I recently bought a 1990 Geo Tracker 4x4 5-Speed Manual.
It has the stock 1.6L 8V Engine.

The guy I bought it from "hot wired" the fuel injector with a toggle switch.
I was guessing it had a bad ECU, and hoping it just needs new caps as there was no CEL (Check Engine Light) when the key was turned on.

I drove it home and pulled it into the garage.  The first thing I did was check the CEL bulb to make sure it was good.  It would not light with B13 grounded, so I pulled the dash and found the bulb had been removed.  I took the bulb from the seat belt light and installed it into the CEL location.  Now when I turn the ignition ON - the CEL flashes 12.

The problem is, the Diag jumper is not grounded so it should not be flashing.  I tried to start the tracker with the toggle switch off "not hot wired" and it would not start.  If I flip the switch to hot wire the injector, it starts and runs but the CEL just keeps flashing away. 12, 12, 12...

I have read through the ECU checks on fixkick.com and I didn't see anything about this problem. 

Has anyone seen this?  I'm guessing the ECU needs new caps, or other repairs, but I didn't want to remove it and without checking the forum first.  I'm wondering if there is another place the (other that internally in the ECU) the diag pin could be shorted. 

Even if this was the case, I believe the tracker should start in diag mode.  I know there are lots of reasons the ECU could have the injector cut off, but because it just keeps flashing 12 (which means the ECU thinks everything is okay) I'm confused...

I'm hoping someone has seen this issue.  Thanks!

Does your fusebox look like this?  If there's a fuse in the diagnostic slot, it will cause the CEL to flash.

By the way, the ECU is bad, that's why the PO hot wired the fuel injector, and it would be a good idea to fix it properly sooner rather than later - that ECU switches both sides of the injector, one of the drivers is burned and if left like that, the other one WILL burn.

I know it's not a good idea to hot wire the injector, that's why I'm trying to fix it first thing.   

As far as the ECU flashing 12s. It was the Diag jumper "Fuse 14" in the fuse box all along.  Previous Owner stuck a 20a fuse in the Diag Jumper.
I thought it was for the Fuel Injection like on 91 and Up...

I read on fixkick that 1990 Geo Trackers made in Canada do not have the Diag jumper in the fuse box...
Reference: http://www.fixkick.com/CEL/DLC/DiagJump.html "Some early Geo trackers were made (early 89) not at CAMI plant in Canada but in actual Japan and are wired like Suzuki's."

My Geo is VIN is 2CN which is CAMI. "Canadian Automotive Manufacturing" but fuse 14 is still a DIAG jumper.

I bought this tracker and it did not have a fuse box cover and I did not have the FSM so I was going by what I read over on fixkick and didn't pull Fuse 14... 

Anyway, I bought the real 1990 Geo Factory Service Manual "FSM" on ebay. When it arrived I looked up the fuses, and it shows Fuse 14 as DIAG.
It does not reference any fuse box for the 1990 GEO Tracker without the DIAG jumper.

Silly me...  I owned a 1990 Sidekick before, and was well aware of the Diag jumper so should have pulled it first thing. 

By the way, the ECU is bad, that's why the PO hot wired the fuel injector, and it would be a good idea to fix it properly sooner rather than later - that ECU switches both sides of the injector, one of the drivers is burned and if left like that, the other one WILL burn.

I am guessing the ECU is bad, but I don't like to guess...  I understand something is wrong, but it's not 100% that the ECU is bad.  According to fixkick there are lots of reasons the ECU will cut off the injector. 

From fixkix:  Keep in mind the ECU is programmed to CUT fuel (injections) for many reasons.  No injections, are not a sure sign of a bad ECU.

So that's why I'm asking if anyone has seen the ECU flash 12 like this without diag grounded. 

I suggest you take what you read at that site with a large pinch of salt.

Okay, I have removed the ECU and it's a virgin.  There are two big Rubycon caps that are toast.  I have removed them and the bottom of the board looks good, but the top has some slight damage where the acid has leaked out.

I have some caps ready to solder in but I'm not sure about the connections on the top of the board. Are there supposed to be pads on the top that are soldered?  The original caps were tight against the board, so I'm not sure if they were soldered there or not?

Pictures Included and I have marked the connections I'm concerned with.  Any Help.

NO - that is not acid damage you're looking at - YES - there were originally pads at the top of the board and eyelets through the board - whoever removed the caps appears to have ripped the eyelets out whilst removing them.

Not having worked on one of those before I'm unable to say how many layers it has, if it's only two, it might be repairable, if it's more than two, it'll probably need to be replaced.

NO - that is not acid damage you're looking at - YES - there were originally pads at the top of the board and eyelets through the board - whoever removed the caps appears to have ripped the eyelets out whilst removing them.

I removed them... Believe it or not, I have an actual college degree in Electronics Technology.     I used a fine tip soldering iron and a solder sucker to remove the solder first.  The caps came out with zero force...  Those locations were covered in Acid.  I used water and Q-tips to remove the Acid, and this is what the pads looked like once cleaned     I believe the Acid eroded the exposed solder and copper, if there was copper there to begin with that is.

Not having worked on one of those before I'm unable to say how many layers it has, if it's only two, it might be repairable, if it's more than two, it'll probably need to be replaced.

It is a two layer board.  The pictures I have seen of other boards do not show the "good" traces without the caps installed.  I am guessing there is supposed to be copper there, but not having a good one to test continuity, it's just an educated guess.  Every other component on this board has solder on the top and bottom, but these caps are unique in that they were tight against the top of the board.  No exposed leads like the other components...  Meaning before the caps are removed, you can not see the traces under them. 

I was hoping someone could tell me if those connections where I made the red lines are correct.  I'm about 90% sure they are right.   

Here are some pictures before I removed the caps so you can see the extent of the Acid damage. 

I have zero college degrees, but about thirty five years worth of work experience, and a lot of it in component level repairs on the older TTL based electronics stuff - commercially made multi layer boards have eyelets for the "through hole" components - the eyelets are missing from that board.

With your knowledge & experience it should not be too difficult to figure out from the shape of the copper traces what those caps were soldered to - you may be able to solder 30ga wire to the cap lead and work it back to an adjacent pad and make a connection there.

The best place to get guide on this is Rhinoman ...

http://www.rhinopower.org/

Look at the top of the page you'll see a forum link, register and post your pics/ask the question.

That's my plan.  You can see in the pictures where I have used a bit of wire to repair one connection/trace already.

Like you say, I'm going by the shape of the traces and that's why I feel about 90% sure.  I just know this is a very common problem that many people have done before, so was just hopping someone who has done this exact board could get me to 100%.

Thanks for the rinopower link.  I had not seen that site before.  I might post something over there.

ECU fixed!  No more hot wired injector.  WoooHoo!

I was able to solder in the new caps and repair the traces with some wire. 

FYI, the connections on the top of the board I showed in the pictures are correct.

Great news.

From fixkix:  Keep in mind the ECU is programmed to CUT fuel (injections) for many reasons.  No injections, are not a sure sign of a bad ECU.

There are very few reasons why the ECU will cut injection, primarily they are if it doesn't see the spark signal or during deceleration if certain conditions are met. Other wise its a fault, either in the ECU or with the sensors or wiring.