1997 E320 - Miss after engine clean
 

Hello all,

My buddy at the cadillac dealership called me on Saturday morning "hey we're slow up here, bring your car in and we'll detail it" Of course I agreed and I must say she is looking better than ever. When we started on the engine I suggested we do a dry cleaning, my buddy insisted that it would be ok, "we won't use much water" So I agreed. We sprayed the engine with cleaner (just the top of the motor) then lightly hosed it off and started the car, letting it run for about 15 minutes....car was fine all day until evening when it developed a miss. Now the miss is intermittend. It seems to be fine for a while if the car has been sitting for a good period. It usually starts when I come to a stop. It feels as though it goes from dropping one cylinder to dropping two.....I changed the plugs yesterday (needed it anyway) everything looked pretty dry and I'm pretty sure that water didn't get down in the plug holes since I made my buddy aware of the possible delima. Unfortunately the problem is still there. Anyhow if anyone has any suggestions I would appreciate the help....I was wondering if there was an issue with one of the coils since the problem seems to me as if it is affecting two cylinders at times.

Thanks for your help,
B-

Change the 3 plug connectors under the coils....
.. I assume you did not use plats ??????
Bosch F8DC4 plugs only on that engine/ignition system

Thanks for the reply Arthur. Correct I used the non resister bosch plugs F8DC4's. What makes you think the 3 plug connector under the coils are bad ? Not questioning your logic, just curious as to why just the 3 ?

Thanks again,

Known faullty parts , specially after they have been moved.
Cheap and recommended with plug change.
This ignition system is a waste spark , meaning two plugs fire in series ,
[ which is why only 3 coils for 6 plugs] so a bad connector can affect two cylinder misfires. The connectors on the other plugs do not suffer the heat encapsulation the coil ones do, and they also have a snap connector, whereas the coil onder ones are a friction/pressure spring fit [ not to anyones liking]
So the others do not have the common fail rate as the three I recommend changing.
Newer systems have coils on each cylinder .
That's why...
http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1D00YU6RY1IL0R2S31&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1997&product=F1010-84561&application=000357357
More details in the archives on these ... enough to fill a NYC phone book.. (:

Thanks for the detail explination Arthur !! Makes perfect sense. I'll change those asap.

Any Idea what I could have gotten wet to cause this problem initially ? I'm 98% positive that we didn't use enough water to get down around the spark plugs. Any connectors that I should pay attention to ? or disconnect and spray with compressed air ?

B-

The connectors usually just give trouble regardless of water shorting cuz of the connector design.. Techs always just change them out with plug change just to eliminate the possible misfires they are known to cause and the low cost.... they are not just a connector, they are also a RF resistor .. that is why we don't want resistor plugs coupled with the resistor connector .. the resistance is in the connector....
Post the results for the benefit of others watching this post, if you could,,,

Absolutely.. I will....So no idea of what may have gotten wet to cause the miss ?

If there was water , it would wind up at the plugs /connectors cuz that is the lowest cavity and no way out til it evaporates, so you may want to blast some air around the plug bases when changingh the plug connectors .. there may even be some moisture trapped in the bubber boots of the old connectors..I would not worry about it .. let the thing dry out a little when you take the cover off...

Brandon,

Dalton is exactly correct. I have had the same problem with my '97 E320. You just can't get any water around the top of that engine or you will end up with a miss. It will eventually dry out and if the connectors aren't corroded it will run OK but the connectors should be changed if the miss doesn't stop and if it does stop replace them the next time you change plugs.
Russ Anderson

thanks guys, I changed the plugs yesterday....I didn't notice any moisture anywhere around the cylinder head area...or anywhere for that matter. The car missed a little this morning on the way to work, but hasn't since and I've been driving it around a good bit... Hopefully whatever the culprit...it's dried now... I'll keep you posted.

Thanks again,
B-

UPDATE: Whatever the culprit, it has dried now and all is good!

Thanks again guys,
Brandon

Good
I would still change the 3 connectors I mentioned cuz the original are known
to be bad . They are cheap insurance and can put a taxing draw on the coils..
Coils , as in $$$$$$$