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09-27-2019, 07:55 PM | #1 |
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Join Date: Jan 2011
Location: Redmond, OR
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Dual tank switch/gauge question
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.
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68 Chev C20- son has it now 83 K20 - bought from son 70 C20 - in progress |
09-27-2019, 08:18 PM | #2 |
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Join Date: Oct 2008
Location: Wentworth, NH
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Re: Dual tank switch/gauge question
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.
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1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
09-28-2019, 12:13 AM | #3 |
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Join Date: Jan 2011
Location: Redmond, OR
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Re: Dual tank switch/gauge question
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
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68 Chev C20- son has it now 83 K20 - bought from son 70 C20 - in progress |
09-28-2019, 09:03 AM | #4 | |
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Join Date: Oct 2008
Location: Wentworth, NH
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Re: Dual tank switch/gauge question
Quote:
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.
__________________
1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
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