Supra Forums banner
1 - 6 of 6 Posts

·
Registered
Joined
·
937 Posts
Discussion Starter · #1 ·
So I'm getting ready to install a Haltech Elite 2500 into my 94TT BPU. The old AVC-R and Super-AFC and FCD and blah blah are all coming out for some nice 2019-modern goodness. I will be installing a VVTi head I have along with some Sard 800cc injectors, just for a bit of a boost, though the main reason for the Elite is for better control, a bit more power, and readiness for a single swap or possibly a Stu manifold GT28 setup.

For the moment though, I will be retaining the stock fuel pump (maybe swap bigger one) and fuel-pump ecu. No real reason to re-wire back there. The Fuel-pump ecu receives +12 via the main EFI2 relay, which is in turn controlled by the Elite2500 via a DPO using pin A24/M-REL. The Elite2500 calls this the ECU-Master-Relay output.

The stock ecu controls the fuel-pump ecu by pin A22/FPC on the stock harness, putting out a LOW or HIGH signal to tell the fuel-pump ecu to run the pump at 9V or 12V. Pretty simple, though I'm not sure if it's a PWM signal or direct 9V. The Troubleshooting Guide page EG568 is self-contradictory though ...
246935
246938

Given that the wiring diagrams show the FPC pin as a 5V pin, I'm guessing that the Low signal (about 9V) is a typo.

Most of the maps I've seen use the Elite2500/ProEfi/AEM pin to control that FPC pin like a regular fuel pump, essentially just putting out a HIGH to "turn on" the fuel pump, but relying on the Master-Relay/EFI2 to actually power the pump.

Kind of seems unnecessary. Unless you're actually using the 5V/12V signal to tell the stock fuel-pump ecu to run the pump and low/high speed, you may as well just tie that FPC signal into it right to +12V telling it to run the pump at +12V all the time. Or, if the stock fuel-pump ecu is removed, then you use a regular relay to turn the pump on/off using the FuelPump function in the Elite2500.

But for keeping the stock fuel-pump ecu, is there any reason NOT to tie the FPC input (pin 5 on connector F15) right to +12V and be done with it ? Safety is still there as the Elite2500 will disable the Master-Relay in the event of an engine stop (crash etc) which will turn off the fuel pump completely. It would be nice to not have to dedicate an output for it ...
 

Attachments

·
Registered
Joined
·
3,662 Posts
It depends on how fancy you want to get. I PWM the factory fuel pump ecu to retain the 9v/12v system. 50% duty cycle until 101kpa and then 100% duty cycle from 101kpa and up. I do this to the Walbro 450 and it works beautifully.

Or you can just run it at full tilt all the time. But this heats up the fuel and is slightly louder.

As long as you have US spec TT Chasis. This will not work on any other models because the fuel pump ecu's are smaller.
 

·
Registered
Joined
·
937 Posts
Discussion Starter · #3 ·
You're running the Haltech 2500 too aren't you ? If you are I'd love to have a look at your map.

Heh, I asked the same question on Haltech forums, Matthew replied with

You can do that if you want, but just switching it as we do has worked for the 1000's of people.
So their default is to just treat the 9V/12V switch as a regular fuel-pump control, so it's basically on +12V all the time.

Meh, if I'm going to do that I'll just tie that FPC pin to +12V and gain a spare DPO output.
 

·
Registered
Joined
·
1,941 Posts
Hey Guys, I'm using Elite 2500/P&P harness for my 2jzgte and I'm just getting into wiring up my dual walbro pumps.
257815

257816

How exactly did you guys do this? Where you able to still retain the 9v/12v oem setup on pump 1 then customize pump2 to come on at (eg. 7psi?)
I'd rather not hack up my oem wiring at the FP ECU but might be the best way?

Thanks!
 

Attachments

·
Mind if I do a J?
Joined
·
3,525 Posts
I know you can use factory fuel pump ECU but I don’t. I wire dual pump systems all the same way. 4 pins on relay - 30 is battery in, 87 is power out to pump, 86 is 12v switch (I get it from ECU), and 85 is a low side ground trigger from the ECU. One available low side trigger for one pump and then another available low side trigger for secondary. On ProEFI I use LS5 and LS7. On AEM Infinity I use LS0 and LS2.
 
  • Like
Reactions: rallly

·
Registered
Joined
·
1,941 Posts
I know you can use factory fuel pump ECU but I don’t. I wire dual pump systems all the same way. 4 pins on relay - 30 is battery in, 87 is power out to pump, 86 is 12v switch (I get it from ECU), and 85 is a low side ground trigger from the ECU. One available low side trigger for one pump and then another available low side trigger for secondary. On ProEFI I use LS5 and LS7. On AEM Infinity I use LS0 and LS2.


PM sent sir ;)
 
1 - 6 of 6 Posts
Top