220 Huntimg

[Comvec]

Can anyone give me any hints as to why a 1993 220 petrol starts hunting all of a sudden.it could be ok for days and all of a sudden when it is idling the RPM goes up and down,new fuel filter,air filter and plugs made no difference,I would appreciate any input,thanks in adavanc.
Jim

 

[Bolide]

Dirty throttle body flap or worn-out throttle potentiometer. It seems to be common on E220s for some reason

Search this forum - there are lots of threads on this

Nick Froome
www.w124.co.uk

 

[Comvec]

Checked

Checked the throttle for dirt and gave it a clean and a good spray of carb cleaner but its still the same,had a look on line for a used potentiometer and they are running at around £100,what MB would charge for a new one I hate to think,the question I want to ask now is there anyone who repairs them or are they throw away units,it would be a lot of money to spend and then find that it is still the same afterwards,I took it for its MOT today and it behaved ok and passed the emission test no problem,on the way back the first set of lights I stopped at it surged again a couple of times and then no more,but with her indoors moaning about it I will have to have it done,anyone know the part number of the unit for a 1993 220TE.
Jim

 

[television]

http://www.ignitionleads.co.uk/

http://www.injectioncorrection.co.uk/index.php?id=models&manufacturer=Mercedes

Here are 2 links, the lower one could be ok

So you have the same fault as Mr Rosher in the other thread

 

[mr rosher]

Can anyone give me any hints as to why a 1993 220 petrol starts hunting all of a sudden.it could be ok for days and all of a sudden when it is idling the RPM goes up and down,new fuel filter,air filter and plugs made no difference,I would appreciate any input,thanks in adavanc.
Jim

hi comvec, it seams we both have the same problem, i own an 1993 e280 that does just what your saying, one minute she runs sweet, then from nowhere you get this hunting for say 5-10 miles, last oct my head gasket went and the engine was cooked, before i found a safe place to stop, after that i have now spent just over £2200, to get her back on the road, i carried out all the work by myselve, head gasket, no problem, or so i thought???
had the head skimmed / decoated / new valves and seals / pressuer tested /
and on rebuild, the wiring harness that feeds the coils air mass / and sensors from e c u burnt out causeing everything connected to it to burn out, later found out these harnesses were made from the wrong type of wires to cope with the heat from the engine then relised becaues the engine was cooked when head gasket went, it also blew the main bearing shells which in turn the cranshaft went south, anyway by this point i had allready spent somewhere between £850 - £950 on her for, gaskets and new sensors and head rebuild / plus the rebuild of the wiring harness, so thought whats the point of giving up now, since then done a complete engine rebuild, and replaced alsorts,
complete engine rebuild,
injecter o rings,
air mass,
lambda sensor,
o.v.p.relay,
coolant temp sensor,
charcoal canister,
air flow sensor,
throttle body,
crank sensor,

to be honest i've changed so manythings i forget, and ever since this i've had the same problem as your getting, if i put a code reader or blink tester on her im getting the same codes everytime, no, 6 pin SRS and no 8, pin hfm air mass, im lost what to do next,
i hope yours is a lot easier then mine to sort out, and if you do, can you please let me know,
please do not get me wrong, these are lovely cars, and anyone who own's one will know this, that is why i have spent so much time and money to put mine wright, have you put yours on a blink tester,
rod

 

[television]

Mr Rosher, I am trying to locate a 1993 book on this by Autodata

 

[kth286]

rod

On pin 8 the diagnostic code for HFM Air Mass is 4 flashes of the led light tester.

Please confirm that is what you are getting ??????

If so it can only be (a) implausably high signal OR

(b) open-circuit.


So, I think you have "cracked it" at last.

It is just a matter of knowing why either of those two conditions exist.

Is there an air leak ?? in the mass tube.

Is the electrical plug fully fitted onto the mass connection and not lose in any way and making only an intermittent connection.

Have you tried driving without the mass fitted and is it better ???

Is the new mass an original Mercedes part ?????? It needs to be (Bosch).

Can you borrow another mass of same spec and try a swap to see the effect.

You need to delete the trouble code before each test you make and see when it comes back - are you able to delete the code OK ????????

Does the return of the code coincide with the actual fault with the car ?????

There is a lot to go for - and so the best of luck - and be sure to let us know how you get on.

 

[television]

rod

On pin 8 the diagnostic code for HFM Air Mass is 4 flashes of the led light tester.

Please confirm that is what you are getting ??????

If so it can only be (a) implausably high signal OR

(b) open-circuit.


So, I think you have "cracked it" at last.

It is just a matter of knowing why either of those two conditions exist.

Is there an air leak ?? in the mass tube.

Is the electrical plug fully fitted onto the mass connection and not lose in any way and making only an intermittent connection.

Have you tried driving without the mass fitted and is it better ???

Is the new mass an original Mercedes part ?????? It needs to be (Bosch).

Can you borrow another mass of same spec and try a swap to see the effect.

You need to delete the trouble code before each test you make and see when it comes back - are you able to delete the code OK ????????

Does the return of the code coincide with the actual fault with the car ?????

There is a lot to go for - and so the best of luck - and be sure to let us know how you get on.

I have a feeling Kieth that the fault is man made,with that I mean an air leak as you think.

Mr Rosher did a super job rebuilding his engine and this fault has only happened after the rebuild

 

[Comvec]

220 Hunting

My engine only hunts when idling and only by a couple of hundred RPM,had no chance to look at whats happening yet but may run it into the dealer to have this free check they are offering,the last thing I want to do is buy parts that are not needed so I will leave it to them and have a quote to sort it.
Jim

 

[recycledjuvenile]

it hunts when it is warming up the cat

 

[Comvec]

Hunting

Thats not the issue,it hunts when at normal operating temperature for example when stopping at the lights,give it a rev and its ok till the next time which could be a week or the next light,no big deal but with her indoors I am worried about it getting worse and shooting a red light before it can be stopped,this business of putting on bits that make no difference but making one poorer is against the grain with me so I will see what the dealer will say and how much,no doubt he will say the engine needs replacing.
Jim