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dcb · 07-01-2008, 10:14 PM

Scope showed up today, it is a cute little portable 15mhz job

I scoped the power downstream of the 7805 and did not see anything, zoomed into max frequency and minimum voltage. It was rock solid, even while hitting switches and the blower and the starter, running or not, and tried the horn, nothing phazed it.

I scoped the injector, typical injector signal. I scoped pins 2/3 and they appeared well protected at the max resolution of the scope. The only issue I saw was the low end of the signal, and this may mean a hardware change is still needed. This is basically what I saw when zoomed in a bit on the pulse:

So the theory is that the mosfets (or whatever switches ground) drop the voltage to just about zero initially, but then the injector (being a large inductor) starts letting more current through, and the voltage rises to something approaching a volt. We *might* need to condition the signal a bit more to ensure we are solidly in LOW mode on those pins. Need to research it a bit more first.

I will have to wait till I fix the batteries on the scope to do anything interesting with VSS, this is a pretty cool tool though

07-01-2008, 10:14 PM	#397 (permalink)
dcb needs more cowbell Join Date: Feb 2008 Location: ÿ Posts: 5,038 pimp mobile - '81 suzuki gs 250 t 90 day: 96.29 mpg (US) schnitzel - '01 Volkswagen Golf TDI 90 day: 53.56 mpg (US) Thanks: 158 Thanked 269 Times in 212 Posts	Initial scoping Scope showed up today, it is a cute little portable 15mhz job I scoped the power downstream of the 7805 and did not see anything, zoomed into max frequency and minimum voltage. It was rock solid, even while hitting switches and the blower and the starter, running or not, and tried the horn, nothing phazed it. I scoped the injector, typical injector signal. I scoped pins 2/3 and they appeared well protected at the max resolution of the scope. The only issue I saw was the low end of the signal, and this may mean a hardware change is still needed. This is basically what I saw when zoomed in a bit on the pulse: So the theory is that the mosfets (or whatever switches ground) drop the voltage to just about zero initially, but then the injector (being a large inductor) starts letting more current through, and the voltage rises to something approaching a volt. We might need to condition the signal a bit more to ensure we are solidly in LOW mode on those pins. Need to research it a bit more first. I will have to wait till I fix the batteries on the scope to do anything interesting with VSS, this is a pretty cool tool though __________________ WINDMILLS DO NOT WORK THAT WAY!!!