93 DX Wagon still has problems

[freebeer]

Replaced the MAP sensor, worked for a few days, then back to the same back-firing, rough running, low power, etc.

So, I have ordered another ECU to try. Getting at it was a major PITA, but it's out.
It looks good inside, but not always an indicator of failure.

Question though, does this also control the Auto trans, or is there a separate TCU hiding somewhere? As I'm still having 2nd gear problems, it could be the solenoid or something mechanical, just trying to eliminate the possibilities.

It's a 1.8L, auto DX wagon, already replaced the plugs, checked dist cap and wires. Odd, that sometimes it runs great, but then not great in the same day.


Any help is appreciated.

[Piloter]

From research and Alldata diagrams, the ECU handles the transmission. No separate TCU.

Have you checked the timing belt? It sounds like timing might be off. What's going on with second gear? Could be bands, could be the solenoid, could be a glitchy VSS...

[freebeer]

The trans has been acting odd for a while, having to manually shift into 1st to start out often, not always. Neighbor is a transmission guy, he looked at it but thinks it may be the ECU because it didn't act the same all of the time. Sometimes was just fine.

After the engine started acting up, the trans got worse. Driving home a few weekeends ago, the O/D OFF light started flashing, before I arrived home, 2nd gear just quit working. It shifts from 1st to 3rd, even if it's manually shifted from 1st to 2nd, the trans shifts into 3rd.
O/D still works.

I'm expecting a used ECU in the mail soon, hoping to solve the engine problem. Also, hoping that the ECU is the problem with the trans as well.
Posted here to see if I'm on the right track. Or if anyone else has had similar problems could guide me through the solution.

I'll check the timing belt, but when I replaced the MAP sensor, the engine was fine for 2 days, so I'm thinking the timing is OK, will check this weekend, though.

Thanks for the reply.

[Piloter]

Yeah, all that wouldn't be the timing.

If it's actually /flashing/ that would indicate a transmission problem, yes, and the ECU should fix everything. Should.

Keep us posted if you can.

[freebeer]

OK, I replaced the ECU, cleaned out the PCV hose and valve.
Not much change. The car starts OK now, but still idles rough.
It accelerates OK, but still no 2nd gear. On to the Transmissions shop, I guess.
But the way it idles still bugs me.

I haven't road tested it yet, but from the way it acts, not really necessary, as it is still not right.

The vibration is hard to explain, it can be felt just sitting in the car, not bad, just annoying to someone that knows it isn't supposed to do that. The front end of the car vibrates as it is idling.

Can anyone point me to something else to check out?

Thanks

[Piloter]

Yup, sounds like the transmission lost something. Let me know what you find out, please, as I have a transmission that's been faintly rattling in 2nd for a while now and would just as soon not have it explode any time soon. =)

The vibration at idle may well be the transmission-to-engine engine mount--these are fairly well known for going bad at ~100K miles. Get somebody to check under the hood while you (with the brake on!) shift from P to R to D. If the engine tilts/jumps more than maybe an inch or so, then it's the mount.

Replacing just this mount, though, will cause accelerated wear and tear on the others....doh! You could also try a new set of (the cheap kind) NGK plugs, properly gapped, to bring down some of the idle vibration when the RPMs drop to barely above stall speed, but that's not going to do a lot to fix the shaking.

[REN69]

I think it would've been easier to take it to someone who would know what's wrong with it rather than to start spending money on random parts here and there till you find what's wrong.

[freebeer]

There aren't any Toyota dealers near here. I was a mechanic for 20+ years(pre-computers) and am just trying to figure out what's wrong with it. The problem appeared fairly suddenly, so I find it hard to imagine it could be this difficult to find it.
Since this is a Toyota forum, I thought that maybe someone may have had similar problems, but it doesn't appear so.
And it's cheaper to replace a few random parts than to let a stealership guess what's wrong and start replacing parts at dealer prices. I've already had that experience with local Ford dealers.