Dual tank switch/gauge question

[dmack91]

I have read Hatzie's thread already and it helped a lot. Thanks Hatzie!


I have been trying to troubleshoot my system to get my gauge to work.

I have an 83 K20 with dual tanks. I have sender readings at both the A and C connections on the weather pack connector. When I plug it into the pollack valve, I don't have a reading at the B wire to the gauge. I have cycled the switch with the key in the on position and still nothing.

I have confirmed that the switch has power at the dash, and that it reverses polarity at the weather pack to the valve.

I have plugged in another pollack valve into the connector (spare used pollack valve) with the same results.

The wire from the B terminal to the gauge was cut under the firewall when I got the truck and I have been working my way from tank valve forward.

My initial assumption was that the switch inside the valve was shot, but I am questioning that when I have the same result on two different, albeit used, valves.

Am I missing something or do I need to get a new pollack valve?

Thanks in advance for any help you can provide.

[hatzie]

Thanks for letting me know it is useful. It's good to hear it.

Make double darn sure the B wire has continuity all the way from the valve plug to the gauge sender spring terminals in the cluster bucket. Your meter should read a dead short 0.0 ohms when it's connected to the B terminal and the cluster bucket fuel sender clips.

On both valves... Make sure you have continuity from B to A or B to C. It'll be one or the other depending on what position the valve is in. If you have continuity on both B to A and B to C at the same time or neither leg has continuity the internal gauge switch is borked.

I have 5-8 each of male and female Weatherpak Metripack etc terminals in my meter bag so I can plug test leads with alligator clips onto Weatherpak etc sensors and plugs without damaging the terminals on the vehicle.

[dmack91]

Hatzie,

Thanks for the quick response and help. I do have clean continuity through the gauge wire from the B terminal plug to the gauge. And I have no continuity between the B terminal and either A or C on either valve.

I guess I see a new Pollack valve in my future. That is what I figured, but when I found the same issue in valves, I wanted confirmation before ordering a new one.

Thanks again for the help.

Dave

[hatzie]

Originally Posted by dmack91

Hatzie,

Thanks for the quick response and help. I do have clean continuity through the gauge wire from the B terminal plug to the gauge. And I have no continuity between the B terminal and either A or C on either valve.

I guess I see a new Pollack valve in my future. That is what I figured, but when I found the same issue in valves, I wanted confirmation before ordering a new one.

Thanks again for the help.

Dave

I'm not positive that the gauge switch will stay connected if the shuttle inside the valve isn't against the stops. You might be able to hang the ABC gauge switch in no-mans-land between connections...
Try applying Hot and Ground to the E & F motor leads of the valve that's out of the truck. If it doesn't wake up the little DC motor inside swap the leads to reverse the polarity. The goal is to drive the valve shuttle all the way to one or the other stop. The diodes in the motor shuttle switch internal to the valve will kill the current to the motor once it reaches the travel stop.
Once the valve is at a stop test the BC BA connections for continuity.

I'm not a fan of the momentary contact ON-OFF-ON switch GM used on the 81-86 NL2 systems and the 87-91 diesels. They assumed you'd hold it down long enough, 5-10 seconds, to run the valve to the stop...
I always mod the 81-86 setup by using the 87-91 TBI ON-ON switch. The diodes in the valve shut off the motor.
There is a notch in the plug that mates with a locator bump key on one of the switch terminals. The Delco D7003 Carb/Diesel switch has a different terminal with a key than the Delco D7809C TBI switch. You can modify the plug to mate with the D7809C switch by removing the Packard 56 terminal from the slot that needs a key and cutting the key with a small round file. Once the key is cut and fits I make sure the terminal latching wing is lifted far enough to engage the connector and re-install the terminal.