Last year we got a 1995 California emission VX with 230?ish miles on it. After a ton of work, converting it to 49state emission, rebuilding transmission, new tires, glass, on and on and on, we have a great-running VX that has hit about 49.8mpg on the highway.
Just brought home another one. Found this one on cars.com. Literally driven by a little old lady from Pasadena... Texas. The car has 148,000 miles on it but the interior and the engine bay are freakishly clean. It looks as if some of the engine components were installed yesterday.
Ok, so it should run perfectly. Well, it's not. It runs out fine, great acceleration. It has achieve a highway mileage of 52mpg with air running. But here is my problem. The low 300rpm idle vibrates. It shakes the steering wheel and the headlights are vibrating if you look at their beam on the side of the house. First thing I did when I got home with it is change plugs to proper NGK, plug wires, cap, rotor, cleaned EGR, and IACV. I ran injector cleaner in the gas. Air filter looks clean. It is as if the engine isn't balanced at that low speed. It's freaky. Our other VX is smooth like glass at the low idle, that we named "happy idle." Well, the new '92 isn't happy. It's also not anticipating events, like AC coming on and headlights. It will load down the engine to the unhappy low idle. I wonder if that points to anything the alternator is doing? I'm going to change it's belt tomorrow, I can run without a belt and see what happens. There are no, of course, CEL events and I even swapped ECUs with another I had on the shelf. Basically the same reactions.
I want to run some Seafoam into the vacuum and put in the gas. I wondered if the lady I bought it from didn't run the car much on the highway, and maybe it's coked up? But I've put over 700 miles on it already. (drove from Houston to Topeka, Kansas)
Any thoughts before I go to the Honda dealer and say, ok you guys, make it run right? I'll post pics in the garage as soon as I can.
You seemed to cover all the other things I would have said, seafoam is great stuff! You may want to just put some Marvel Mystery oil in the crank case and the gas I have had minor problems disappear on prior cars I have owned...
The management system is definitely not anticipating the loads from lights and AC. The voltage reads out at 14, so it's making electricity OK, just not pulling up the idle like it should. But there seems to be more to it. It's as if the engine just seems to have bad balance at low low rpms. Is that possible?
While I've been testing things, I had a '94 ECU in there this afternoon. Drove it awhile and, I don't know if I was imagining it, but it seemed like the handoff from regular burn to leanburn was smoother? Could that be with the '94/95 revision that they made refinements on that?
I've tried for a year to figure out the differences between the revisions of ecus. I have one of each and have swapped them back and forth, never noticing a difference. It must be something and I suppose that could be it. Nobody here seems to know.
I agree with TomO, at least as a possibility, that the load detector in the fuse box could have been disconnected or bypassed for some reason during it's previous life. That would cause some of your problems. If it went bad, it might throw a code, but if it were bypassed it might not?
I have a swapped z1 in my 90 hatch and have always experienced a very rough idle below 500rpm. In my case its because I have the wrong flywheel in the car. From what I understand, the flywheel in the vx is quite a bit heavier in order to smooth out that low speed idle, but I didn't find that out until after I finished my swap. Mine idles just like you describe, the whole car shakes, but other than that I have absolutely no complaints, so I'm not inclined to try to change anything at this point. I know its unlikely, but if the clutch had ever been replaced in your car and the flywheel had gotten damaged, perhaps somebody swapped it out for the wrong one? Just guessing here, but then, aren't we all? Congrats on the pair.
It makes sense that they could have revised the operation in the revision to make it smoother.
Regarding the load detector, this is a 100 percent original car owned by 2 owners. One had it until 48K and the other was the little old lady who traded it in to the dealer I bought the car from. I can't imagine that anything would have been changed like that, and for what reason? It would only make the car run badly.
The car was involved in what looks like a minor fenderbender in the right front, but I can't imagine that taking out the transmission. There is no Carfax record of any accident. Every part in the engine bay looks new. And I've thought about engine mounts, yet they all "look" fine. I don't want to just replace them on speculation. I'm kind of stumped here.
The flywheel thing did cross my mind. But I assumed I had the original clutch here. But it was my understanding that the VX flywheel was lighter.
I just read this on ecomodder.
"that why I suggested a stock lightened flywheel, just weighed a vx one and it came to 15.5 vs the stock 18lbs or so. I trust Honda, there was a reason the vx came with the lightened version"
"One reason for the lighter flywheel is probably because the vx makes better low rpm power and therefore does not need to store as much inertia."