steve40

iTrader: (18)

i got a 99 ls1 pcm running a 6.0 in a 97 (lt1) style firebird. the tach has work previously. just swapped in a 99 pcm to see how it compares to the 01 one for the transmission.

anyways everything is working cept for the tach. the scan tool does see rpm, just nothing to the dash

any ideas? not really sure where to look. the rest of the dash does work. i do have to do a case relearn, would that affect the tach?

Frost

iTrader: (45)

Cam sensor and/or it's wiring... do you get a stumble, fart, or back fire every few startups? That's a sign of the same.

steve40

iTrader: (18)

haven't seen any of those

also....efilive does see rpm thru the scanner...just not getting thru to the tach...it worked last week and all i changed was the pcm

Frost

iTrader: (45)

Right, the PCM is referencing the crank reluctor for RPM, so it will see it.

I may not be clear on your problem... is this an aftermarket tach tied into the harness' white RPM signal wire that is not working?

steve40

iTrader: (18)

it's the factory 97 dash

steve40

iTrader: (18)

ok, did a lil work today.

swapped my 01 pcm back in....tach works. put the 99 back in....no tach again. tried reflashing the cal and op system, no luck there too.

ended up going to the 01 and put in the 99 op and cal.

any ides on the 99 pcm, would suck to have the license wasted on what could be a good spare pcm to have around