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1994 g30 extended 1...
 
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1994 g30 extended 1 ton water in my fuse box

  

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Topic starter

A few months ago I was out working and my 1994 g30 chev 1 ton extended passenger van up and died on me .since then I've replace fuel pump ,sending unit ,tank,sparks plugs and wires ,rotary distributer cap ,coil ,fuel pump fuse and relay but I am still not getting my new pump to power up at all .it will run with starter fluid but it also fires up on the wrong way most times and almost gives me a heart attack .I've checked all the grounds I can find and once I started poking around the fuse box under the dash I found water in my fuse panel.would this water cause all of these issues and how could I fix it.i believe it's coming in from a spot under the goods where all the lights hook up to right on the fire wall .hope all is well and thanks 


Oh and I'm sorry I failed to mention it's a 5.7 tbi


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3 Answers
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I tried, but I couldn't resist.

Your fuel pump circuit is pretty easy to diagnose.

If you can find that test connector, put 12 volts to it.

If you can't find it,

You have 2 oil pressure sender/switches. I think one is down by the oil filter and that one isn't in the diagram.

The other one is in the back of the engine and it's part of the fuel pump circuit.

Its purpose is if the fuel pump relay fails while the truck is running (if the oil pressure is sufficient), the truck will keep running.

So you can just pull its connector off, jump the 2 sockets and you should hear the fuel pump running.

Let's look at that part of the circuit, shall we? (I'll highlight it in red):

Orange wire going to the oil pressure switch has 12 volts + or -.

The Grey wire coming out goes to the fuel pump.

So, at that oil switch socket, the orange wire has to have battery voltage. (around 12 volts)

If it doesn't, the fuel pump relay can't work either. (Then you'd suspect that fusible link in the wiring up near the junction block terminal has fried.)

If it has voltage, and jumping the socket terminals doesn't work, then you'd suspect that the 20 amp inline fuse has fried and the fuel pump relay can't get power to the fuel pump either if that fuse has fried.

 

So after making sure you have voltage on that Orange wire, jump the socket terminals. Does the fuel pump run? If not check that inline fuse on the Grey wire.

If the fuel pump works, it's time to check the PCM control and the Power/ground at the relay.

Let's look at that side of the circuit:

First, you replaced the fuel pump relay so the pin assignments should be easily visible.

 

 

Pins look like this. The smaller pins are the relay coil control (D & F)

So now I'll highlight this part of the circuit in Red for power, Black for ground (when the fuel pump relay coil is energized by the PCM) ((refer to the pics of the relay pin map and relay spade sizes above to use a test light to figure this out))

(((I'm talking about the corresponding female spade connectors on the relay connector))):

 

So, First, just use a piece of solid wire and "jumper" pins A and E.

If the previous Oil Switch circuit checked out OK, then the fuel pump should run when you do this.

Now, engine off, you have to have Ground at "Pin D" and you have to have 12 volts at "Pin A".

(if the "jumper" worked, you have power to "Pin A" and the wiring/fuse between the relay and the fuel pump are OK).

If that checks out OK.....

Next, check if the PCM is controlling the relay by providing 12 volts to "Pin F".

When you first turn the key to "ON", the PCM will send 12 volts to "Pin F" for a few seconds to energize the relay coil.

Use your test light to see if the PCM is doing that at "Pin F".

If it isn't, you'll pierce the "F6" wire (Dk Green/Wht) at the PCM's Blue Connector, connector connected, to see if the PCM is outputting the 12 volt Control to the relay coil to energize it for a few seconds, KEY ON.

 

 

Let us know your findings

 

 

 

 

 

 

 

 

 

 

 

 


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Feared watering the fuse panel there's no saying what's been shorted out probably needs a new main computer too I don't know if it's worth fixing to tell you the truth


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Topic starter

Oh well thanks for your input and that really sucks .can't afford a new car so maybe a new computer is in my forecast.my van is 11 passenger and I have 7 kids so hopefully I can figure it out .thanks again 


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