Interesting Problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Big Port Jimmy 6 · 03-01-2011, 10:23 PM

I am having an issue with the switching valve on my truck. (87 GMC) It was originally a TBI truck with the motor driven valve. I have installed a 5.3 ls, and now it is pumping out of the right tank and returning to the left. The meter is also not changing. The pumps switch from side to side. Either the valve is stuck, will not handle the 60 psi or I have flubbed up the wiring some how. It was working fine when parked in July(famous last words). Further investigation with a diagram in the near future. Jay

**old Rusty C10** · 03-01-2011, 10:58 PM

i had an old f 150 that did that and it was the crossover valve

dammitmitchell · 03-02-2011, 01:11 AM

soulds like your valve had gone to crap.

Jonboy · 03-02-2011, 10:53 AM

I think Bob (Glock) had found a higher pressure switching valve when he did his LS swap. It's towards the front of his build thread.

03-01-2011, 10:23 PM	#1
Big Port Jimmy 6 Addicted to Rust Join Date: Dec 2009 Location: Abbeville SC Posts: 1,030	Interesting Problem I am having an issue with the switching valve on my truck. (87 GMC) It was originally a TBI truck with the motor driven valve. I have installed a 5.3 ls, and now it is pumping out of the right tank and returning to the left. The meter is also not changing. The pumps switch from side to side. Either the valve is stuck, will not handle the 60 psi or I have flubbed up the wiring some how. It was working fine when parked in July(famous last words). Further investigation with a diagram in the near future. Jay __________________ Current trucks: (48 GMC100 320 inliner) Gone (48 Suburban in pieces) Sold 87 GMC CCSB 5.3 4l60E Daily Driver ECTA National record holder XO/PP We never really grow up, we just learn how to act in public.

03-01-2011, 10:58 PM	#2
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	Re: Interesting Problem i had an old f 150 that did that and it was the crossover valve __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

03-02-2011, 01:11 AM	#3
dammitmitchell the pollock Join Date: May 2008 Location: abilene, texas Posts: 4,423	Re: Interesting Problem soulds like your valve had gone to crap. __________________ Jack of ALL trades, Master of none.. (but one... procrastination) Army vet 02-08 RIP El Jay! Miss you brother! http://67-72chevytrucks.com/vboard/s...d.php?t=343538 http://67-72chevytrucks.com/vboard/s...d.php?t=386042

03-02-2011, 10:53 AM	#4
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: Interesting Problem I think Bob (Glock) had found a higher pressure switching valve when he did his LS swap. It's towards the front of his build thread. __________________ 1974 Jimmy- 5.3/4L80e/NP241



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.