96 850 turbo no spark, most of the time Topic is solved

greg850r · Post by **greg850r** » 08 Feb 2018, 13:03

I didn't figure the code meant anything, just mentioned it because it was there.

I do have a known good coil and IDM on the 96 850 turbo. I traded it with the one on the running car and the car still runs so I didn't switch them back.
I'm not getting a good pulse signal at the coil. With the IDM plugged in, both red and blue wire to coil light the LED solid red. I checked the running car and same result, -when running both light the LED solid red.
I'm not getting a good pulse signal at the plug to the IDM. The green led varies so slightly when cranking it's almost imperceptible on #3. On one, the green dims a bit when cranked and #2 the red dims a bit when cranked.

Post by **RickHaleParker** » 08 Feb 2018, 16:22

I'm not getting a good pulse signal at the plug to the IDM. The green led varies so slightly when cranking it's almost imperceptible on #3. On one, the green dims a bit when cranked and #2 the red dims a bit when cranked.

It looks like the problem is upstream of the IDM.

Next I would pull the ECM and probe for shorts between the pins on the IDM plug end. This should determine if shorts in the harness is the problem.

If that does not pan out, I would leave the IDM plug disconnected, reinstall the ECM, locate the signal pin on the ECM and see if the ECM is putting out a good signal. If it is, most likely there is high resistance between the ECM and IDM.

greg850r · Post by **greg850r** » 09 Feb 2018, 12:12

sounds like it's time to finally learn which pin goes to what on the ECM socket on an 850.

Post by **RickHaleParker** » 09 Feb 2018, 12:42

On Bosch Motronic 4.3 and 4.4, pin B11 is the IDM signal.
See attached file.

greg850r · Post by **greg850r** » 27 Feb 2018, 11:56

RickHaleParker wrote: ↑31 Jan 2018, 10:30 This should be easy to trouble shoot ... when in a no start condition.

Go to Harbor Freight or a parts store and get a Computer safe automotive logic probe, they look like the old trouble lights but they have two not one connector on the end of the cord. You connect both of the connectors to the battery and use the probe tip to trouble shoot.

Connect to battery and probe for Ignition pluses at the Blue ground wire on the Ignition coil as somebody cranks the engine. Move the probe to the Red +12V and make sure the Coil primary is getting power.

Right next to the Ignition Coil is the Di Power Stage Module.
Solid Blue and Red wires go to the Ignition coil.
Black is Ground.
Yellow/White is +12V.
Blue/Red is the Ignition pluses from the Engine Control Module.

Report finding and we will go from there.

Computer safe Automotive Logic Probe $9.99 at Harbor Freight

I finally got back to this one today and here is the report:

IGNITION OFF
GREEN=Black is Ground.
GREEN=Yellow/White is +12V.
GREEN=Blue/Red is the Ignition pluses from the Engine Control Module. [/list]

IGNITION ON
GREEN=Black is Ground.
GREEN=Yellow/White is +12V.
RED=Blue/Red is the Ignition pluses from the Engine Control Module. [/list]

greg850r · Post by **greg850r** » 27 Feb 2018, 12:10

By the way, blur/red is the middle wire

Post by **RickHaleParker** » 27 Feb 2018, 12:39

GREEN=Yellow/White is +12V.

Green connected, Red disconnected?

greg850r · Post by **greg850r** » 28 Feb 2018, 23:41

The yellow/white wire reads green on that tester ignition on or off.
Tester says; green=negative, red=positive

Those results were from unplugging the plug and sticking the probe into it so it was not attached to the coil assembly for the test.

I just copied and pasted the list, which may have been confusing when I look back on it.

IGNITION OFF
Black wire=GREEN
Yellow/White wire=GREEN
Blue/Red wire=GREEN

IGNITION ON
Black wire=GREEN
Yellow/White wire=GREEN
Blue/Red wire=RED

Also, I just got some parts delivered and among them was a new Bosch cam position sensor so I installed it but it didn't help.

Post by **RickHaleParker** » 01 Mar 2018, 02:02

IGNITION OFF
Black wire=GREEN
Yellow/White wire=GREEN
Blue/Red wire=GREEN

IGNITION ON
Black wire=GREEN
Yellow/White wire=GREEN
Blue/Red wire=RED

Exactly what is expected .... so far.

Ah shoot! ... I got the first list wrong, don't know why.

Black wire is ground.
Blue/Red goes to the fuse box. (+12.)
Yellow/White is the command line.

Does the Yellow/White pulse when you crank over the engine?

See attached file.

greg850r · Post by **greg850r** » 01 Mar 2018, 12:20

White being signal wire helps. I see no pulses on it, the green light stays lit. What it does do is vary ever so slightly in intensity due to starter load on battery while cranking. Nothing that could be construed as a signal though.

I don't know it it matters but the yellow tranny trouble arrow on the dash is flashing when the key is on and it wasn't before this problem.

96 850 turbo no spark, most of the time Topic is solved

Re: 96 850 turbo no spark, most of the time