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Discussion Starter #1
K.. i'm had my s10 for about a month now and changed the fuel pump along with all the typical tune up things... it's an 87 2.8 FI 98,000 miles, 4x4, manual... anyway.. it's throwin code 54 i was told it was low fuel pressure or egr or something. Donno for sure, need some help. When i come out of first though, it's really rough and the idle needs to be terribly high for it not to stall, not sure if that is a related problem or not. Thanks, Jared
 

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life begins @ 20 psi
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As per Haynes Manual:

Trouble code:
Code 54

Circuit or system:
Fuel pump

Probable cause:
Low fuel pump voltage. Sets when the fuel pump voltage is less than 2 volts when reference pulses are being received.

Sounds like your truck isn't getting all the voltage that it should be getting. What is the condition of the wires going to the fuel sending unit on top of the gas tank? On my 88 S10, I had to replace the ground terminal because it had almost rusted in two. HTH's

Mike Campbell
 

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Discussion Starter #3
I also had to replace the ground. I hose clamped the end of the ground that goes to the frame straight to one of the "pipes" that comes out above the fuel pump.. the wire itself is cut and repaired in probley 4 spots it appears... maybe the problem? Isnt it also like an egr or something like that that haynes says? Thanks, Jared
 

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life begins @ 20 psi
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Whoa, back the truck up! Did you say that you used a hose clamp to hold the ground wire to one of the fuel lines??? NO, NO, NO you CAN'T do that! Grounds MUST be in sheet metal or heavy metal (engine block, frame etc.).

My method is as follows: Take a ring terminal and pull the insulated portion off with a pair of pliers. Sometimes they will not come off. In that case, heat it with a heat gun or use a lighter to heat it up a little and it will come off. Crimp the wire in the ring terminal and then SOLDER the wire into the terminal. Use a wirebrush or sandpaper to clean where the ground will connect down to BARE METAL. Smear grease on the bare metal to keep rust from forming. Use a stainless steel bolt to attach it and you are set. Sounds like a lot of work but, a bad ground will create all kinds of CRAZY problems.

On the top of your fuel sending unit, there should be a ground wire that goes DIRECTLY to your frame. There should be another one that goes from the tank filler neck to the sheet metal in the bed. If the ground that goes from the top of the fuel sending unit is not propertly grounded, your fuel pump WILL NOT operate correctly! Sounds like you will have to solder the ground wire to the top of your fuel sending unit. There should be the remains of where it attached originally. It attaches to the the outer portion of the fuel sending unit near the lock ring that holds the fuel sending unit in the tank. The way to confirm if a ground is good or not is to use an ohm meter and connect it on both ends of the circuit that you want to check. You want to see a zero when you do this. If you have DMM (Digital Multi Meter), use the diode check and listen for the beep. Even if the ground strap looks intact, if it is a nasty green color it is best to replace it. HTH's

Mike Campbell
 

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Discussion Starter #5
no dude, i know better than to ground to a fuel line. I can see where you'd misunderstand, i doid a terrible job of explaining these things without being able to show you. My ground goes from the top of the sending unit to the frame, looks like from the factory where it is connected to the frame. I didnt see a wire that goes from the filler neck to the bed. If this is true, and the whole problem is a bad ground then why did it work perfectly when i gave it a constant 12 volt source?? Thanks for the help SY2932.
 
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