What are the chances?

[ZeroLux]

So myself and someone local to me that knows Honda's pretty well got to talking a while ago. Little things, this and that, what we each want to change on our cars. I got up the idea to say "hey, let me run something by you and see what you think". I describe the problem I am having with my LX-i and the first thing out of his mouth, almost without hesitation, was "ECU is bad".

Hmm.

Now there's an interesting idea I honestly had not considered before. What are the chances that my ECU is screwy? How can I test for this? And since I'm pretty sure the answer to that is going to be "get another ECU and swap", how do I go about junkyard diving and finding the right ECU to pick up? I figure this is an easy enough swap (please, PLEASE correct me if I'm wrong) so for cheap it's worth a shot.

Car is an automatic, stock A20A3, standard options for an LX-i I guess (cruise, etc, if that matters any). I know there are different codes for different model ECU's and I don't know which one is stock like I have now. What should I be looking for at the local pick-n-pull?

Also I imagine the removal and installation is fairly straightforward, remove seat, unplug and remove ecu, installation same in reverse?

Thanks!
Zero

[A18A]

yup removal & installation is the same, what was the problem anyway? chances of the ecu being bad i would think is very slim. to get the right one just get the ecu out of the same car as yours, if your car is a 86-87, get one from a 86-87, if it's a 88-89, get one from a 88-89.

[ZeroLux]

It's hard to fully explain the problem with the car, so I'll put this as basic as possible:

If I drive, at a speed of 45-50mph or better, for any distance longer than a few miles at a time, non-stop, the performance of the engine severely declines and makes it very hard to keep at speed, I cannot go above 55mph most of the time or at least that's what my speedo tells me (I personally think it's less and telling me wrong). If I continue to drive it beyond this point it gets worse and degrades so bad that it's almost intolerable to drive anymore. Valves chatter, smoke blows, car hesitates. Likewise if I drive it for several miles at speed, and then come to a stop at a light, as soon as I set out from the light NOT pushing it even, the performance is horrid and the chattering and smoke happens again for a few seconds, quits, car moves on as normal (whatever normal is for this car).

* By "degrades" I mean "takes a miracle to maintain speed going up a small inclined road like we have many of here". It almost feels like the car is literally choking itself, freaking out, and then resetting almost as if nothing had happened.

I have replaced sensors, checked vacuum lines, used injector cleaners and treatments, just about anything I can think of within reaosn. Nothing helped.

In short, the longer I drive it at any given time, the worse it gets and I can't put my finger on the cause. I cannot take it on the highway AT ALL, I cannot go from one side of town to the other without problems or the need to stop at least once, I pretty much cant go anywhere beyond a certain distance from home safely.

Zero

Also a quick edit: NO this is NOT an overheating issue.

[A18A]

oh okay yeah another ecu may help

[ZeroLux]

So what is it that could be going wrong with the car? I'm not sure I understand 100% why it does this. Any hints?

[labeledsk8r]

for some reason i feel the ecu would atleast throw a code if it was the problem... have you looked for vac leaks and stuff, i didnt read all of the symptoms but these cars are slaves to there vac systems

**edit** just re-read and you said you checked vac... but i still think the ecu would throw a code

[codyJDM]

Replace your fuel filters and plugs, I ran injector cleaner and it cleaned out my system enough to fuck my fuel filter and foul my plugs and made it bog down like crazy. Ran great afterward though.

[Nafs Asdf]

for some reason i feel the ecu would atleast throw a code if it was the problem... have you looked for vac leaks and stuff, i didnt read all of the symptoms but these cars are slaves to there vac systems

**edit** just re-read and you said you checked vac... but i still think the ecu would throw a code

I don't think the ECU would necessarily throw if it was bad, after all, it would be broken. ;)

[Demon1024]

^ 2x
i think i may be in the same boat here (JACK!) j/k
I cant even make mine throw a code. i can unplug whatever i want map,iacv,o2 doesn't register on the dash or the ecu. i thought when i got this one i had solved my ecu problems! Oh well. i'm looking for a new one again folks!

[cygnus x-1]

It seems unlikely this would be a faulty ECU but it's certainly possible. It does sound like an overheating problem though, not the engine but a only a specific component. When it smokes, I assume the smoke is black?

C|

[Oldblueaccord]

Unless the ECU has gotten wet from being under the seat or and electrical surge they just dont go bad. But I think swaping one with a junk yard one cant hurt you at this point. Double check how it is grounded as well.


wp

[lostforawhile]

there is a code listed for bad ecu,but i can't remember what it is. it may or may not throw it. have you checked the ecu ground under the seat near the unit? and they can go bad, these are 1980's electronics. could be a gremlin hatched in there too.

[AC439]

I'm leaning towards Cygnus that the car seems to have an overheating problem (mechanical rather then ECU). I assume it doesn't smoke right away but it starts to smoke after a few miles of driving. Sounds like after the engine warms up, the tolerance changed therefore allowing engine oil coming into the cylinders. I'm thinking about a possible clogged PCV. Valve chattering......hmm......oil not reaching the top ? Oil pump possibility ? Coolant passage clogged ? How about a complete cooling system flush?

[ZeroLux]

The more I try the harder I find it is to explain exactly what is going on. The smoking is temporary... as in, I can be driving, it might rattle under a slightly increased load, a little bit of smoke, then it stops without me ever changing anything (speed or throttle).

Not to disagree, but it does not appear to be overheating or necessarily heat related. Only thing I could think MIGHT be having a temper tantrum is the dizzy- maybe it's heating up from lack of lube on certain parts? Maybe? I still need to get around to the poor man's rebuild that I might do tomorrow.

Zero

[ZeroLux]

Maybe I could explain this better if I just make a video of it doing it's thing? Only problem is that it's hard to really know when it's going to happen or not. I'm sure I could make it have some issues though if I get on a long enough road. Not sure how much it would help but it could demonstrate what I am describing better than I can put it into words.

[headbanger]

it might be the catalityc converter?could be really bad stopped up .

[ZeroLux]

it might be the catalityc converter?could be really bad stopped up .

Checked that already incidentally. Cat was fine. I figured it was a backpressure buildup somehow too but everything is flowing as expected.

I'm tellin' ya, this car has me stumped pretty bad. I appreciate the effort in helping me figure it out though.

Zero

[cygnus x-1]

I'm leaning towards Cygnus that the car seems to have an overheating problem (mechanical rather then ECU). I assume it doesn't smoke right away but it starts to smoke after a few miles of driving. Sounds like after the engine warms up, the tolerance changed therefore allowing engine oil coming into the cylinders. I'm thinking about a possible clogged PCV. Valve chattering......hmm......oil not reaching the top ? Oil pump possibility ? Coolant passage clogged ? How about a complete cooling system flush?


I was thinking more of an electrical part overheating causing it to go flaky, not the whole engine. If the smoke is black it indicates too much fuel. I wonder if one of the injectors is overheating and getting stuck open. At highway speeds the load on the engine is higher so the injectors will have to work harder. Running cleaner through them may or may not help anything.

A flaky distributor is also a possibility but I don't think it would cause any smoking.

If you want , I have a bunch of old injectors sitting around. I could send you a set to try out to see if it helps anything. I have a few different types (all Hondas) and I know some of them are from an Accord, so if you can get a picture of one with the plug off it would help me figure out which ones you need. The plugs aren't all the same.

C|

[ZeroLux]

I would really appreciate that, since just last night I was looking online for replacements and could not help but notice how expensive they are. Mine are leaking, not sure from where, looks like the connection on the upper rail is the source. Send me a PM with the cost and I'll see what I can do. I was going to rebuild the fuel system today but I am not sure now if I'll have the chance.

Thanks!

Zero