Welcome, Guest. Please login or register.
Did you miss your activation email?

News:

Author Topic: Fuel pump ECU  (Read 24204 times)

Offline toylexus

  • Jr. Member
  • Posts: 93
    • View Profile
Re: Fuel pump ECU
« Reply #15 on: February 02, 2008, 02:07:37 AM »
Based on the schematics i've looked at, no.  The lexus ecu can't control the circuit opening relay.  i see two ways to control the fuel pump. The first one is to unplug the relay and jumper power to the fuel pump at the connector. This is the way i'm going to have to do it for initial test start, because funding hasn't allowed for purchase of a fuel pump ecu yet. With this method,  you would have to find another way to turn the fuel pump  on and off (like a switch on the dash or something). 

...and the second way is to use the fuel pump ecu and wire it into the lexus harness the way it was designed.  Since this is the way it was designed to operate on my lexus setup, i would prefer to keep it that way. Sorry about the confusion, i'll do whatever i can to clarify better if this is still confusing. Let me know if diagrams are better than words, or words are better than diagrams. i'm a picture person myself  ;D
« Last Edit: April 02, 2008, 07:18:41 PM by toylexus »

Offline toylexus

  • Jr. Member
  • Posts: 93
    • View Profile
Re: Fuel pump ECU
« Reply #16 on: February 09, 2008, 01:30:54 AM »
Here's the pics of the toyota circuit opening relay. This is to show the location on the '94 4Runner, connector, and fuel pump control wire.


This is the top of the circuit opening relay.



This is the location of the relay behind the passenger side kick panel, and above the toyota ECU. The toyota ECU has already been removed in this picture.



This is a slightly backed out shot of the relay. This is looking at the heater and a/c box with the glove box removed. The relay is in the upper right area.



This is the front of the connector. Note the blue wire on the left. This is the B+ voltage supply directly to the fuel pump. When a battery is connected to the toyota body (Battery connected to the B+ fuse block wire, and negative (-) to chassis ground) and this wire is connected to battery positive voltage, the fuel pump will run. The chassis ground has to be connected to the battery negative terminal, and positive voltage must be used from the same battery or the pump won't run.



This is the back of the connector.



...and this is where the relay plugs in.



By jumping 12 volts to the blue wire on the circuit opening relay connector (the relay has nothing to do with the fuel pump running at this point. Just unplug the relay and set it aside) the fuel pump came to life and pumped out some nasty, stale, yellowish 1-1/2 year old gas. Once i saw and smelled the condition of the gas, i grabbed a bucket and put it underneath the fuel line near the back right corner of the engine and let it run until most of the gas had been pumped out of the tank. From this point forward, for initial starting and testing of the engine, the fuel pump will be run by jumping 12 volts to this wire until the fuel pump ECU can be purchased and wired in to the lexus ECU.
« Last Edit: April 02, 2008, 07:20:16 PM by toylexus »

Offline Chewy

  • Full Member
  • Posts: 224
    • View Profile
    • Email
Re: Fuel pump ECU
« Reply #17 on: February 12, 2008, 11:18:11 PM »
Ok, I read through this thread a couple of times, but I still have some questions (just so I'm clear)...

1.  If I'm going to use a 1UZ from a 97 SC400, is it absolutely necessary to get a fuel pump ECU?

2.  Is it possible to forgo the ECU and simply hardwire the fuel pump to 12V?  Is there a major disadvantage/problem in doing this?

3.  The fuel pump ECU wires directly into the engine ECU,  correct?

Sorry, but I just want to be sure before going out and sourcing one of these things...

-Chewy
« Last Edit: August 06, 2008, 08:12:34 PM by Chewy »
98 4Runner 1UZ V8
77 Celica

Offline toyminator

  • Jr. Member
  • Posts: 67
    • View Profile
    • Email
Re: Fuel pump ECU
« Reply #18 on: February 13, 2008, 08:39:21 AM »
I think what he means is that the standard Lexus ECU can't turn the Fuel Pump on and off Because thats the job of the Fuel Pump ECU.   The Toyotas ecu can.  The only way to make the fuel pump work with the Lexus ECU without the Fuel Pump ecu is to wire it direct to 12v and either use a manual switch or switch it to your iginition. 

This can be dangerous though if its involved in an accident because there is nothing to turn it off.
1989 P/U
1988 4Runner

Offline Chewy

  • Full Member
  • Posts: 224
    • View Profile
    • Email
Re: Fuel pump ECU
« Reply #19 on: February 13, 2008, 10:14:50 PM »
Ok, that makes sense.  Question though...will different model (SC300) and earlier year fuel pump ECU's work for a 97 motor?
98 4Runner 1UZ V8
77 Celica

Offline toylexus

  • Jr. Member
  • Posts: 93
    • View Profile
Re: Fuel pump ECU
« Reply #20 on: February 13, 2008, 11:58:42 PM »
Ok, I read through this thread a couple of times, but I still have some questions (just so I'm clear)...

1.  If I'm going to use a 1UZ from a 97 SC400, is it absolutely necessary to get a fuel pump ECU?

2.  Is it possible to forgo the ECU and simply hardwire the fuel pump to 12V?  Is there a major disadvantage/problem in doing this?

3.  The fuel pump ECU wires directly into the engine ECU,  correct?

Sorry, but I just want to be sure before going out and sourcing one of these things...

-Chewy

(OBTW, motor is going into a 91 FJ80)

(1) i would say that it's a good idea to use one. i looked up the schematics for fuel pump control on the 97 SC400 and it also has a fuel pump ecu.  i am not thoroughly familiar with toyota and lexus controls to know if it will cause any driveability problems if you decide not to use the fuel pump ecu. The other thing you might want to consider is with the 97 SC400 being an OBDII vehicle, you may set codes related to the fuel pump ecu if it's missing.

(2) It is possible to hardwire the fuel pump. Once you do that though, you have to figure out how you want to turn it on and off. Most if not all of the fuel injected cars i've worked with usually have the ecu controlling the fuel pump.  Once you take the control away from the ecu, you have to figure out how you're going to control it, which could involve turning it on manually with a switch, or wiring it into your ignition switch as toyminator stated, which is entirely up to you. The problem i would have with that kind of arrangement is that i would need to remember to turn it on before starting and turn it off when i'm done driving. That choice is completely yours.

(3) The fuel pump ecu does wire directly to the powertrain/engine ecu by way of several connectors in between the two. According to my reference, the 2 wires that connect to the powertrain/engine ecu for your engine are:

 -Pin 21 of engine ecu connector E11 (pink wire) connects to pin 2 of the fuel pump ecu
-Pin 22 of engine ecu connector E11 (red w/white wire) connects to pin 3 of the fuel pump ecu

There are 3 other circuits going to the fuel pump ecu: Battery positive voltage from the efi relay, fuel pump voltage(to the pump), and what looks like a fuel pump ground feedback circuit (probably used to see if the fuel pump is running).

 i looked up a 97 SC300 fuel pump ecu schematic and the connections and wiring are the same. The same reference also shows the part number to be the same between a 97 SC300 and SC400, 92 SC400, 92 SC300, 94 SC300, and a 95 SC400: P/N: 8957024010. Looks like they found something that worked and stuck with it.



« Last Edit: February 14, 2008, 12:35:00 AM by toylexus »

Offline Chewy

  • Full Member
  • Posts: 224
    • View Profile
    • Email
Re: Fuel pump ECU
« Reply #21 on: February 24, 2008, 01:35:04 AM »
Awesome info!!  I found a couple of Lexus' in the wrecking yard today so I'm gonna go back and see if I can pull the Fuel Pump ECU/harness.  Thanks a bunch!!!
98 4Runner 1UZ V8
77 Celica

Offline freddy4runner

  • Newbie
  • Posts: 37
    • MSN Messenger - bj_73@msn.com
    • View Profile
    • Email
Re: Fuel pump ECU
« Reply #22 on: March 05, 2008, 04:58:23 AM »
Hi Guys, I used the Fuel Pump ecu in my conversion and it works really well, there is only 5 wires to hook up and your done, you will need to splice it into the circuit opening relay wires, if you sit down and study the 2 factory wiring diagrams for the lexus and 4runner is pretty easy to work out. took me about 30 minutes to work out.

If I can find my diagram on the weekend I will post it for all to see
1995 4runner sr5 v6 limited with alloy bullbar, 2" OME lift and spotties, 32" BFG'S. 1UZFE in the garage being prepared for installation.