RESISTOR QUESTION-What ohms?

[TITE3NBIGD]

BMW uses a resistor in the middle of the ground wire that connects the six ignition coil ground wires to the engine cylinder head. These wires(coil ones) plus the single ground wire with the resistor are inside the harness holder that runs from front to back alongside the fuel rail atop the engine. I opened the harness holder the other day as part of trying to figure out why car will not start(it cranks) but will not turn over.

New crank, cam, engine coolant temp. sensors, TPS and spark plugs. Fuel pump and DME main relays good(checked voltage) and fuel pump runs .

Back to the resistor. When I opened the wire harness holder I see the resistor between these two little black pieces(part of the ground wire) and they look burned along with the resistor. I must admit when I first saw the resistor I did not know what it was but the fact that it looked burned could not be a good thing.

So , I did some research and when I looked in the Bentley manual I see in the electrical diagram for ground distribution the resistor as part of the ground wire. I went to the dealer and they could not even find the wire. I am trying to figure out the ohms for the resistor. In Bentley they show the ohms for the resistor for the 98 models as 240ohms, however for models up to 1997 yhey show the resistor but not the ohms. I see one red line on the resistor(mine). Not sure if there were more and got burned off.

Has anyone seen the resistor I am talking about and if so do you perhaps know what ohms it is rated at? Or if you own a E36 up to 97 could you open the plastic harness holder and see what color are on stripes are on the resistor. Apparently that is how they identify the ohms for resistors.

My car is a 94 325is. My thinking is and I hope that this burned resistor is the reason why my car is not starting.
FYI: I have Bavauto performance coils in the car.

Your input and help in this issue will be greatly appreciated. Sorry for the long post. I bet many people are not even aware of this resistor. thanks again.

[JDStrickland]

If the resistor is open, it could be a problem that you want to fix, or if it is a dead short. But you can put in a 240-ohm and it should be fine. My Bentley shows the resistor on all of the sixes, none of the 4-bangers. The sixes all get a 240-ohm resistor.

[Eric93se]

Understand that resisters don't only have a resistance rating, they also have a power rating in watts (power dissipation ability). If you were to put to small of a power rating then it will overheat and fail quickly, they are like 1/4, 1/2, 1 watt etc. You can get a 10w resistor at 240 ohms.

Yes that resistor may be bad, but the simplest thing to do is measure it, use an ohm meter and measure on bare metal (or wire) on both sides of the resistor. If there is no continuity then the resistor is burnt. Also realize not all ohm meters are self ranging, you have to select the range on the meter, otherwise it will just blink and you may misunderstand that as a being no continuity (dead resistor).

Another thing, people don't talk about the performance coils anymore because there was a time when they prematurely failed (poor quality), so I don't know if that's the case with your or not. No one recommends them.

Did you ever open up the DME?? Was the car exposed to the heavy rains?

[JDStrickland]

To measure the resistance of the resistor, you must disconnect one side, else you can read resistance through the rest of the circuit and the readings can be false. Open is open, but a value that is not open can be false. Be sure the resistor is not in the circuit when you are measuring it.

It's true that resistors are 1/4, 1/2, 1, and so on, watts. This is not the value of the resistance, it's the value of the load on the circuit. A 1/4 watt resistor will be physically much smaller than a 1 watt. You can use a resistor that has more power capacity -- you can use a 1 watt instead of a 1/4 watt -- but you cannot use one that has too little power capacity -- you cannot use a 1/4 watt instead of a 1 watt. The physical size is a clue to the wattage.

[Eric93se]

Took a look at the benley. Looks like even if that resistor was bad the ground would still be maintained through the DME. You can still replace it though. Here is a site that has some, I would go with the 250 ohm ceramic 8w, 2 for $1. Pay with paypal so they don't have your CC number.

https://www.allelectronics.com/categ...sistors/1.html

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Also there's this on ebay, should work fine.

http://www.ebay.com/itm/250-Ohm-10w-...-/282524174898

[JDStrickland]

I believe the purpose of that resistor is to suppress noise. It should not create a no-go condition.