Yay! Another no spark issue (did reasearch, stumped)

[E34Rocky]

Hey everyone new to the forum but not the car world. I’m currently at a complete loss with my E34. Some background to start is it’s a 89 535i, auto. Been driving the car about a year now with no issues. Went through a drive through for breakfast the other morning, was asked to pull up and wait for my food. So I did and shut the car off. Quite literally one minute later I was handed my food and the car would not start. So had it towed home nd started my journey. I’ve been all over the forums and google for days trying to figure this out and I’m just stumped. Car has fuel, and injectors are working. I have great spark from the coil wire to dizzy. NO spark at plugs. I checked cap and rotor looked very crusty and burnt so replaced, still nothing. Did some research thought it could be a crank position sensor. Ohm test came back at 466 just outside of the acceptable tolerance. So I replaced it. Still nothing. New sensor ohms out at 545. Tested the main relay for the dme by jumping it and everything seems to make all the correct clicks as if everything is powering up. I’m just lost at the fact that I have terrific spark from the coil wire to dizzy then all is lost. Any help is greatly appreciated

[moroza]

Hello and welcome!

Spark to the distributor but none of the plugs (how many did you check?) means a physical problem in the distributor or the main coil wire. Remove the cap and see if the rotor turns with the engine. Check for damage to the main coil wire - perhaps it conducts when flexed to hold a sparkplug, but not in its normal position. Try replacing it with one of the plug wires for testing. If it fires up on five cylinders, it's a bad main wire.

[E34Rocky]

The rotor does spin. I’ll have to try that plug wire trick. I’m starting to think timing issue? I would think even with that though I would still have spark just at the wrong time. Has anyone ever had these motors jump timing? Would think it would be hard in a timing chain motor

[moroza]

It's uncommon but possible, though I'd expect some noise from a failed guide or tensioner. I don't know how likely this is, but I can imagine timing jumping just enough that the ignition coil sparks when the rotor is right between two cap terminals, such that neither terminal gets the spark.

[E34Rocky]

It seems far fetched to me but at this point I’m lost by such a simple design

[demetk]

It's pretty easy to check timing on an m30.

[E34Rocky]

Do you have a link?

[demetk]

There may be youtube vid but I haven't checked. The online TIS manual is a good start. http://www.bmwtechinfo.com/repair/main/. Bentley manual should also have the procedure.

Basically what I do is this. Align the O|T mark on the harmonic damper (36mm socket fits the crank sprocket, turn clockwise). Pull off the valve cover, which you will want to do anyway to check the chain and guides.

Both valves on cylinder 1 should be pointing down,



and this should line up,

[E34Rocky]

Timing looks spot on. Changed coil for the hell of it and the car still doesn’t run. Somehow I’m just losing spark in the distributor. I’m wondering if the main wire of the coil to dizzy is cause the spark to weaken enough to not travel through the distributor. Does anyone know what the ohms of that wire are supposed to be? I’ve tried looking it up and I can find the plug wires themself are supposed to be around 6000 but I can find anything on the coil to the distributor wire.

[whiskychaser]

I noticed you changed the rotor arm but did you change the distributor cap too? If not, is the carbon brush in the centre still there and free to move? Also, how are you confirming if spark is arriving at the distributor and plugs?

[E34Rocky]

At this point I have replaced cap, rotor,(twice Incase I someone got fault ones) coil, and crank sensor. Sensor ohm test showed it was bad, didn’t fix it, cap and rotor were very crusty and burnt, replaced no changed. The only thing I’ve actually just thrown at it as a guess was the coil. I’ve checked timing it seems to be right on. I know I have fuel. It is a spark problem for sure. I have spark from the coil to the distributor and I can’t get anything after that.

[moroza]

Have you tried my suggestion of another main wire?

[demetk]

At this point I have replaced cap, rotor,(twice Incase I someone got fault ones) coil, and crank sensor. Sensor ohm test showed it was bad, didn’t fix it, cap and rotor were very crusty and burnt, replaced no changed. The only thing I’ve actually just thrown at it as a guess was the coil. I’ve checked timing it seems to be right on. I know I have fuel. It is a spark problem for sure. I have spark from the coil to the distributor and I can’t get anything after that.

Suggest you ohm out the terminals on the distributor, including the center pin. As was said, maybe the center pin is not conducting.

[E34Rocky]

Have no tried another coil wire yet because I have no access to one. Order one but couldn’t get it until tomorrow morning. Ohm test on both coils comes back within spec. I tried to make a plug wire work to see if I could at least get it to run but I couldn’t make it fit on the coil for a good connection.

[moroza]

Coil resistance is important, but what Demet meant was to check for continuity between all seven internal posts in the dizzy cap, and whatever they connect to.

[whiskychaser]

This is where a strobe would come in really handy. Mine sits next to the dwell meter in my tool box

[ross1]

This is where a strobe would come in really handy. Mine sits next to the dwell meter in my tool box