need Help, 09 Twisted Turbo m8- how do u know if fuel pump craps out??

[av8er]

I rode on sat. no issues, went to go riding on sunday, and as sled was warming up I heard a whistling sound coming from the fuel tank, if i got on the gas fuel pressure would go down to 20 psi, normally at 40, took sled home, drained all of the fuel from the tanks, some minor fuel contamination in the form of some brown lacquer like stuff from the barrel, vacuumed out contamination, cleaned the screens on the fuel pucks, cleaned out the tank, put in about 2 gallons of avgas pre -mixed, sled has oil delete, now when you punch the sled and boost builds the sled falls on it's face, fuel pressure goes down to about 20 psi, do I have a bad fuel pump in the tank, or what? thank you for the help.
whistling noise disapperaed.

 

[Hardass]

When my buddy adjutsible regulater took a dump last week he had 40 pounds and when he hit the throttle it would go to 10 pounds every time . Replaced the regulater and back to rising rate.

 

[backcountryislife]

Funny... just finally lost my FIRST day of riding in 2 years on my stage II to a fuel pump.

For me, ran perfect, then next day no fuel pressure at all.

Haven't dealt with testing or anything yet.

On yours do you perhaps have a blockage in the pump lines? if it's pumping fine, but you had some gunk in there, is there a bottleneck that's perhaps restricting flow?

Could junk in the smart valves (pickups) do this?

I'd clean out your fuel reg though too... seems like if you got gunk in there I'd check everywhere that could have caught some of it.

 

[Whimp]

power your fuel pump with an external 12v battery. Start sled and test the plug that normally powers your fuel pump for voltage. If it is reading correct voltage then its most likely your fuel pump. i have seen a few act like this with an electrical issue or stator problem but theres a good chance its the pump....

On a different note.... While you are in the tank remove the rubber grommet from the pick up valve which is in the rear of the tank. Then put the smart valve back together. This will keep this thing always sucking fuel even if it tries to close on you.(less stress on the pump) We have had a few sleds that the smart valves have been finicky.. They close when they aren't supposed to.. My theory is when we are climbing hills and all the fuel rushes to the rear of the tank and the front two smart valves close then we are sucking 100% of our fuel from the rear pick up. I think we are sucking so much fuel that it can sometimes suck closed on us.......You can tell when the pump is stressed cause it will whine.... After removing this rubber grommet most of the sleds stopped whining. A few still whine regardless.....

good luck... hope you get it figured....

 

[av8er]

Talked with Stanger

He mentioned to check the Capacitor voltage at low idle and then at higher idle
also to take out the fuel pump and the fuel pucks, dis assemble them and clean out the screens with brake cleaner. he mentioned when fuel pumps go bad, they just quit working, no pressure what so ever. I'm not sure how i'm going to get the fuel pump out my forearm is too big won't go in the hole. I had to have my Brother reach in there before. capacitor voltage should be 12v at low idle and 14v at high idle

 

[m8lovin]

Buddys 09 did the exact thing you describe and he got a new pump from shane and it fixed the problem. We checked capacitor output first but it was ok.

 

[m8lovin]

Something to check is pull your pump out of the tank and remove the machined aluminum barbed fitting on the bottom of the pump. it is just a friction fit and comes off with chanel locks or pliers. There is a screan in there and make sure it is clean.

 

[av8er]

Update

pulled fuel pump and pickups out of the tank, took apart pickups, cleaned out screens with brake clean, removed the diaphram in the rear pickup, lost one of the stupid little springs, macgyvered a spring from a click pen, cut it down and replaced the cut down spring from the fountain pen in to the rear pickup, also cleaned screen in fuel pump, re-assembled and tested. Sled ran flawlessly, did not fall on it's azz like before , fuel Psi would increase as boost increased, made 6-7 high speed passes and put everything back together- No Issues- HIP HIP HOORAY-

THANK YOU TO ALL MY SNOWEST FRIENDS

 

[m8lovin]

Glad it worked out. Just out of curiosity was there junk in your fuel pump screen? And is the whining noise from your fuel pump less now?

 

[av8er]

the whining is gone

was told that the whine noise is from the fuel pump straining to do it's job, also when I pulled the screen off the pump it was pretty much clear of debris. the screens in the pickups had either barrel rust or schlack from the barrel. I did pull the rear diaphram from the fuel puck.

 

[BigAir]

What is the chance of sucking air from the rear pickup if you pull the diaphragm? Say you are going down a steep hill and nail the throttle?

 

[Whimp]

Been running with rear pickup like this for Long time! No issues down the hill...

 

[TheBreeze]

What do you use to clean out the regulator, etc? Also, what is this "diaphragm"?

 

[Whimp]

To clean a Fuel Reg blow compressed air through it in the direction the fuel flows. for the diaphram... its the rubber washer/seal that is in the pick-ups. It is what causes the pick-up to stop sucking fuel. Take apart a pick-up pod in the tank and it is very evident.......

 

[Polarisrocks]

Well on shanes 09 kits he sent out a capacitor kit to adapt some ac power from the accessory yellow black plug.. He sends a little wire harness and a capacitor wired to a bridge rectifier.. But the problem is the bridge recifier "uses" 1.7 -1.9 volts so you my have a lower voltage to your pump which may have caused your issues, killing the pump. I test my voltage at 1800 rpm idle and its only 11.53 volts at the pump.. pre capacitor/rectifier its over 13..

I am adding a battery in place of the capaitor so i can prime fuel pump and power up my fuel box if i need to make a change..