Holley EFI: Inconsistent start

[David Hodgkins]

302, Holley HP multiport EFI

The car is inconsistent in the way it starts. Sometimes it just cranks away before firing. I can't use any throttle other than sometimes if it won't start I add an extremely light touch. Other than that it seems to always want no throttle at all. Mostly, it'll crank for several seconds before firing. Sometimes it takes several tries before it catches.

Any ideas why it's so hard to start? I believe the timing is set to 10 or 11 degrees currently.

Car has only 1200 miles on it. Plugs look clean.

:)

[Papa]

Dave,

On mine, a Holley Sniper, if I just put the key in and try to crank it, it does as you describe. If I turn the key to the on position and wait for a few seconds, it fires right up every time. I think the ECU needs to boot and the fuel needs to prime. That's what is going on in those couple of seconds.

Dave

[bobl]

The Holley systems take a couple of revolutions to sync before it will actually fire. Also, most aftermarket fuel systems don't hold fuel pressure when the key is turned off. So it takes a second or 2 to build pressure at key on. At key on the IAC goes through a cycle to achieve it's programmed setting. I've found it works best if you turn the key on and wait for a second or 2 before cranking. If it doesn't start cleanly turn the key back off and on to restart the sequence. Each time you turn the key on it introduces a pulse of fuel so cycling the key acts like pumping the throttle on a carb. This is a programmable parameter. You can also adjust cranking fuel and where the IAC parks to introduce air at cranking.

Bob

[bobl]

David, I just sent you an email with a video. I don't know how to post a video to the forum.

Bob