Fuel pump (circuit) problem

[Jacksnife]

When I start the motor it kicks in the pump, pressures up and starts every time. But after a while at idle it will start to cycle power to the pump.... then finally no power to the pump at all and dies. Pump works fine hooked straight to battery.

So I have some kind of electrical issue. I cleaned the contacts on the fuse and relay... even swapped them with the fan's, no help. Now I'm thinking there is some kind of oil pressure switch inline with the fuel pump but I can't follow the wiring diagrams very well. Has anyone worked on this circuit?

PS. I replaced the fuel pump with a Premium 5211007 (autozone) and it works fine on straight battery power. It fits better than the Bosch too because it's fatter and comes with hard rubber surround. I changed the line from the filter to the pump to 3/8 too.

[Jacksnife]

Oops! never mind... it is crapping out even with the fuel pump directly connected to a battery. When the pressure starts dropping I can pinch the output hose of the pump... then it'll get a burst of fuel and fill back up again. It's acting like it's not getting fuel to the pump... or maybe not enough fuel and getting too hot? I'll go run it into a gas can until the tank is empty to see if it has good constant flow.

[Jacksnife]

Pumped a whole tank out no problems... cool as a cucumber. Next I hooked up the regulator to see if I could get a tank through it... nothing coming out of the regulator at all!! so I think I was overheating my pump is all. I don't think I'll find one that mounts like this one, so I'll first try taking it apart haha

[Jacksnife]

Easy enough! problem solved. The regulator is just like any spring loaded regulator. Cleaned it up and it's ok now. I have it set at 60lbs and it runs fine... but I think I remember reading 73lbs?

[Jacksnife]

Found it on pg 53 in the 2009 manual

Fuel pressure adjustment Never make unnecessary adjustments. The factory recommended settings are correct for most applications. The recommend fuel pressure is 3.5kgf/m2 (49.8 psi). It’s not necessary to adjust fuel pressure unless the fuel pressure really needs to be adjusted. To adjust the fuel pressure: 1. Loose the lock-nut with a 14mm spanner as the following picture. 2. Turn the adjustment-bolt clockwise with a inner hexagon spanner to increase the fuel pressure, and counterclockwise to decrease the fuel pressure. 3. Keeping one eye on the fuel pressure indicator while turn the adjustment-bolt, when the indicator shows about 3.5kgf/m2 (49.8 psi), stop turning, and tighten the lock-nut.

Until it shows "about 49.8psi" haha

[charlie]

So are you Allset did u readjust it to factory spec

[Jacksnife]

I got it as close to 49.8 as I could : )

It still doesn't run perfect yet though. It sputters sometimes at full throttle and feels like it loads up at crawling throttle. It is new to me and I had to start with a complete overhaul, so I don't know how many other problems I need to deal with... but it feels like some sensors are AFU. The motor was smoking like a chimney when I got it, and by the looks of the motor internals they ran it like that a loooong time. I'm guessing the O2 sensors are trash? I wish I could hook up something to read the computer. There must be a way, I'll study that today.

[charlie]

I don't know of anyway to read the computer I know no limits Powersports had something and silver bullet motor sports did maybe McCoy motor sports too or a wide band AF??

[Kinarfi]

I run 35 PSI on my regulator, Hook a light across your fuel pump to monitor the voltage,

also, on the computer pin out. X1-70 - MIL - Mal-function Indicating Lamp Output could be hooked up to show if you actually have a malfunction. If you want to do that, just remember that pin X1-70 is a sink to ground, that means that 12 volts is supplied to a light and the light is grounded via X1-70 if there is a mal-function.

[Jacksnife]

It ran pretty good yesterday, no stuttering or sputtering just good clean acceleration. It was running much cooler than normal too. It's getting happier with its new home : )