Bosch K-Jetronic Specialist in the Aberdeen Region

[bob1179]

Hi all,

I was wondering if there are any Bosch K/KE-Jetronic gurus up in this part of the world?

The Panzer has a a fuel injection fault and due to a combination of work and generally not wanting to fiddle with the black art that is 80's mechanical fuel injection I was hoping there is somebody that can help me diagnose the fault correctly.

Any advice would be welcome.

Cheers in advance.

[rossub]

Taylors on the Lang Stracht would be my first port of call?

[Lastinclass]

What's the fault? I'm old enough to remember how to repair K jet and KE but don't have a pressure gauge set anymore.

[bob1179]

rossub said:

Taylors on the Lang Stracht would be my first port of call?

Cheers for the advice Ross.

[bob1179]

Lastinclass said:

What's the fault? I'm old enough to remember how to repair K jet and KE but don't have a pressure gauge set anymore.

It seems to be one of those faults that may have a few different causes.

The car starts fine when it is cold and as it warms up the idle becomes erratic then it will die. After this point it is either very difficult to start or won't start at all.

Unfortunately I don't have a pressure gauge set either and due to work at the moment I don't really have much time to star pulling things about myself.

Any ideas would be gratefully received!

[paulqv]

The most common fault with symptoms like that is the pressure plate in the main housing. They wear out and then the pressure can be erratic over the plate causing symptoms like you describe.
Only solution is to put in a new or recon unit as far as I recall. It hides under what is usually a ribbed plastic cover and looks like a plunger /piston with a flat metal plate at the bottom when you uncover it.
The problems are usually erratic. The cold start sensor can also give weird symptoms, but usually disappear when the car is hot.
Difficult to be certain until you see the car but these are the two most common faults as far as I recall
It is a simple system.
Paul

[jith]

bob1179 said:

Lastinclass said:

What's the fault? I'm old enough to remember how to repair K jet and KE but don't have a pressure gauge set anymore.

It seems to be one of those faults that may have a few different causes.

The car starts fine when it is cold and as it warms up the idle becomes erratic then it will die. After this point it is either very difficult to start or won't start at all.

Unfortunately I don't have a pressure gauge set either and due to work at the moment I don't really have much time to star pulling things about myself.

Any ideas would be gratefully received!

Can I take it the car is the S class in your profile pic? Post up a pic of the engine bay with the air filter housing removed and I'll talk you through a check procedure. I need to know if it has a cat or not. From what you are saying it could be drawing air somewhere, but the same symptoms could be down to a temperature time switch.

J

[bob1179]

paulqv said:

The most common fault with symptoms like that is the pressure plate in the main housing. They wear out and then the pressure can be erratic over the plate causing symptoms like you describe.
Only solution is to put in a new or recon unit as far as I recall. It hides under what is usually a ribbed plastic cover and looks like a plunger /piston with a flat metal plate at the bottom when you uncover it.
The problems are usually erratic. The cold start sensor can also give weird symptoms, but usually disappear when the car is hot.
Difficult to be certain until you see the car but these are the two most common faults as far as I recall
It is a simple system.
Paul

Hi Paul,

Thanks for the advice. I have found a bloke who knows is way around older Mercs up past Kintore, we are trailering the car up to him today. I've explained the symptoms and his response was similar to yours. I shall update when I get a bit more information!

[bob1179]

jith said:

Can I take it the car is the S class in your profile pic? Post up a pic of the engine bay with the air filter housing removed and I'll talk you through a check procedure. I need to know if it has a cat or not. From what you are saying it could be drawing air somewhere, but the same symptoms could be down to a temperature time switch.

J

Hi Jith,

Thanks for the offer, it is the car in my profile. A real old bus but I love it!

My biggest problem at the moment really is a lack of time to do my own spannering. I've found an ex-Mercedes guy who runs a garage on the other side of town and he is supposed to be very good. My car actually has a full Merc main dealer history, but I know that this sort of problem will probably just leave the techs scratching their heads due to the age of the system and car. Plus even though I get a 25% discount on parts and servicing, it will still be really expensive!

[jith]

bob1179 said:

jith said:

Can I take it the car is the S class in your profile pic? Post up a pic of the engine bay with the air filter housing removed and I'll talk you through a check procedure. I need to know if it has a cat or not. From what you are saying it could be drawing air somewhere, but the same symptoms could be down to a temperature time switch.

J

Hi Jith,

Thanks for the offer, it is the car in my profile. A real old bus but I love it!

My biggest problem at the moment really is a lack of time to do my own spannering. I've found an ex-Mercedes guy who runs a garage on the other side of town and he is supposed to be very good. My car actually has a full Merc main dealer history, but I know that this sort of problem will probably just leave the techs scratching their heads due to the age of the system and car. Plus even though I get a 25% discount on parts and servicing, it will still be really expensive!

OK Bob, good luck with that. The problem with K Jet is that you really have to know how the system works or you're just guessing. It's one of the best fuel systems ever designed and is so reliable. My 500SEC still has all the original components and it runs perfectly at 140K. The trick is to keep on top of it, keep the fuel and the filters clean.

J

[bob1179]

jith said:

bob1179 said:

jith said:

Can I take it the car is the S class in your profile pic? Post up a pic of the engine bay with the air filter housing removed and I'll talk you through a check procedure. I need to know if it has a cat or not. From what you are saying it could be drawing air somewhere, but the same symptoms could be down to a temperature time switch.

J

Hi Jith,

Thanks for the offer, it is the car in my profile. A real old bus but I love it!

My biggest problem at the moment really is a lack of time to do my own spannering. I've found an ex-Mercedes guy who runs a garage on the other side of town and he is supposed to be very good. My car actually has a full Merc main dealer history, but I know that this sort of problem will probably just leave the techs scratching their heads due to the age of the system and car. Plus even though I get a 25% discount on parts and servicing, it will still be really expensive!

OK Bob, good luck with that. The problem with K Jet is that you really have to know how the system works or you're just guessing. It's one of the best fuel systems ever designed and is so reliable. My 500SEC still has all the original components and it runs perfectly at 140K. The trick is to keep on top of it, keep the fuel and the filters clean.

J

This is one of the reasons I don't like playing the fueling, however I have to agree that once set up properly it is absolutely wonderful. I've never had any issues before so hopefully it won't be anything too complex.

The old girl wouldn't even start when we tried to get it onto the trailer so now I'm completely stumped. I'll update when I get some news from the garage.

[Cosie23]

I am interested to hear how the car got on at the garage.I have a 2.3 Cosworth 190E it changed from running normally to only running for 5 seconds. I have had the electrics checked and fuel pump, any ideas,it does not run at all now.

[Pentoman]

How long does it run for? 5 seconds or longer?
This is going back a bit but:
When you start one of these, the fuel pump runs, on a circuit inspired by the starting condition.
However once running, the fuel pump is kept running by the fact that there is a crank sensor signal.
If you have a crank signal problem, it will start at first and then die because there is not crank signal and therefore the fuel pump is not kept running.
This can be easily proven by jumping the fuel pump terminals to rule out the conditions above.
Good luck.

Also on these, make sure there is enough slack in the throttle that the switches on the throttle linkage engage when you let off the throttle. They don't idle at all if these switches do not engage.

Sorry just some random input, not sure what I'm doing here in the Scotland forum...