October 7, 20195 yr Author comment_585291 Len, Just to be clear I disabled the starter per the manual to make the measurement at pin 4 . I measured the voltage at W47 and the voltage is 9.8 vdc. However, the motor starts right up and runs very nice. I did notice that the fuel pressure was at about 5 psi before I started the car. Not sure where the leak down is, but at least it starts. Ron Link to comment https://www.classiczcars.com/forums/topic/62952-75-280z-not-starting/?&page=2#findComment-585291 Share on other sites More sharing options...
October 7, 20195 yr comment_585311 Ron, 10-4. As long as it's starting, take the Win! ? As a teaser, here is how I would check the crank signal using the HellFire ECU on my 77-280. (I added the two big red arrows in photoshop) Note: the help screen, too. You can't tell from the screenshot, but as you move the mouse over the ECU pins on the help screen, the description changes and tells you what each pin is. I still need to add into the program to show you the actual real time voltage being reported back from the ECU for each pin as you move around. The actual injector pulse width can be seen in the bottom right as the two yellow positive pulses (around 5ms each). This screen shot was taken in stock L-Jet mode so the ECU is batch firing two injector pulses/cycle. The second screen (added not because it has anything to do with the crank signal, but I just think it looks cool) is just a snapshot of the VE table as if you were running Speed Density instead of the stock AFM or an aftermarket MAF. Technically since the MAP sensor is on board, the VE table can always be calculated/interpolated even if you are running with the stock AFM. The reported grams/Sec from the stock AFM can then be compared to the VE table as a sanity check all the time. I haven't decided how to handle the case when the disagree with each other. I'll probably just make it a configurable item and let the user pick which one takes precedence. TPS is also available so there is actually a third Alpha-N table that can be thrown in the mix for even more redundancy if desired. Len Link to comment https://www.classiczcars.com/forums/topic/62952-75-280z-not-starting/?&page=2#findComment-585311 Share on other sites More sharing options...
October 8, 20195 yr Author comment_585330 Len, very cool! So is this a program you developing? I wish I had something is see whats going on with my beast. BTW my voltage is being sucked down by the ignition resistor or what ever is hooked to the IGN wire on the ign switch. when I disconnect both of these the voltage jumps back to battery voltage. Now I just have to discover why! Ron Link to comment https://www.classiczcars.com/forums/topic/62952-75-280z-not-starting/?&page=2#findComment-585330 Share on other sites More sharing options...
October 8, 20195 yr comment_585331 It's not just software, Len is designing a "replacement" ECU that can be enhanced with sensors not available on the 280Z when it came out. Link to comment https://www.classiczcars.com/forums/topic/62952-75-280z-not-starting/?&page=2#findComment-585331 Share on other sites More sharing options...
October 8, 20195 yr comment_585333 Ron, I'll have to look at the schematics again and see where else that wire runs to. It sounds like you are on the path though. As for the HellFire, as Steve said it's a drop in replacement for the stock analog ECU. Unplug the stock ECU, plug in the Hellfire, hook up the laptop and you can look at every sensor, configure every table, adjust for any engine modification. Plug and Spray! Len Link to comment https://www.classiczcars.com/forums/topic/62952-75-280z-not-starting/?&page=2#findComment-585333 Share on other sites More sharing options...
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