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Hardtopper
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Discussion Starter #1
Besides kbprice, anyone else done this? I talked to kbprice on the phone for a couple of minutes about this, and since I am not using the MAF then I figured I could get this done by splicing the wires from the ECU side that he was talking about, and using the stock OBD2 MAF plug (since I dont be using a MAF period - VPC) and run the resistor on the plug like normal... I dont see why it wouldnt work but maybe someone else here has tried it? I know its probably not something common but its worth a shot. Thanks
 

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Hardtopper
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13,043 Posts
Discussion Starter #3
michaelvanle said:
kbprice converted
OK did you even read the thread?
 

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Hardtopper
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Discussion Starter #5
whats funny is that kbprice and i live in tampa, both of our names are kirk, and both of us own 96 NA 5SP supras....... :lol: anyways... I just need to know if anyone else has done this like me
 

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Hardtopper
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Discussion Starter #7
afr0den said:
sorry man...it is pretty hard to understand what you have wrote...
i was drunk last night when i typed that :freak:

But I am sure whoever reads this and has done it before will know what I mean.... :)
 

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Newbie
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11,221 Posts
kbprice said:
I converted... :lol:
TO bring this thread back. I'm thinking of converting too. I'm getting a 94 Supra OBDI NA auto ECU. Will that work?

Also I talked to Kirk #2 (lol), he said that there is 2 wires you cut or something? And that's it. I don't have to mess with the MAF harness because I have a VPC.

So Kirk #1 (kbprice), can you tell me which wires I cut/splice or whatever? Or can you tell me step by step what I need to do?

Lastly, going to an OBDI will get rid of that open loop/closed loop shit right? OBDI NA's are always in open loop?
 

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Over Medicated
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2,718 Posts
The 2 wires that we cut were for the #1 and #2 oxygen sensors. We tied B48(OX1) into B47(OX2) This eliminated the need to have both front and rear OX sensors on the exhaust manifold, rear sensor now supplies both signals. As for the MAF conversion it is fairly straight forward as long as you can understand the Toyota service manuals. I'll do my best to expalin it though.

There are 5 wires on the OBDII MAF, you will only use 4 of them(Black w/Red not used).
1. Black/Red - 9-14v Power (not used)
2. Yellow/Red - VG signal from B66
3. P/L - THA signal from B45
4. Brown/Black - Ground E1
5. Brown - E2

There are 5 wires on the OBD1 MAF
1. Brown/ Black - Ground E2
2. P/L - THA signal from B45
3. LG/B - Karmon signal from B66
4. L/R - VCC signal from B41
5. Brown - Ground E1

The only difference is the #4 wire on the OBD1 plug. This signal needs to be gotten from the TPS sensor #4 wire VCC signal.
OK so here is the overall way it connects:

OBDII #5 - OBDI #5
OBDII #4 - OBDI #1
OBDII #3 - OBDI #2
OBDII #2 - OBDI #3
OBDII #1 - Not Used

OBDI #4 - TPS #4

I know this may be confusing but if you have a service manual it really helps.

As for your other questions. Yes a OBD1 auto ecu will work. The open loop thing I am not sure about however. You will need a MKIII chip for your VPC and make sure your resister is in the correct position.



Disclaimer: I am not responsible if you fuck up your car trying to do this conversion!
 

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Newbie
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I have an fmax exhaust manifold. There seems to be two o2 sensors in there. I guess that means I have 2 fronts sensors and one rear sensor. Would I still just splice 47 and 48 together? Also I installed an OBDII fooler, should I get rid of it and rewire the o2 together (the mp one).

Lastly, I have a vpc, can I just leave the resistor where it is and keep the OBDII maf plug?
 

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Over Medicated
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If you are already using both O2s I would leave it alone then. As for the resistor I am guessing that you will have to place the resistor in different pins.
 

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Hardtopper
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13,043 Posts
Discussion Starter #13
kbprice said:
Disclaimer: I am not responsible if you fuck up your car trying to do this conversion!
:lol:

I converted my car to OBD1 from just looking at his and my car runs flawlessly! you will install the VPC resistor on the same wire colors... dont touch the MAF plug if you are going OBD1/OBD2 and have a VPC... just run the resistor between 2 + 3
 

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Over Medicated
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2,718 Posts
kirkMKIV said:
:lol:

I converted my car to OBD1 from just looking at his and my car runs flawlessly! you will install the VPC resistor on the same wire colors... dont touch the MAF plug if you are going OBD1/OBD2 and have a VPC... just run the resistor between 2 + 3
Glad to hear it is running good now.

Now there is going to be this big run on OBDI NA ecu's. Everyone will start asking $300 -$400 for them... :) By the way I've got 2 OBDI 5speed ecu's for sale :D
 

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BoostAddict4Life
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how much for the ecu.....

let me know and dont you dare say 400 or ill convice kirk to come shoot you. :werdlol:
 

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Supra Member
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1,822 Posts
kbprice said:
Glad to hear it is running good now.

Now there is going to be this big run on OBDI NA ecu's. Everyone will start asking $300 -$400 for them... :) By the way I've got 2 OBDI 5speed ecu's for sale :D
let me know when you sell all of yours... I'll sell mine next :lol:
 

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Newbie
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OK, I have the OBDI ECU in hand and also the MKIII chip so I'm ready to rock.

This is mainly for Kirk (black Supra) as he's running the vpc like me.

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1. Is this how the wirings should go? I wanna be positively sure before I cut and shit:


2. Did you even change the maf plug? I don't think you did, but just asking. In that case, is this how you have the resistor installed?
 
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