1984 318i M10 No start, need help

[daiku]

Hello quick info towards the car and what i've done.

318i M10 engine, sat for around a year, poured new gas with stabilizer into it and swapped batteries, car ran for awhile and slowly died, attempted more jump starting and eventually had the car running for about an hour (thought success..)...

After the hour or so the car randomly died and now will not start back up, engine turns over but no start. Poured some more fresh gas into the tank hoping it might be the issue, nope..

So onto troubleshooting....

pulled gas line to fuel rail and placed into a cup, on start Pours gas into cup (assume fuel is ok).

Pulled spark plugs, all looked a little foul but should have been ok.
Tested for spark at the plugs, Appears to NOT have spark.
Tested Coil, has voltage, tested coil HT Lead to distributor cap with spark plug for spark, Nothing.

Tested Coil and Ignition control unit with a dvom, both 'appear' ok and inrange, battery was tested also and has a full charge.

Replacement items I've done.
New Spark plugs,
New Ignition Coil,
New distributor cap and rotor.

It appears as though I'm not getting a spark and I don't really know where to go from here...

M10's (according to other posts) Do NOT have a CPS to check. But I did find information stating if the Coolant Temp Sensor isn't functioning (the one that the DME reads) then the car will not start. I am not sure which is the sensor I need to replace as there are 3 on the thermostat housing, a yellow, brown and brown with 2spade plugs.

Any thoughts or suggestions would be greatly appreciated.
Thanks.

[TobyB]

The coil having power at + is good.

But what makes spark is the - terminal being switched to and from ground.

There IS an engine position sensor in the distributor, and it triggers the ignition
module (screwed to the firewall/cowl, I seem to remember).
That, in turn, fires the coil.

I'd check the distributor and the wiring from it, as it can deteriorate, and if the
plastic failed, the wires may have fatigued.

It's been a long time, but I don't recall the ignition being controlled by the ECU...

http://www.wedophones.com/BMWManualsLead.htm for wiring diagrams.

hth

t

[gone002]

mine did the same a while back

it turned out the throttle position sensor took a shit

[daiku]

There IS an engine position sensor in the distributor, and it triggers the ignition
module (screwed to the firewall/cowl, I seem to remember).
That, in turn, fires the coil.

I'd check the distributor and the wiring from it, as it can deteriorate, and if the
plastic failed, the wires may have fatigued.

It's been a long time, but I don't recall the ignition being controlled by the ECU...

I knew there was 'something' in the distributor that acted as the CPS for the m10, didn't realize exactly what it did.

I'll definitely recheck my distributor but it 'appeared' ok and spins when cranking.

I read somewhere (can't recall) that the ignition control unit 'controls' the coil in some way. I can confirm that without the ICU the coil has 0volts.

Thanks for the info and that wiring diagrams link.

it turned out the throttle position sensor took a shit

Hah, I'll have to take a look at the tps, haven't had much time on her the past few days.

Update

Took the ICU (Idle Control Unit) off the firewall, checked for voltage at the harness, 12v on 2+4. ICU had some resistance but seemed sketch. Ended up breaking it taking it apart more (thing came apart).

Ordered new spark plug wires and ICU. Installed those today and she still wont start.

New ICU seems to have different pins with resistance than the old one and appears to be not working at all.
Old ICU PN# 0 227 100 111 080
New ICU PN# 0 227 100 123 250
Both appear to be of parent ICU 'BM302'

Still have 12v to the ICU harness but 0v @coil with the new ICU with the ignition 'on/start', ICU has resistance to pins 2 and 5 | 2 and 6.
Old ICU I only checked 2 and 4 (12.x volts with ignition 'start' | 2 and 5 (nothing) | 3 and 6 (nothing) before it broke.

Thinking it's the ICU still, but now have the distributor and tps to check. My coolant temp sensor appears in spec for resistance though.

Thanks for the comments guys and I'll keep you all updated as well as I continue, probably wont have much time till the weekend though unfortunately. Hope for more feedback :D

Found this in another e30 forum that I plan on trying possibly tomorrow towards the distributor, Thoughts?

"Pull up and down on your distributor shaft. There should not be any play. If there is, then that is the cause of your difficulty timing the engine. As the distributor ages, the surface at the top of the shaft just under the centrifugal weights wears and the whole shaft and rotor can move up and down as the engine is running. This is bad because the gear is helical and as the shaft moves up and down, so changes your timing. There is no stable starting point. As it wears further, you will experience a bouncing tach needle and intermittent missing. This won't do anything but get worse. In order to fix this you either need a rebuilt distributor or disassemble the distributor and add some shims to the top of the shaft not the bottom. You want the shaft to be up flush with the original shims and washers that the factory installed just above the bottom gear. If the shaft drops down further, your rotor will begin missing the contacts for the spark plug wires in the distributor cap and you will experience very real drivability problems. I don't know if putting a few drops of oil on the felt under the rotor as a part of routine maintenance would have prevented this from happening, but I'll bet that most people never think of doing that.

This is a problem that is happening in a lot of 318i cars with distributors. Watch for the symptoms: difficulty timing engine, bouncing tach needle associate with a slight stumble or periodic sharp miss, high idle."

Out of the 'symptoms' listed above, the only one I noticed was a high idle, it really liked around 1k rpm.