Another Subtank Question, OEM Setup Related

[elmariachi]

I have scored an Oz OEM subtank transfer pump assembly, the later 6-wire in-cab switch and the OEM ECU, including all wiring connectors and pigtails. I have searched every thread and still have questions (maybe for the Oz crowd):

1. Does anyone know where the OEM ECU (labeled a Fuelpump Control on the unit) was originally located? Is there wiring in the harness to power this (I have the pigtail connector from the donor)?

2. Is there wiring in place for the subtank switch? I have had my dash apart many times and if I know Mr.T, he was saving every penney of copper by not including this on US trucks because I cannot find it.

3. Does anyone have a Toyota wiring manual from a 1996-1997 truck?

Thanks.

 

[elmariachi]

For those who later find this post, I have figured out that all trucks produced after 1/95 have the fuel transfer system intelligence built into the ECM (though i am guessing it would be impossible to wire into and out of it. Prior to 1/95 its a separate transfer ECU located inside the truck behind the interior trim panel above the driver's side wheel well (3rd row seat area.) If anyone has a pre-1/95 truck and would happen to have that panel off, see if you have a grey 20 pin connector in that area.

I have read every post on Mud and I'm still not sure about the switch wiring.

 

[SWCruiser]

Subtank

El mariachi,
I have the transfer harness also but haven't looked to see if it will connect directly to the cruiser harness. I would imagine that if it does the wiring would already be set up for wiring to the ECU, no? My subtank harness, which came with my tank clipped into the rear harness of my lx450 and evidently ends up at the front of the DS interior panel.


chris

 

[elmariachi]

El mariachi,
I have the transfer harness also but haven't looked to see if it will connect directly to the cruiser harness. I would imagine that if it does the wiring would already be set up for wiring to the ECU, no? My subtank harness, which came with my tank clipped into the rear harness of my lx450 and evidently ends up at the front of the DS interior panel.
chris

I gather that the transfer assembly clips into the harness near the rear frame crossmember (haven't dropped my spare to confirm because I still don't have a tank or neck.) That harness then supposedly goes up to the DS kickpanel, right? Is there wiring to get it from the DS kickpanel over to the switch? If so, where is the switch socket? Also, check your email, I just sent you a question.

 

[Cruiser804]

I belive only the wiring for the sending unit is present in the empty gray plug on the rear sill harness. In the FAQ subtank thread I posted some picutes or both ends. There are only 3 empty cavities in the cab.

There is another small unused plug that exits the cab under the DS rear door. But only after I bought all the parts, $16 a splice did I realize the wire gauge was way too small to power the pump.

I have a complete spare DS floor harness. I'd be happy to loan it to you if you want to get out you continuity tester and see what you can figure out.

I think I have a wiring diagram from the subtank but I am not sure which set up it is for. PM me if you want it.

BTW I also have an extra set of harness side OEM plugs and splices for the OEM transfer unit.

 

[Romer]

I found it easier to make my own harness rather than just tapping into the existiong wiring. Easier for me that is. I used Georges ECU so I can't help you with the ECM. Does the ECM shut off the pump when the tank is empty like George's. I don't have a gauge (ran the wire for later) so I like ebing able to turn on the transfer pump knowing it will turn itself off.

 

[elmariachi]

Yes, the OEM ECU I have does that, per the seller. But its pointless now because its for a pre 1/95 truck, which is apparently wired for it. I don't believe my '97 is wired for this unit because its functionality is built into in the main ECM. So rather than decode how this box works, it will be easier for me to go with George's unit. However, if someone can find me an Oz wiring diagram that shows what each of these 20 wires do and where they go, then I can use it.

 

[Romer]

from the tank and the pump, you only need to run 4 wires up to the cab Jim. Then pull of 12V and the + and - for the backlight. I know I know. Thats not as much fun.

 

[elmariachi]

Yes, the OEM ECU I have does that, per the seller. But its pointless now because its for a pre 1/95 truck, which is apparently wired for it. I don't believe my '97 is wired for this unit because its functionality is built into in the main ECM.

I stand corrected. The 20 pin plug for the fuel pump ECU IS there behind the rear panel, pic below, along with a pic of the unit and the donor pigtail. With the key on at least one wire is hot. NOW I need that pre-95 OZ OEM wiring manual.

 

[Cruiser804]

Which side is that on?

I just emailed you the wiring diagrams I have. Let me know if they are useful and I will post them .

 

[Cruiser804]

Ok I am little bit of a spaz. I used my spare floor harness to check this plug. It is on the DS and a number of the wires do run to the unused 10 pin plug behind the DS kickpanel. I didn't check them all but I will if you want me to. Also, some of the wires in this empty 10 pin plug run to the 4 pin plug I mentioned above. So as with the sending unit wires some of the Sub Tank wires are present in the DS floor harness but also dead end behind the DS kick panel.

Would be cool if you could get that thing to work!

 

[SWCruiser]

Wiring

So basically if you have the transfer pump harness and sender harness these should be plug and play. You should only need to do some splicing of the wires that go into the 10 pin plug in the rear DS.

In other words, if you want to mount George's ECU in the back DS panel you just need to splice the empty signal from the front to the 10pin in the back and then splice three wires (transfer for light, and pin 6, pin 9) of the dash switch. Does that sound right??

I would think then that the 12V+ to the 10 pin in the back should have sufficient gauge also?

What do you guys think?

Chris

 

[Cruiser804]

Sort of, the sending unit harness would get you from to the sending unit itself to one of the 20 pin plug behind the DS KP. Its ends with 3 empty pin cavities on the cab harness side. If you buy the pins you simply plug them in and splice them to the gauge and Georges ECU.

Sending unit harness to sill harness to floor harness.

I haven't been able to determine where the wiring for the transfer pump could possibly be. The pin/splice set from Toyota for the transfer pump is pretty heavy gauge, like 14(??). But from what I have seem the splices are one size fits all on the wire side. One plug housing could have a few different gauge wires coming into it but Mr T only makes one size splice that fits that housing.

Anyway I am not sure how may amps the pump draws but I am hoping 16 gauge will be enough because that is what George's ECU came with.

There are couple wires in the empty 10 pin housing that look like they could carry the load.

 

[elmariachi]

Thanks for the input thus far. Based on my research and tinkering with the truck while out of town this weekend, I think I have figured out "most " of the factory wiring for this circuit. Hopefully you guys can help me determine if its viable (pics borrowed from other threads):

1. When I look at my Oz transfer and solenoid assembly wires, I have red/blue and red/black wires feeding them (with a white/black common ground color on both.) These two primary wires also happen to be in the small, flat, white connector in pic 1 below, located by the frame rail under the driver's side passenger door. The other red/stripe (can't see for all the road grime) wire going into that same connector would assumedly be from the auxiliary tanks sending unit (which I don't have yet so I don't know the actual color.) The other connector next to it is the main fuel pump, so it would stand to reason that these would be together. So that's my assumption....the three units (pump, solenoid and sender) all converge into that connector and enter the harness there. From what I can tell, all of these primary wires then pass through that fuel transfer ECU and connector I am showing in post #9 above.

2. I removed my DS kickpanel. I have an unused white 10 pin connector (pic 3 below) that has all of the same colored wires coming from the fuel transfer ECU. The $20,000 is "what plugs into that connector? Just a harness to the subtank switch? " Input/comments appreciated, especially if you have an Oz truck.

(Yea, I know I could simplyify this by using George's ECU and the ad-hoc wiring, but I like the challenge of seeing if I can recreate the OEM install, especially given that I have the OEM ECU.)

 

[JPHockerAZ]

What is the part number (if any) stamped on the ECU?

and any progress with this?

 

[elmariachi]

What is the part number (if any) stamped on the ECU?

and any progress with this?

The part number I have in my notes is 89670-60110; the # on my ECU was printed on a decal and it has since faded away. The ECU is not available through US dealers, bought mine on eBay Oz.

I am making progress. I have everything I need to do the entire install except the tank and hoses, which should all be here in a couple weeks. I have wired up the overhead console using an OEM harness that came with it (from an Oz salvage yard.) I have fitted but not installed the console because of the sunvisor conflict...still thinking on how to resolve that. Below is the OEM wiring diagram for using the pre-1/95 ECU. Finding that was tougher than finding the parts. All of the rear pump/tank/solenoid wiring shown below is already in place on our trucks.

Last night I built a harness from the fuse box and dash power to serve the B/R and B/W wires below, as well as gauge power and rheostat for the overhead console. Today I will finish the switch harness and will ohm out the floor harness to confirm which wires I need to tap into up front (I think via the connector shown in the earlier post above.) All of the wires shown below enter the harness through the ECU connector in the cargo area, but I am having a tough time finding the two pink wires in the kickpanel that serve the dash switch.

I will be posting the entire install here on Mud once I am done. Email me if you want to discuss or if you want a hi-res version of the diagram.

 

[SWCruiser]

harness

Jim,
I am pretty sure the sending unit from the subtank plugs into the connector at the rear center of the truck. I have a transfer pump assembly wiring harness with the connectors that plug into the white connector and the grey one located at the sill. This harness plugs into both subtank 2-pin plugs (solenoid and pump)and also plugs into the main tank from what I can tell. This harness then plugs into the 2 sill plugs (grey and white).

Chris

 

[elmariachi]

Jim,I am pretty sure the sending unit from the subtank plugs into the connector at the rear center of the truck. I have a transfer pump assembly wiring harness with the connectors that plug into the white connector and the grey one located at the sill. This harness plugs into both subtank 2-pin plugs (solenoid and pump)and also plugs into the main tank from what I can tell. This harness then plugs into the 2 sill plugs (grey and white).Chris

Yes, that is correct. As the wires come forward in the floor harness to the kickpanel, they enter several different connectors (two are pictured, ID3 and the dead-end connector not numbered in the EWD.) There are 8 wires required that run from the ECU up front and using an ohmmeter you can locate them all as follows. Format is "connector name, wire color, pin location in connector and function":

-ID1, Y-R, 17. Fuel sender to gauge.
-ID3, P, 7. Dash switch.
-ID3, P-B, 8. Oz EWD says fuel filter light...probably not used on petrol models.
-ID3, P-G, 9. Dash switch. (NOTE>> EWD error. This wire shows as P-B on the diagram above and is actually P-L on the donor pigtail I have from a 1993. BUT...its in fact P-G on my truck's ECU connector and P-G up front.)
-ID3, B-R, 10. To fuse block ECU-B fuse.

-The Y-L wire is in the dead-end connector in the pic below. Ignition 12V+.

- The B-L wire is also in the dead-end connector. It connects the ECU to the D1 Data Link Connector. I think I can splice it into the same wire traveling to the DLC from the Cruise Control ECU, also in the left kick panel.

**ALL of the above 7 wires ended in their respective connectors and did not have a pass-through wire on the female side. They are also all indicated with a "X" in the US EWD, meaning they are not required by the US electrical scheme. I have extracted all 7 of these wires in tact from their connectors and will be bringing them together in a new Toyota housing, which will then be a fully grouped subtank harness to the ECU. Into that housing will connect the dash switch wiring, the sending unit wire from the overhead console and the B-R and B-W power source wires shown on the diagram that power the ECU.

- NOTE>>The B-W wire is already passing through ID2 and is the Ignition + wire to/from the ABS system, per the US EWD. Because this wire is hot with the key on in the 18-pin ECU connector, I assume it is already spliced in and properly routed into the harness so I am leaving it in its spot in ID2.

 

[aboulsimm]

Hey Guys,

I know this is an old thread, but I've been troubleshooting my OEM subtank on my 96 FZJ80 and everything checked out until I realized there was no ECU behind the PS rear quarter pane, just an open plug like the one in post#9.

I tried connecting the diagnostic connectors Tc & En and nothing flashes

I tested the pump / solenoid / sub tank level switch / and main tank level switches...all good.

I disconnect the battery to rest the ECu and the Fuel Tank light goes off, but when I hit the sub tank switch I can hear the pump running but the solenoid doesn't open and this goes on for a few seconds before it stops and the Fuel Tank light comes on again.

I by bypassed the solenoid even and forced it open , reset and activated fuel tank...worked for a few seconds too before stopping and the FuelTank light came on again ( I did hear fuel being transferred into the main for that few seconds)

Any ideas? I'm starting to get desperate here!!!

Thanks