Getting ready to fire up my engine for the first time. This is on a 69 XR7. Going through the cluster lights and gauges. Not seeing any gauge movement at Fuel, Oil or Temp. The circuits at each post are pulsing on the test light which indicates IVR is working - right? Could dirty nuts/posts be blocking the current to each gauge? I noticed some posts pulsed while others did not. No voltage is present at the fuel sender leads. The Oil sender lead is disconnected so I could have a pressure gauge installed.
I am also getting the same pulsing at the coil + with the ignition in run position.
I have Pertronix 2 with a Rocketman Tach conversion.
Something is not right but I am not sure where to look next.
One of the three gauges (fuel, oil, temp) are misaligned and the posts are touching the metal housing. They are all tied together with the IVR output line. This is a bitch to isolate which gauge is the problem. The easiest/cheapest solution is to remove the circuit card and line each rectangular hole where the rear of the gauges poke through with black electrical tape to keep them from shorting to the case.
The pulsing at the coil is expected: this is due to the points (or whatever the Pertronix II does) opening and closing.
1 Like
Thank you. I tried jiggling one of them around while connected to ohm meter and could get it under 14 ohm but soon as I tightened it it would be out of spec 25 - 35 ohm. checked the other gauges with the test light and realized they were all connected. I will pull the gauge cluster out tonight and do as you suggest.
If you measure the post to the case, and if you see 1 or 14 ohms, then the gauge(s) are shorted. You should see much more resistance than that if the gauge is properly positioned.
What specifically were you measuring when you found 25-35 ohms? And where did that spec come from?
I was measuring from the post to the case. I guess I had that backwards. I am pulling the gauge cluster to get better access. The new speedo cable won’t release with the clip pressed down. trying not to force it.
Removed the gauge cluster today (Broke the speedometer cable in the process). The oil pressure gauge was the issue. The other gauges all measured in 50 to 80 ohms range. Remounted the oil pressure gauge and now have the same results. Thanks for the guidance.
1 Like
Damn! I am taking off the dash pad/cluster this weekend and the speedo cable I know I need to be careful with…any reason why you think the clip did not work/it broke? In theory, seems to be pretty simple…press down on the top of the clip and pull???
Thanks!
Joe V.
I must not have the technique right. I pressed the top tab down and even tried depressing the plastic tab with a tool and it just seemed stuck. It finally disconnected with the little plastic lock tab falling to the floor. 
1 Like
Son of a! Sorry! Any issues with the other gauges…they are just basic electrical connections, right?
Thanks.
Oh screw that! G
1 Like
You can get a screwdriver back there?
The gauge cluster was removed. I drilled a hole in the clip. Installed the cable and screwed the screw! I just hope it is in the channel. The cable does not move.
Nice! Hope that holds…I am going to be extra careful and hopefully mine slides right off…thanks!
Joe V.