The highlights of today are, I heard the engine run, a couple of times, but it certainly wasn't smooth sailing. Long post warning.
Started the day pretty good. Hooked the battery up and no smoke, sparks or pops. Headlights, tail lights and dome light worked, figured I'd check the stock systems first. Then tried the key. Found my trigger wire to my relay didn't power with the key. Not a big deal, found the needed power source. Then had the megasquirt and fuel pump relay power reverse. No problem, swapped plugs moving on. Things were looking good at this point. The system powered up, the megasquirt was reading the sensors, the engine cranked when pressing the start button. Though it seems the neutral safety switch is out of adjustment as it won't crank in park, but will in neutral. Won't crank in any of the gears so it somewhat works. Problem for later. Then it started to go down hill from there....
Started working on checking the fuel system and first the lift pump wouldn't prime, so I threw 7 gallons of fresh fuel in the tank (probably needed fresh fuel anyways) and used the shop vac to blow air into the filler neck and the lift pump promptly started leaking at both ends..... After tightening up the fittings, the filter, breaking at least one hose clamp, I tossed the pump and got a new one that had the fitting built in and a new filter. Only bathed in a gallon of gas in the process *blah*. Had a minor leak at the fuel rail and ended up moving the fuel pressure gauge to the regulator. By now it was mid-afternoon so I figured I'd skip filling the cooling system with water because I'd have to promptly drain it, and proceeded right to start up :thumbs:
Started the car up a couple times for ten or so seconds at a time and topped off the transmission fluid as well as ran it through the gears (speedo works now! Didn't when I got the car), and while doing this had no problems. The engine started reasonably well and shut off when I turned the key off like it should until......... it didn't...... The big difference between when it was working fine and when it didn't was I rev'ed it up high enough to get the alternator charging, and when I turned the key off the alternator was feeding the system, but cut off from the battery because I had the charging wire on the wrong side of my master relay and then bad things started to happen. The engine didn't shut off, but didn't sound right either, and I hit the power switch to the megasquirt to kill the engine but it was too late, the damage was done. When I key'ed back on the megasquirt did not power up. I checked and the fuse was good, it had power on the wire going into it, but nothing. Took a sniff at it and it smelled burnt =/
Dragged it into the house and opened it up and yup, a few cooked parts, some obvious and some not so obvious. Using the obvious visual cue's was easy for the damaged parts, but I hooked it back up to the JimStim and started testing the power circuit to find the two bad diodes. Started testing and replacing parts until I had power at the processor pins, and turned out just to be the two diodes.
Here is an obvious exploded capacitor
And an obvious burnt out power trace. (the copper color, it's not copper and doesn't conduct)
So I started troubleshooting. The exploded capacitor is essentially the first part that is installed when building a megasquirt and is part of the power circuit. So I started there. Fortunately I have some spare parts (not that any of them are exotic, but I was able to get it going again today). I replaced these four parts. The capacitor on the top right may not be bad, but I didn't trust the way it looked compared to the good ones. The bottom two diodes were toast, no conductivity in either direction.
New capacitors installed.
A jumper wire installed in place of the cooked trace. (it doesn't look pretty, but will work and is hidden in a case!)
So I went back out and took a video after the fact =D The phone picks up the fuel pump sound more than you can actually hear it in person. http://youtu.be/ljgzz8O__Ck
Rebuilding an OHC Pontiac 250 with EFI and a Turbo