83 Brat - No ECM and failing emissions

[spatulaisgod]

First Post, first time owning a Subaru - and I spent at least an hour searching to do my best to make sure this wasn't a duplicate post.  My apologies if this has been posted before, but I did my best.

 

I purchased a seemingly clean 1983 Subaru Brat (108K original miles) after searching for many years for the right one.   It ran great when purchased, still runs great, but trying to get it to pass Colorado emissions is my only challenge.   It leaked oil bad, so bad that the amount dripping on the exhaust caused the emissions testing facility to stop testing cause of the smoke caused by the oil on the tail pipe (no smoke out of the tail pipe).   I remedied this by removing the engine and replacing all the gaskets on the engine - no leaks or issues on the re-install, fired right back up.   In doing the engine removal, I noticed that the O2 Sensor had no wire attached to anything, in fact no wire at all coming from the sensor.   So, I bought an O2 sensor, and was referring to the manual to try to figure out where it hooks to on the wiring harness, and couldn't find the lead.   Upon further inspection (supposed to be a Red/White wire on the harness that splits to the middle of the engine compartment), I noticed that there was a lack of a thing the book refers to as the ECM.  I see the triangle bolt pattern where something was supposed to exist, but there is no ECM.  Despite this, the car runs great and I have no complaints and love it to death.  

I am however, faced with a quandary.  Do I try to get a salvaged ECM off of ebay or used Subaru parts shop and try to hook it up (looking at more work than I ever imagined with a hopeful and successful outcome), or will I set fire to my wiring harness and beloved brat by trying to hook up something that a previous owner has evidently intentionally deleted.  I know there are a broader range of possibilities than those, but those are my main fears.  At this point, I'd just like it to pass emissions.  Any help or guidance would be appreciated.

Thanks,
BratFanBoy10023

[Mykeys Toy]

Whcih parts of the smog test did you fail? Have you taken the test to a local shop to see if they can point you in the right direction?  Just a starting point..When was your last tune up?  Are you missing any of your emissions stuff?  Check your EGR.  Tat is all I can come up with @ 5:13 a.m.

 

Mike

[BuckarooBanzai]

Great looking Brat! Hope you get everything sorted out, seams like a relatively small fix.

[skishop69]

So if they stopped the procedure, it didn't truly fail. I doubt it had and ECM to begin with. IIRC, 84 was the first year for the electronic carb and it came on California models. It had an ECS (SES) light under the speedo. Someone most likely bought a direct fit CAT which would have been generic to all models and included the O2 bung. Instead of finding the correct plug, someone spent $20 on a cheap O2, cut it and installed it. If Colorado still does the visual inspection, you need to pull that and put the plug in. They might see that and suspect the rest of the components have been removed and fail you on that alone. Check the engine sticker on the underside of the hood. It will either say conforms to Federal emissions or California emissions. If it says Federal, no ECM.

[turbosubarubrat]

So if they stopped the procedure, it didn't truly fail. I doubt it had and ECM to begin with. IIRC, 84 was the first year for the electronic carb and it came on California models. It had an ECS (SES) light under the speedo. Someone most likely bought a direct fit CAT which would have been generic to all models and included the O2 bung. Instead of finding the correct plug, someone spent $20 on a cheap O2, cut it and installed it. If Colorado still does the visual inspection, you need to pull that and put the plug in. They might see that and suspect the rest of the components have been removed and fail you on that alone. Check the engine sticker on the underside of the hood. It will either say conforms to Federal emissions or California emissions. If it says Federal, no ECM.

My 82 brat has a ECM, cruise control, a electronic carb, o2 sensor with cat deleted from previous owners, and all the high altitude equipment. So did a 1980 hatch back i got parts off of at a junkyard. All my other carb cars have just a o2 sensor, regular hitachi's, and cats. The o2 sensor when it's original came with a rubber connector plugs that can be put on the new o2.

[spatulaisgod]

The first test it failed a visual smoke test from the oil on the exhaust.   After pulling the engine and fixing all the leaks, and re-testing, if failed CO2 levels only.   That is why I figured it was the O2 Sensor, but the info on the Federal vs. California is very revealing.  I hit panic mode when I saw the space where the ECM was supposed to be, and the O2 Sensor with no wire to the wiring harness.   It is awesome that the repair book fails to make it clear that the O2 sensor and ECM are California specific.

 

Mine is not a California Emissions, so  skishop69, your post makes total sense.

 

Thank you all who took the time to read this, and respond.   I very much appreciate it.

[greg454]

I had a problem initially trying to pass Colorado smog test with my '84 brat. They insisted it was supposed to have a computer and o2 sensor and wouldnt listen to me when I told them it never had a ECM. After about an hour with the manager he figured out if he looked it up in his computer as a Subaru truck (he was looking under car) it then showed correctly on his computer and it passed with flying colors. Next time I went back I told them to look it up as a truck and they found it just fine.

[spatulaisgod]

I just double checked the failed report, and they did test it as a truck, and the carbon monoxide limits are 60, and mine was at 122.  i'll double check the EGR and vacuum lines again.  When we pulled the engine, the carb was not very tight, and one spark plug was finger tight - so I am hoping that had something to do with the fail.   I'm going to re-tune, re-test, and hope for the best.    Thanks for the response.

[skishop69]

I did not know they had ECU's that early. Duly noted. Did you fail idle or cruise CO? There is a difference in the approach to fixing the problem. Cruise CO is generally a CAT and idle CO is usually a rich condition or incorrect timing. Plugged air filter, PCV issue, too much blow by, float level too high in the carb, timing not advanced enough, idle mixture set too rich.