225 promax vst question

**jaybluez** · 07-16-2015, 12:53 PM

96 225 promax high pressure pump in vst will only run when the cannon plug is disconnected and then reconnected. Won't kick on when when key is turned on under normal operation. The high pressure pump will kick on when cannon plug is disconnected and reconnected whether the key is on or off. Boat runs fine, just not performing like it's supposed to. Any suggestions?

**jaybluez** · 07-16-2015, 04:56 PM

Let me ask this question, could you run a wire direct to fuel pump to kick it on when the key is turned on? Would it hurt anything for the pump to run constantly while key is on?

**whipper** · 07-16-2015, 05:42 PM

i wouldnt do that. If the pulse pump is getting week it wont meet the demand of the motor and pressurize the VST enough? Prostock setup is the way to go on these motors if you have a store to buy everything you need near buy. Boch pump lines regulator. Frees up the intake area also. Way less restrictive. The VST works good only when the pulse pump is working good of the crank.

**jaybluez** · 07-16-2015, 09:49 PM

Pulse pump working fine, it's the only thing fueling the motor right now. High pressure pump does work but not when needed. It'll kick on when the cannon plug is reconnected after being disconnected but won't come on when key is turned on like it's supposed to. Guess in its the wiring or ignition?

**TEXAS20225** · 07-16-2015, 10:29 PM

if it is in fact the fuel pump driver ,you can disconnect the two wires on the fuel pump run a isolated ground to the pump and a hot wire from the Bakelite bar on the switch box plate it has purple wires on it now, one is a efi wire the other is a extra may be one more but they come on when you hit the key , dont worry about the pulse pump ive done this several times with no adverse results you can limp till you figure out what it is and it may be the driver good luck

**jaybluez** · 07-17-2015, 05:20 AM

Excellent. Thanks for the replies gentlemen.

**tux974** · 07-17-2015, 05:35 AM

Bobby, good info!

**tlwjkw** · 07-17-2015, 06:02 AM

one of these, cheap, keeps load off "little purple" wire.....till ya fix whatever is causin' tha problem, which most never do..

http://www.summitracing.com/parts/sum-890023

**Dave Strong** · 07-17-2015, 08:19 AM

Pretty common to see the fuel pump driver go bad on these ECU's running the pump off a separate relay should not be an issue. Just remember the pump will run all the time if the key is on and not time out as it does when driven by the ECU. The ECU could work fine forever other than having a bad fuel pump driver, big expense just to have the fuel pump driven by the ECU.

Dave

**speedinstream** · 07-17-2015, 08:57 AM

Originally Posted by Dave Strong

Pretty common to see the fuel pump driver go bad on these ECU's running the pump off a separate relay should not be an issue. Just remember the pump will run all the time if the key is on and not time out as it does when driven by the ECU. The ECU could work fine forever other than having a bad fuel pump driver, big expense just to have the fuel pump driven by the ECU.

Dave

I have one running for years like that

**jaybluez** · 07-17-2015, 09:57 AM

Hopefully that'll take care of it. Heading to the store right now to get some wire and terminals

**jaybluez** · 07-17-2015, 07:07 PM

Update, got the high pressure pump running but now boat won't get above 3500rpms. Looks like bigger issues with ecu, guess it's due for a trip to Simon Motorsports. Thanks again S & F.

**Dave Strong** · 07-17-2015, 07:21 PM

You check your stator?

Dave

**TEXAS20225** · 07-17-2015, 08:21 PM

stator sounds like!!! Dave next time you got your mota running check that vst pump you will see the only time out is when you first turn on the key and vst pressures up after its running it never quits and yes the pump will run till you turn key off, im not a believer in installing a relay any more ive seen these run forever on just a single 16ga wire, but thats why there are chevys and fords too each his own