Hi everybody!

As you can all see I'm a noob at this forum. I've been reading it for the last few weeks and have found nothing but great information. I just installed my first TPI system a few weeks ago. I'm very happy with it, but the calibration is still off and I'm having some stalling issues with it. I'm very temped at purchasing a pocket programmer and re-adjusting the calibration myself, but I don't think I've done enough reading. This site is nothing but encouraging though.

Here's my question. My engine has a 230 duration @.050, (280 advertised), and .480 lift. At idle the vaccum signal bounces just because of the nature of the cam. Could this cause the fuel pressure to also bounce? If the fuel pressure is bouncing, wouldn't that cause the ECM to hunt all the time because the pressure isn't steady? So to fix this problem I could simply remove the vac signal from the pressure regulator and make it run full 43 psi all the time?

I don't see this being a problem because my idle in closed loop is way too lean anyway. Are there any other reasons why I wouldn't want to run full pressure all the time?

Thanks,

-HD

 

If you feel up to it I would check out Craig Moates page(http://www.moates.net) and the DIY PROM section https://www.thirdgen.org/techbb2/for...?s=&forumid=16 for a emulating(real time tuning) device or a standard programmer.

If it is a map system then it may hunt on the factory calibration with a so called non-ecm friendly cam. I don't think the fuel pressure would affect the idle unless it is a large sweep in pressure.

 

I'm assuming you've installed the tpi on your chevy 1500.

I could be wrong here, but I do not believe that the ecm monitors fuel pressure.

I don't know much about cams, but I may be able to help with your fuel pressure problem.

Your jittery f/p guage is probably caused because you do not have a pulsator valve on the fuel line. The action of the injectors opening and closing causes the pressure in the rail to "pulsate".
The pressure drops a few psi when the injectors open, and then comes back when they close.
A pulsator valve would absorb the jitters before they get to the fuel rail.