S500 Coupe ASR Fuel Problem ?

[Drex]

Was driving my car yesterday when the car started to become eratic with its acceleration.When you put your foot down it would have trouble accelerating.

Then after about 40 miles,the ASR light came on and i lost all power.
Pulled the car over,turned it off,turned it back on again and the ASR light went out.

The car sill had trouble accelerating,done about another 60-70 miles and same thing happened.This happend in a total of 4 time over a 350 mile trip.

Never had a problem with this car at all.

Filled the car up to just over 3\4 of a tank before i set off on this trip......never filled the car up over 1\2 way before !

Could it be dodgy fuel ?

 

[jibcl500]

Might help if we knew the age and model of S500, suspect the electronic throttle as a quess, I assume yours to be a w140 S500.

You need to get it on a computer to see if anything is on there.

jib

 

[Drex]

Sorry...........I thought i put 94 in the title description !

Anyway 94 \ L W140

Found a similar problem on these forums,saying that it is the MAF \ MAS airflow meter ?

 

[jibcl500]

No I think there earlier type of MAF tend to be a little more robust, on a 94 w140 there are several thing to think about.
Check your distributor caps and rotor for condition, might be worth replacing them anyway.
has the engine been power washed at all???
Check the leads for condition.
Your car is also prone to engine loom failure, shorts etc.

If your near cambs you can drop it in.
jib

 

[Drex]

No I think there earlier type of MAF tend to be a little more robust, on a 94 w140 there are several thing to think about.
Check your distributor caps and rotor for condition, might be worth replacing them anyway.
has the engine been power washed at all???
Check the leads for condition.
Your car is also prone to engine loom failure, shorts etc.

If your near cambs you can drop it in.
jib

Thanks for your co-operation in letting me drop it into you.

Unfortunately i live to far away !

Ok, so you think i should check \ change the following first

Distributor caps
Rotor arms
Leads

 

[kth286]

Do one of your tyres need inflation, as that will cause the ASR to light up ??

 

[Drex]

Do one of your tyres need inflation, as that will cause the ASR to light up ??

Does it really ????????

Any idea about the acceleration problem ?

 

[Drex]

The problem has been identifieid by Mercedes main dealer service department as the throttle body potentiometre.

Whatever that is......

They said they we 80% sure that is what it was, but they also recommended changing the accelerator foot switch first as there maybe a slim chance that this may cure the problem ?

Fitted price for the Potentiometre is £836.78, would i be able to find one of these cheaper myself and can any half decent mechanic install it ?

Is the Potentiometre a specific part in the "Electronic Throttle Actuator" ?

And is this what i should be looking for ?

 

[television]

It sounds to me like they are not sure, your car has an electronic throttle pedal that is connected with the ASR, your car has ASR11 and it is a specialist job fixing them

I do have some links somewhere

 

[jibcl500]

There are companies that specialise in reconditioning the ETA, the sucess rate is low. I had one for your car but couldnt give it away!!!!!!

Sounds like the dealer doesnt know if this is the problem either, when they fail it goes into limp mode with all the lights on, have you checked your battery condition as a low voltage or failing battery will cause the same problem.

jib

 

[Drex]

Thing is,this problem only seems to occur when the car gets quite hot

50 miles or so....

it won't ever do it, backwards and forward to work...10 miles in total !

So could it still be the battery then ?

 

[television]

It will not be the battery if it does it when hot

http://pages.prodigy.net/jforgione/MB_asr.html

 

[Drex]

I had a look at K6JRF's page before posting on here.....

It sounds like the problem he had is very similiar to mine !

I think my Mercedes service department are right in thinking that it is the potentiometre.

So now i need to find a reasonably priced Electronic Throttle Actuator as this contains the potentiometre inside it.

Is the ETA the same on the coupe as it is in the saloon model ?

Is the ETA easy to fit, can any half decent mechanic fit it, or will i have to get Mercedes to fit it ?

 

[jibcl500]

I had a look at K6JRF's page before posting on here.....

It sounds like the problem he had is very similiar to mine !

I think my Mercedes service department are right in thinking that it is the potentiometre.

So now i need to find a reasonably priced Electronic Throttle Actuator as this contains the potentiometre inside it.

Is the ETA the same on the coupe as it is in the saloon model ?

Is the ETA easy to fit, can any half decent mechanic fit it, or will i have to get Mercedes to fit it ?

Any 1993/1994 W140 R129 5.0 V8 will have one they do change from 95 onwards and are not interchangable, easy to fit, remove the air box, unplug the air meter and remove, the air meters have screw clamps on them which are impossible to get access too, you might fit if you rock the air meter gently side to side it might just be ok to remove without undoing the clamp. Below the air meter is the ETA, held in place with 4 Torx or hex screws, your ETA I think has a lever connected to it and a large spring, be careful as these are fiddly and could spring off. should take 10 mins to remove everything.
Hope this helps.
jib

 

[Drex]

Jib.....Thanks for the information and advice.

I will try and source one of these and let you know how i get on !

Thanks

 

[jibcl500]

look on ebay.de as they tend to have more forsale over there.

jib

 

[Drex]

Found a second hand one for £270.00.........a bit of a gamble i know !

Surely i can't be that unlucky for this unit to play up as well ?

My local garage had a look at it today and they reckon that it will take 4-5hrs
because they will have to take the manifolds off ?

Any input,much appreciated !

 

[jibcl500]

Ive replaced one recently ad didnt have to remove the manifolds!!!!
1 hour tops to remove and refit. Also make sure the battery is disconnected beford its removed.

jib

 

[Drex]

What will happen if they don't disconnnect the battery ?

Jeez,I wish you were fitting it !

Maybe i should bring it to you !

 

[jibcl500]

http://pages.prodigy.net/jforgione/MB_asr.html

follow this link, this chap has the same CL year and the proceedure is there for removing the ETA.

Sorry about the typing in the other post, wifes getting me some new fingers for christmas.


jib