Help finding non-resistor plugs - PeachParts Mercedes-Benz Forum

mbzman · #1 09-17-2010, 09:09 PM

I have a uneven idle that I've been trying to figure out. You can hear and feel the engine surge while idling. I did install a new set of Bosch HR9DC plugs and Beru wires last year to no effect. Can resistor plugs make that much of a difference?

mak · #2 09-18-2010, 11:44 AM

Quote:

Originally Posted by mbzman

I have a uneven idle that I've been trying to figure out. You can hear and feel the engine surge while idling. I did install a new set of Bosch HR9DC plugs and Beru wires last year to no effect. Can resistor plugs make that much of a difference?

the uneven idle is most likely due to a dirty/clogged Idle control Valve . clean out the ICV and it run evenly.
mak

mbzman · #3 09-19-2010, 02:07 AM

Quote:

Originally Posted by mak

the uneven idle is most likely due to a dirty/clogged Idle control Valve . clean out the ICV and it run evenly.
mak

Cleaned that awhile ago. Was quite clean when it was removed and the valve operated freely. Didn't make a difference.

86560SEL · #4 09-19-2010, 03:25 PM

Quote:

Originally Posted by mbzman

I have a uneven idle that I've been trying to figure out. You can hear and feel the engine surge while idling. I did install a new set of Bosch HR9DC plugs and Beru wires last year to no effect. Can resistor plugs make that much of a difference?

Not sure if its your problem or not, but when my moms 300SEL did this (when it was my car) it turned out to be the voltage regulator, but we also had "flickering" lights.

Now I am in the market for new plugs for her car... non-resistor plugs are hard to find... thats whats in there now, I didnt know, but one local MB mechanic said they were not good for the M103 engine.

Update - just went to Advance auto and they were out of the $1.79 Bosch, so got the $1.99 NGK plugs... not the BP5EFS, but 5TK or something like that, lol... that was all the NGKs they had for this car. Guess they are better than whats in there. Oh well. Good luck!

mbzman · #5 09-20-2010, 02:47 AM

Quote:

Originally Posted by 86560SEL

Not sure if its your problem or not, but when my moms 300SEL did this (when it was my car) it turned out to be the voltage regulator, but we also had "flickering" lights.

Now I am in the market for new plugs for her car... non-resistor plugs are hard to find... thats whats in there now, I didnt know, but one local MB mechanic said they were not good for the M103 engine.

Update - just went to Advance auto and they were out of the $1.79 Bosch, so got the $1.99 NGK plugs... not the BP5EFS, but 5TK or something like that, lol... that was all the NGKs they had for this car. Guess they are better than whats in there. Oh well. Good luck!

Yeah, the alternators are pretty weak on these cars considering the amount of electrical equipment they have. My seat heaters will often get bumped off at idle if I also have the headlights, radio and fan going. I don't think the VR is defective though. You are definitely right on the non-resistor plugs being hard to source.