Fuel Pump has no Power

[ABC]

07 LSV with the Indmar 325. Was running great and then wouldn't start. Starter runs fine but the fuel pump isn't running. Checked the safety lanyard, all the fuses and relays that I could find. Unplugged the fuel pump and checked for power at the connector and there is none with the key on. When you turn the key, the perfect pass comes on and you hear the beep and all the lights and ballast pumps work, but the fuel pump never runs.

I read through the similar thread from 5 years ago and tried everything in there, but still can't get power to the fuel pump.

Any help or ideas will be greatly appreciated.

[trayson]

Did you try the red breaker that's next to the ECU?

I just rewired my fuel pump harness, because I found that every so often I was getting a short and it wasn't priming on key start...

[flydoc]

Happened to my mobius, it was the oil pressure switch. I wired around it and never got around to fixing it. If their is no oil pressure the fuel pump doesn’t run so you can’t run your engine dry of oil.


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[Stazi]

Replace the oil pressure switch that the fuel pump gets the signal from.


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[ABC]

OK... Where is this oil pressure switch? I did check the breaker by the ECU.

Also, where is the low pressure fuel pump located? I think I was only looking at the high pressure pump.

[Stazi]

It’s in the valley between the heads and the back of the engine. You can trace the power wire back from the fuel pump to it.
Looks like this, although not necessarily on a T. If you find it you can jump the two wires and see if that kicks the fuel pump on with the ignition on.

https://forums.iboats.com/filedata/fetch?id=7001572&d=1400632031



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[trayson]

OK... Where is this oil pressure switch? I did check the breaker by the ECU.

Also, where is the low pressure fuel pump located? I think I was only looking at the high pressure pump.

Low pressure pump looks like this:
https://www.bakesonline.com/pub/media/catalog/product/cache/74c1057f7991b4edb2bc7bdaa94de933/c/a/cartersupplypumplg.jpg

High pressure pump looks like this:
may or may not have the black rubber boot around it.

https://bpi.ebasicpower.com/mm5/graphics/00000001/CRU47039.jpg

[parrothd]

Low pressure pump looks like this:
https://www.bakesonline.com/pub/media/catalog/product/cache/74c1057f7991b4edb2bc7bdaa94de933/c/a/cartersupplypumplg.jpg

High pressure pump looks like this:
may or may not have the black rubber boot around it.

https://bpi.ebasicpower.com/mm5/graphics/00000001/CRU47039.jpg

Just remember there will be no power to these with the key in the on position. When you first turn the key on the high pressure one should see voltage for a few seconds. You need to test with the key in the start position.

[trayson]

Just remember there will be no power to these with the key in the on position. When you first turn the key on the high pressure one should see voltage for a few seconds. You need to test with the key in the start position.

Which pump is the one that you hear with that characteristic BUZZ as it primes on key ON?

Also, the wire harness for the fuel pumps has the positive and negative for both pumps coming from the exact same leads on the harness. So if the LP pump is getting voltage, the HP pump has to likewise be getting voltage.

[parrothd]

Which pump is the one that you hear with that characteristic BUZZ as it primes on key ON?

Also, the wire harness for the fuel pumps has the positive and negative for both pumps coming from the exact same leads on the harness. So if the LP pump is getting voltage, the HP pump has to likewise be getting voltage.

The black one makes the buzzzz noise with the key turned on the first time.

The round one makes more of a clunk clunk and usually only runs when the key is in the start position and when the boat is running. Think these were added sometimes to help with vapor lock, how it's installed may be different.

I would trace the wires all the way till you get good ground and 12v with the key in the starting position. My guess there's a relay, when you first turn the boat to on the pump should prime, then run again once the boat is starting or running.

[Engine Nut]

Only carbureted engines have oil pressure activated switches for the fuel pump. The fuel pump in an EFI engine is controlled by the ECM. There is a small fuse holder with a cover that has three fuses. The fuse holder is attached to the ECM racket near the three relays. One of the fuses is a fuel pump fuse. you need to check it before you do anything else.

[gregski]

The '07 didn't come with a low pressure pump. Many have added one to help with vapor lock issues.

[ABC]

The '07 didn't come with a low pressure pump. Many have added one to help with vapor lock issues.

That explains why I couldn't find it!! I did check all the fuses and relays.. finally gave up and took it to the dealer... I'll post the solution when they call me.

[Turbinesurgeon]

Did you troubleshoot the tether cord kill switch? On my 06 that switch cuts the fuel pump

[Tom Benaglio]

I have the same issue with no power going to the high pressure fuel pump. Checked relays and can't find any fuses, just circuit breakers with red reset buttons. What am I missing?

[ABC]

After a couple of weeks, the dealer called me and quoted me $4k to replace the fuel pump, the ECU and the battery. The fuel pump runs when you connect it directly to a battery, so I don't think its bad. The battery is 2 months old and just needed to be charged.. I told them I'd come pick it up and wasn't paying $4k for them to repair a bunch of stuff that isn't broken. Not sure how to check the ECU, but maybe that's an issue. I did check the little fuses and all the relays mounted on the front of the engine.

I checked again today, and my meter reads .05v at the fuel pump. That doesn't change when you turn the switch on and it just drops a bit when you crank it. Any advice on what to do next would be greatly appreciated.

[cal99]

I had a similar issue with my 1998 Supra. It turned out that I had a bad fuse link feeding the engine electronics with lower voltage. In this situation, the computer didn't have enough power to switch on the fuel pump relay. Before I replaced the fuse link, I got it running by bypassing the fuel pump relay with a short piece of wire. I would suggest checking the fuel pump relay and the voltage at the engine computer. Good Luck!

[Turbinesurgeon]

Check the kill switch with your multi-meter. It’s directly inline with the fuel pump

[ABC]

I finally got around to working on this boat again.. I sent the ECM in for diagnostics and he said it was totally fried. Probably due to a power surge or battery connected backwards. Got a new ECU installed and have the following really weird problem now.

I turn the key and don't hear the fuel pump run, so I put a meter on the fuel pump to see if its getting voltage and it magically starts working. As long as I have a volt meter on the power terminals of the fuel pump, it works perfectly and the engine runs.. as soon as I take the volt meter away, the pump stops working and the engine dies.

I think I'm pretty smart, but there must be some mystical electricity stuff going on that I just don't understand. Anyone have any ideas?

[Branden967]

I finally got around to working on this boat again.. I sent the ECM in for diagnostics and he said it was totally fried. Probably due to a power surge or battery connected backwards. Got a new ECU installed and have the following really weird problem now.

I turn the key and don't hear the fuel pump run, so I put a meter on the fuel pump to see if its getting voltage and it magically starts working. As long as I have a volt meter on the power terminals of the fuel pump, it works perfectly and the engine runs.. as soon as I take the volt meter away, the pump stops working and the engine dies.

I think I'm pretty smart, but there must be some mystical electricity stuff going on that I just don't understand. Anyone have any ideas?

That’s definitely odd. Could it be somehow grounding the fuel pump when your using the meter? What exactly are you hooking the meter too?

[Turbinesurgeon]

Sounds like a ground issue possibly


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[z28ke]

I agree with a grounding issue, which could also explain the fried ECU.

Probably best to start at the negative battery terminal (the large cable and the smaller wires on the screw post) and follow the wires from there checking all connections and for ground with your multimeter. It would be a good idea to check the ohms (resistance)on all the primary ground wires to make sure there isn’t an unseen issue with the wire itself (like major corrosion inside the casing or a break).

Good luck and just remember the number one rule of wiring I was taught many years ago: Don’t let the smoke out of the wire, if you do you are fuc*** hahaha

[Turbinesurgeon]

I think there’s also a ground cable from the shelf the ECU sits on to the engine block.


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[ABC]

not sure if it was the + or the -, but cleaning the corrosion off of the connectors and terminals as well as the quick-connect fixed the issue. Was probably the only issue last year before I fried the ECM for $900. Lake testing today