New CVR not working correctly.

[WesChapman]

78 Scout terra, stock electrical system.

My old cvr was only producing 1.3 volts average, measured via analog multimeter. As a result, my gauges read slightly low. I ordered a new bwd r307 cvr and installed using the directions from a post on this forum by caperodder.

I believe I connected the new cvr properly. Attached is a picture on my setup:

I reconnected the gauges and fired up the truck. The gauges read even lower now, and I could see the gauges bounce up ever so slightly with each pulse and then settle back towards 0.
I put my analog meter on the output and saw 5 to 9 volts, but the cvr would only pulse once every few seconds. The old cvr would pulse constantly about once per second, maybe faster. The new cvr, pulses, then nothing, nothing, nothing, then 1 pulse, then nothing, nothing, nothing. I checked the input voltage; truck running it's a little over 12v.
Could the new cvr be deflective? Do I have it wired correctly?

 

[Robert Kenney]

I would hook it up on the bench.. An time the on/off cycles. Should be rough 50%.

See photo.

 

[WesChapman]

Dredging up my own old thread....jeez time gets away.
Pulled the dash apart yesterday to work on this some more. Cvr is wired correctly. Duty cycle is about 1 second on, 3 to 5 seconds off. Output voltage is all over the place. One pulse will be 7 volts, then the next 2 volts, then 10 volts, then maybe 3 or 4 in a row at 7 volts.
Engine off I have 12.26 volts feeding the cvr, so my guess is the new cvr is bad?

 

[Greg R]

Check that the ground is solid, try a wire from the gauge pod and cvr mounting screw to a known good ground on the dash/body. Also sometimes the pin connector for the 12v gets flaky from dirt or looseness.

If it doesn't get any better, then I would agree the cvr is defective.

Nice clean job you did there

 

[WesChapman]

Removed the cvr tonight and bench tested. Same result as when installed. Since it appeared to be no good, I did what any guy would do; I took it apart. Wow, can't believe something so flimsy and simple could cost so much. Since it was apart and apparently broken I did what any guy would do; I tinkered with it. Noticed there was an adjustment screw and messed with it. Amazingly I was able to increase the duty cycle and get it working better. Enough so that the gauges are reading mostly normal-ish. It will get me by until I either get another new cvr or try my hand at the solid state setup.