M103 resistor tip question
 

My car recently started running rough. All I did was change the oil and removed and reinstalled one of the spark plug wires. I eventually replaced new plugs w/o avail. It appears I should replace one or all the resistor tips rather than replace the wires due to $$$. Can someone give me advice on how to do this? Do I really need a special tool? What parts do I order that need replacing?

thanks in advance....

- Remove resistor from spark plug.

- Resistor is about 3"-4" long - metal.

- At the end of the resistor where it connects to the spark plug wire, you'll see a small runner piece that can be folded down towards the resistor.

- Once that folds down, you should be able to simply unscrew the resistor from the plug wire. Loosen counter-clockwise. It's that simple.

Some may be a bit more stubborn. Steve Brotherton wrote about this a ways back - forget when - about a year or more ago.

Resistor removal
 

I'll try and remove the suspected bad resistor tonight. Once it's out, what do i look for to identify if it's bad?

thanks,

Checking resistor
 

If you have access to a multimeter you can check the plug wires without removing the resistors. Just connect one meter lead to each end of the wire. If I remember correctly the resistance should be about 1k ohm, I think it tells exacly on the metal part of the connector.

If the resistance varies by more than 20% I would replace the connector.

John

repair
 

If the resistor was damaged by pulling on the wire, can this be fixed without buying a new resistor tip?

thanks...

The ceramic inside the resistor can sometimes get damaged. I've heard this sort of thing doesn't always show up using and ohm test as John described. Can't say for sure that I know this to be true.

An MB tech I know told me that they often times are damaged on removal if you do not pull them straight off. If you get into a back & forth or circular type motion, you could damage the ceramic interior portion of the resistor.

Some here have suggested using dielectric grease to lube the connection in order to facilitate removal the next time around. You might try doing a search on dielectric.

Hi Mike,

I'm trying to remove the resistor tips on my 300 TE. I've studied the resistor tip but couldn't find this small runner piece that folds down that you mentioned. Can you tell me exactly where it is and how it looks like? I've tried to loosen the resistor by turning it counter-clockwise. It turns counter-clockwise but I can't remove the resistor from the black rubber that it's attached to the end of the wires.

The reason I'm trying to remove this resistor tip is bec. I have high gas consumption. If you have time, maybe you can see my recent post High Gas Consumption by ako.

Thanks,

RV
-----------
92 300 TE 115K miles

I almost never got my old wires off!!!!
 

I ended up having to unscrew the tip from the plug, with the tip still up inside the wire boot.. Remove the plug. Put the plug in a vise.. Screw the wire back onto the plug... And hammer it off with a punch..The tip was literally FUSED to the inside contact of the wire. I used anti - seize on the plug tips when I re-installed them..
Everything seems fine.. I still pull the wires off on occasion just to be sure I can still remove them.. THe tips on these plugs don't unscrew...