power latch relay?

[arkansasduck]

what is a power latch relay? and what does it do?

[old_man]

It keeps the power to the computer for a few seconds after turning off the ingition. It gives the computer the time to reset the IAC to the start position before the power goes away.

[5-90]

A "power latch relay" (called variously here a B+ relay or an ASD - Automatic ShutDown - Relay) is typically used in electronic engine management systems to provide power to a few systems after they key is turned off, so that they may return to "Engine Start" state from "Engine Run" state. It's meant to help decrease cranking times with start.

"Latching" a circuit, in electronics, is essentially "locking" it to a certain potential - briefly or permanently. "Latching to Power," in this case, means tying various circuit sources to battery power - it just happens to be for a definite time (30 seconds or so, I think.)

Is there any particular reason you're asking, or just for your own edification?

5-90

[langer1]

On renix it keeps power to the ECU on long enough to reset the IAC to 0 when the key is turned off.

[old_man]

You guys are getting too slow :compwork:

[5-90]

You guys are getting too slow :compwork:

Gimme a break - it took me over 20 years just to type as fast as I do now!:kissyou:

5-90

[CreativeSN]

Where is the latch relay on a HO?

[CreativeSN]

Anyone? My engine revs to 1800 on start up. That cant be good.