Jetronics experts

[OxfordSteve]

I have a W126 420 SEC with jetronic fuel system. Can anyone recommend a specialist able to diagnose and fix problems with this system. I live in north Herefordshire but wiling to travel for someone who thoroughly understands Jetronics.
Thanks
Steve

 

[alabbasi]

Any Mercedes specialist that's familiar with 80's models will be able to help diagnose issues. I'm not in the UK but I expect the SL shop will have a good handle on it.

Mercedes, Ford, VW and Rolls Royce all has CIS so you can interview others.

 

[190]

Might want to be more specific about which version of Jetronic as there are several. I assume it's either K Jetronic which is the purely mechanical system or KE Jetronic which is the same with some electronic assistance.

 

[alabbasi]

If it's a 420, it will be KE

 

[ALFAitalia]

Mk 2 Golf GTI experts will be able to help. I was pretty handy with it as I owned a couple as well as working at the dealership.....but I think most of that info has been wiped by alcohol over the years!! It pretty simple compared to modern injection systems...or even the later KE Jetronic.

 

[alabbasi]

9/10 times at this age (or even 15 years ago), it will be the fuel distributor or the injectors that are gummed up from sitting fuel. The little gasket between the two halves can fail which is also a problem.
Symptom:

1. Running rich
2. Miss at idle
3. Stuttering under load

That's if it's running. Sometimes, it's vacuum. Those engines have vacuum lines all over them and unmetered air causes chaos.

 

[OxfordSteve]

As Alabbasi says it should be Jetronic KE 3.1, and as he says I was assuming that any Jetronic specialist would be able to help me. So I am still looking for a specialist that is not too far away. I did contact the SL shop but their quote, even for just the diagnostics, was scary!!.
Any suggestions ?
Steve

 

[alabbasi]

From reviewing the posts, I think you’ll find that the majority of members on this forum own newer (2000s or later) models. There are still a few who have older CIS-injected cars (or even D-Jetronic and mechanical fuel injection), but we tend to do our own work. If you’re looking to have the work done by someone else, I’d suggest checking how long they’ve been in business. If they’ve been around since the 80s or 90s, there’s a good chance they’re familiar with CIS systems.

Feel free to share your symptoms if you’re planning to tackle it yourself, we’ll do our best to help you out.

 

[Spyros777]

I have contacted these guys (Home Page) for my w201

 

[190]

I had KE Jetronic on my 190E which I ran for 21 years. The biggest problem I came up against on a DIY basis was that there isn't just one fixed version of the KE system at a detail level and that's before you start talking about the later ones with a cat and closed loop control. The generic book descriptions of KE didn't match my car as far as the cold start functions were concerned and a so called specialist wasn't able to fix a problem of excessive richness. There was nothing wrong with the temperature sensor so what I did in the end was experiment with resistors in parallel with the temperature sensor to fool the CPU into thinking the engine was warmer than it was. A fudge, but it ran perfectly after that.

While it's understandable that the KE system had some detail development changes over the years it may mean needing someone with very specific knowledge of a particular car to solve some problems.