KE Jetronic Expert London Area

Page may contain affiliate links. Please see terms for details.

nullogik

Active Member
Joined
Apr 29, 2008
Messages
456
Car
1993 190LE, 1994 190LE, 1998 S420
Hi,

Can anybody recommend a KE Jetronic expert in the London area who can look at my 190E? Doesn't necessarily have to be a Mercedes specialist since VWs, Volvos, Saabs etc. of the era used the same system.

Quite a few "Mercedes specialists" I have encountered are ok with routine work but it when it comes to diagnosis if it doesn't involve plugging in Star they don't know where to start.

I need someone who knows this system inside out. Where proper diagnosis involves testing individual components of the system to reach a conclusion that "x" part is faulty.
 
Last edited:
The duty cycle is all weird and it idles roughly such that the car vibrates excessively.

Before I took it to a Mercedes specialist
The duty cycle voltage reading used to cascade from approx 6.5v down to 2.5v whilst the engine was warm. The engine would momentarily hiccup and the duty cycle would pop back up to 6.5v before falling down to 2.5v and repeating the cycle. I know this is wrong because from the research I have and the other 190E I have own it should fluctuate between 5.5V-6V.

It drives fine, fuel consumption is on par though it is a bit sluggish. Borderline emission failure/pass

However, it idles badly. When it has warmed up to operating temp the whole car vibrates badly at idle in both D and P and there is slight miss. When accelerating it is fine. When the car is cold it is ok. Always starts first time, hot or cold.

I took it to a Mercedes specialist who did some "testing" and said that is might be the air flow potentiometer though they couldn't guarantee it was (more about this later). At £200 for a genuine one I need more than a "I think" guess before I open my wallet.

After I took it to a Mercedes specialist
Whatever the specialist did it seems to have more oomph. It still idles badly and vibrates when warm.

However, the duty cycle is now stuck. Previously it used to cascade now it is stuck rigidly on 6.5V and sometimes sticks at 2.5V?! When I mean stuck I mean it - it does not fluctuate at all. This is very wrong. I have tried adjusting the mixture using the allen key and it doesn't make any difference to the voltage reading - where previously it did before the garage did their "diagnosis" on it.

What I have done

I have replaced the following with quality parts:
- All new Bosch injectors
- Correct resistor-less Bosch spark plugs (tried different brands too)
- New Bosch ignition leads, Beru cap and rotor
- New fuel pump relay
- New MB OVP relay
- New rear MB exhaust box
- Sprayed carb cleaner into the throttle body
- New engine and gearbox mounts

I have also researched various components. I tested the air mass potentionmeter myself using data from the internet and it is exactly within spec - if the garage had done this they would have found this out too and not incorrectly told me the part was faulty. I have tested the idle actuator motor (cylindrical thingy) and the voltage readings are within spec. Also tested the lambda sensor voltage and it is within spec too. I've looked carefully, listened and sprayed liberally the engine area to identify vacuum leaks and can't find any. I'm stuck.

I now need someone who is an expert on KE Jetronic to diagnose the issue. I am happy to pay for diagnosis but don't want to get ripped off by someone parking in it a corner and then telling me that they **think** it is X when they clearly haven't tested it.
 
Have you checked the idle switch in the throttle body...NOT the idle over run switch which you can see on the throttle linkage?

PM me your phone number and I will have a chat to see if I can give you some more ideas.
 
Hi SL300-24,

Thank you for generous offer I will PM you in a minute.

I didn't know there was an idle switch in the throttle body. Do you have a diagram or picture of it? Is it accessible with the throttle body in place or do you have to dismantle it? Can it be probed to check the voltage?

I have checked the voltage reaction of the other idle run-over switch - the one by the end of the throttle cable. It too is behaving within spec.
 
I have tested the idle actuator motor (cylindrical thingy) and the voltage readings are within spec.

Just thought of something else. I unplugged the electrical lead to this whilst the car was warm idling and it didn't make any difference. I thought it would stall?
 
Possibly the alternator voltage regulator? [YOUTUBE]4sLoOpBaySU[/YOUTUBE]
When you were checking the Duty cycle voltage did you check the alternator output was stable also? when you do this test the assumption is always that the supply voltage is stable.:dk:
Other possibility with older cars is a partially collapsed catalytic converter
 
Possibly the alternator voltage regulator?
When you were checking the Duty cycle voltage did you check the alternator output was stable also? when you do this test the assumption is always that the supply voltage is stable.:dk:
Other possibility with older cars is a partially collapsed catalytic converter

1) That's a good point I haven't checked that. I'll add that to my list

2) Catalytic converter - it had crossed my mind. I'm hoping it isn't (£££) but as my issue seems to be temperature related I had thought a clogged/disintegrated cat might be the issue. It is a 1993 car so I presume I can't de-cat it as that would be an MOT failure?
 
Solved - Conclusion

Thanks to all who offered suggestions and help along the way.

I tested almost all the likely KE components to the best of my basic multimeter use ability. All checked out within specified parameters.

Finally gave up and took it to a Mercedes specialist who confirmed after testing that the EHA was at fault. He replaced the EHA, tuned the duty cycle and it now has a lot more go and the idle vibration has been eliminated. Duty cycle is now fluctuating correctly around ~50% mark.

Just posting the conclusion for this should anyone else ever search and stumble upon this thread.
 
Why not tell us which specialist it was, he obviously deserves some public recognition.
 
Steve certainly is old school. In fact a 124 is probably a bit young for him!
EHA failure is relatively common however and should have been picked up by any half decent indy. You will notice a significant improvement in performance I'm sure.
 
Looks like sadly Steve Redfearn in Wimbledon went into liquidation in 2022 as per filing here

Does anyone have any more recommendations for a West London or nearby 190e KJet expert as I'm having issues with my KJet system too?

Many thanks
 
Looks like sadly Steve Redfearn in Wimbledon went into liquidation in 2022 as per filing here

Does anyone have any more recommendations for a West London or nearby 190e KJet expert as I'm having issues with my KJet system too?

Many thanks
The company did not fail. It was wound up and the director/owner provided a declaration of solvency. The last set of accounts showed it has £0.5m CASH in the bank.
 

Users who are viewing this thread

Back
Top Bottom