1974 Pontiac Firebird tach won’t work

Changed HEI coil,cap. Now car sputted for about 10 mins but tach worked. Then tach stopped working and sputting stopped?

Not a question although you used a question mark. Did you change the rotor as well? Did you re time the engine? Change spark plugs at the same time? Which engine? Miles? Answer my questions and ask yours and we’ll try and help.

I used this kit. The old cap was a Accel.
I didn’t change plugs, they were done in the spring. Car wouldn’t start found rotor bushing on top of insulator. So I replace this new kit.

Tach was working fine before that.

After the kit tach worked for a few minutes but car sputtered when I got on it a little. Suddenly tach went to1 and car ran fine.

Factory tach or aftermarket? Are the HEI 12v and tsch connections in good physical shape, no corrosion, nomfrayed wires?

Again, which engine?

I think so it’s in the dash.
Wires look good

400

I’d suspect a problem with the pickup coil inside the distributor, or the ground wire. Also wires inside the cap may have gotten pinched when re-assembled. Take it back off and look inside for a damaged wire.

This is the second kit I have put in and both have the same issue.

Then either the kit is not the right one, or the kit parts are not the problem. Did this car originally come with the HEI or was it a points distributor car converted?

When I got it, it had a HEI Accel cap coil

That’s not the same as “originally come with the HEI” I’ll have to assume you don’t know how it was originally built.

I’d suggest trying another cap and coil from another manufacturer if you can’t find any damaged wires.

i had a rust free 79 camaro from ariz in the late 90s in mn. which is nice. i went to look at a 74 T/A SD and the seller asked why i wanted 2 camaro/firebirds? my wife asked the same question so i did not buy the SD. for 2500. i sold my camaro for 2k a month later and went back to the TA seller but it was gone. sniff.