454 mag vst problem please help
 

I bought a crownline with a 454 mag mpi and just got the bravo one installed. I drained all the oil and add new and then tried to start the boat. At first I had fuel at the shrader valve but it stopped for whatever reason. I can squirt raw fuel into the intake and it will fire up. I have fuel pressure at the input of the VST tank but nothing coming out of the output side when I start the boat. How can I test the vst? I took off the return line and the output but no fuel came out while the boat was running on raw fuel. Should I take the vst apart or hot up the grey wire to the vst to see if it comes on? Could the oil pressure drop from the oil change cause the vst to stop working?

I plan on taking the connector apart and checking for 12 volts while the engine turns over.

Am I asking for a expensive endeavor taking the VST apart?

THe oring is expensive as far as orings go....
hook a fuel pressure gauge to the shrader valve

Make sure your sitting down when you check the price on the fuel pump in the vst tank

So i dont have fuel pressure. I took the vst apart and it wasn't to bad but again I unplugged the output to the vst and only a little bit of fuel would come out under higher rpm. I put a gauge on it and nothing. This gauge allows me to add pressure so I did while it was running and as long as bgh added pressure the boat would stay running for about a minute and then died again. I believe the fuel pump in the vst to be bad. Is there any replacement that will replace the vst and manual fuel pump?

I'm looking for something for specific or some write up where it was done with success.

When you turn the key to ON/RUN before you start do you hear the VST pump run?

If not, put a volt meter on the connector going to the VST and see if you get voltage when you turn it ON

I do not remember what the cross reference is to the VST pump, but there is the same pump acvailible from someplace besides merc that doesnt carry the 700 dollar merc price tag...I found out about that after I bought a 700 dollar pump.......

Ok double check this but I believe the merc part number for the vst pump is 808505T01. List price is $720.. Googling the part number gets this..


If I just saved you $600 bucks, You sir, owe me a frosty beverage.....

Man i got exited last night when I found a Caltric pump for $35. I think this one may be better.... well if you go by price but now I'm worried. Anyone ever use the Caltric pump?

That pump looks different looks like it's for a outboard but it looks like the pump I need just goes into a different housing. I got to check into this part number.

It is the same pump. How about that! You sir deserve a frosty beverage!!!

:evilb:

You should look down in classifieds and buy my extra fuel rail with adjustable fuel regulator and then ditch the VST completely and put a good electric fuel pump on it plumb it to the top port of the rail and then the bottom port of the fuel rail plumbed back to the fuel tank as a return and be done with it. much better

Alldodge you were correct no voltage. Chased it back and found a bad fuse. Pump primed and started leaking from the top. Took it apart to see which oring was leaking and broke the plastic piece that holds the electrical post onto the housing.

i cannot find these parts and don't want to buy a new $740 fuel pump for two plastic pieces. Anyone got these pieces? Or an old VST that needs built?

Have a VST that I removed from my 502 when repowering, it was working without issues. If your in the lower 48 I'll sale it for $350 shipped.

You could also change the VST to a cool fuel or other pump if your willing to reroute the fuel lines

Ouch those stupid plastic pieces are one expensive mistake. I think I'll look around for a little bit.

Are those on this pic ? If so, which one's ?

https://cimg4.ibsrv.net/gimg/www.off...27c166f2f5.gif

It says 8 and 10 but it also shows 8 to be the fuel pump and other pieces. Its the one with two marks pointing to both at the top of the electrical connectors. Its the two pieces that the electrical connection actually sit on and the nuts screw down to.