Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
I'm hesitant to say that the tach not working and the long crank are related, but it's possible. Lets start with the long crank:
Is it more prominent after filling the gas tank?
If you remove the gas cap before trying to start it does it go away?
If you cycle they key (turn to run for 5 seconds then off then run for 5 seconds then off, then start) does it start right away?
Does it get any better based on temperature outside?
How old is the fuel pump?
No trouble codes stored right?
What kind of pressure readings are you getting?
Check for the fuel pressure to bleed off too quickly. It should bleed off less than 5 PSI in 1 minute once the fuel pump is shut off.
I can't find anything in the wiring schematic that would make it long crank and also kill the tach.
If you'd like I'll opt out and see if anyone else has any insights.
The only two things I have ever seen cause a long crank are low or bleeding fuel pressure and a bad EVAP solenoid.
Can you monitor fuel trims with your scan tool?