anyone have much experience with motronic ingition

[pureboiracer 0]

Hey guys, need a little guidence, i have just done a hefty amout of wiring mods on my motronic loom, i now have no spark, have battery voltage and the pos side of coil, and the black wire on the coil is ok back to the pcm, are there any other sensors or anything that the pcm looks at before it allows spark?

Car is a e30 325i with motronic 1.3

Cheers oli

[jochen 4]

Hey guys, need a little guidence, i have just done a hefty amout of wiring mods on my motronic loom, i now have no spark, have battery voltage and the pos side of coil, and the black wire on the coil is ok back to the pcm, are there any other sensors or anything that the pcm looks at before it allows spark?

Car is a e30 325i with motronic 1.3

Cheers oli

Look at the E30 wiring diagram, that'll tell you everything

Of course, you need the right diagram for your car:

eg a 1991 E30 325i convertible shows:

Speed signal input

A/C On input

Closed throttle input

Wide open throttle input

Coolant temperature input

Oxygen sensor heater control

Whereas a 1987 E30 325i shows

Fuel pump relay control

Oxygen sensor heater control

Barometric pressure unit

Start input

Reference point input

Air flow meter connections

Coolant temperature input

Engine Speed input

Oxygen sensor input

PS: I do not understand why you rewired a working system. Perhaps I have missed something...??

(In my industry we have a saying "Never touch a running system")

Anyway, if you're working without a wiring diagram, you're working blind.

Get the right wiring diagram for your car and all becomes crystal clear.

[Guest FrantiC]

Crank position sensor on the front of the engine.

Either it's plugged in wrong (there are 2 identical plugs that come out of the loom it can plug into, 1 is for #6 inductive pickup, 1 for crank sensor), try swap them around.

Or the sensor is bad..

That is pretty much the only sensor that stops the ignition, as there is no timing reference given to the ECU...

[pureboiracer 0]

i changed it because i cant leave anything alone, lol yeah i tried the crank pully to no avail, fixed it today though, the black wire on the coil is a sheilded wire, ie it has a wire core, then insulated and another wire around it and insulated agian,

turns out you wont get spark it the 2 bits of wire touch,

Thanks for you help guys,

[mr E34 11]

If you need it i have the Motronic 1.3 schematics (down to component level) + the explanation on how it all works.

Be careful shorting those coil driver wires, you can damage the output stage in the ECU.Still reckon it's a mistake incorporating the power driver stages in the ECU, Bosch/Siemens should have external drivers which can be replaced easily.