scarceller

Your info has me very confused? The ICV can NOT be vibrating if DME pins 18 & 35 have no power. But you stated earlier that the ICV was vibrating with key in 'RUN'. 18&35 MUST have power with key in 'RUN' those pins are powered directly from DME relay pin 87.

Edit: I see you updated that you do have power on 18&35. good.

scarceller

Your next step is to check for pulses on the ref and speed sensors.

Unplug the DME from the harness and put a LED test light across:
- Pins 25 & 26 (ref sensor)
- Pins 8 & 27 (speed sensor)

Crank the motor over and the LED will flicker.

EDIT: I just tested these pins with a basic simple 1.5vdc LED (no resistor needed) just put a basic simple LED across those pins at the DME connector and crank the motor the LED will flicker.

scarceller

One other thought, are you sure the coil '+' has 12v with key in 'RUN' and 'Start'?
Remove that wire from the coil's '+' and test for 12v with key in 'RUN' but also be sure you still have 12v with key in 'START' while cranking.

Is it possible that the after market alarm cuts the coil's power? This is why I suggest testing for power at the coil.

Also, do you see any indication that the DME harness has been altered near the DME? Like some other wires tapped into the harness? like wires that just don't look stock?

Turbo

Ok will check this within an hour....need to get some leds from my attic :-)

Turbo

Well my guess is also that my aftermarket alarm is the cause of all problems ...
I found 2 boxes Gemini 1160 and 1023 under the dash

All wires look stock...no strange things there


Thanks for your support already by the way

scarceller

The Ref sensor will flicker the LED once per crank rev (1 pulse per rev).
The Speed sensor should light the LED a bit more, since it generates 129 pulses per rev.

Turbo

Yes, my mistake.....
Bad contact to ground...did the measurement again because I also found out this could not be correct .

Second measurement with good ground contact proved the 12V

Turbo

Can this also be measured with cable still connected on pos 15 of the coil?
Why should this one be dis-connected. Just trying to understand...

scarceller

Sure, no need to remove the wire from the '+' post just go ahead and check for 12v in RUN and START.

But check the ref speed sensors for pulses with an LED, that's your next step for now.

Turbo

Did the test with the leds
Both give a pulsating light (low beam light).

Checked the 12 V on the coil.....with help of a friend which is a real electronic specialist

With the scope we don't get a block diagram...so we keep constant 12V after the coil

Now checking the FET inside the ECU DME. ....looks also ok

scarceller

Is the Ref LED a bit more faint than the Speed? it should be.
At least you know you have pulses. But if you have an o-scope now I suggest you scope them and let your buddy verify that the speed pulses look clean and well balanced above and below grnd. They should be about 2.5v saw tooth peak to peak. If they are less than 2.5v then the air gap between the sensor and the flywheel may be to large.

Would be really nice if you could have your DME put into another 84-89 car to be sure it's not the DME.
Then try another ignition coil if you have one or can borrow one.

Where are you located?

Turbo

Just did the scan with the scope on the connector (without the ECU DME unit connected)

Speed sensor gives 2.5V (1.342V Rms) at 335Hz

didn't check the reference sensor yet

scarceller

That wave form looks fine, check the ref sensor now

If both the ref and speed sensor show good wave forms I suspect the DME or the coil is the issue.
Any change you can try another coil? Even a basic MSD coil just for test purpose will work.

Turbo

Here is the plot of the ref sensor.

Not a nice wave form but this times spikes.
Graph is set +3/ -3 V peak/peak

So also a nice signal from ref sens

scarceller

Those look good. Can you now scope across the coil '+' and '-' with the DME plugged in.