GT-40 Fuel Pump Problem.

[Txpilot83]

1996 GT-40 in a 176

When I put the key to the notch before the starter the fuel pump or pumps dont kick on and the engine wont start.

I have installed 2 new relays and a new low pressure fuel pump but still no luck.

The boat was running fine before I had the fuel filter changed by the dealer. Any ideas? Thanks

[jankedm]

Did you check the electrical connections on the pump located inside the FCC?

[Txpilot83]

I did last night and they seem to be fine. Im thinking the pumps arent getting any power. If the connections on the HP pump are loose would that cause the LP pump to not run? Im about to go buy a volt meeter and start taking some readings to see if the pumps are even getting power. Thanks for the advice and keep it coming.

[Txpilot83]

Volt meter is not showing any power going to the pumps when the key is cycled. Could my ignition switch be bad? The PO bypassed the kill switch and his wiring job there seems to still be good. Any ideas? Seems like Im at dead end and will have to bite the bullet and take it to the dealer.

[DanielC]

"The boat was running fine before I had the fuel filter changed by the dealer. Any ideas? Thanks"
You need to talk to the dealer that did the work.

On the back of the engine are two relays. both relays need power on pin 30 in the relay socket.
Here is info on the relays.
http://www.planetnautique.com/vb3/sh...=fuel+pressure

This thread shows you how to check the fuel pressure. In the thread, it shows how to make a connection at the test port on the engine that causes the engine computer to turn on the fuel pumps.
http://www.planetnautique.com/vb3/sh...=fuel+pressure

[Txpilot83]

Thanks a lot for those links. I tried using your jumper trick shown in picture 2 but the pump still didnt come on. I might have missed something and not done the test right though. To check the power to those pin 30s should I just put the positive end of the volt meter on pin 30 and the other on the ground (pin 85 i think you said)? I hooked my old pump directly up to the battery and it runs fine. Guess replacing it was a waste. Thanks again.

[2001SAN]

I had the same problem once but the fuse board breaker for the ignition system had popped out. Reset it and all was well. Yours could well something more complicated.


D.

[Lewy2001]

Check for 12 volts on both sides of the EEC 12.5 Amp breaker and the 20 Amp fuel pump breaker.

[DanielC]

Ground to something metal on the engine when checking for power at pin 30 of the relay socket. I also would suggest just using a test light. Many volt meters use so little current to measure the voltage, that a very poor connection will show 12 volts, but the bad connection will not pass any current.

Never assume your test light is good, or has a good ground connection. If I was looking for power at pin 30 of the relay sockets, I would connect the ground clip of the test light to ground, then touch the probe to the big red wire on the starter, to see if the lights works. Then check for power at pin 30. If the light does not come on, recheck the test light on the starter.

You can down load the GT-40 service manual form the down loads section of this site. it has some very good electrical diagrams in it.

By the way, the computer switches the ground connection on the fuel pump relay coil on and off, pin 85. If you used that for a ground connection with a volt meter, or a test light, I would not expect the test light to come on, except if all the conditions were met to make the fuel pumps come on. In that case, the engine would would be running.

Another quick test is to make a short jumper with a male 1/4 spade connector on each end. Plug one end of the jumper into pin 30 of the fuel pump relay socket, and the other end into pin 87 of the fuel pump relay socket. This should make the fuel pumps run.

[Txpilot83]

Does the other relay need to be plugged in when Im testing one? Which one is for the fuel pumps? Is it the one closest to the circuit breakers? Are there any other circuit breaker I should be checking besides the ones next to the relays? If so where are they?

I tried the jumper test between pin 30 and 85 on both relays and nothing happened. The ignition was in the second notch.

I got the light tester and with the ignition on, the only receptacle that would light up is the one for pin 86 on the relay next to the circuit breakers. Again at this point the other relay was unplugged.

Any ideas? Thanks everyone for the input so far.

[Txpilot83]

I also tried your trick to force the pumps on again using the jumper on the EEC tester (picture 2 of your fuel pressure thread) put nothing. Could the computer be bad?

Is there another way to test the kill switch? The PO used a jumper to connect the two wires that go to it and they seem to be fine.

I did hard wire the new fuel pump I installed directly to the battery and it ran fine so I know the pump is good.

I still have a feeling it was something to do inside the FCC if thats possible.

***I just read one of your old posts and now know which relay is for the fuel pumps. Guess I got ahead of myself.***

[Txpilot83]

So after plugging in the relay for the computer and hearing it click when I cycle the ignition there is still no power to pin 30 for the fuel pumps. What could this mean? Guess that explains why the jumper from pin 30 to pin 87 wont kick on the pumps.

[DanielC]

My bad, I did not make it clear.
You should always have power at pin 30 in both relay sockets. The only time there is not power there, is if the battery is disconnected, or dead.

Down load the GT-40 service manual from this site. It has wiring diagrams near the back.

[MTRBTR]

I had a very similar problem with my 97 sport. Turned out to be a loose connection at the ground from the battery cable. The ground cable was tight at the battery but then it had a secondary wire that went to a different pole (in a rubber boot about a foot off the battery cable) that connection was loose. The starter would turn over when I tried to start it but no power to the fuel pumps). Once I found this loose connection every thing ran fine. Just my experience.

[Txpilot83]

Prostar I just got home from a trip and checked the battery connections and that was exactly what it was. THANKS! Same situation as you. The connection had corroded under the rubber boot so it wasnt easy to see. Thanks again to everyone on here for the input.