So I finished my f23 transmission swap from an f35 on my lsj, speedometer only going to 20 mph at max and low speeds doesn't really do much.. So it's wanting to do something but its not working right. Anyone had similar issues on these vehicles at all? Is there an input speed sensor on the manuals?

 

just a quick look at a couple tunes shows the reluctor wheels in the transmissions have different tooth counts. the f35 has 85 teeth and the f23 has 29 teeth. this can be changed using hp tuners under the speedometer settings.

 

I did an f23 swap on an lsj (04 ion redline) and the speed sensor settings did not need to be changed. I compared the speedo with GPS after the swap and everything was right. I would check your sensor resistance and wiring job.

 

doesnt the 04 ion use the speed sensor on the intermediate shaft? i seem to remember that was a different tooth count than all other f35s

 

Thats why I included the year. Im not sure that makes a difference.

 

I will double check the wiring tonight and if all is well I will see about possibly switching the speed sensors. Only person with hptuners near me is about 4 or 5 hours away

 

For the time being if you need to drive the car, you can get a free GPS speedo app on your smartphone.

 

Will do man I appreciate it

 

 

Bump from the grave

I have an LNF F35 and swapped to an HHR F23. I have the same problem with the speedometer being off. In HPTuners I'm using 4.17 FD and 72,616.13 vss pulses per mile. I have also tried the F35 speed sensor in place of the F23 one and that didn't make a difference. Any halp?




https://www.cobaltss.net/forums/driv...4/#post7742908

 

when you changed the tune, did the gear ratio box have 3.84 in it, or was it set at 1.00?

in a fwd the final drive ratio doesnt factor into the vehicle speed calculations due to the location speed sensor. in a rwd with the speed sensor on the transmission, the rear end ratio plays into the calculation.

if you look at my above post, the f35 has 85 teeth, the f23 has 29 teeth. either try putting 2.93 in the final drive ratio box, or put that at 1.00 and multiply your pulse per mile box by 2.93

 

Did you ever get this issue resolved? I am having the same issue. Tried several settings in HP Tuners, wheels diameter, PSS setttings, final gear ratio, but the results are the same. Speedometer never goes over 20 mph. Any help would be appreciated.