'88 325is M20 - died at idle, now cranks but no start

[randomsv650]

The engine management system has experienced a short or has a short in it now. But you still have another problem. Power to the coil comes from the ignition switch and that in turn is powered by the large battery cable. The blow fusible link has nothing to to do with the lack of power to the coil.

Right, not sure where the short occurrde but i replaced the in line 50 amp fuse so thats good for now. Just need to figure why im not getting 12v to the coil still.

[jlevie]

The engine management system has experienced a short or has a short in it now. But you still have another problem. Power to the coil comes from the ignition switch and that in turn is powered by the large battery cable. The blow fusible link has nothing to to do with the lack of power to the coil.

[randomsv650]

Ah! So a friend told me to check the inline fuse coming from the battery (in trunck). Apparently this controls both spark and fuel? Anyways, it's blown. Guessing this must be the culprit. Pic for reference if anyone else is in the same boat. Didnt solve my issue, though, so im guessing i did something to blow the fuse

Slit the wrap around the twi wires and the fuse is underneath. Then there's a little plastic cover over the fuse itself that you need to peel off, and this is what i found:

[randomsv650]

Does the coil positive still nat have system voltage on it? If so that is the first problem to solve.

OK, so with the new coil im getting the same readings.

When key is on, testing from the main lead on the coil to a ground on the car, it's showing approx 8v. When i crank the car over to start, it still drops to approx 4v.

Should i be looking at the ignition switch?

[randomsv650]

Does the coil positive still nat have system voltage on it? If so that is the first problem to solve.

Didnt even think to test that again, duh. I'll try that and report back. Thanks!

[jlevie]

Does the coil positive still nat have system voltage on it? If so that is the first problem to solve.

[randomsv650]

So i popped in (from a running car of a friends) another ECU and Crank sensor. Same result. Still no spark.

Ignition switch? Distributor/rotor? Main relay?

Anyone else have some tips?

[randomsv650]

i dont know much but i would check the icv

Goodluck!

ICV works, buzzes as im told it should. Also swapped with another know to be working used one, still same result

[m3/e30fanatic]

i dont know much but i would check the icv

Goodluck!

[randomsv650]

OK so i am back from vacation (car died a few days before we left, naturally) and am planning on tackling this issue tomorrow.

Things I need to check:
- CPS (already tested, suspicious of it)
- Distributor (and associating bits)
- ECU
- Main relay
- Ignition switch

New stuff:
- Plugs
- Plug wires
- Ignition coils

I have the clymer, need a bentley really, but and fairly certain i can test the other stuff Any other stuff to check or tips to check them?

[barry]

Great information
Thanks
Barry

[randomsv650]

just a useful link my father found, some good info. Will need to read through this a few times but it's a big help just understanding how the system works.

http://www.e30zone.net/e30zonewiki/index.php/Ignition

[randomsv650]

The ignition coil is powered by the ignition switch via C101. What you are seeing suggests a high resistance in that circuit. Start at coil and trace back to the switch to find the problem.

Note: You must measure the coil power lead from the coil to ground. Not to the coil negative lead.

Ok, good points to check, ill look into that. And yes when we checked the coil it was from the coil power lead to a ground on the car, not the neg part on the coil.

^ I've had that problem with a flaky contact in the ignition switch. My car would just randomly die while driving, then when I'd go to restart it I wouldn't hear all the regular noises I usually hear when I turn the key to the "ON" position. I'd sit there turning the key on and off until that contact would hit. Sometimes it'd take quite a few tries.

However seeing as though you just changed the CPS, I'd be suspicious of that as well.

In the ignition/key switch itself? I was suspicions of something like that but the fact that it died at a stand still has me wondering. It did start again once (after i pushed it) and died suddenly and hasn't started sense.

What about he readings from the CPS? From my understanding if they are out of spec at all they need to be replaced. Im thinking i need to just do the CPS and dist/rotor anyways. Although the CPS i put on when we did the rebuild

[Bullet Ride]

^ I've had that problem with a flaky contact in the ignition switch. My car would just randomly die while driving, then when I'd go to restart it I wouldn't hear all the regular noises I usually hear when I turn the key to the "ON" position. I'd sit there turning the key on and off until that contact would hit. Sometimes it'd take quite a few tries.

However seeing as though you just changed the CPS, I'd be suspicious of that as well.

[jlevie]

The ignition coil is powered by the ignition switch via C101. What you are seeing suggests a high resistance in that circuit. Start at coil and trace back to the switch to find the problem.

Note: You must measure the coil power lead from the coil to ground. Not to the coil negative lead.