914 1.7 d jet , early type without idle mixture adjuster on ecu.

Hello there D jet enhousiasts,

I have a early 914 107 in original condition.
At idling the mixture is to lean... aprox 0.12%
checked for air leaks, none found , although rubber parts have become hard...
drives good, Warm starts after a 5 minute stop are terrible...
how can i adjust the mixture on idling,
measurements on a four gas tester gives , no Co , only 150Hc , and about 12% CO2 with 2.3% O2 leftover...

best regards

Hi Unknown,

I would check injectors first and then switch to ECU / MPS combination that supports idle-run rheostat and thermo time switch.

Hi unknown,
did you check the fuel pressure?

Are all parts the original ones, especially the injectors?

Regards
Norbert

i realise i havent given many details, so here i go.
i have checked the throttle position sensor , it works fine. fuel pressure is a steady 2.1 bar... , axilary valve is in good working condition and closes completely after warmup.
i have co measurements with a cold engine from about 6.5%, but it does dissapear completely when the enige is warm. air temp sensor is aprox 285 ohms at 20 °C.
will check cilinder head temp sender today
will perform a smoke test to check again for air leaks .
the car has only 60.000 km from new, and everyhing is as original as can be, would you suggest i clean the injectors ultrasonic anyway as the Hydro carbons are only 150ppm? Injectors are yellow as they should be.
I have theasnu injectortester / cleaner and can perform cleaning and testing myself , but some injectors ( especialy worn ones ) do get stuck later on , when you are lucky they will get stuck in the closed position... but open can also happen, so i'm a bit in the twilight zone here regarding cleaning injectors with only 60k km....
thanks for thinking along
best regards Pascal.

about me? well i m a car enthousiast with a big interest in old cars, seven years ago i traded my job for the classic car passion and started my own shop. I have worked on D jet injected cars before, mostly Mercedes, and Volvo , have done another 914, but that one did have a mixture adjusting srew on the ecu... R107's is the car i see most of all. mostly k jet...

Hi Pascal,
I think it makes sense to clean the injectors. They get clogged not only by runtime, but by lifetime. too.
A car with such a low mileage must have been sitting for manyy years over all.
The alternative will be to make a spray - and flow-test only and not a cleaning.

You have to be careful with the injectors. Yellow ones could be those for L-Jetronic with much lower flow rate or chinese ones that wear the Bosch parts-# but not the Bosch logo.

All D-Jetronic-injectors have a parts-# below 0 280 150 050

Regards
Norbert

injector nrs are 0 280 150 009
ecu nr is 0 280 000 013 and Map 0 280 100 019 and following this website they match...
cleaning is in progress, i will test them tomorow if flow rate is ok , for now spray patern of 2 injectors is a bit off.
if injectors are ok, and co is still to low, what are my options then? since it is not adjustible at the ecu?
regards pascal