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Discussion Starter · #1 ·
Went to my friends house, truck ran fine. Then went to leave and truck won't start up. Cranks fine, but there is no fuel getting to the engine.

Fuel Pressure gauge reads zero when I turn the key.

Iv tried to shoot down all the easy fixes, such as all fuses and relays for the fuel pump/ inertia switch and fuse for the KB BAP. All relays click when key turned.

Thing is, where the truck is they dont have a lot of tools so I'm looking to see if there are any suggestions on what to track down, before I get it towed home to start getting under the truck and taking down the fuel tank etc..

No way both fuel pumps would fail at the same time, would they? :smt102

Thanks for any input!
 

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Still kinda sounds like the inertia switch behind passenger kick panel... fuel shut off switch, sounds like it got reset.

You did check it you said?
 

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Discussion Starter · #5 ·
Checked the reset switch and it isn't popped up but I did find a very small 4 pin connecter that isn't plugged.into anything and Is running up behind my console. Can't find where it would even be plugged into.?
 

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Innovator of the Bombassani exhaust
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Hose pop off in the tank??? What year Truck??? I think the '99-'00 models had a problem with this. If you do pull the tank.... Replace the worm clamps (if you have them) on your hoses. They will cut into the hose over time.... Also replace the plastic Y connector with a stainless one.
 

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Discussion Starter · #8 ·
I can't fit.under the truck but the hoses look good. Its an 01. Im gunna run to my uncles to grab a jack and a volt meter to see if there is any power getting back to the tank. Also where can you grab the wires to the pump to see if a jump will get them to turn on. Wish I had a wiring diagram
 

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Hose pop off in the tank??? What year Truck??? I think the '99-'00 models had a problem with this. If you do pull the tank.... Replace the worm clamps (if you have them) on your hoses. They will cut into the hose over time.... Also replace the plastic Y connector with a stainless one.
It'll still crank and run if a pump is not connected but, if he's going in there he may as well upgrade the "Y", hoses, and clamps. Sounds electrical, may be the relay above the intercooler pump.
 

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Discussion Starter · #12 ·
finally got under the truck and found out that there is deffinitly voltage getting to the fuel pumps.. so Im towing it back to my garage to start dropping the tank.
 

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Innovator of the Bombassani exhaust
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Wonder if the Y broke off and the pumps are circulating fuel......... Turn the key on and place a broom handle or screwdiver to the tank. Put your ear to it and see if you can hear fuel jostling around or if you hear the pumps humming.
 

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Discussion Starter · #14 ·
So I got the truck home and plugged my SCT in and it read a code P0232; Fuel pump, secondary circuit High.

The code description on here tells me this..

Inertia fuel shutoff (IFS) switch not reset or electrically open
Open circuit between the fuel pump and the FPM connection to the FP PWR circuit
• Poor fuel pump ground
• Fuel pump electrically open
• Fuel pump secondary circuits short to power
• Fuel pump relay contacts always closed
• Open FPM circuit between PCM and connection to FP PWR circuit
• Damaged low speed fuel pump relay or concern with related circuits (if equipped).
• Damaged PCM


Diagnostic Aides..

Continuous memory P0232 can be set if the IFS switch was tripped, then reset, or if the fuel pump circuit is activated when the PCM expected the circuit to be off (i.e. fuel system test or prime procedure


So I guess it is not mechanical.. and its back to electrical? But there is power to the pumps.. :smt102

I think Im still dropping the tank
 

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Discussion Starter · #17 ·
So I think there might be something wrong with the MSD Booster 2350.. everything is hooked up correctly with no abrasions to any wires, but there is no voltage supplied back to the pumps. The Original Fuel side of the relay (shown below) supplies 6.54 V to that relay. Is that enough to close the loop?

 

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... The Original Fuel side of the relay (shown below) supplies 6.54 V to that relay. Is that enough to close the loop?
Nope. 10.5-11V might do it, but it really should be battery/alternator voltage. You might check & be sure there's a good ground on 86.
How do you have it wired with the 2 pump setup? You know its only good for 230W output? If you have 255 Walboros at 13.5V & 50 psi they're 10A each, so that's 270W. I'm unsure of the stock pumps, but the 190 Walboros are 7.2A at 13.5V & 50 psi, that's 195W. As you increase voltage (which is why you bought the box), the current also increases (the 190s at 12V only draw 6.8A), so it looks a like the MSD box is a little undersized if running both pumps.
Maybe you have it wired to just 1 pump and everything would be great, I was just researching the MSD boost-a-pump because I didn't know they made one.
 

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Discussion Starter · #19 · (Edited)
Thing is, the seller only told me it has dual pumps and he didnt know the brand, but its been running outstanding the whole summer with the same fuel pressure readings . So somewhere along the line Im loosing half the volts to not turn over that relay. I spent a good 4 hours troubleshooting this.. hope I find the cause soon.
 
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