</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by slowverado:
<strong> does the inline have to be on all the time? or can you set it up to run from a switch to only have it on when you want it on. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">there are 3 ways to control an inline fuel pump.

1) just let it run all the time, if your presure under a light load or idle doesn't creep up i think this is the best way to do it.

2) WOT swith or hobbs swith, this will take care of the fuel presure creeping up on you at idle but there is a brief dip in presure when the pump turns on, for my set up that could be a bad deal or maybe it isn't a real concern, not sure how significant that dip is.

3) variable speed controler, runs the pump slow most of the time and speeds it up at WOT or under boost, this is a prety trick way to do it. you can run a big *** inline that would normaly overrun your return line but at partial speed will not, then speed it up once your fuel demand increases. since it is always running some you wont see a dip when it speeds up.

the 340 inline pump doesn't seem to have enuff capasity to overrun the return line but it may also not have the capasity to feed a really high hp set up. something like an aromotive 1000 with a variable speed controler would be prety bad *** and i think it would feed a monster set up too. lots of $$$$$ though.

 

so for a heads cam, nitrous injected 6.0 it would probably be best to just leave the pump on all the time, it shoudln't hurt anything to have it on during normal use since it's a bigger motor using more fuel with cam etc. and at wide open throttle it should hold up nicely and feed the wet kit nicely

 

i don't really know what i am looking at with those pic's but it sure seems like anything that would work on the camaro would work on the truck since they look very similar. i hope you figure out what the deal is, i really wanted to just order a twin intank set up like some of those camaros can but they(racetronics) didn't seem to want to work with me.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by slowverado:
<strong> so for a heads cam, nitrous injected 6.0 it would probably be best to just leave the pump on all the time, it shoudln't hurt anything to have it on during normal use since it's a bigger motor using more fuel with cam etc. and at wide open throttle it should hold up nicely and feed the wet kit nicely </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">i would think just the 340 inline pump(running all the time)would be enuff for that set up. i wouldn't try the nitorus without a fuel presure gauge just to be sure.

 

actually right before i read what you said about a fuel pressure gauge i placed an order for one from jegs. what kind of pressure should i be seeing from it before hand to make sure i'm good for the n20.

Matt

 

i see about 62psi but the boost forces it up some, without boost i think ~58psi, that part isn't critical. you want to make sure it doesn't fall off when you hit the juice, just a quick flick in the gauge when first hit the button is probably ok just as long as it goes rigth back to where it was before. when i was maxing out the stock pump i would see it drop from 62psi all the way to 40psi, it is prety easy to see.

 

Matt- Our fuel systems are supposed to run at 58 psi. Our injectors are calibrated to feel the correct amount of fuel at 58 psi. If for some reason, out fuel pressure were high the PCM wouldn't know it and at WOT you would be rich. If it were low, you'd be lean, and bad things happen. Watch the pressure and make sure it stays pretty consistently at 58 psi.

Jim- Those pictures are of the stock intank fuel "sender", I think it is what we are calling the pump. One for our truck, one for the camaro.

For the truck, here is what the numbers point to:
1. Fuel pressure sensor
2. Fuel strainer
3. Fuel level sensor
4. Sensor retaining clip
5. Fuel pump electrical connector
6. Electrical connector retaining clip
7. Electrical connector to the fuel level sensor.

On the car, #2 and #3 are the fuel pressure regulator. It is mounted on our fuel rail, but on the car, it just dumps back to the tank from this spot instead of having a return line from the fuel rails.

 

Some people need to read this, other know most of it. Here is GM's description of the Fuel system in our trucks:

Fuel System Description - CSFI

The central sequential fuel injection (Central SFI) system is controlled by the control module located in the engine compartment. The control module is the control center of the system. The basic function of the fuel system is to control fuel delivery to the engine under all operating conditions.

The main control sensor is the heated oxygen sensor (HO2S). The HO2S is located in the exhaust system. The HO2S tells the control module the amount of oxygen in the exhaust gas. The control module changes the air to fuel ratio to the engine by controlling the fuel injector. Efficient catalytic converter operation requires a 14.7:1 air to fuel ratio. Because of the constant measuring and adjusting of the air to fuel ratio, the fuel injection system is called a Closed Loop system.

Several other important engine operation parameters include the following items:

The engine speed
The manifold pressure
The engine coolant temperature
The throttle position
These parameters determine the mode of engine operation.

Modes of Operation
The control module monitors the voltages from several sensors in order to determine how much fuel to give the engine. The fuel is delivered under one of several conditions called modes. The control module controls all of the modes.

Starting Mode
When the ignition switch is turned to the ON position, before engaging the starter, the control module energizes the fuel pump relay for 2 seconds allowing the fuel pump to build up pressure. The control module then checks the engine coolant temperature (ECT) sensor and the throttle position (TP) sensor in order to determine the proper air and fuel ratio for starting. The control module controls the amount of fuel delivered in the starting mode by changing how long the injectors are energized. This is done by pulsing the injectors for very short times.

Clear Flood Mode
If the engine floods, clear the engine by depressing the accelerator pedal down to the floor and then crank the engine. The control module reduces the injector pulse width in order to increase the air to fuel ratio. The control module holds this injector rate as long as the throttle stays wide open and the engine speed is below a predetermined RPM. If the throttle is not held wide open, the control module returns to the starting mode.

Run Mode
The run mode has two conditions called Open Loop and Closed Loop.

When the engine is first started and the engine speed is above a predetermined RPM, the system goes into Open Loop operation. In Open Loop, the control module ignores the signal from the HO2S. The control module calculates the air to fuel ratio based on the inputs from the engine coolant temperature (ECT) sensor and manifold absolute pressure (MAP) sensor. The system stays in Open Loop until the following conditions are met:

Both HO2S have varying voltage output, showing that they are hot enough to operate properly. This depends on engine temperature.
The ECT sensor is above a specified temperature.
A specific amount of time has elapsed after starting the engine.

The specific values for the above conditions vary with different engines. When these conditions are met, the system enters Closed Loop operation. In Closed Loop, the control module calculates the air to fuel ratio (injector on-time) based on the signal from the HO2S. This allows the air to fuel ratio to stay very close to 14.7:1.

A normal functioning system may go into Open Loop at idle if the heated oxygen sensor (HO2S) temperature drops below the minimum requirement to produce the voltage fluctuation.

Acceleration Mode
When the control module senses rapid changes in the throttle position and the manifold pressure, the system enters the acceleration mode. The system provides the extra fuel needed for smooth acceleration.

Deceleration Mode
When the driver releases the accelerator pedal, the air flow into the engine is reduced. The corresponding changes in the throttle position and manifold air pressure are relayed to the control module. The control module reduces the injector pulse width in order to reduce fuel flow. If the deceleration is very rapid, or for long periods, such as long closed throttle coast-down, the control module shuts off the fuel completely in order to protect the catalytic converter.

Fuel Cutoff Mode
The control module cuts off fuel from the fuel injectors when certain conditions are met. This fuel shut off mode allows the powertrain to protect itself from damage and also improve its driveability.

The control module disables the injectors under the following conditions:

Ignition OFF -- prevents engine run-on
Ignition ON but no ignition reference signal -- prevents flooding or backfiring
High engine speed -- above red line
High vehicle speed -- above rated tire speed
Extended high speed closed throttle coast down -- reduces emissions and increases engine braking

Converter Protection Mode
The control module constantly monitors engine operation and estimates the conditions that could result in high converter temperatures. If the control module determines the converter may overheat, it causes the system to return to Open Loop operation and enriches the fuel mixture.

Battery Voltage Correction Mode
When battery voltage is low, the control module compensates for the weak spark delivered by the ignition system by increasing the following items:

The injector ON time
The idle RPM
The ignition dwell time

 

Parish - Have you ever tried driving with the inline pump turned off and just the intank running? I was just curious if the truck drove ok like that. Remember what I mentioned a while back about the motor starving for fuel when my inline pump died. I just wanted to see if that happened on the trucks since the fuel system is slightly different.

If it does then running the pump with a controller may be the only other option along with running it all the time.

One of the things I've heard about putting a 340 in to those "senders" that BigTex showed a picture of is that the pump pickup can become uncovered due to the fuel "basket" design. This is mainly a problem with light fuel loads and under acceleration. That's one of the reasons that Racetronix hasn't made a plug and play setup for this stlye sender. <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />

There are some pictures someplace on this site that I can't find right now that show a 340 install into one of those newer "senders". They are either in the FI, Ext eng, or Fuel section.

John

 

nope, my aux fuel pump realy is controled by the stock fuel pump power circuit. i did pop that fuse once and it still had presure at idle but that is all i can tell you for sure.

i say just let it run.