Over fueling

dabranco · 11-25-2011, 07:49 PM

Car is my 84 RX7 with a 12A

This was my surprise... well at least it was to me. I go to start my car to empty the last of the fuel out of the fuel system. The fuel pump is disconnected (wires cut awaiting a factory style replacement). So here is my question what would cause the carb to fill to the brim with gas?
My assumption is a fuel pump pushing to much fuel to the carb. Aftermarket pump routed in the car hooked up the auto trans connector by the shifter.
If I am right then I am assuming that would cause about .25-.5 gallons of gas to end up on the floor of the garage by going out of the exhaust system I do have to admit I found all of my exhaust leaks this way.

So to make this short as possible since one of the PO decided to replace the pump halfed ass it over fueled the carb causing fuel to come out of the exhaust of the car. If I replace the fuel pump and do it correctly then my fuel pump will not over the fuel the carb and that should correct my over fueling issue. Is there any other things I can do to prevent this from happening again?

rxtasy3 · 11-26-2011, 08:58 AM

could be trash in the float needles causing it to not shut off the fuel, or they're stuck. if the pump pressure is too much they also wont shut off the flow. in this case u just need to add a regulator. the stock carb only needs like 2-3 psi fuel pressure.

dabranco · 11-30-2011, 12:12 AM

OK replace the old (aftermarket fuel pump) with a brand new OEM style pump. Here is my question now. When I go to start the car it just cranks I get no pump prime until I turn the key from start to run and I get a 1 second buzz from the pump. What would cause this and yes there are about 2-3 gallons of gas in the tank.

Kentetsu · 11-30-2011, 04:36 PM

An 84 will not start the fuel pump until it senses spark on the secondary ignition. In other words, it won't start the pump until you are cranking the engine over.

If your Float Bowl Vent Solenoid is not working, it will cause fuel to flow into the carb after shutdown. That is where I would start looking.

.

dabranco · 11-30-2011, 06:54 PM

Quote:

Originally Posted by Kentetsu

An 84 will not start the fuel pump until it senses spark on the secondary ignition. In other words, it won't start the pump until you are cranking the engine over.

If your Float Bowl Vent Solenoid is not working, it will cause fuel to flow into the carb after shutdown. That is where I would start looking.

.

Well I know I have spark, I can start it will starting fluid. So I am ruling out the first issue. The second one would be how hard is it to change the float bowl vent solenoid... also what does this exactly do? Also would FBVS prevent the car from getting fuel into the carb?

dabranco · 12-01-2011, 01:06 AM

OK fuel pump issue resolved it works!!!!!!!! Had to reconnect the choke lever. Now I have an issue of fuel getting out the exhaust and a very lean condition with heavy smoke. So now my next question would be what would cause fuel in the exhaust and heavy white smoke?

Note: Plugs are new and gapped correctly, fuel is fresh, 8 gallons apx in the tank, I am about 100% sure the carb is way out of adjustment (was told it was rebuilt),

Kentetsu · 12-05-2011, 03:28 PM

A stuck float would cause the fuel issue, but white smoke could be coolant seals...

dabranco · 12-05-2011, 05:12 PM

Quote:

Originally Posted by Kentetsu

A stuck float would cause the fuel issue, but white smoke could be coolant seals...

I pressure tested the cooling system and the only leak is a slow one for the coolant level sensor (need the washer) .5-1 psi drop per hour also no signs of coolant in the oil. So I am assuming the seals for the motor are good. Would excessive gas in the cats cause it (white smoke)? Also how many floats are there? I thank you guys for all the help so far.

Kentetsu · 12-07-2011, 04:55 PM

There are two floats. Large amounts of fuel can cause white smoke. What does it smell like?

dabranco · 12-07-2011, 05:17 PM

Gas. I do not have the "sweet smell" ass. with coolant. Next on the to do list is rebuild the carb, well new gaskets, and new floats.

11-25-2011, 07:49 PM	#1
dabranco Rotary Fan in Training Join Date: Nov 2011 iTrader: (1) Posts: 47 Rep Power: 0	Over fueling Car is my 84 RX7 with a 12A This was my surprise... well at least it was to me. I go to start my car to empty the last of the fuel out of the fuel system. The fuel pump is disconnected (wires cut awaiting a factory style replacement). So here is my question what would cause the carb to fill to the brim with gas? My assumption is a fuel pump pushing to much fuel to the carb. Aftermarket pump routed in the car hooked up the auto trans connector by the shifter. If I am right then I am assuming that would cause about .25-.5 gallons of gas to end up on the floor of the garage by going out of the exhaust system I do have to admit I found all of my exhaust leaks this way. So to make this short as possible since one of the PO decided to replace the pump halfed ass it over fueled the carb causing fuel to come out of the exhaust of the car. If I replace the fuel pump and do it correctly then my fuel pump will not over the fuel the carb and that should correct my over fueling issue. Is there any other things I can do to prevent this from happening again?

11-30-2011, 04:36 PM	#4
Kentetsu RCC Contributor Join Date: Feb 2008 Location: Grand Rapids, Michigan iTrader: (1) Posts: 530 Rep Power: 17	An 84 will not start the fuel pump until it senses spark on the secondary ignition. In other words, it won't start the pump until you are cranking the engine over. If your Float Bowl Vent Solenoid is not working, it will cause fuel to flow into the carb after shutdown. That is where I would start looking. . __________________ "Learn from the past, or it will become your future...." '85 GS 12a + LSD/Sterling carb/Respeed coilovers/Respeed front swaybar/Respeed adj. rear spring perches/Illuminas/Bilsteins on rear AutoX vids @ http://www.youtube.com/user/Kentetsu1

11-26-2011, 08:58 AM	#2
rxtasy3 rotary madness Join Date: Apr 2010 Location: spartanburg, sc iTrader: (0) Posts: 78 Rep Power: 15	could be trash in the float needles causing it to not shut off the fuel, or they're stuck. if the pump pressure is too much they also wont shut off the flow. in this case u just need to add a regulator. the stock carb only needs like 2-3 psi fuel pressure.

11-30-2011, 12:12 AM	#3
dabranco Rotary Fan in Training Join Date: Nov 2011 iTrader: (1) Posts: 47 Rep Power: 0	OK replace the old (aftermarket fuel pump) with a brand new OEM style pump. Here is my question now. When I go to start the car it just cranks I get no pump prime until I turn the key from start to run and I get a 1 second buzz from the pump. What would cause this and yes there are about 2-3 gallons of gas in the tank.

12-01-2011, 01:06 AM	#6
dabranco Rotary Fan in Training Join Date: Nov 2011 iTrader: (1) Posts: 47 Rep Power: 0	OK fuel pump issue resolved it works!!!!!!!! Had to reconnect the choke lever. Now I have an issue of fuel getting out the exhaust and a very lean condition with heavy smoke. So now my next question would be what would cause fuel in the exhaust and heavy white smoke? Note: Plugs are new and gapped correctly, fuel is fresh, 8 gallons apx in the tank, I am about 100% sure the carb is way out of adjustment (was told it was rebuilt),

12-05-2011, 03:28 PM	#7
Kentetsu RCC Contributor Join Date: Feb 2008 Location: Grand Rapids, Michigan iTrader: (1) Posts: 530 Rep Power: 17	A stuck float would cause the fuel issue, but white smoke could be coolant seals...

12-07-2011, 04:55 PM	#9
Kentetsu RCC Contributor Join Date: Feb 2008 Location: Grand Rapids, Michigan iTrader: (1) Posts: 530 Rep Power: 17	There are two floats. Large amounts of fuel can cause white smoke. What does it smell like?

12-07-2011, 05:17 PM	#10
dabranco Rotary Fan in Training Join Date: Nov 2011 iTrader: (1) Posts: 47 Rep Power: 0	Gas. I do not have the "sweet smell" ass. with coolant. Next on the to do list is rebuild the carb, well new gaskets, and new floats.