Artifically Enriched

[Carter Powell]

Being an old motorcycle desert racer one of the things that we used to do if we had to run wide open across a dry lake bed that was miles wide was to hit the kill button with our thumb every ten seconds or so to stop the ignition and let a cool charge of fuel help with the heat factor.
This was an old factory trick that would ensure surviveablity in a long race. Is there any way that a switch could be tapped into the EFI system to allow a person to keep the injectors working after a wide open run for a couple of seconds. From all the posts that I have read it seems that many engines are destroyed on trailing throttle after a wide open run. This way when the throttle is shut down you could still keep some lubrication and richness in the motor for a few critical seconds. Any response would be appreciated.

Carter

[Liqui-Fly]

I don't think it would worh on an outboard because once you killed it the pistons would stop; with a motor cycle in gear the piston(s) would still be moving right? LF

[JTS Racing]

Depending on the injection system, it can be "tricked" into richening the charge a number of ways without killing the ignition. Mainly by opening or closing some sensor circuits. If you use a fully programable controller like the motec then the possibilities are endless.

[sosmerc]

Some of the ECU's Merc uses greatly increase the time the injectors are held open every time the "start" circuit is energized. So, in theory, you could rig a switch that would put 12 volts to this circuit to force this "enrichment". You would have to separate this circuit from the starter solenoid so as not to engage the starter everytime you wanted additional enrichment. You cirtainly don't want to do anything that will "kill" the ignition system as the ECU depends upon an ignition signal to determine when to fire the injectors! One could also rig a switch that would create an "open" circuit to the tpi or the temp sensor...this would also cause an instant "rich" situation. But why not just "back off" gradually from long wide open throttle runs?