LQ4/4L80E - Need speedometer help
LQ4/4L80E - Need speedometer help I'm working on a LQ4/4L80E swap and I'm planning on getting an aftermarket 6 gauge setup (Speedo, tach, mech. water, mech. oil, volts, fuel) like from Autometer or something similar and i have no idea how to get any speedo to work with this trans? Not sure if i need an electric speedo or mechanical, if so how what drives it?
I did a search on it and not much help so any help is appreciated
I did a search on it and not much help so any help is appreciated
the rear VSS sensor on the 4l80 is typically a 40 pulse per revolution sensor...
that goes to your pcm, and then your pcm can be calibrated to send out a xxxx pulse per mile signal to send to any electric speedo
If you buy an Autometer speedo, they typically are set to read a 16,000 pulse per mile signal...so you just change the tune to make it ouput that many pulses per mile
otherwise, analog, cable drive speedo, just requires a special adapter that you put on the trans to drive it and run a cable up into the dash like they did in the old days.
that goes to your pcm, and then your pcm can be calibrated to send out a xxxx pulse per mile signal to send to any electric speedo
If you buy an Autometer speedo, they typically are set to read a 16,000 pulse per mile signal...so you just change the tune to make it ouput that many pulses per mile
otherwise, analog, cable drive speedo, just requires a special adapter that you put on the trans to drive it and run a cable up into the dash like they did in the old days.
Definitely get an electric speedometer. I have Autometer gauges, and the speedo is set by pushing the trip button and driving a mile or two, can't remember exactly since it's been a while, but in the odometer when you're driving to calibrate it, it counts off pulses per mile. I used the VSS out wire that went to the original speedo to wire it up, and since my tune was set to my rear gear ratio, I set the PPM on the speedo to 4000, which is what comes out of the PCM, works perfect.
Definitely get an electric speedometer. I have Autometer gauges, and the speedo is set by pushing the trip button and driving a mile or two, can't remember exactly since it's been a while, but in the odometer when you're driving to calibrate it, it counts off pulses per mile. I used the VSS out wire that went to the original speedo to wire it up, and since my tune was set to my rear gear ratio, I set the PPM on the speedo to 4000, which is what comes out of the PCM, works perfect.
gotta drive 2 miles....
the issue with that is that you really have to know what 2 miles is....and pretty darn close to as exact as possible...
its easier to just pick an arbitrary number like 4000, drive until it says 4000, then just set it in your tune in your pcm.
and like I said... default in the Autometer is 16000.....why they picked that is way beyond me....I have no idea WTF they were thinking on that one...
TECH Enthusiast
Joined: Feb 2008
Posts: 503
Likes: 1
From: Ventura, Ca
I recalibrated my PCM to match my gear ratio and then used an iPhone app called Speedometer that is free to drive the 2 miles to calibrate the speedo. The app was accurate to 1 pulse of my calculated pulses on the pcm calibration. You really need to do both for an automatic tranny setup otherwise it probably woun't shift properly unless your ratio setting is close.
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Teching In
Joined: Aug 2012
Posts: 45
Likes: 1
From: Colorado
Not sure how a 95 is hooked up but, on our 89, we just hooked up the PCM output wire(from the 98 LS1 setup) to the wire that the original ECM (for a 4.3)output for the speedo used. When we removed the old ECM, we just clipped the wire from the ECM connector and spliced it to the wire from the new PCM. Then all we had to do was to set the PCM up with gears, tire size, etc. It is very close, if not dead on. Hope this helps.
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Staging Lane
Joined: May 2012
Posts: 59
Likes: 0
From: Fairfield,CA
I've got the speedhut GPS speedo and its great. Good price and the customizing possibilities are extensive. I actually ordered mine with high beam and turn signals, but instead of turn signals i had them put in a red and an orange led. Red for meth and orange for my check engine light. They even changed the wiring from positive out of the gauge to negative so it hooks up directly to the pcm.
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Joined: Oct 2017
Posts: 1
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the rear VSS sensor on the 4l80 is typically a 40 pulse per revolution sensor...
that goes to your pcm, and then your pcm can be calibrated to send out a xxxx pulse per mile signal to send to any electric speedo
If you buy an Autometer speedo, they typically are set to read a 16,000 pulse per mile signal...so you just change the tune to make it ouput that many pulses per mile
otherwise, analog, cable drive speedo, just requires a special adapter that you put on the trans to drive it and run a cable up into the dash like they did in the old days.
that goes to your pcm, and then your pcm can be calibrated to send out a xxxx pulse per mile signal to send to any electric speedo
If you buy an Autometer speedo, they typically are set to read a 16,000 pulse per mile signal...so you just change the tune to make it ouput that many pulses per mile
otherwise, analog, cable drive speedo, just requires a special adapter that you put on the trans to drive it and run a cable up into the dash like they did in the old days.
On The Tree
Joined: Jan 2006
Posts: 180
Likes: 16
If you use a non-computer 4L60 (or TH700R4) trans, you can swap the tailshaft housing for 1 from an older trans that came from the factory with the speedo cable connector on the tailshaft housing. I think those are also available aftermarket, but mine just cost me a trip to the Pick'n'Pull.
Teching In
Joined: Jan 2016
Posts: 11
Likes: 0
Holy crap. Read this entire post with hopes of having my gauge work with factory faceplate for reasonable price and find nothing since 2014. This makes me very sad...
Edit. Wrong thread responded to... I think? Oops
Edit. Wrong thread responded to... I think? Oops
Last edited by ChromeDaddy0; Jul 13, 2018 at 08:15 PM. Reason: Wrong thread responded to... I think? Oops
There are a few builds on here where someone has taken an electric GM speedo and modified it to fit behind an old face,not easily though. May be difficult to find in a search,hopefully someone has one saved.
