Replacement or repair for fuel metering head - 1982 W123 Mercedes 230 E

[jsbains]

Hello
Does anyone know of a U.K. based company that may be able to repair a 'fuel metering head' on a 1982 W123 Mercedes 230 E ?
Thanks, Jay

 

[ajlsl600]

Is that bosch ktronic? Think that's wot I had on g230 102981 motor. Tho was 25 yr ago

 

[jsbains]

Yes, its a Bosch part - "MERCEDES W123 FUEL METERING HEAD 0438100071 0438120116". I have managed to find a used & working part on ebay now and the mechanic will hopefully be able to fit it in the next couple of weeks. It would still be useful to know if anyone can repair these things just in case the ebay part doesn't work.

 

[mattkh]

What are the symptoms at the moment..??

 

[jsbains]

What are the symptoms at the moment..??

The engine was idling unevenly and running 'rough'. Part way to getting it looked at by a mechanic, the engine started spluttering and stalling. This was intermittent to start with, became more frequent until the car wouldn't start and had to be towed to the garage. The mechanic was able to fire it up a few times the following day and diagnosed a faulty fuel metering head and said that too much fuel appeared to be getting into the engine.
Some background: the car has been largely unused for the part 10 years and my brother (who was mechanic and sadly passed away recently) was in the process of getting it back on the road - a task which I have now decided to complete !

 

[mattkh]

.... said that too much fuel appeared to be getting into the engine.

Sorry to hear about your brother.
Overfuelling can be a leaking/stuck injector.
The saucer in the metering head has to have very clean circumference in order to move up and down freely.
Also consider the condition of the fuel in the tank.

 

[jsbains]

Sorry to hear about your brother.
Overfuelling can be a leaking/stuck injector.
The saucer in the metering head has to have very clean circumference in order to move up and down freely.
Also consider the condition of the fuel in the tank.

Thanks - I've asked the mechanic to look out for these issues.

 

[ajlsl600]

That was very reliable system only ever had one fault on mine G and unlikely to be as ur issue if more hassle try running fuel from Independant source to engine

 

[jsbains]

Sorry to hear about your brother.
Overfuelling can be a leaking/stuck injector.
The saucer in the metering head has to have very clean circumference in order to move up and down freely.
Also consider the condition of the fuel in the tank.

The mechanic says that the saucer in the current is moving *too* freely and sinking back into the chamber with virtually no resistance. Presumably, this movement somehow controls the fuel supplied by the other side of the unit (excuse me if this is incorrect - I'm not a mechanic!). Anyway, we'll fit the new part on the weekend and see how the old girl responds. Thanks again for your response.

 

[rayhennig]

It would still be useful to know if anyone can repair these things just in case the ebay part doesn't work.

I seem to recall an injection wizard somewhere in or near Stevenage. But I'm dashed if I can find the name.

Maybe I've found it:

Home Page

Anyone have experience of these people? I recall good reviews.

RayH

 

[bikeman]

Hi, my 1st post, not yet done my bio.

Anyway, KMIPetrolInjection in Bedford rebuild WURs and Fuel distributors. They seem to be the only company that does this in the UK.

As far as I can ascertain, they do not replace anything other than the orings, gaskets etc and there are some parts of these units that either machined to very fine tolerances (plunger) or are just not available (bi-metal strips) and I do wonder how they deal with such problems.

A bigger problem for me is that they wont test units. They only test after they've rebuilt them and their charge to rebuild is pretty expensive. So you really do need to have tested and verified your problem before sending them anything.

My car was misfiring badly and a Mercedes 'specialist' identified a fuel distributor rebuild. Because of the cost I bought a pressure gauge and saw that the fuel pressure was fine from the pump but low across the warm up regulator. All it needed was me to adjust the warm up regulator.

So my advice to you is to question your mechanic on what exactly he done to reach his conclusion. Or better still ask him to cover the cost if he's wrong.

Chucking 40 year old parts at it from ebay is probably not going to be cost effective.

ps the saucer is sucked by vacuum against fuel pressure on the distributor plunger and a spring. it should move freely with little resistance. if there's no resistance then I'd suspect the plunger is stuck up in its bore (could explain over fuelling) or the spring has broken/disengaged (unlilkely). It's pretty easy to remove the fuel head and check the plunger moves freely.

 

[mattkh]

........ the warm up regulator. All it needed was me to adjust the warm up regulator.

Please refresh my memory about what you call the warm up regulator.

 

[bikeman]

Please refresh my memory about what you call the warm up regulator.

Its the fuel pressure regulator for the metering head. It's bolted to to the engine block and controls the fuel pressure according to engine temperature.

Another possibility if it's getting too much fuel is the cold start valve might be stuck on and overfuelling continuously.

 

[bikeman]

Yes, its a Bosch part - "MERCEDES W123 FUEL METERING HEAD C 0438120116". I have managed to find a used & working part on ebay now and the mechanic will hopefully be able to fit it in the next couple of weeks. It would still be useful to know if anyone can repair these things just in case the ebay part doesn't work.

Those two parts (0438100071 0438120116) are detachable. I very much doubt somethings wrong with both of them.

As the car has been standing for a while, if it has been running prior, I'd bet my last £1 that the problem is simply fuel gumming up the fuel distributor's metering plunger (0438100071). The plunger is lifted as the venturi disc opens to deliver more fuel to the injectors. If the fuel is a bit gummy it can get stuck up and then too much fuel is delivered. Its pretty easy to check by disconnecting the injector lines and removing the metering head.

This and the cold start valve are the most obvious causes of over fuelling. If neither, then find a mechanic with a fuel pressure gauge. Without a gauge you'll just be chucking parts at it which is what most mechanics like to do these days. I fixed my car by buying a gauge and learning how kjet works. Its not that difficult and was probably the best thing I ever did, I think these cars will bankrupt owners who dont learn how to maintain them.