Car running rough, ground strap question

[94325is]

I bought this 1994 325is in late July. It has run fine since I bought it, except for 3 episodes where it suddenly began to run rough. It would last usually 5 minutes or less and then went away and all was fine. Two weeks ago it happened again, and this time it is not going away... it seems as if it's only running on 5 cylinders... I have not driven it much since, although I did run a bottle of injector cleaner through it thinking that may be the problem. I finally had the chance to pull things apart today and I notice that there is only one ground strap on the coils. The on all the way back on the number 6 coil is there, but from what I am reading there should also be on on number 3, and there isn't... could this be my problem?, and if so, why all of a sudden is it acting up??? any advice is appreciated... thanks

[94325is]

I'd also like to add that there is no Check Engine Light either... anyone???

[94325is]

Here is an update.... I changed plugs today and found the number 5 plug had no electrodes left... fine, that must be the problem... so I button it all back up, and fire it up and the same thing... I'd like to add that the engine idles fine, RPM's hold at a constant 750, but there is a strange exhaust note, and a slight vibration that you can feel through the car.... Also there is no second ground strap, and it appears af if there never was.... after more testing It appears that the number 5 cylinder simply isn't firing... Piece of electrode stuck in exhaust valve perhaps....

[Furious]

good investigative work , if 5 isnt firing , you might wanna get a pro to check that out, it may be a more involved job,


just go over the basics again, compression , spark , fuel.

sorry i cant be more help

[93 325i]

Is it normal for the electrodes to wear away like that?

[94325is]

If you check out the spark plug replacement article on Pelican Parts, they too have seen the electrode issue... I have fixed the problem. I discovered that by swapping the coils the problem also moved, and I discovered by driving the car that it was somewhat intermittent, that is It would run better or worse as I drove... Okay, so it's not a stuck valve as I imagined it may be... that narrowed it down to either the coil itself, or the boot on the coil, which I am told do wear over time.... cheapest fix first, I purchased the new boot, installed it and put the car back together and voila.... runs fine... it was just a coincedence that the cylinder with the bad plug, also had the bad boot... I am back up and running.....