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Can the ECM be eliminated/bypassed on an EA-81?


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I've searched through the posts and have it pretty well figured out that I can eliminate most of those annoying hoses on my EA-81 engine. What I couldn't find is what to do with the ECM and what it controls. Can I just unplug the ECM and throw it away? It seems unlikely. How do I get around that obstacle? Thanks for the info.

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New York State plugs into the computer through the OBDII port, so they don't check anything built before 1996. Therefore, I can be a little more creative with an older vehicle.

 

My concern is, if I convert this car to a Weber, what do I do with all of those hoses?

 

Question, are there any problems with keeping one of these running OK as you eliminate this stuff?

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Removing all the extra hoses and what not on my brat actually made it pass emissions when it was failing before hand. However, the brat never did have an ECM so I didn't have the extra wireing to deal with. Just hoses and hoses. Basically the only thing you need to keep it running good, is the PVC valve breathing to one head. the other head breather to the air filter. Actually look in the book and it gives you a nice simplified air flow path you should have, minus the egr stuff. And other than that, just need your vacume advanced hooked up, vacume line going to the dash hooked up, and break booster hooked up. Watch out for that egr sylonoid, they sometimes get stuck open and without a hose on it, will leave you with a huge vacume leak.

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OK, now I'm confused. I thought that there is an ECM in all of the EA-81's just to run all of the crap that is connected to all of those hoses. Apparently not, though. How do I know if my car is ECM equipped or not? My car has a bunch of solenoid valves connected to all of those hoses, hence my assumption of having an ECM somewhere. Can someone please explain all of this to me? Thanks.

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Ya know, that is an interesting question, Most ea81 cars I've seen have one too, But my brat for some reason never did, the wireing isn't even there for one. The ecm is located underneath the stearing colum, it's actually mounted directly to the steering colum bracket, usallaly theres an interior panel in the way, held in by 2-3 screws... But yeah thats where it'll be if you have one. Generally another way to tell is check your y-pipe exhaust Cat for a O2 sesor, if it does not have one, chances are you also do not have an ecm. IF it does have an 02 sensor, you probably have an ecm.

 

OK, now I'm confused. I thought that there is an ECM in all of the EA-81's just to run all of the crap that is connected to all of those hoses. Apparently not, though. How do I know if my car is ECM equipped or not? My car has a bunch of solenoid valves connected to all of those hoses, hence my assumption of having an ECM somewhere. Can someone please explain all of this to me? Thanks.
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Hi. I'm hoping you'll get your original question answered. As in "Can the ECU be disconnected/bypassed.

 

I have an 83 Sta Wag, EA81 w/ECU. Can't get spark

Also have an 85 Brat also with an EA81. No ECU. But it runs

Diff. distys.

 

So I'm wondering what can be done to eliminate ECU. I have emmissions in RI, but have a sticker good for 2 more years. So now all I want now is for the 83 to run. And so far I've replaced the disty 3 times and still get the same problem. No spark.

Replaced coil, too.

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is the coil any good? are you getting power to the coil?

 

 

As for eliminating the ECM? I bet you could. Think of it this way...how many carb. vehicles are out there that don't have a computer in them. Now just think of what it really takes to make a car run: Fuel (maybe you might have to rework the FP relay), power to the starter, power to the coil (for spark), air(if you don't have air I don't see how you could be reading this).

 

i don't know how the gauges work but you could lose them in the process (if ecm controled)

 

 

I just totally lost my train of thought... (wife complaining) you can see where I am going with this.... think it out and maybe you could overcome some of the small things to make it all come together.

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The ECM/ECU in an EA81 uses the O2 sensor's output to control a pair of external-to-the-carb- duty solenoids that effect the carb's mixture at idle and part throttle. The carb is set slightly rich, and the duty solenoids admit air into the emulsion tubes to lean out the mixture.

 

You should be able to disconnect the ECU without any noticeable effect, and it will have no effect anyway if you go with a Weber.

 

The ECU may also control the EGR system and the charcoal canister purge as it does in the EA82, but I haven't seen anything to confirm or deny that.

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So are you saying that I can just unplug the ECM from under the dash and throw it away? I'm actually hoping this is true, but the betting man in me is thinking that this can't be done. I'm guessing that the ECM is tied in with enough other stuff that you have to at least keep it plugged in so the car will run. This is the confusing part for me. If I install a Weber, what do I do with all of that "stuff" connected to the carb now? I'd actually like to remove the air system as well if I can. In my search, I found a picture of an EA-81 with a bare engine and a Weber setting on top. That's my goal. I want to make the engine room so clean that it doesn't look like it ever had any vaccuum hoses running all over the place. Maybe I'm working on a lost cause, but I'd like to try to pull it off. Thanks again.

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My '82 BRAT had an ECM under the dash when I got it, also came with an EA-82 engine swapped into it. ECM wasn't controlling anything in the engine bay, so I think you can ditch yours. I swapped a Weber onto that engine, and ditched all of the extra stuff around the manifold. You'll need some caps to block-off the un-used vac ports. As mentioned before, vac lines needed for brake booster, heater controls, disty vac unit, all others can be capped..

 

I've since swapped that Weber onto 2 different EA-81 engines, no ECM(s), and ditched all of the extra stuff on them too. The Weber is currently on my '86 BRAT mounted on an EA-82 carbed manifold. Some modding of the manifold is meeded to put it on the EA-81 engine. I can help you with that if you want to go that route.

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EA-81 and EA-82 engines can both be run without the ECM. That is all we use in our hunting boats in South Louisiana. No emmissions testing on hunting boats. A weber 3236 has one vacuum port that runs to the the disty. Every other vac port on the intake should be plugged. We remove the EGR and plug the ports also. One valve cover piped to the PCV and the other either vented to atmosphere.

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EA-81 and EA-82 engines can both be run without the ECM. That is all we use in our hunting boats in South Louisiana. No emmissions testing on hunting boats. A weber 3236 has one vacuum port that runs to the the disty. Every other vac port on the intake should be plugged. We remove the EGR and plug the ports also. One valve cover piped to the PCV and the other either vented to atmosphere.

 

that's how I set mine up as well. I threw mine away on my 82 Brat...

I usually pull the intake manifold off, and remove the hard tubing as well. really cleans it up nice....

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that's how I set mine up as well. I threw mine away on my 82 Brat...

I usually pull the intake manifold off, and remove the hard tubing as well. really cleans it up nice....

 

I wanted to grind off and weld up the vacuum ports when I switched from a carter weber to a hitachi last year, but my mig-rig was out of argon at the time and I didn't feel like making the 30 mile round trip to swap out the bottle. If I find a need to pull the intake off again, I'll be cleaning it up also...

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Two things stick in my mind after being a mechanic for 35 years.

1. Years ago I witnessed a young trainee throwing emissions components over his shoulder into a dumpster faster than he could name them, and telling the customer as he stood and watched, "hell yall don't need this stuff anyway, they just put it on for looks" and I thought about the poor engineers that went to school all those years designing these systems....

2. Someone once told me, what people don't understand, they just throw away!!

Attached (I hope) is a picture of a properly desmogged induction system, from a company in Colorado, I'll try to find some info

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I have done this to so many subaru's, I lost count, my 81 wagon had an ecu and all the emision's carp, how i did it is if i didn't know what it was it went bye, EVERYTHING went!

 

I unplugged the ecu to see what affect it had..............hmm, none, acros the parking lot it went!

 

Put a weber on her has never ran better, even run ALOT! better than all my friends car's that still hace all that crap.

 

Every car i worked that i have done this too, the owner allaways thanks me!, Saying "Thing run so much better than it ever has".

 

I have had very good results with removing that junk, i say go for it!.

 

~Dayten~

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Thanks CHIM! I figured somebody on here must have tried unplugging the ECM. This car I'm working on now may become "for off-road use only" in the future, and I don't want to have to paw through all of those hoses every time I want to experiment with something under the hood.

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