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peterpete190
peterpete190, Auto Technician
Category: RV
Satisfied Customers: 24682
Experience:  Over 17 years diagnosing and repairing various model vehicles.
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I have a 94 bounder will run only when you put gas in the

Customer Question

I have a 94 bounder will run only when you put gas in the carb. Has no power to the fuel pump. Replaced fuel pump relay no luck. Pcm?
Submitted: 1 year ago.
Category: RV
Expert:  peterpete190 replied 1 year ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

My info is somewhat limited on your model here but I had seen no one else has responded and would like to see if I can help here.If at any time you feel that I cannot help with this please let me know.

Inspect the wiring running to the fuel pump and see if any wiring is found damaged or corroded in any way.In allot of cases I have found damaged or corroded or even shorted wiring that will cause this here with the wiring needing replaced or repaired.If the wiring is found to be o.k. let me know so we can continue.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.Thanks Pete.

Customer: replied 1 year ago.
Wiring from fuel relay back to fuel pump is found to be good. At the fuel relay I have an
orange wire it's hot all time
Red wire Is 6 in long does not go nowhere
Grey wire
Green wire
Black wire
Only the orange wire is hot no power to nothing else
Expert:  peterpete190 replied 1 year ago.

I don't have the specific diagram on this model here but usually the gray wire is the power feed wire back to the fuel pump when the relay is energized.The orange wire is hot/power at all times.The black wire should be a ground or ground turn on from the engine computer (this needs tested for ground at all times or ground the first two seconds the key is switched on) and the red wire is either ignition on power for the first 2 seconds the key is on or power at all times with the key on.Let me know if you have any of these signals with the key on and off.

Thanks Pete

Customer: replied 1 year ago.
How do I test it? Just a standard test light?
Expert:  peterpete190 replied 1 year ago.

You can test these signals with a test light or a multi meter.A multi meter is usually best as you can then read the voltage signals from the meter to make sure you have around 12 volts DC on the orange and red wires.

Thanks Pete

Customer: replied 1 year ago.
Like I mentioned earlier the red wire don't go anywhere. It's 6 in long with a plug on the end but don't hook to anything
Expert:  peterpete190 replied 1 year ago.

Does the green wire have power or ground on it at all times,with key on or for the first two seconds the key is on.The red wire is a prime wire most likely to jump power to to run the pump when testing pressure.

Let me know,thanks Pete.

Customer: replied 1 year ago.
Only the orange wire has power. No other wire heat up with or without key on
Expert:  peterpete190 replied 1 year ago.

O.k.,which ones have a ground signal?Ground at all times key on or off and ground with key on or key on for the first two seconds?

Customer: replied 1 year ago.
Black wire shows ground
Orange wire hot all time
Red has nothing
Grey has nothing
Green has nothing
Note red wire does not hook to anything. It has a plug on the end but no place to plug in
Expert:  peterpete190 replied 1 year ago.

O.k.,the red does sound like a fuel prime wire meaning on some models you can connect power to it to prime the pump.I don't have the exact diagram here to be sure of this but this usually is what this means when it is bare or has a plug on the end of it.

Grey should be your feed wire to the fuel pump.If you can see the fuel pump wiring at the pump there should be a grey wire attached to it and this is usually the feed wire.

When the relay is energized it should send power from the orange wire to the grey wire to run the pump on most models.

The way this sounds is like your missing an ignition power feed signal most likely the red wire and your missing a ground switch on feed which is most likely the green wire from the engine computer.

I would double check the wiring leading to the relay all wires except the red and grey and see if you follow these wires if any damage is found to any of them needing repaired.It is odd to have two signals missing at this relay which leads me to believe this is due to damaged wiring needing repaired.Usually if it is a component like the computer or something else you would only have one signal missing and in this case you have two missing.

Thanks Pete

Customer: replied 1 year ago.
I hooked a hot wire to the red wire nothing happened. I put a hot wire on the green the relay clicked and pump comes on. I traced the green wire as far as I could but not sure what pin it is at the pcm/ecm
Expert:  peterpete190 replied 1 year ago.

O.k.,the pump relay must have a ground of some kind then if it clicked and turned the pump on.The green wire looks like it should have power and usually this comes either from the PCM in most cases or the ignition switch itself.Unfortunately I do not have a diagram of this on this model here to see which pins or where it leads to.You might check for this wire at the pcm and test the resistance from the green wire you locate at the pcm to the relay and see if you find near 0 ohms resistance on one of the green wires at the pcm to the relay,this would be the wire in the pcm to test.If you have no power out of this wire at the pcm itself when the key is switched on the first two seconds or when cranking the engine I suspect the pcm is faulty needing replaced.

Thanks Pete