4wheelsoffury

Bought the newest version 5 yellowbox from rick's after installing 4.56s last week. I followed the wiring guide in the DIY section. Everything is set up as described and all the connections are good but the speedo is inoperative and after driving up the street I got a cel. I don't have my diagnostic tool at home so I can't pull the code until tomorrow.

After this happened, I immediately reviewed everything and its all installed correctly per the thread and the yellowbox instructions. After I double checked the wiring and connections, I disconnected the yellowbox and reconnected both ends of the Blue/White VSS wire and bam everything works again. I did this back and forth and got he same results each time.

The odd part about this whole situation is if I put the yellowbox in its 100hz output test, I can use it to test the speedo and force the mph to climb and fall with the buttons but it will not do anything under normal operation. Supposedly this means everything should be working fine, though its obviously not.

Here is the picture of how it is currently set up with male and female connectors until I figure this out. Power is coming from the IGN accessory tab on the underdash fuse box and its grounded with the other ground wires just left of the ecu. Yellow wire is the input from the VSS, Green wire is output to the speedo/ecu. And yes I have tried switching them for shits n giggles and it changed nothing of course.



Thanks in advance for any inputs or ideas. I'm really stuck here because I can't find any reason why it shouldn't be working and theres noone to call for support as its labor day.

xviper

I can't tell from your picture what's really going on there. It's been a long time since I installed mine. From my recollection, there are 2 Blu/White wires in very close proximity to each other. One seems to be incoming and the other is outgoing to the ECU and/or speedo. You've likely go the wrong one. Additionally, I have found that both the Yellow Box and Yellow Jacket speed compensators are very sensitive to ground connection. I've actually run my speed comp ground wire directly out the firewall and attached it to a metal part of the engine.

4wheelsoffury

Its the blue/white wire 4th pin down on the 2nd row for the blue c101 connector. The only other wire I think people could confuse it with would be the white/blue wire in the terminal right next to it. I read and searched almost all I can. I'm 100% sure it is set up exactly the way the diy threads describe. The yellow box itself works fine. Powers up when the Ign is turned on and all the functions work which make me wanna rule out power and ground but thats all I have left. I'll reground it somewhere else and try to tap power from the vss power source wire and see if that changes anything tomorrow. I'm just aggravated as hell. I spent hours yesterday screwing with my gfs phone since it broke and this just decided to screw with me at the worst time.

xviper

Like I said, it's been a real long time since I did mine so I can't remember which pin or row or connector is the right one. I remember the frustration of trying to find the correct B/W wire at the ECU and I ended up taking the splice directly from the B/W wire at the speed sensor harness right at the tranny.

4wheelsoffury

Thats gonna be my step 3. I didn't want to splice anything outside of the cabin but I have some spare wire around I can try it with. Regardless, thanks for the input. I'll just have to mess with it tomorrow.

s2ka

The Yellowjacket instructions do a good job of showing the wires you need to tap into.

http://modifry.com/products/yj/yj.htm

4wheelsoffury

Just wanted to update for future reference for those that may have issues installing their own yellowbox. I switched my power source and now everything operates as normal. Instead of the 12.xx volts from the accessory IGN tab on the fusebox as was described in the DIY thread, I tapped into the Yellow/Blue wire that goes through terminal #6 on the blue C101 connector as described in Modifry's instructions for the yellowjacket. This gave me roughly 5.xx volts to power the yellowbox and apparantly send out the output wire to the ecu/speedo. I checked voltages with my dvom and I can only assume the ecu/speedo didn't like receiving the 12.xx volts coming through the yellowbox and out through the output wire.

C/N: Don't use the accessory IGN tab on the underdash fusebox to power your yellowbox. Use the Yellow/Blue wire going through connector C101.

sahtt

I know this is an old thread but I had a couple quick questions as I begin to install my Yellow Box. I've got two white/blue wires coming out of c101 going toward the ecu/dash. I read these instructions:

"Its the blue/white wire 4th pin down on the 2nd row for the blue c101 connector."

Since it is critical to splice the correct wire, can someone elaborate on which one it is? They happen to be right next to each other on the connector. For instance, a) is it on the column of pins (looking from the hood release toward the pedals) on the side closest to the firewall or the side closer to the gas pedal and b) is it toward the steering wheel or toward the floor?

Secondly, after I cut the correct white/blue wire, I assume I connect the side of the wire still connected to c101 to the 'input' wire on the yellow box and I connect the side of the white/blue wire now only connected to the dash/ecu to the 'output' wire on the yellow box. Some posts make it look like there is a cut made for the 'input' AND an additional cut made elsewhere for the 'output' bringing the total number of cuts/splices to three (splice for power on the yellow/blue wire, a cut made for the input, and another cut to splice the output).

Thanks,

Steve

xviper

You can always go to the Modifry site and see his instructions (post #6). It's got pictures. You know you have 2 wires coming from that connector with similar colors (actually, one is blue with white stripe and the other is white with blue stripe). Only one will be the 4th pin down on the 2nd row. The other one won't add up no matter which way you count from. The speed signal goes TO the ECU, so when you cut it, the output side of the YB goes TO the ECU.
It's only critical to get the speedo to work. If you reverse the speed signal wires, nothing bad will happen. The speedo just won't show any speed. Back out of the garage 50 feet and you'll know. If there is no speed showing, go back in and reverse the wires. Don't drive too far without the speedo working or you'll have to clear the CEL.

sahtt

Thanks for those additional tips xviper (as always). Sounds like I only need to make one cut and attach the output on the side heading toward the T (that splits to the ECU/Dash) and attach the input on the other side that connects to c101. Since there is another blue/white wire that goes from the T to the ECU I thought maybe the output goes there and not between the T and the c101 connector.