Speedometer was only off by 5mph and now progressively off? Why?

[PlayingWithTBI]

PlayingWithTBI .... thanks for the explanation.

Glad I could help.

 

[TSALI137]

Has anyone found a solution to this?
I just had my 97 5.7 k1500 recalibrated when I installed the 0411pcm for a performance engine upgrade. It read dead on with the OEM 100mph speedometer. Then 2weeks later I did the 99-00 Escalade 120mph swap. Now my speedometer is reading anywhere from 5-7mph off below 60 and around 10mph off above 60. Escalade speedo was tested before I purchased it and was said to be working correctly. Has anyone figured out the solution to this or is it just simply take it to a shop and have the PCM/ECU recalibrated?

 

[kennythewelder]

Has anyone found a solution to this?
I just had my 97 5.7 k1500 recalibrated when I installed the 0411pcm for a performance engine upgrade. It read dead on with the OEM 100mph speedometer. Then 2weeks later I did the 99-00 Escalade 120mph swap. Now my speedometer is reading anywhere from 5-7mph off below 60 and around 10mph off above 60. Escalade speedo was tested before I purchased it and was said to be working correctly. Has anyone figured out the solution to this or is it just simply take it to a shop and have the PCM/ECU recalibrated?

When I did the Denali cluster swap, I had to recalbrate the speedo. I simply changed the tire size setting. I have a jet flash programmer, so it's no big deal fore me. I would say, yes have the ECM reflashed. My speed is dead on at all speeds now, but it was off a good bit when I did the swap.

 

[TSALI137]

When I did the Denali cluster swap, I had to recalbrate the speedo. I simply changed the tire size setting. I have a jet flash programmer, so it's no big deal fore me. I would say, yes have the ECM reflashed. My speed is dead on at all speeds now, but it was off a good bit when I did the swap.

Awesome, thanks for your help. I've been searching 2 days online for a definite answer before I posted on here. I'll have it recalibrated next week when I get my initial crank up tune on the new crate engine. I'll have it checked again in a couple of months after the initial break in and I put the long tubes on to get it Dyno tuned.

 

[Nad_Yvalhosert]

Awesome, thanks for your help. I've been searching 2 days online for a definite answer before I posted on here. I'll have it recalibrated next week when I get my initial crank up tune on the new crate engine. I'll have it checked again in a couple of months after the initial break in and I put the long tubes on to get it Dyno tuned.

Where did you find long tube headers that fit an IFS 4x4? All the ones I've seen interfere with the front driveshaft.
And the torsion bar.
And the fuel lines.
And the tranny crossmember.
And the fuel tank.

 

[DonYukon]

like others i recalibrated mine years ago when i added the 35s then swapped to the 120 speedo and same issue. I have a theory that the calibration is only good to the OE cluster. as it tells the stepper motors how much to move. the 120 speedo being more cramped to allow for the higher speed its actually correct but shows wrong on the dash. think about it like a watch that was calibrated perfectly but you moved the face a few degrees in one direction. it would never read the right speed. as for the progressive speed fluctuations im unsure of.

 

[TSALI137]

Where did you find long tube headers that fit an IFS 4x4? All the ones I've seen interfere with the front driveshaft.
And the torsion bar.
And the fuel lines.
And the tranny crossmember.
And the fuel tank.

I haven't bolted them on yet but according to all my research the pacesetter long tubes from summit.Here is the link.

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Get fast, Free Standard Shipping on orders over Summit Racing Equipment from $109 -- no shipping, handling, or rural fees! Exclusions apply.

www.summitracing.com

Also if you have an EGR delete you can do away with the tube and put a plug in the intake and a cap on the headers port. They are a 5/8 flare male plug and 5/8 female cap. When I finally get the headers on in about a month or so depending on cost, I'll post back.

 

[TSALI137]

like others i recalibrated mine years ago when i added the 35s then swapped to the 120 speedo and same issue. I have a theory that the calibration is only good to the OE cluster. as it tells the stepper motors how much to move. the 120 speedo being more cramped to allow for the higher speed its actually correct but shows wrong on the dash. think about it like a watch that was calibrated perfectly but you moved the face a few degrees in one direction. it would never read the right speed. as for the progressive speed fluctuations im unsure of.

So if the thing is calibrated correctly in the pcm, the 120 speedo is always going to be off if I understand you correctly? Is there a way to adjust the pcm? I have the 0411pcm in my truck. I'm 42 and used to carburetor engines and actual speedo cables and gears in the transmission. This computer stuff is a little above me but it's something I really want to know more about.

 

[Supercharged111]

EFILive has a function that allows you to plug in indicated speed and actual speed, the software does the rest to correct the speedo. I calibrate my speedos at 70mph. Down at 35 they're off by a few. No way around that. The Escalade/Denali cluster is driven by a different circuit board, so you can't swap just the cluster you need all of the guts to make it work. Even so, mine was off 5-7 or so when I first put mine in my 1500, less for the dually. All that said, it doesn't account for OP's cluster growing a mind of its own. The stepper motor is probably dying.