.

My parts catalog says it is A 000 141 22 25 and the cost is scary, over 150 :-(

As for cruise control, how long do you have? It could be loads of things, but in most cases it is either a problem with rear brake light bulbs or the amplifier unit has dry solder joints.

Good Luck,

Richard