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Hi All.
I have an Innovate AFR / boost gauge that has a shift light. I'd like to use it. I am trying to find a wire for the Tach Signal. I read the Fly'n Bryan (old) post but his wires are nothing like mine. (Late 03 Z - C6 Fuel system - maybe more than that is different?)
In his really good write-up, he pulls a bunch of foam wrapped wires from the LEFT of the 'U' shaped brace above the Knee Bolster - I don't have THAT harness in THAT location. In fact, I have only 2 white wires (no 'bone' colored) - and neither of them work the shift light or a DVM - I tested with engine running and changing RPM. Here's a pic of what I have...
The only harness I have is under the Styrofoam. Only 2 White, No 'Off-White'. Neither are my Go-To.
Sorry for the blurry pic.
I really do NOT want to go to the PCM for this signal. Nor do I want to tap a coil wire. Is there another way to get 'engine speed'? I already have the bolster off so finding it under there would be really nice. I'd be happy with using a fuse tap in one of the fuse boxes - I think lifting a fuse box and splicing into a wire underneath (like adding Fog Lights) is kinda dangerous - but that's just me. Is there a fuse dedicated to the Tach (Engine Speed) in one of them? I'm lost and don't like that feeling.
Thanks for any help.
Ain't Hot Rodding fun?!
Look and see if you can get the Shift Light Output in the Tune when you wire it in right. Just have to pin and tune it. It's not RPM based, so if you need that specifically then PCM RED 10. Nothing wrong with using it.
Thanks for the reply, Merv. I'm not following you 100%. Are you saying to data log and add it as a PID? It's kinda already in the list - RPM - and I DO log it. I'm not sure where HP Tuners gets the signal though. I assume it comes straight outta the Computer.
The strange thing is... The White wire I had it on first would fire the shift light at random, goofy times. I tried to track when it did but it had no pattern. I first thought I tapped the Skip-Shift wire but I don't think that's the case.
The wiring diagram in the original, OLD post shows exactly where to get the signal, BUT, you can't see then connector without seeing the back of the cluster. This is the post from '03. Pics are in the beginning. My foam doesn't look like that anymore - it is 20 years older.
Thanks for the replies. I talked with Innovate about the settings (pulse, number of Cylinders, etc) to make sure I had it right - or it could be on tapped into the right wire but not read. We discussed taking it from an injector - lots of LS guys use that - He said 'Don't do THAT'. I never thought about a Coil Pack wire. Which one do you tap?
I also saw an old post from LionelHutz - A true Hall-of-Fame guy here. He was helping a guy with a broken Tach, tracing the path from the PCM to the tach and said...
"It's a white wire goes from A17 on the PCM to pin 10 of connector 2. It passes through the underhood electrical center in at pin A3 and out at pin D4.
You could check it with a volt meter set to DC. If it is working, the voltage would be low at idle and go up as the rpm's go up. Probably something like 0-10V."
What exactly IS the 'Under Hood Electrical Center' - The fuse block? If I can intercept the PCM's wire there it would be the same distance into the interior as if I used the Coil Wire - Right?
Can anyone tell me where this ' Electrical Center' is located?
Thanks for the reply, Merv. I'm not following you 100%. Are you saying to data log and add it as a PID? It's kinda already in the list - RPM - and I DO log it. I'm not sure where HP Tuners gets the signal though. I assume it comes straight outta the Computer.
What you see Datalogging comes out of the OBDII Connector, why you plug your laptop or anything else in the car at that Connector. Serial Data wires in there that transfer that data.
What I'm talking about is in the tune, just have to turn it on and wire it into the PCM Connectors. It's a single wire, Blue 71 if I remember right. PCM is the ground when it enables so the other side of the light is 12v when you install it.
Tach Signal wire - Yes, Again...
