W124 230TE High Idle speed.

[Tashman]

Bought a 1986 W124 230te 3 months ago, very pleased with it but now the idle speed has risen to 1500 which can be annoying with the car always wanting to pull forward in drive.

When I bought it the idle was 1100 but according to 'autodata' the idle should be 750 plus or minus 50 rpm.

Autodata also says that its not manually adjustable.
What should I do to rectify this?
Many thanks.

 

[jibcl500]

Idle control valve, my 230 was lumpy on tickover so I removed the control valve and cleaned it, the tickover was much better but the revs increased to 1000rpm, there is a small wheel at the base of the valve which turns very easy I rotated this and the revs increased or decreased.
If stuck and local come over.

jib

 

[turnipsock]

Have you checked the cable isn't sticking?

 

[kth286]

Tashman

Idle is and was too high even at 1100. Autodata is about right depending on whether the car is manual or automatic.

Which is it ????????

As you car is a very early 124 is it the carb version or injectors. ?????

Even if injectors it is a mechanical system - (do not be confused by name with tronic in it)
K-jetronic, and should be adjustable.

Are you sure you are looking at the correct autodat sheet for YOUR car.

Where you located perhaps we can recommend an inexpensive indie.

 

[Tashman]

The throttle cable is definately not sticking. The car is automatic.

My first suspision was a dirty idle speed control valve as the car has just reached 200k miles, but where do i find that on my engine?

Imagine I've removed the round air cleaner box assembly, whats it near?
Its a very early 124 with mechanical fuel injection. (Ke-jetronic??)
I'm located in Hampton in west london. I have basic mechanical competence and am prepared to attempt most straight-forward tasks.

My second line of thinking is 'Perhaps the intake side of the engine could have an air leak?' Is that likely?

This fault is causing high fuel consumption when driving round town, basically slow driving your right foot is continually resting on the brake so as not to go into the car in front. I've started putting it into neutral all the time so the cars not tugging away, but its wasting fuel doing twice the normal idle speed, and it gets too hot much quicker sitting in traffic at 1500rpm.

 

[television]

You have Bosch KE on your car idle 750

If you do not have the rotory idle valve then you have a idle speed screw under the air filter,,its a large flat bladed screw.

Its possible the the switch on the throttle body is not switching over to the idle relay and its running on the main ECU

 

[Tashman]

Just followed jibcl500's advice.
Found the little rotary wheel, and screwed it in as far as it would go.
The idle speed is now down from 1500 to 1000 rpm!!
Hurray the car is much more relaxing to drive and doesn't overheat.

I cleaned the valve while I had it out aswell and looked at how it works - it basically lets a small amount of air in, the more you do up the screw the less air gets in. The fact that I can't get the idle speed down to 750 makes me think that there must be a small amount of air leaking in somewhere - something to look at another day perhaps.
Thanks for the advice guys.

One other thing I've noticed now that the idle is lower is that the oil pressure when hot idling is about 1 bar lower aswell. Its now 2.5 in neutral and 1.5 stationary in drive. Is that normal? It goes back to 3 as soon as you drive off.

 

[jibcl500]

Tash.

Some of the rubber hoses on the idle valve on my 230 where very wasy to remove, If they are not 100% air tight then that will increase the RPM also.
Ive also noticed in the last few days after doing mine that the cars got better with use.

Oil 1.5 sounds about right, mines at 2.5 on tickover in drive and 3 running.

Have you done an oil chnage recently and used gen MB filters.
jib

 

[Tashman]

Yes i did one last week with a genuine merc filter.
The mercedes parts man explained that the design of them has been superseeded and they're much shorter now. The one that came off was at least 2 inches taller.

I used Mobil super S 10w40 semi-synth, thats ok isn't it? (not too thin?)

 

[jibcl500]

Do you get rattle on cold start?, mine does but the but the hydraulic lifts on the the 230 are only good for 100k and need replacing, mines just done 200k +++and they rattle, I used some wynns anti lifter rattle which worked for about a week so I think I will replae them soon.

A thicker oil on this engine is better but mine runs well enough.

jib

 

[turnipsock]

Do you get rattle on cold start?, mine does but the but the hydraulic lifts on the the 230 are only good for 100k and need replacing, mines just done 200k +++and they rattle, I used some wynns anti lifter rattle which worked for about a week so I think I will replae them soon.

A thicker oil on this engine is better but mine runs well enough.

jib

I found that using a modern (thiner) oil caused the engine to seem a bit rattley. When I started using one of recomended ones, things improved. I also replaced the hydralic valve lifters at some point (probably 170k).

Tashman, it could well be an air leak somewhere, there are enough pipes coming from the inlet manifold. The performance gauge should give an indication.

Did the idle suddenly go from 1100 to 1500?

 

[Tashman]

When the car is started from cold, you hear a loud clattering for about 6 seconds sounding like an engine running without oil!
Then the second the oil pressure gauge needle flies up the clatter goes quiet.
You get a few mini clatters if you rev up the engine while its cold.

To be honest I don't think you hear half of the noises the engine makes because of all the sound deadening.
Last month I had to replace the wiper motor and had to drive a few miles without the all the padding around that area attached - I thought something was seriously wrong with the engine! Sounded like a bag of nails. But low and behold put the padding back -quiet engine.

I've tried the Wynns hydraulic lifter treatment from Halfords to try to alleviate the noise but it made only a minor difference.
Was tempted to try the Forte Top End Treatment because Forte products have impressed me in the past with their effectiveness.

How difficult is it to replace the lifters?
How much would a set cost?
I'm not afraid to get my hands dirty and learn something on the way.

I found that using a modern (thiner) oil caused the engine to seem a bit rattley. When I started using one of recomended ones, things improved.

What are the recommended ones?

Come to think of it, its harder to start these days, and it used to start easily on the oil that it came with when I bought it. Maybe thicker oil helps it pressurise up better. I think this could be the opposite of the problem I used to have on Ford Zetec engines when people would put say 15w40 in when they require 5w30 and the hydraulic valves would over-pressurise and not close again stopping the engine from starting.

 

[Tashman]

Jib
I know what you mean about those hoses - most of mine were very oily and barely pushed on and they all came away in my hand when I went for the idle control valve. Put them all back together more securely and got the idle down another 50-100 rpm!

 

[jibcl500]

Maybe worth wasting a can of easy start on the idle valve again to get it really clean, I will be replacing the pipes around the valve as soon as I can be bothered to find the part numbers and order them.

Lifters are easy enough to change, I think they are about £8 each but I could be wrong, might ask and see, if you want soom then I can get both sets at the same time and get some better discount.
jib

 

[Tashman]

I gonna wait a few weeks untill a time when I don't need the car every day to change the lifters.
Just had a browse through the haynes manual at the precedure - doesn't look too difficult.
So i suppose you need 8 of them at £8 = £64

 

[turnipsock]

http://www.bp.com/managedlistingsection.do?categoryId=9007433&contentId=7014328

I just use the lubricant selector on the BP site to get an idea of which oil to use.

As Jib says, they are about £8 each.

I also seem to remember there two sizes of shims involved somewhere. The fractionaly thicker one was to allow for wear in older engines.

It does sound like the oil is to 'thin' when cold and is draining out of the oilways. It is taken a couple of secs to pump the oil round.

 

[turnipsock]

I had a look through the threads that I have started, hundreds of them, and found the one about my tappets...

http://forums.mercedesclub.org.uk/showthread.php?t=16058

It looks like Hugocat also had the same problem and it was the oil as well.

 

[mattkh]

JFound the little rotary wheel, and screwed it in as far as it would go.
I cleaned the valve while I had it out aswell and looked at how it works -

Hi
If you did not take any pictures, could you please do a little drawing for me of this rotary wheel and valve. Thanks.

 

[harrisonaard1]

As a last tip for the idle, there are many vacuum pipes around and under the inlet manifold. The ones under the manifold seem to degrade quicker and affect the idle speed, ignition timing and smooth idle. You do need to be very dextrous and have a cold engine. Girls hands are better, but being unfortunately attached to a woman, that may not be a good idea. Anyway, check ALL the pipes and don't forget to set the timing. Another thing that only rarely happens is the idle switch (on the throttle body/AFM) may not make contact correctly, effectively giving no 'idle'. Check that it does. It's so lovely to fiddle about with these engines as they sound so grateful afterwards. It's the electrical problems that are soooo tiresome.
The idle valve is under the air filter box, at the back, usually snugly between no3 and no4 inlet pipe. the adjuster is a 20mm plastic wheel, usually on top, but could be underneath if someone else has put it back incorrectly. If the wheel is stiff, screw it out and clean it gently.

 

[St3ve]

Thank you!

I know this is an old post, but I just wanted to say thanks to harrisonaard1 for his last comment. I removed my Idle Control Valve and cleaned it out. I turned the mysterious grey plastic wheel knob a few times to see if it moved anything inside the valve chamber. Re-installed it, which required a lot of playing around to get it back in place between the two steel (manifolds?). Car was running horribly after that so I figured I'd probably need to play around with the grey plastic knob, which I did and idling improved, but certainly nowhere near what it was before.

I now realise that I must have re-installed the ICV the wrong way, because my grey plastic knob is facing down. Will turn it around tomorrow and see if makes a difference and then report back. I'll put some pictures too, so other 1992 W124 230E owners are able to locate it.

Further to other posts on this thread, the plastic (aged rubber?) pipe going into the engine towards the rear was cracked, which I fixed with pratley quickset steel, I did the job in situ though, while it was attached to the mount, I'm still getting a serious hissing sound from there, so I figure I need to do a better job of sealing it up it tomorrow.