Hypothetical question

[Steve Cole]

So I took my truck to a local engine tuner to get it fine tuned after my LS swap. He had it for 2 days and texted today that it was ready. I showed up and paid him and when I went to leave, I noticed my factory tach wasn’t working so I went back in to tell him.
His first response was he only hooked to the OBD11 port and didn’t mess with the tach or anything to do with it. I knew he had no reason to mess with the tach so at first I chalked it up to bad luck for me.
Then on the drive home I remembered something he had said to me earlier. He said “I changed your shift point from 5000 to 5800.” I know he took it for a drive and he told me it was burning the tires between shifts. My question is this: if he revved the motor to 5800-6000 rpm while driving, could this damage the tach that only goes to 5000 rpm or would the needle just continue on past 5K?

[Jackson's Dad 64 C10]

My truck doesn't have a factory tach, but is there a needle stop at the top end of the gauge sweep? I'm wondering if pegging the needle against the stop wouldn't cause problems...

[ls1nova71]

Is it an original factory tach or aftermarket? I've had a couple of aftermarket tachs burn up on me. The first one was warrantied, but the second one I had had too long. Took it apart and found a big resistor burned up on it so I tried replacing it to see if it would fix it, it did not. Bought another one and so far so good, but I think the quality of a lot of aftermarket parts is just abysmal at best. The stuff only sells because there isn't a lot of other options.

[Steve Cole]

Originally Posted by ls1nova71

Is it an original factory tach or aftermarket? I've had a couple of aftermarket tachs burn up on me. The first one was warrantied, but the second one I had had too long. Took it apart and found a big resistor burned up on it so I tried replacing it to see if it would fix it, it did not. Bought another one and so far so good, but I think the quality of a lot of aftermarket parts is just abysmal at best. The stuff only sells because there isn't a lot of other options.

This is an original tach, not aftermarket. Do you think revving it past 5k would cause it to stop working? The computer is outputting as it should.

[cadillac_al]

You would think they got wound higher than 5k rpm on test drives when they were new. GM must have known they would get revved past 5k rpm. I would chalk it up to bad luck and old age.

[ls1nova71]

Originally Posted by Steve Cole

This is an original tach, not aftermarket. Do you think revving it past 5k would cause it to stop working? The computer is outputting as it should.

I seriously doubt over revving it would hurt the tach. Like te other guy said, it's probably just bad luck and/or age.