You can get adjustable Hobb's pressure switches too, mini-truck guys use them all the time to control air compressor on/off cycling. Just a little FYI.

 

maby just a litle off topic but what about instead of using it for pump controll, use it for Meth/NOS controll.

 

Probably doable with a little rewire and control over the ECU parameters.

 

waking this thread from the dead but I was thinking about this and I was curious what if we run each pumps off a resistor just like stock. In fact splice in some when it sees 12v each pump has its own resistor.

Then for the second pump run a direct 12v source to a 30amp bosch relay that is triggered from the signal from the factory ecu.

What do you guys think ? Yes no ?

 

Unless you "smart" bastards figure this out, i'm going to be short 5 bones from a br double....Keep diligently working Mike!!!

 

Whatever you just wrote is really confusing.

In any case, if only 1 pump is needed at idle/cruise, there is no need for the second pump to have its own resistor.
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What I'd like to know is if someone has a quick guide of pictures for where all of the factory relays are and where the resistor bridge is. I would think that thing would generate a decent amount of heat....

 

Ill try and get a print out at school off All Data. I hate trying to explain things in writing Im not very good at it.

Hopefully once we have a nice diagram we can figure something out.

 

Fact it there really is no need to run a resistor to your fuel pump what so ever, unless for whatever reason you are using it to tune with.... i.e. use a resistor to reduce fuel pressure instead of an AFPR, which is basically what the factory does. But to keep things even you would need to put the same resistors on each pump otherwise when the second pump turns on you will effectively reduce your fuel pressure when the pump without the resistor over powers the pump with the resistor and starts pumping fuel back into your fuel tank. When I get home from work I will post up a picture of the circuit from the FSM. As it sits everything you need to control a second pump/meth/nos/whatever is in the car, first problem is you won’t have any control over when the ecu triggers the relay. Until someone asks really nicely to get some of the other gurus to find the map/switch for us. sorry I have looked at an evo rom in IDA pro and got lost as soon as it opened (I felt really DUMB) second problem is the circuit is basically backwards from a normal circuit, the ecu completes the ground under light loads then opens the circuit letting the relay close to bypass the resistor. So you can’t really use a standard bosch relay for that, but the factory fuel pump bypass relay will work fine.

 

1) The pumps should not be able to create backwards flow through eachother.
2) Many of us would like to keep a resistor on one pump, but this should be all that is needed unless you want (for some ungodly reason) both pumps on all the time with a resistor under the switch point Also, AFPR's cannot dynamically alter flow and reduce it beyond base fuel pressure at idle. The resistor helps to eliminate waste energy caused by pumping gas around the system and also should help idle slightly.
3)The FSM diagrams are in the first post, thanks anyway
4) I'm pretty sure Bosch relays come in both NC/NO configurations. If not, there are plenty of other relays that do. They probably do this since it would be better to over-flow at idle rather than under-flow at WOT if something were to go wrong.

Yes, we still need to get a disassembler on this

 

Or you plan to do an inline external pump setup instead of twin intanks and need both pumps on at all times.

I'll need an AFPR either way to crank the fuel pressure to 100 PSI base anyway though. Gotta love the Injector Dynamics injectors.

 

1) didn't think factory fuel pumps have a check valve in them to keep fuel from running back wards but i could be wrong, that has been known to happen. i was just thinking simple fluid dynamics pump a putting out 50 PSI will normally over power pump B at 40 PSI and usually cause ill effects. at the very least you will still end up with 50 PSI only with a little more volume. which i guess is fine.

to me if i wanted to run dual pumps i would just splice in an extra wire from the stock pump and have it switch a relay to power the second pump on. using this circuit to power a second pump makes no sence... now using it to switch on something else NOS/Meth...

2) OK, i will agree with that one...

3) toshay... guess i can stand to look like an *** every now and then. thats what i get for going straight to page 3.

4) you sir are probably correct, I'll bet you can get a Bosch relay in either config. but i will bet you 99% of what you will find at the auto parts store are N.O. but why go buy a relay when Mitsubishi has already given you one...

here is a quick and simple way to mod the circuit... only problem is, if it is something goes wrong and you lose power to the relay plan on having whatever you have hooked up to it dumped into your intake. until we figure out the switch/table in the ROM. any way.

 

Lol, nice comments in the diagram

 

Many high powered cars actually use a two stage pumping system just like the EVO. Toyota used it back in '90 on the MR2 turbo. They do this because a fuel pump that can supply adequate fuel for 300+ HP is typically LOUD. Most people don't like the whine of a fuel pump overpowering the exhaust at idle.

The redundancy is there for a reason. Relay 1 is to insure the fuel pump only comes on when the ignition is in the run position. Otherwise a short in the line could easily cause the fuel pump to run. Seems redundant, but when you get in a car wreck, you typically don't want the fuel pump turning on when a couple wires get crushed and this will reduce the chance of that happening.

Relay 2 allows the ECU to control the fuel pump. This is where most cars with quiet fuel pumps stop.

Relay 3 allows a high/low fuel pump control. Very nice for the cars that have loud pumps.

All of this seems pretty simple to me. Guys that are running dual pumps either use a hobbs switch or an AEM to trigger the second pump. The factory ECU has the ability to do this, why not use it?

 

So did we stop work on this? I am sure David (Tephra) probably could tell us what controls pin 39 or if we need to add code to do it ala map switching?

 

This may sound silly, but is there a discreet output on the USDM cars for the second solenoid in a dual solenoid boost control system? If so, I think it might work really well to just set the DC to 100% for the second solenoid and tie this output to the switching relay. Then your minimum load for boost control also becomes your 2nd pump load switch-on point.

Am I making this too easy in my head?

(we could even set it to 128% DC just in case)