Back To Basics … and an output diagram.

I got the new ECU in and discovered the old one wasn’t bad. As I plugged in the new ECU, I had the same issue … the fuel pump wasn’t kicking on when I turned the key to the on position. My heart about fell out on the floor. Like I said before, this is R&R wrenching and I do not like it. I then started playing with the wires on the ECU. Low and behold … the pump kicked on. Holy smokes. The problem was not with the ECU, but with the fuel pump relay wire coming from the ECU not making connection at the pin. I then pulled out the pin from the connector, played with it a little bit (read: used a pair of pliers on it to make it have a little better contact), re-pinned it in the connector, and have been rewarded with a consistently working fuel pump since then. Engine still isn’t starting, but the fuel pump runs! Yay, small victories! Even if your victories come after setbacks … argh.

I’ve decided to go back to the drawing board a little bit. I’ve found a couple of charts on RS25.com which will probably help. I’ve seen these charts before, but haven’t given them much mind until now. Yes, folks, I can be dense (enter: not seeing the forest for the trees cliche here). Here are the two charts I’m talking about:

42353853

42353893

What these two charts show is each of the important connections at the ECU and what their values should be with the ignition/engine in the off, on, and running positions. The plan for today is to go through each connection at the ECU with the key in the off and on positions, then back-probe the ECU to get each of the values from the pin. I’m hoping in doing so I’ll be able to figure out if something is not reading. It will be an arduous task, but I think it will provide results which may help me figure out why the engine isn’t starting.

Fried Turkey for Thanksgiving?

While we did have a fried turkey for Thanksgiving, I’m almost positive I’ve fried the ECU as well. Just to put anything aside, I’ve gone ahead and purchased another one off of eBay. I know this goes against everything I hold dear with regards to working on cars … as in … I do not do R&R (Remove & Replace) wrenching. There is no worse form of diagnostics. It always costs more money than you can afford. It’s really just wrenching at its lowest level without diagnostics. I guess I can say I’ve actually done some diagnostics, though. Let me explain what’s going on …

I’ve been troubleshooting the Impreza trying to get it to start. I found two plugs in the engine compartment which looked like they belonged together. Plugged them up and they snapped right into place with each other like a matched set … turned the key on and no longer heard the fuel pump kick on. I went around to the other side of the car where the ECU is at and you could smell the acrid smell of burnt electronics in the air. Yah, one of those heart sinking moments. I turned the key off and on again hoping I was just hearing things, but sure enough, no fuel pump. I went through and checked all of the fuses and couldn’t find any which were bad. I can ground the wire to the fuel pump relay and the pump kicks on just fine, therefore I know the relay and connection is just fine. The common denominator here is the ECU. I took the shell off of the ECU and you could smell it had a burnt electronics smell to it. I took the board off of the shell completely and did a complete once over on it. While I couldn’t pinpoint any fried capacitors, transistors, or resistors, something in there smelled burnt.

Since I’m about 95% sure I’ve fried the ECU, I went ahead and ordered it. Just one more thing I’ve had to purchase. While I’m a little stumped by why this thing won’t start in the first place, hopefully this will get me one step further towards the end goal of a rocket ship for my kiddo.