When monitering engine parameters with a laptop, I see that the RPMs jump around. Say I'll hold the RPMs at 4000 RPMs and the Haltech displays 3700-4300 and jumps around.

The Haltech is controlling a 350 with a TPI style intake. I'm using an HEI distributor with the coil in cap. I pick up the tach signal from the distributor and I also run another wire for the tachometer.

I'm guessing that the tach signal needs to be filtered.

That is the only signal that is jumpy.

 

Anybody?

 

I'm not sure what model the Haltech F3 is, but I have the Haltech E6GM. In the manual, it says that if the tach signal is jumpy or off, that the trigger angle in the ignition setup is wrong. You may want to check that. Otherwise, if your car runs well, try a tach filter. Would you mind sending me a copy of your maps so that I can compare them to mine? Thanks, Good Luck.

 

Thanks for the post, knew it would be an oddball one.

What is trigger angle? The manual for mine doesn't mention this, but I should reread it.

 

From what I understand, it tells the computer where to trigger the number 1 cylinder spark. If the distruber is set outside a certain angle, the electronic advance/retard won't work properly.

 

I have an older style Haltech (F3) that only does fuel injection. Ignition is the old style 5 pin HEI with mechanical and vacuum advance.