Good RPM signal on Dyno????

[2001 GTS]

Been to the dyno twice now and can't get a solid RPM reading through the pull. Twice now it has stayed good until 3800-4000rpm then it fluctuates.

The dyno is an inertia DYNOmite.

We have tried getting readings from: 1st,3rd,5th and 4th plug wires with no good results, as well as right by the coil packs.
Also tried the ground off of the PCM, Pin 31 on C3, and Pin 1 on C1.

Nothing gives a solid RPM

What can we do..this is getting really frustrating.

Car has MSD wires.

Thanks,
Steve

 

[Joseph Dell]

Vipers are notorious for bad tach signals for the dyno.

I've had the best luck with the coil pack wires.

I used to keep a stock #3 wire around just for the dyno. i'd swap out my magnacore or MSD wires in favor of the 'stock' and that would produce a good tach signal.

sorry to not be much help. I could never get a tach w/ MSD wires, BTW.

JD

 

[2001 GTS]

Well thats some good info...I still have the stock wires laying around. So changing #3 back to stock should work good?

 

[Madduc]

I had the same problem with my stock wires. Switched to a set of Quality Wires from AB and had no problem since.

 

[2001 GTS]

Is there any reason why the dyno clamp couldn't pick up a signal from the tach wire (Pin 31 on C3 or Pin 1 on C1)???