Actually, it seemed that the problem was that the distributor was generating "extra" pulses. Dave T. is right; it puts out a sort of sine wave, except that, because it is an odd-fire engine it puts out 2 waves fairly close, then a larger gap, then two again, etc. The problem we were seeing were random, spurious, very narrow "spikes" within the large gap where there sould be no pulses. These were picked up by the ECU and translated to the ouptut (as confirmed by comparing channel 1, input to channel 2 outputon the 'scope). This also explains the "twitching tach". We suspect the resistor attenuated the amplitude of these narrow pulses enough so they they fell below the threshold of the ECU. Dave D. confirmed that he initially solved the problem by increasing the resistance until the problem went away (hence the 2700 ohms). I still don't understand the reason for these random spikes, but it might have to do with charge building up and not being discharged completley where it should. Tom N >From: "David Teitelbaum" <jtrealty@xxxxxxxxxxxxx> >Subject: [DML] Re: Still running 2700 ohms... > >If you want to get technical about it the resistor is moving the >baseline of the sine wave. 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/