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milehigh69
04-02-2011, 11:27 AM
I am at my wits end on this so hopefully someone has a good idea. Problem I have is when the car warms up at operating temp 180 ish , eventually the fuel pump (external walbro 255) begins to oscillate and cant keep pressure up and leans out the engine. I have had the regulator in the engine bay. Now have it back at the tank running a single line forward. Recently found out my EFI has a ability to add a separate line to the ground to control the voltage to pump. It was working great then the fuel overheated. Tank is near full. Filter is downline and is a high flow aeromotive.
Like I said I dont get it. But really a pain and dangerous. Any ideas.

1969CamaroRS
04-02-2011, 11:36 AM
How long is the feed line to the pump?
Is the pump's intake below the feed line from the tank?
Is it as short as possible? Pumps don't tend to pull well.

When the pump starts to oscillate what is the temp the fuel?
Is the pump really hot or the fuel?
If so what about a inline fuel cooler?

What is the voltage at the pump?
Good ground?


hope this helps,

dhutton
04-02-2011, 11:42 AM
Is the tank properly vented? If it is then maybe one of these Aeromotive fuel pump controllers will help lower the fuel temperature:

http://www.summitracing.com/parts/AEI-16306

1969CamaroRS
04-02-2011, 11:55 AM
I was worried about fuel overheating and plumbed in a inline fuel cooler on the frame rail:
https://static1.pt-content.com/images/pt/2011/04/th_FuelSystem001-1.jpg (http://i328.photobucket.com/albums/l346/Marroweter/Engine/Engine%20Install/Fuel%20System/FuelSystem001.jpg) https://static1.pt-content.com/images/pt/2009/04/th_FuelSystem026-1.jpg (http://i328.photobucket.com/albums/l346/Marroweter/Engine/Engine%20Install/Fuel%20System/FuelSystem026.jpg) https://static1.pt-content.com/images/pt/2009/04/th_FuelSystem029-1.jpg (http://i328.photobucket.com/albums/l346/Marroweter/Engine/Engine%20Install/Fuel%20System/FuelSystem029.jpg)

Its a 12" long Barry Grant inline with -10 fittings, but flexlite makes some framerail ones too. BG claimed a 90* drop, dunno about that but I figured on the framerail at any speed should be worth some reasonable amount of cooling.

milehigh69
04-02-2011, 12:35 PM
Good info. I have a 12" in line fuel cooler to the front. Effectively I have a fuel pump controller integrated in my EFI. The fuel pump does feel warm to the touch. Not sure what the temp of the fuel is. My car is at 180. One common element I have from the previous design to this one is the Fuel regulator. Can these go bad when hot?

milehigh69
04-02-2011, 02:50 PM
I just tried bypassing the regulator and that did not do the trick. The car had cooled down also and I had just put in fresh cool fuel. The pump started to oscillate and make the whining sound. Maybe I have a bad pump. I just bought it this spring. Its a walbro. I may bite the bullett and go with Vaporworx.

Vegas69
04-02-2011, 03:05 PM
A member on Lateral G had an aeromotive paper filter clog last month. You may want to check it.

dhutton
04-02-2011, 03:26 PM
If your EFI is varying the voltage to the pump instead of using PWM control then that could be your problem. Fuel pumps need full voltage. The Aeromotive controller uses PWM control.

MrForce
04-02-2011, 03:40 PM
What size is your return line? dhutton is correct about varying voltage (bad idea) (PWM good) and is your tank vented? When the pump starts acting up, stop, leave the engine running and remove the gas cap and see if the pump sound changes. Pumps usually make noise when the fuel gets aerated (bubbles) Any and all of the above reasons could cause the problem, and all the suggestions above are worth looking into.


Good luck,


Rob

Denvervet
04-02-2011, 07:08 PM
Did you move your pickup down on the tank or are you still bringing it up and over with the Rob MC pickup?

CarlC
04-02-2011, 10:21 PM
If I understand correctly, the mechanical regulator still in the system but is being used in a deadhead arrangement. Is a pressure sensor used to monitor the fuel pressure and adjust the speed of the pump? If the mechanical deadhead regulator is used, what is the pressure set to vs. the pressure sensor setting?

Hammered
04-22-2013, 03:46 PM
What size is your return line? dhutton is correct about varying voltage (bad idea) (PWM good) and is your tank vented? When the pump starts acting up, stop, leave the engine running and remove the gas cap and see if the pump sound changes. Pumps usually make noise when the fuel gets aerated (bubbles) Any and all of the above reasons could cause the problem, and all the suggestions above are worth looking into.

+1 Aeromotive
+1 vented cap

Most vented caps only allow venting of air into the tank, but not out of the tank.

Also check your tune to make sure you are running enough timing advance. A few degrees of advance can sharply reduce the amount of fuel you might be burning in the exhaust which could be heating your tank up too.

LSXperformance
04-26-2013, 07:31 AM
I always run walbros in tank to keep em cool. they get hot fast... just an idea you can easily modify senders to make them work like that even on old tanks. and the controller wouldnt be a bad idea. kenne bell boost a pump works well too. It varies voltage, they make a set up thats boost referencing as well depending on your set up that ramps voltage to 17v controlled by a simple dial reostat and kicks in anything over 3 psi. I havent had a bit of issues on em yet but I run dedicated pump circuits controlled by relays and ignition circuits I can draw you up a diagram if needed. and you can compare to how yours is set up. Maybe would help? msd makes a pump controller as well but I havent used it. I think operates similar. pm me if I can help

MonzaRacer
05-05-2013, 02:45 PM
First of all PWM control can and does, if properly operated , will actually be able to make a pump run at higher voltages than battery power.
Now, my curiosity gets me, IF your pump is external and after it runs for a time the pump starts making noise, it actually sounds like it may be overheating and the clearances opened up causing it to cavitate.
Too ask some specific questions.
1) is it ran from a relay, if so how heavy of wiring on the load side and are all connections solidly crimped AND soldered?also is relay power directly from battery
2) is the pump grounded to the frame, body structure, or separate ground?
3)How are the lines connected to and from the pump, compression, AN, Inverted flare, other.
A fuel pump MUST be relayed and have heavy connections to perform properly.
Just some ideas.

CarlC
05-11-2013, 01:49 PM
First of all PWM control can and does, if properly operated , will actually be able to make a pump run at higher voltages than battery power.

Can you please explain how using PWM will make a pump run at higher voltages?