Coil driver? for Don or others

[Jonesy23]

Don, I was doing some electrical testing today on the 01 promax 300x. I was testing the ohms on the coils and the coil drivers per the directions in the manual, the driver that is mounted on the number 6 coil on the starboard motor is showing out of spec. The manual gives a spec of 85 ohms +/- 10%, this one was reading 105 ohms. This is the motor that blew the number 6 piston and my previous mechanic replaced two bad coils on this motor but he did not tell me which coils he replaced. I did an ohm test on the "bad" coils that I kept and they showed to be in spec but I have not hooked them up and done a spark test under load so?? My question is, can a bad coil driver simulate a bad coil and could a bad driver have caused my detonation issue on my number 6?
Four of the 6 drivers (between the two motors) were out of spec, the others were closer at around 97 / 98 ohms. How important are these readings?

[Nikon Man]

Interesting question...........I'm all ears...

[EuropeanAM]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by Jonesy23 &raquo;</td></tr><tr><td class="quote">Don, I was doing some electrical testing today on the 01 promax 300x. I was testing the ohms on the coils and the coil drivers per the directions in the manual, the driver that is mounted on the number 6 coil on the starboard motor is showing out of spec. The manual gives a spec of 85 ohms +/- 10%, this one was reading 105 ohms. This is the motor that blew the number 6 piston and my previous mechanic replaced two bad coils on this motor but he did not tell me which coils he replaced. I did an ohm test on the "bad" coils that I kept and they showed to be in spec but I have not hooked them up and done a spark test under load so?? My question is, can a bad coil driver simulate a bad coil and could a bad driver have caused my detonation issue on my number 6?
Four of the 6 drivers (between the two motors) were out of spec, the others were closer at around 97 / 98 ohms. How important are these readings?</td></tr></table>

Electrical circuit resistance tests can be quite deceiving.

First, let's clarify that resistance tests (in the absence of a TEMPERATURE SPECIFICATION) are to be taken at an ambient temperature of 70-75 degrees F. This means that the component, and the ambient temp need to be in this range (unless otherwise specified in the manual).

I would not have concern with those that read 97-98 ohms (the spec is 85, +/- 10%). We can easily account for a 5 ohms variance from one meter to another (or even within a set of meter leads)...

However... the one that tests at 105 ohms should be rechecked at an appropriate ambient temp. My recommendation would be that when in doubt (especially being as this is the driver related to spark production signal on the affected cylinder)- throw it OUT. A replacement driver is far cheaper than a replacement powerhead.