Tach issue/questions 2001 5.0 L

[ayleeuss]

2001 5.0 carb. Havng issues with the tach reading inconsistently. Doesnt seem to be any rime or reason as to when its right and when its wrong.

When its wrong, its about 200 rpm off at idle (reading higher) and at wot its about 600 rpm off. All connections on the back are tight and clean. I do have another tach i can put in to test (not a matching one)

Where does the tach get its signal from? any ideas other than the gauge itself?

 

[dtwolcot2]

Re: Tach issue/questions

I think the tach connects to the neg side of the coil. testing with a known to be good tach would be a good place to start. You sure the engine isnt operating at the rpm that the gauge is reading?

 

[kghost]

Re: Tach issue/questions

If you connect a new/different tachometer up make sure you disconnect the original from the circut.

 

[chiefalen]

Re: Tach issue/questions

Did you cycle the switch on the tach back and forth ? Then make sure you set it back on the amount of cyl you have.

 

[ayleeuss]

Re: Tach issue/questions

Put a known good tach in there and its reading accurately on the hose. Will update when i water test it.

Noticed today the old tach would sorta float to about 3k for a second right after the engine starts, then come down to 800. engine idles at jus over 6. Im pretty sure the tach needs to be donated to the reef under my dock.

Chief, didnt turn the switch. pointing right at 4 pulse.