pistons 2-7 are not working

Hi Jetronic community,

I have checked the cabling from ECU to the injectors system components and to the main relay box. Everything is corresponding to the cabling details mentioned in the pinout diagram. I have two ECU boxes.
The ignition distributor and the amboss openings were check again as per instruction of Volker and Norbert and fine tuned.
Today we tried to run the engine but after a very unstable idle and some misifiring the engine stops. We have tried both ECU boxes and the result is the same.
Previously the injector valve cables were checked one by one with a 1,5 V lamp (due to lack of ossiloscope). only injector valve cables for pistons 2 and 7 did not glow ( very low illuminaton in the rest of the cables).
The engine mechanic claims that we have to obtain electricity on these two terminals to make the engine run.
I have also tried to get a signal with the use of a multimeter from the ignition distributor connections which was successful. after two or three turns the signal disappears for each connection. So I guess the amboss contacts are working.
Could the switchgear of transistorized ignition be part of the problem?
What do you recommend?

Best Regards and have a good week-end
Juan

Hi Juan,

ist is definitely not the transistorized ignition module. It is very unlikely that you have 2 broken ECUs. So that leaves us with trigger contacts, wiring from TC to ECU, wiring from ECU to injectors, injectors and wiring from injector to engine ground.

Can you find an oscilloscope? Then it would be best to monitor 14 and 6 both on ECU and on TC / injector to verify.

Hi Volker,

thanks again for your support. I have a 25 Mhz oscilloscope with only two ports. Will this be ok for measurements?

BR,
Juan

Hi Juan,

yes, connect 14 / 14 in comparison and 5/6 as well .

BTW: 6000/min = 100 /s, so we have a frequency range of up to 100 Hz. No need for MHz.

you mean 14/13 right?