325i doesn't give a decent spark on cyl. 6

[EndreM]

It has a spark, but not a good one.

We've changed the plugs, the plug leads, the distributor cap and the rotor, but it still wont work properly.

Any ideas?

[spiDmang]

low compression? how bout the ignition coil?

if you have an ohmmeter, check the resistance of the ignition coil. it should be .50 ohms. if you have higher resistance than .50 ohms, replace it.

(straight out of the bentley manual :p )

[EndreM]

Going to do a compression test tomorrow, and change the coil.
But if it was the coil, how would only one of the six cylinders be affected?
It doesn't make sense to me.

[spiDmang]

Going to do a compression test tomorrow, and change the coil.
But if it was the coil, how would only one of the six cylinders be affected?
It doesn't make sense to me.

true, just throwing it out there. id say compression test her, and see what happens. GL!

[EndreM]

Will do, thanks! :D

The thing is, that we took the sparkplugs out and widened the gap, and on the other five cylinders it was okay, but the spark couldn't jump the extra gap on number six.

Excuse my bad english..

[spiDmang]

weird...i would think it was the leads, or the cap and rotor. but since those were changed, i dont know!?

[E30_fiend]

I have seen multiple posts like this and they all lead back to one thing. ECU. They have a tendency to fail after 20+ years. This could definitely be your problem.


Taylor

[EndreM]

Thanks, I didn't know what to search for.

I'll see if I can find a similar ECU somewhere and try.
We actually thought about it, but figured that if the ECU was broken, none of the sparks would ignite properly.

[E30_fiend]

I would think the same thing in your situation. BUT, youve replaced basically every part of your ignition system. Only other thing I could think of other than the ecu is possibly the injector main connector. A bad injectors can cause a misfire just like a spark plug. But that still wouldn't explain the weak spark on #6.


Taylor

[jlevie]

When you changed the distribution, rotor, and ignition wires did you use new parts. And if so did you use Bosch wires? What did you set the plug gaps to?

This isn't likely to be a problem with the DME or coil. Either of those should affect all cylinders equally.

[EndreM]

I would think the same thing in your situation. BUT, youve replaced basically every part of your ignition system. Only other thing I could think of other than the ecu is possibly the injector main connector. A bad injectors can cause a misfire just like a spark plug. But that still wouldn't explain the weak spark on #6.


Taylor

Yeah. The car has a lot of water leaks aswell, but the ECU seemed dry.
We'll try another ECU and check.

When you changed the distribution, rotor, and ignition wires did you use new parts. And if so did you use Bosch wires? What did you set the plug gaps to?

This isn't likely to be a problem with the DME or coil. Either of those should affect all cylinders equally.

Brand new OEM parts. I must say, this isn't my car, it's my friend's. I don't know what the gap is, but it's the same on all six.

I'm actually running his old ignition parts minus the plugs on my car, and it's fine.

[jlevie]

Brand new OEM parts. I must say, this isn't my car, it's my friend's. I don't know what the gap is, but it's the same on all six.

I'm actually running his old ignition parts minus the plugs on my car, and it's fine.

Okay, then pull the plugs and make sure they are set for the correct gap.