Exhaust Valve Relearn Knowledge

[AdrenalineAddict]

I'm seeking knowledge about the exhaust valve relearn from those who understand the process.
Back story:
1) Finally discovered why my sled wouldn't run
2) Exhaust valve retaining bolt unscrewed itself from the valve.
3) Disassembled entire exhaust valve train, unhooked from servo, removed cable, cover, reinstalled valve and bolt, aligned valves, reassembled.
4) Took out for a test run today, runs great, no codes
Many have told me I now need an exhaust valve relearn. Why would I need a relearn if the sled was never powered up with anything disaasembled, there is no distance adjustment on the cable, couldn't lengthen or shorten the pull if you tried???

 

[Sheetmetalfab]

I'm seeking knowledge about the exhaust valve relearn from those who understand the process.
Back story:
1) Finally discovered why my sled wouldn't run
2) Exhaust valve retaining bolt unscrewed itself from the valve.
3) Disassembled entire exhaust valve train, unhooked from servo, removed cable, cover, reinstalled valve and bolt, aligned valves, reassembled.
4) Took out for a test run today, runs great, no codes
Many have told me I now need an exhaust valve relearn. Why would I need a relearn if the sled was never powered up with anything disaasembled, there is no distance adjustment on the cable, couldn't lengthen or shorten the pull if you tried???

same thing happened to my brother.

his sled runs fine without a relearn.

 

[AdrenalineAddict]

I guess I'll just call it good and let er rip. When your closest competent dealer is a 475 mile round trip sometimes you have to just do what you can do and hope for the best.

 

[Murph]

I guess I'll just call it good and let er rip. When your closest competent dealer is a 475 mile round trip sometimes you have to just do what you can do and hope for the best.

Run it.

E-VES relearn and position achieved is based on Hall Effect sensor in the Actuator (servo). If the sensor reads that the actuator is reaching the stored postions in the ECU all is good-- in your situation.

This type of system is also why your sled didn't throw a code when the bolt unthreaded itself from the valve-- the sensor reached its position and the system was completely unaware that the valve wasn't opening. Same thing happens when a cable breaks, no code, just won't pull above about 7700 rpm.

Because you didn't change cable, cylinder, etc it probably wasn't necessary. The manual will say that because you re-aligned valves a re-learn is required. I have switched any number of E-VES components and had both outcomes-- codes and re-learn required, and no codes.

If it was me, with no codes, I'd run it. When you happen to be near a dealer, plug it in to DW for a re-learn. I re-learn my E-VES (with no codes showing) regularly during the season/ life of the sled to compensate for cable stretch. I want to make sure my E-VES valves are fully open and the ports are unshrouded at max rpm.

 

[AdrenalineAddict]

Thanks for the explanation, much appreciated.