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How do you all scope signals? Splice into the wire, or probe a connector? I am having a hell of a time getting my speedometer to read, which is effecting the shifting. I?ve rang all the wires out from the vss, and trans connector to the tcm. I?ve also tried multiple sensors. Speedo only shows half speed, and won?t go any higher than 25. What I see in HPtuners matches what the Speedo shows. I?m very desperate, any help would be greatly appreciated.
What is your vehicle config?
If you're getting any speed signal at all, it's likely the wiring is OK. You could have an issue with the sensor or with the speedo config. You should upload your tune and a log.
If you want to scope the speed signal you'll need some sort of scope. At a minimum, you may be able to use a normal AC multimeter to measure AC voltage between the VSS wires. I have used a cheap Aliexpress oscilloscope for looking at various signals, including VSS.
Attachment 162332
The vehicle and hardware is
07 trailblazer ss awd
4l80e converted with bw-4485 t case from Escalade.
E67 ecm
T42 tcm
4l60 to 80 adapter harness from pcmofnc
Ecm and tcm both from pmcofnc set up for my truck and trans.
I have a scope, I’ve never used it before but it was too good of a buy to pass up. I might have a log, I’ll report back when I can.
Thwnks for the reply.
Attachment 162336Attachment 162337Attachment 162338
Some logs I uploaded the other day.
Is the temperature data accurate? Like, you're running at 235F+?Quote:
Originally Posted by Tonyorlo
It was at that moment. The e fans weren’t kicking on, helps to have the ground landed. That was the first drive after swapping the trans.
Attachment 162363
the tune
This isn't our tune. this is just what is needed to get the 4l80 going.Quote:
Originally Posted by Tonyorlo
Is the wiring all stock? The wiring for VSS are normally a twisted pair to cancel noise.
I’m in no way saying anything you guys did is wrong. I labeled that as pcmofnc tune just for my records, and I posted it just for information.
The wiring is stock. I am going to try to count the teeth on the reluctor wheel today. That’s about all that I have left.
This may be frowned upon, but I’m at the point of needing it to work. Do any of the aftermarket gps senders put out enough current or voltage to signal the ecm?
Have you checked the wiring diagrams to confirm where it is getting speeds from? Different applications pull it from and send it to different places.
Have you checked where the vss sensor is reading? Is that a toothed wheel with maybe a different tooth count?
GPS signal would have too likely put out the correct voltage range and frequency also.