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.
I’m still working the issues, but no joy. I am able to get the Impreza to crank, but there’s no life in the engine. I can hear the fuel pump kick in. There is fuel in the tank. I haven’t checked the pressure at the fuel rail, but I’m assuming there is pressure there. There is power to the injectors (verified). I don’t think the ECU is getting a signal to fire anything. The plugs are dry. I did pull one out and cranked the engine. I didn’t see any fire at the plug, so I’m assuming there’s nothing there. The engine started prior to pulling it. This was on ether, as the fuel pump in the SVX wasn’t working. Since it was running on ether, it would mean the crank/cam sensors should be working providing input to the ECU and spark at the spark plugs. Still, I’ll be checking the crank/cam sensors as they are just hall effect sensors and should provide some type of electrical movement as the field is broken across them.
I’m going to try and get the DLC connector for the ECU hooked back up, or at least get wires ran for it so I can attach my code reader. This should (hopefully) give me some insight into what might or might not be happening in the ECU. I have heard rumor, though, that these Subarus didn’t have OBDI, but rather just the Subaru brand of engine management. I guess I’ll have to play with it and see if I can figure something out.
Wouldn’t you know it … I looked on Craig’s List today. Found an EJ22 for $450 out of a 96 Impreza with supposedly low miles … If I had only known …
I haven’t gotten much done to the Impreza over the last few weeks. I’ve been working on a class for my Masters. I also spent most of a week out of town for work, so that didn’t help. Plus the release of TitanFall2 … too much fun and not enough time!
What I’ve been trying to figure out lately is how to get the wiring harness into the Impreza. There have been a few stumbling blocks. I was given some wiring diagrams for the Impreza which were okay, but they were B/W and hard to read. It was VERY hard to tell what the layout of the ECU connector was and the labeling of the wire colors was terrible. Luckily a guy on Stack Exchange provided me with some color ones, which are awesome. Here’s what they look like:
Looking at the two images, the right side of the top one connects to the left side of the bottom one. The ECU plug shown in the diagram actually looks like this when disconnected:
It’s actually upside down. Pin #1 is on the lower right side of the connector and runs across to pin #16, then continues down from there. I’ve found most of what I need to cull out of this to plug into the SVX ECU to make it work. We’ll see how it goes. I’m going to clip the wires I need off of the back of wiring harness (probably leave a pigtail) to connect. I’ll blog about it as I’m hoping to get the car started this weekend.
One of the other things I needed was a diode to fool the ECU into believing the “automatic” transmission is in park. Since the transmission in the Impreza is a standard shift, you have to include the diode in the mix so it will think it’s in either park or neutral. Without it, it thinks the transmission is in gear and that’s all she wrote … no cranking will occur. I was wondering what size of diode I’d need and where I’d be able to find one. Luckily, keeping the old wiring harness pays off. There just happens to be a pair of them already in the harness which you can use for this purpose. Here’s what they look like:
I’m still unsure of how they go into what I’m doing. Not sure of the direction alignment. Not sure of a lot of things, but ultimately I’ll get it figured out.
Like I said, I’m hoping to get it started this weekend. I’ll blog about my endeavours later most likely :o)