yj tach w/v8

[justjeepin86]

Does anyone know if the factory 4cyl tach in a yj can be made to work with at v8. I know the aftermarket ones have wires to clip for v8 and v6. I just don't want to buy one if I don't have to. Any help would be appreciated.
Michael

 

[BUCKETOBOLTS]

I would say it probably will not work correctly. During 1 crank rpm the coil will fire twice on a 4 cylinder, and four times on an 8 cylinder. So the tach calibrated for the 4cyl should read twice what the 8cyl is actually turning. Don't know how you can re calibrate the factory tach for this.

 

[BUCKEYE PERFORMANCE INC.]

yj

yes it can you have to install a resistor in the tach wire i cant remember what size id use a varible resistor from radio shack and adjust it with an external tach

 

[justjeepin86]

thanks, I found something yesterday about putting a variable resistor in. I just need to find a tach to borrow to set the rpms right.

 

[snappy]

Talk to your local mech. most nicer timing lights have a built in tach that are pretty accurate.

 

[Erik]

my 89 throttel body injected4 banger tach seemed to read right at idle but when driving i thought it was taching a bit high.... ran an rpm calculator and when my tach reads 5200 rpm's i should actually be taching about 3300 rpms.... i was going to pull it out and look for some sort of adjustment but i haven't had time yet....