The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 03-06-2020, 09:35 AM   #11
hatzie
Moderator
 
hatzie's Avatar
 
Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,916
Re: 1973-1991 Dual fuel tank systems theory of operation

It sounds like someone wired past the valve directly to the LH sender.

The valve and switch are working as they should.

Does the SPID (Service Parts Identification) label in the glovebox call out Option NL2?

The six position Weatherpak on the valve is lettered A-F. F should not have a wire so A is on the opposite end of the plug... easy to find.

With your Digital Volt Ohmmeter. What ohmage do you get when checking resistance between Valve plug A to ground & Valve plug C to ground. One of them should be 90Ω ish and the other should be somewhere around 29Ω ish... give or take a few Ω. The graph in my post above shows Ohms VS gauge position.
__________________
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...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.

Last edited by hatzie; 03-06-2020 at 09:44 AM.
hatzie is offline   Reply With Quote
 

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 01:30 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com