jpmountainboy

Ok, yes ive searched, and fooled around with this for a while so take it easy on me.

I threw a 99 M/T Taco 3.4 into a 94 ex-cab. Been driving it for a while, but never got the speedo wired up. Its a three wire, but cant really figure how to get the signal to the ecu, AND the combo meter. the wiring diagrams just show the G-L (3vze) going from the combo directly to the ecu...where is the actual sensor feeding signal to the combo meter? Perhaps the diagrams are for a cable fed speedo?

The 5vze diagrams actually show the sensor wires go into the 3.4 combo meter, and then to the ecu. I've combed over all the wiring diagrams I got my hands on but cant seem to figure a logical way to hook her all up. the only thing I could think would be to split the wires to ecu and meter, but seems like that would cut the signal and mess with the resistance.

From what I can tell it seems the signal should go from the sensor, to the meter, to the ecu...is this correct? how do i get the signal into the the combo first?

Please, any help...I know its probably simple but for some reason this is the one thing thats really stumping me on the whole swap.

thanks.

hamish_18

my 90 was different in that the speed sensor is IN the combo meter. And I don't have the 94 EWD's. But I do have the 93, so take this with a grain of salt. The Veh. Spd. Sen. is in the tranny it looks like, and the wires are in the C2 connector over in the right kick panel. For the 93 pickup its C2 pins 8,13, and 19. So you need to take the wires that are on the engine harness that goes to the plug in for the tranny. Actually I am seeing that the vehicle speed sensor is for the 3rz? I have to go home, and will continue looking there. Interesting.

jpmountainboy

Yes, in the diagrams it looks like the 3.0 sensor is in the the combo meter, but that doesnt make any sense given the wires come from the transfer case to the combo...which is why i am confused. I dont see any sending unit in the diagrams even though there are obviously wires coming from it ( yes i looked in my trans sections to). i did the swap a while back and played with the signal wire in different locations with no avail. I put it down for a while, and now that I have a fresh look at it again, i still just dont see how to incorporate the two different speedo hookup systems. Ive been running a CEL, and am worried that the motor is in limp mode because of it-maybe running to rich or lean...the obd2 wont even complete a scan on the o2's and air meters. seems to have decent power, but not that impressive. I have a stock taco with a 3.4 and it seems like it has a better response when comparing...tire difference aside.

I will say this...during the whole swap I had to use two different wiring diagrams (3vze) to match all the colors and plugs when figuring all the other swap wiring; it seemed like no one diagram was a complete match for my vehicle. ive tooled through all the hookups again and again to try and get a read on the systems, but everything seems to make sense, but the obd2 is not happy...the speedo is the only thing that is not hooked up, so im chasing this down in hopes it will have been the colprate and not something i did wrong with the wiring.

I really want to get this figured now as im going through the whole rig before my first long distance trip planned at the end of august, and want to make sure everything is tip-top. tired of ignoring the Check engine light and pretending its all good.

hamish_18

Sorry I never got on my comp last night. I am looking into it further now....

jpmountainboy

Sweet, thanks.

hamish_18

wait I didn't even see on the 93, you still have the wire going from the combo meter to the ecu. Is that hooked up? Just to confirm. Does your speedo work at all??

hamish_18

So you should have a plug on your engine harness, that goes down towards your tranny? And does it have 3 wires? my EWD's aren't complete for the 99, so I can't tell where the vehicle speed sensor was. But you should just have to take the wires from the harness and get them to your VSS. on the 2000 diagram it looks like there is a pink,G-R, and L wire.

Ugh, I am not seeing if the sensor is on the tranny? I think it is? if so do you have the plug from the 3vzfe that you can splice into the new harness? Or just run the wires straight up to where they originally went? this is confusing...

jpmountainboy

yes it is confusing.

there is a sensor on the end of the transfer case, 3 wires. I just dont see them on any diagrams, and how they actually route between the combo and ecu.

tach works (did mod) speedo never got to work.

hamish_18

Then that is your sensor then. on the 93, the sensor looks like its down lower like on the passenger side of the tranny. So look for the connector and check the other end. For some reason I can't find what the IK2 connector is which is what the VSS uses. Those 3 go to the three that correspond to the combo meter for yours. that circuit really doesn't change other than you ripped the wires out when you pulled the harness of the 3.0. Just replace the wires with the 3.4.

dntsdad

https://www.yotatech.com/forums/f160...23/index9.html

jpmountainboy

finally got it.

for one, I realized the the two different diagrams I had for the 94 didnt match a lot of things, especially the vss...and they didnt even have a speed sensor listed.

Luckily I dug through old piles of garbage and found my old 3vz harness that I thought I had thrown away. from there i found the wire colors on the old plug, and matched them to to the positions/corresponding colors on the new sensor plug, traced em to the cab, and whammo.

incorrect diagrams had been keeping me out the whole time, so watch out newbies to the 3.4, use your common sense and dont always trust diagrams, and dont throw away that old greasy harness the second you clip the plugs off.

thanks for all the help yotatech

hamish_18

Glad to hear that you got it. Have fun!!