Group. The circuit in Dave's drawing is a one shot monostable circuit. Meaning as soon as there's power, the output to relay coil is energized, closing the contacts. So the RPM relay is set to pre-prime before there's a tach signal. Don't know if the new relays have the same schematic. Steve VIN#04421 --- In dmcnews@xxxxxxxxxxxxxxx, doctorDHD@... wrote: > > > > For Dave S and anyone else interested... I posted the schematic of the RPM > relay in the files section, back in July 2005. It's still there. Now > someone with intimate knowledge of how a 555 timer works, will need to decide if it > is supposed to prime or not. > > > 7b. Re: RPM relay (was I think my fuel pump...) > Posted by: "Dave Swingle" swingle_dmc@... daveswingle2 > Date: Tue May 1, 2007 11:36 am ((PDT)) > > To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/