david braun

Hey bought a 95 runner with a 3.4 swapped into it, wiring harness ecu all the good stuff I think, anyways it gets 11 in town and I know that isn't right
Now correct me if I'm wrong but should the runner have the obd2 instead of the older obd1? Already looked under the dash..
Anybody know where on the wiring harness the plug comes off?
Wanna try and get this solved I was expecting 16-17 mpgs with a little work
Thanks

vital22re

iTrader: (2)

look near the glove box. If this swap was done by the PO, it could be anywhere or no where. I generally mount them in the glove box or passenger side so there aren't a bunch of wires running the the driver side.

david braun

Well it seems as though it does not have a obd2 port..
I looked under the hood and mounted to the intake manifold was a jumper box for a obd1 mounter to the 3.4? Thought that was a little odd any way to make that system work with the newer engine?
Also how hard would it be to plumb in a obd2 port? Any wright ups?
Why would anyone remove that port? Seems like it would be pretty handy if you needed it in the future...

SacRunner

Do you know what year and model the donor 3.4 (or more specifically the ECU and electronics) came from? If it was a 95.5 Tacoma it will still be OBD-I, Toyota didn't adopt OBD-II until the 1996 mandate; everything '96 and later will support OBD-II, which will be ~90%+ of the possible donors.

To add the OBD-II connector you need to know the year and model of the truck that the ECU ("Engine Control Unit") came from. Look for the ECU in the passenger kick panel, read the part number off of it (it will be printed on a sticker, most likely facing away from the interior of the cab), type that part number into Google and with a little bit of poking around you should be able to find out where/what it came from.

From there create an account on TIS (Toyota Technical Information System; https://techinfo.toyota.com/) for 48 hours ($15), and download the EWD (Electronic Wiring Diagram) for the 5VZ Engine Control for the application that your donor ECU came from. While you're at it, download EVERYTHING for your donor application and for your '95 4Runner (both the repair manual and the EWDs).

The 5VZ Engine Control EWD will tell you which pins on the ECU should have the OBD-II (Data Link 7, D7 *I think*) signals. From there, look at your ECU, if those pins are empty (no wires coming out) the PO did not wire up the OBD-II port, if there are wires, follow them to find where that connector might be hidden.

david braun

Thanks the guy I bought it from said it was a 98 but I have my doubts because that obd1 jumper box, I'm gonna call the guy that wired it all up tomorrow and see what he says thanks for the info about the ecu ill take a look tomorrow see what year that actually is
Ecu motor and wiring harness is supposed to be from a 98 tacoma

The pins that would come out of the ecu for the obd port now wouldn't that have a connector unless the wires where cut?
Very good info I thank you

Ill keep ya informed really wanna see what codes this think kicks out
It's running really rich :/
This site rocks

vital22re

iTrader: (2)

They have a "diagnostic" box under the hood. But that is more for testing. The obd2 port has 4 wires.
A white with black stripe(chasis ground)
brown with red stripe (signal ground)
Purpleish violet (power)
White (signal wire from ecu)
The two grounds can be combined, and power from any 12v source. The signal wire runs to the ecu and depending on the year will be the only plug to the ecu not from the main engine harness. Not super hard to wire up, just need a little know how. I usually mount the ecu in the same place the old ecu was, passenger kick panel.

david braun

Awesome thanks man one last question which should be pretty easy..
last time I checked all obd2 ports on most cars are the same with a few adapters, what I'm wondering is if it is indeed missing the plug that goes into the reader could I just pull it off another car with an obd2 port? For instince would toyota Camry obd2 port have the same wire color coding as the 98 ecu? Seem like that kinda stuff is pretty universal..

Correction lol ODB 2 not obd2 lol sorry for the mix up noob mistake lol

david braun

Confirmed that the ecu was a 98 and I found the signal wire from the ecu for the ODB2 port
Is that the only one that I need from the ecu The other 3 wires are grounds and positives right?
Also found out the o2 sensor before the cat wasn't pluged in.. Pluged it in but I think it was the stock one from the 3.0 didn't know if they where interchangeable or if it would mess with the ecu.. Might have been my problem with it running rich.
Can't wait till I get the I get the odb2 wired just looking for a plug at this point

anthony1

iTrader: (1)

If you're not in CA, maybe the po didn't put in the O2 sensors. That's one of the reason for low mpg.

david braun

Thats Exactly what happened I bought a front o2 sensor for it and am getting much better milage rear ones still not hooked up and the obd2 port still needs wired in
Much happier