Wiring Diagram Help Needed, 91 V3500

[nvrenuf]

First the truck: 91 V3500 3+3 w/ tbi 350 (bone stock, 150k, normally runs fine)

The problem: 2 times now the engine has shut off while driving like the key was turned off and 2 times the truck will only turn over but not crank and run. Every time switching the dual tank switch from side to side seems to correct the problem and the truck starts and runs perfect. There has been plenty of gas in the tank each time and the guage seems accurate

My question: are the fuel pumps wired through the dual tank switch on the dash? I'm wondering if the dual tank switch is dying and causing the problem. /forums/images/graemlins/thinking.gif

TIA!

 

[nvrenuf]

TTT for the night crew /forums/images/graemlins/dunno.gif /forums/images/graemlins/1zhelp.gif

 

[unclematty]

sounds like it. you need to put a volt meeter on it and see if it actually switches next time it kills /forums/images/graemlins/waytogo.gif

 

[tarussell]

Can any of Ya'll electrical guroos help a brotha out ? /forums/images/graemlins/thumb.gif

 

[unclematty]

just a thought after coming back to this post, I re-read the 1st post and you said that it quit like the key had been turned off. if thats the case then your fuel pump might not be the answer, if it looses fuel pressure, the enginewill start to slowdown and cough and sputter till it quits you said yours just "shuts off" sounds like an ignition problem, lemme know I've been a diagnostic tech for years I'll help as much as I can. /forums/images/graemlins/whistling.gif PM me if you can

 

[marine_enlisted]

Here is a schematic I pulled from Alldata I don't know if it big enough for you to read though. Power for your pumps does go through the selector switch and the valve itself. Maybe someone can make this large enough for you to read.

 

[nvrenuf]

I agree with what you're saying about it "starving" before actually dying. My main reason for centering in on the switch is because flipping it from side to side or sometimes simply tapping on it will make the truck crank.

I will spend some time this weekend and try to more closely diagnose this. Thanks for offer of help I may be bending your ear some tiome tomorrow. /forums/images/graemlins/thumb.gif

 

[nvrenuf]

Thanks for the diagram!! Even downsized like that it helps looking at the paths.

Thanks!! /forums/images/graemlins/peace.gif

 

[1-ton]

My 1991 V 3500 3+3 Crew Cab 4x4 P/U is having a similar problem on the left side tank only. I am pretty sure the problem is crud in that 13 year old, original fuel tank is plugging up the fuel pick up sock because every time it shuts down it sounds like it is running out of fuel. It will only shut down when my left side tank gets down to about just above a quarter of a tank.

After I get my front end steering linkage straightened out my next project is going to be an auxiliary 40-gallon fuel tank in the bed. Then all that high pressure fuel selector switch wiring cr@p will be gone.

I just got a 1.50 OD Heavy Duty tie rod from Sky Manufacturing, Heavy Duty 4" drop Drag Link, new steering stabilizer with bracket, and new tires from 4WPW, but I have not gotten a chance to put the stuff on yet.