I have a dumb question. What does a throttle sensor do on the carb motors. Im stumped on a problem that im having. Would love to have some help

 

whats the problem you having?

I think the TPS controls the timing advance.

 

I use the engine for tractor pulling. I use first gear only. I run 200 foot track pushing 12,000rpm the way up the track. About 100 foot i start loosing power. i can let out of the gas alittle and it will pick up then times it wouldnt im lost.

 

it sounds like your running out of gas. What kind of fuel pump are you running? Is it at the proper psi?

 

Fuel psi is good. Im running at stock pump with stock fuel lines. I did have a impact crack in my computer box. It was cracked all away around. i replaced it but i havent tested it yet. I have a pull tomorrow.

 

If its not the box. Do you have the fuel source and pump in front of the carbs or behind it? If the source is too far behind the carbs, the force of the vehicle moving may be just enough to not allow the fuel to flow.

On the bike, the fuel source is right above the carbs, with the fuel pump right below it. If your tank is behind the carbs, and the fuel pump is well, that may be why its starving for fuel.

I'm not positive, but I think the fuel pump only puts like 1.5-2 psi of pressure. Its more of an assist to the gravity feed to the carbs. If you remove the gravity feed and try to make the fuel pump feed up to the carbs, it may be starving for fuel.

you may have to get a fuel pump in the 4-5 psi range.

 

Yeah still the same thing. Will a 5-7psi pump be to much

 

I'm really not sure. You have to make sure as to not overpower the floats in the carbs. I was just putting it out there that the low psi stock pump may not be enough for what your doing. In all honesty, it truly sounds like fuel starvation, so I would put on the higher psi pump, and probably also install a fuel pressure regulator. You should be able to find one with a gauge for around 30 bucks. You can then increase the psi in 1 psi increments to see if the problem goes away.

Also, even though I dont think its the issue, I would measure the resistance in each coil to make sure they are within spec. A weak coil can cause high rpm sputters, however, the problem usually doesn't go away, its always there at that rpm. But its something just to rule out.