Mystery Misfire

it is, but theres a vacuum line that feeds an electorin server [(???) I'm ashamed to say i work in an IT building] my brain isnt working currenly. Its like a boost gauge that shows digital psi, if that helps...

Well the needle swings smoothly then immediately stops at 20 like they'res something blocking it. I'm assuming if there were a vacuum leak it would come to a more smooth stop. Considering all this talk of OBCs sounds like wizardry to me I'm going to try removing the cluster and see the needle will physically move past the 20 mark.

Originally Posted by Microtesties

Well the needle swings smoothly then immediately stops at 20 like they'res something blocking it. I'm assuming if there were a vacuum leak it would come to a more smooth stop. Considering all this talk of OBCs sounds like wizardry to me I'm going to try removing the cluster and see the needle will physically move past the 20 mark.

As usual, please post the results

Unfortunately I've been pretty busy lately and I'm not sure when I'll have a chance to remove the cluster. Also back on topic, my new cap and rotor are to arrive here on the 17th according to FedEx. 6 more days feels like forever, but maybe I'll get lucky and it'll come early. I'll be sure to let you all know about the misfire and cluster situations when I'm able to work on them.

Alright everyone, update on the MPG gauge situation. I have removed the cluster and as I suspected when I move the needle with my finger I can feel there is much more resistance around the 20-15 area. When I push the needle past the 15 mark it's back to normal, but when I release it it swings smoothly and then will get stuck at the 15 mark. I don't know what to do about this one, ideas?

Ignore it


That is what I would do on a 23 year old car with 250k miles on it.

Originally Posted by snowsled7

Ignore it


That is what I would do on a 23 year old car with 250k miles on it.

Yeah, I'm gonna say I would need a new tach/ exconomy gauge to put in my cluster. So I've reassembled everything and maybe I'll buy a new one in the future.

Alright, I'm glad to say my new distributor cap and rotor FINALLY arrived in the mail today. I will install it as soon as I get a chance and the weather's right. After looking at Bentley I'm curious about the dust cover o-ring it mentions. I don't know if I have one on there currently and I can't find them for sale anyone, not even listen on realoem. So does this O-ring exist?

Originally Posted by Microtesties

Alright, I'm glad to say my new distributor cap and rotor FINALLY arrived in the mail today. I will install it as soon as I get a chance and the weather's right. After looking at Bentley I'm curious about the dust cover o-ring it mentions. I don't know if I have one on there currently and I can't find them for sale anyone, not even listen on realoem. So does this O-ring exist?

Looking forward to seeing if this fixes it for you.

Can you quote the page number and section in Bentley for the question about the o-ring?

Originally Posted by BMR_LVR

Looking forward to seeing if this fixes it for you.

Can you quote the page number and section in Bentley for the question about the o-ring?

Yes, you can see it on page 120-5 Ignition System - DME

Originally Posted by Microtesties

Yes, you can see it on page 120-5 Ignition System - DME

Very odd that it doesn't show up on realoem. Perhaps you will have to check with the dealer

Originally Posted by BMR_LVR

Very odd that it doesn't show up on realoem. Perhaps you will have to check with the dealer

Yeah looks like that's what I'm gonna have to do. If I get no luck with them and my current O-ring has to be replaced I figure I'll just RTV it. It will kinda suck next time I change the distributor, but can't really do anything else.

Originally Posted by Microtesties

Yeah looks like that's what I'm gonna have to do. If I get no luck with them and my current O-ring has to be replaced I figure I'll just RTV it. It will kinda suck next time I change the distributor, but can't really do anything else.

You might check with a auto parts supplier or some type of commercial supplier of o-raings to see if they would have it. Measure the diameter and then measure the thickness with a digital measuring caliper or micrometer if you can and then do a google search.

Hope that helps.

Originally Posted by BMR_LVR

You might check with a auto parts supplier or some type of commercial supplier of o-raings to see if they would have it. Measure the diameter and then measure the thickness with a digital measuring caliper or micrometer if you can and then do a google search.

Hope that helps.

Yeah I did put a little thought into going direct to an O-ring manufacturer, but considering how big it is it seems unlikely they would regularly supply them. To be completely honest I just want my car to be back functioning properly as soon as possible, and that would be more shipping, and possibly a special order. Of course if I don't feel like the RTV will be sufficient I would rather wait and do the job right than have to do it again, I'm just hoping I can get it done soon.

Alright everyone, I FINALLY got my new distributor installed. Got to use a nice heated shop instead of my cold driveway.

Anyway, my car is running amazing so far. I did only install it about 15 minutes ago... But still. Quicker starts, more power, and not even a hint of a misfire. Glad to have my baby running smooth again

Thank you everyone for your help, couldn't have done it without you guys!

Originally Posted by Microtesties

Alright everyone, I FINALLY got my new distributor installed. Got to use a nice heated shop instead of my cold driveway.

Anyway, my car is running amazing so far. I did only install it about 15 minutes ago... But still. Quicker starts, more power, and not even a hint of a misfire. Glad to have my baby running smooth again

Thank you everyone for your help, couldn't have done it without you guys!

Glad she's purring again I suspect that she will continue to run that way for a long time since you have given her some new ignition parts.

I havent owned an M20 E34, but my M20 E30s were similar, it doesn't go off the end even when thrashing it. I remember it because I too thought it was odd. Not sure what my 316i does, i have only ever floored it once or twice but only to avoid other stupid drivers. My V12 goes so far the needle disappears LOL