thanks cmscott

that clip again - I keep hearing about the "clip" or a "leaf spring" - but I don't think I have one. My car is a 1979 280CE (123 coupe) with a downdraft (i.e. air flow is downards into the cone) Bosch K-Jetronic system (not KE).

I've just removed the air flow plate and had a good feel about with my fingers (very dirty inside my cone) but there is definitely no clip below the plate. I read in a service manual that I should knock a "guide pin" inwards to adjust the plate height - but the pin doesn't seem to be connected to the plate or its lever in any way - perhaps a "clip" is missing. I've attached a picture with a green arrow pointing to the top of what I think is the "guide pin".

Any suggestions are most welcome

Andrew

[IMG]local://upfiles/3134/2E4AA923729C4F3F8D29CFCBA719F030.jpg[/IMG]

 

both of you got different system, but the same principle. discuss more, share ideas, and you will eventually get on it.

 

scott

[IMG]local://upfiles/1/5622DFD739D14B249E52CB91DBB799C6.jpg[/IMG]

[IMG]local://upfiles/1/761A2A215D76419CB7E7A9FCA2403171.jpg[/IMG]

[IMG]local://upfiles/1/255D3BB7629048E3BC8316CFAC60FC4A.jpg[/IMG]

 

mrtest

[IMG]local://upfiles/1/37ADCAA8F4554E6C940400EBD0FC9189.jpg[/IMG]

[IMG]local://upfiles/1/79BBA860C9D346A9891FDBFF88D78659.jpg[/IMG]

[IMG]local://upfiles/1/6D2DC679013541AE8A54F1C38222DE9F.jpg[/IMG]

 

many thanks sleepwalker

however, the guide pin on my unit cannot possibly affect the neutral height of the plate. I suspect a previous owner or mechanic has damaged it and some small part ( a clip or leaf spring) is now missing.

Do you know from your experience how the guide pin's position sets the neutral plate height?

Andrew

 

i have never done knocking those pins before. the only thing i have done to throttle body is replace the gasket and cleaning. i always leave it to the original position.

 

OK thanks - I realise that this isn't a common problem.

I'll need to find a similar car and have a look inside its injection unit if I can. Not easy because rust has killed most 123s in Scotland.

Andrew

 

Well, there seem to be 2 test ports on my fuel distributor, one at the top and one near the bottom. For some reason now my car will only run for about 30 seconds, but i did manage to get a reading of 80psi (5.5 bar) from the top test port, and 70 psi (4.8 bar) from the bottom.

I'm guessing that the top port is upper control pressure and the bottom is lower control pressure. You had said earlier that there needs to be a difference of 1 bar between the two. Since I can't change the upper control pressure, I decided I needed to lower the lower control pressure, to get a difference of one bar. I unscrewed each lower control screw out 1 turn, and tested again. This time the reading from the bottom port was 75psi (5.1 bar.)!!! When I step on the accelerator the pressure drops about 2 psi also. What am I doing wrong? What should I be looking for, and what do each of these test ports actually test? By the way, I couldn't read your chart of pressures you posted, so maybe you could post them again.

 

not 1 bar. sorry for the error since i got no idea about your engine type till lately. i have mistaken it for a later version. but now i am asking at least the first 6 VIN number before giving info to omit such mistakes.

the difference should be 0.4 bar.

your car is running very rich.

your engine is 103.
system pressure: 5.3 - 5.5
lower chamber pressure: 0.4 bar lower than system pressure. (0.5 is also acceptable).

 

So, since my lower control pressure is approximately .3 bar too low, does this mean i need to screw in the screws to raise the pressure?

(Note- i did try screwing the screws in about 1 turn and nothing changed. am i doing something wrong?)