Trigger Point Conumdrum

Hi Peter,

well it is clear that idle-run is worse if you remove throttle switch. ECU does not know your engine is idling. 1.8 mm are very little for cams.

How do you adjust A/F ratio?

Hi I had to take the throttle switch  off to fix it but I may not have adjusted it properly with a feeler guage or notches. I turned the big screw at the top/ front of the engine to adjust air flow (idle).

But that does not adjust A/F ratio...

Ok I think I may have it.
Whilst it was running its was missing a lot. At first I thought it was spark but after testing and replacing a spark plug I pulled the injector leads off to see if that made any difference. Low and behold (I probably should have done this earlier) I found that 4 injectors / 2 banks were not firing. I tested the ECU again for the injector resistance ( and all were 1.6 Ohms). I then tested the ECU with an LED test light and both the Yellow (pin4) and Grey (pin 5) did not flash. I measured the voltage at the Trigger Point connector (whilst the car was running) and 2 pins measured roughly 2.7 - 3 Volts whilst the other 2 pins were around .035 Volts ( Iput all the results in the attached table. I have also included a picture of the original connections which caused all this dismay in the first question. So it sounds like Volker and Norbert were correct all along and the cam actuators are too far gone.
However, to be sure can I swap the solid colours of Yellow and Green and also White and Red (at the T/P connector) to see if the ECU reading/led test gives a different result. This should tell me whether it is the ECU or the Trigger points shouldn't it????
Regards
Peter

Hi Peter,

I am not sure I can follow you. But: All 4 signals on T.C. should deliver same voltage levels on a Multimeter. And they are connected one to one to ECU. There are nos. written on the connector. If not check my appendix B where you will also find those colours.

Hi Peter,
I don't understand why you don't readjust the points using my tool. This will bring the unit up to the original values and all trouble is gone.

All this measuring doesn't bring you any further on. You have a defective unit and have to fix it.

I can send you a figure so you can produce the tool on a lathe or I send you a ready produced one.

For sending the figure I need your real email-adress you can tell me via PM.
Please contact me this way, too, if you prefer a ready produced tool. Shipment is no problem.

Regards
Norbert

And I am not sure from that picture: Is it the type T.C. with cable connected and isolation brokw completely off? Then I would even guess that soldering inside that connector is now broken. And it is a hi temp soldering as well. Do not solder on it and swap cables.

Hi Norbert,
I'm sorry - I did make and use your tool and I thought that it tested well on the bench (with an Ohm meter). Y/Red and Y/Blue measured 145 degrees 'on" Whilst Y/Blue and Y/Green measured 155 Degrees 'on' ( 'on' means zero resistance) Unfortunately, Pin 4 and pin 5 on the ECU are not 'firing' (In red highlight) nor are the 4 injectors on these circuits.
What I do find strange is that I would have thought that the #22 T/P Connector (pin 4 on ECU) would have had a low voltage reading as it was not working.
Conversely, I would have thought Pin 3 on ECU #13 T/P connector would not fire as it does have a low voltage.
Sorry for the annoyance but I do appreciate your help - and if nothing else I am learning a lot about this car.

Hi Peter,
I didn't remember you adjusted the trigger points with my tool.
By readjusting the unit you elaminated the wear of the cams - the points will operate as new ones. The 10 degrees difference between the points don't matter at all. This is not a direct injection system and the 10 degrees are within the system tolerance.

I don't remember you tried another <compatible> ECU?

You could interchange the trigger-leads between the operational and non operational-lines. When then still the same injectors don't fire, this would be an indicator for a broken ECU.

Else - as Volker wrote before - the leads at the points unit could be broken. I once had such a unit to repair. When the sealing misses - like it does at your unit - the leads break away quite easily, only a little bending from one side to the other and the leads break away, the wires still being hold in position by the sealing glue.

Did you check the trigger points signals in mounted position, signals at the ECU connector?

Regards
Norbert

Hi all,
Norbert - Your tool worked really well but I'm not sure that I have adjusted it correctly. I don't have another ECU to test this one but I did do some more tests and have included them below. The tests were taken from the ECU and the T/P connector). What was interesting was that when I disconnected the black wire (Y/Black) at the T/P connector near the distributor the car increased its RPM and I got an LED reading (at the Connector on all 4 of the other wires. Mind you the Y/Gr (pin 3) and Y/Red (Pin 1) flashed so fast they looked like the were always on. Depending on whether the black was connected or not determined which bank of 2 sets of injectors fired but at least they all worked. I'm wondering whether there might be a short on the actual T/Point board??
Red highlight means it is not working.
Regards
Peter

Hi Peter,
I have to admit I don't understand what you are testing.

Removing the black (central) wire means setting all trigger points out of function.

This is the ground wire of the unit - the trigger unit doesn't (or shouldn't) get any ground from the distributor directly.
This ground is being switched by the trigger, the ECU injects when one of the four lines report it has been grounded.
In addition, there is a flip-flop in the ECU that prevents the same line from firing until another line has fired and resetted the flip-flop.

When you remove this central ground wire the engine should stall - or the trigger points unit does have a ground connection it shouldn't have. Maybe via the spring of the heavy worn oil-felt touching the camshaft? Maybe this would produce an intermittend signal, too.

Looking at your trigger unit - I don't believe the unit is adjusted properly.
Inserting the tool, you should have a distance between tool and points-cams of about 1 mm.
This distance should be 0.5 mm!

Maybe the points stay closed all of the time and the ECU is getting triggered by the ground signal it gets via the closed points from the felt-spring touching the camshaft.

Could you please post a picture of the unit with the tool inserted?


Regards
Norbert

Hi Norbert,
I wish you were here - I am really getting confused. Today when I started the car and tried to remove the black wire it did stall. The only pins that were 'firing/flashing' were the 2 with the yellow arrows , not like yesterday where they alternated depending whether the black wire was connected or not. And it doesn't matter which wires you put into those female sockets (from ECU NOT Distributor) eg; swap the green and the yellow only those 2 female sockets (with arrows) flashed with a test light. I also tested the wires with an Ohm meter and they did alternate between L and 0 ohms.

The tool I used looks exactly like the one in your picture and the specs I used are the same as yours. I am just a little reluctant to take the distributor out as I have finally set the timing and it took me ages to get it right last time. However, I think I am going to have to . Hopefully you'll have some ideas as to why it is acting this way otherwise I propose we start from the beginning and you give me one thing at a time to diagnose.
Regards
Peter

Hi Peter,

I repeat: You have the cable version of trigger contacts and it looks like all isolation/fixing on T:C of that cable is gone. Then the cable can break off there and you will have missing contacts. It will not help you to swap cables. And it seems that you do not have orignal cables anyhow as colors are not original.

My recommendation: Buy a working T.C: and do not play further with this.

Hi Peter,
I made a figure of the correct wire-connections.

You have to open the points and /or isolate them to get the correct readings for the continuity.

- All wires of the unit I own have a yellow-based isolation, in the figure I only used the applied stripes.

Maybe you own an older version of the cable without the yellow base-isolation.



Regards
Norbert

Hi Peter,
maybe I now found out the reason for your probs:

The wires at your unit seem to be not in correct order.
Looks like two wires are reversed.

The ECU fires, when the leads are being grounded.

The next firing is done only if a flip-flop has been resetted in the meantime before the points close the next time.
This flip-flop is being resetted by a corresponding other trigger-signal.

Maybe the reversation of the wires prevents the flip-flop from getting resetted.

I'm not the ECU-specialist as Volker is. Maybe I'm right...

Regards
Norbert

Norbert,

you are an expert! ECU expects a specific sequence. Otherwise it assumes stupid double contact closing and ignores it.

Ok the wires coming into the connector from ECU are Yellow with trace but the others are solid non matching.
Do the T/P wires and Injector wires match at the ECU ? That is does pin 21 Y/Red TP input go with pin 3 Green Injector output? Which wires do you think are reversed?

Hi Peter,
maybe I got confused by the color-marks you made.
Maybe this is all fine <except the colors of the wires don't match with the original ones you find at the ECU,too>.

But what about this screw? Does it ground the line 22? Looks like it is loose...

Regards
Norbert

Hallelujah,
After a seeming eternity I found the fault. Nothing wrong with the ECU or TPS or the TP. Two wires at the base of the joining connector (ECU and T/P) had frayed to the point that they were just holding on. I re-soldered and away it went. Well 7 of the 8. In the process I found that Injector 1, whilst receiving a pulse and having the correct resistance must be stuck - I will work on that next. But a big thank you to the both of you. It goes to show how such a small thing can cause such a headache.
Signing off ( for a little while at least )
Peter
Thank you

Hi Peter,
congratulations to you and thank you very much for the feedback.

Harness problems are THE problems of the D-Jetronic that occur more often than all others and they can drive you crazy.

Great you found this reason for your probs - but maybe it was not the only one. Maybe the trigger unit was worn - and the connector was damaged by all the fiddling around with this cable.

Hope you get rid of the remaining injector problem soon and can enjoy the car...

Regards
Norbert