Hello all,

My 1992 Accord LX Automatic has a bouncing speedometer and keeps popping out of 4th gear to 3rd erratically.

Edit: 233,000 miles on my car.

Events:

Few years ago: Speedometer began bouncing. I just dealt with it and got used to it.

1 month ago: Car started to pop out of 4th gear to 3rd. D4 light flashed.

The TCU was replaced ~10 years ago with a 722 model. We sent that same TCU to a rebuilder on ebay (ASI). They said they found issues and rebuilt it. We got it back, put it in, and the issue continued.

We got another computer from ebay and put it in. The car would not shift out of 4th, and the D4 light was solid no matter where you put the gear **** (park etc.). I sent that computer back for an exchange a few days ago and am expecting another very soon from the same person.

We took it to a very good Honda mechanic in the area last week and he fixed the flashing D4 light. He said it was the harness that plugged into the VSS(we actually put in an OEM VSS a few weeks ago). So no more flashing D4, but the bouncing speedo remains(he said to replace the cluster). He said that the car popping out of gear is due to the TCU, which is what I am waiting on.

Do you all agree with this? I just want to pass this by you guys since you might see something we are overlooking. I should note that the Transmission Solenoids are alright (my dad cleaned them out). We've tried junkyards for this TCU, but can't find any. Could the ECU have something to do with this? Also, could there be a correlation between the bouncing speedometer and the popping out of gear? I really appreciate your help!!

 

I would check for codes to be thorough. The common diy thread on top of the gen tech help forum has a link to check engine codes.

I would wait for a properly working TCU before diagnosing further. I know the speedometer signal is generated by the ICM inside the distributor. You may wan to pull of the distributor cap and take a look at the wires (four of them) that plug into the ICM.

There is also an important ground bolted to the thermostat housing. I would unbolt that, clean the bolt/eyelet with a wire brush or sand paper, then reattach.

 

ICM in the distributor creates the tachometer signal, not the speedometer??

VSS on the transmission should be the speedometer signal. I think in 1992 that VSS signal goes to the cruise-control & speedometer. (1998+ it goes to the PCM first...)

When the speedometer is bouncing, does the cruise-control work OK? Or does it jump around?

 

So I pulled a Code 15 today. I then reset the computer by pulling the 7.5v and then putting it back. No codes showed. I drove it for a little (30mph) in the neighborhood and it was alright. Later on when I was heading to work though, it started to act up again and popped out of gear(usually happens 40mph or above). This is what it has been doing for a while. After work tonight, I pulled a Code 15 again in the parking lot.

I'll only drive this car to work since it's so close. I don't like to drive it too much with this issue going on. I'm uncomfortable with the car revving so high.

I'd like to add that the tach along with the car jerks a bit, could that be related to the ECU?

I will try to find the ground wire. As for the distributor, I will take a look at it, but we put in a brand new one last year.

EDIT: The Code reading is from the D4 light.

 

I cleaned the heck out of that ground wire yesterday. Speedometer still bounces. A TCU should be arriving Saturday, so let's see how it goes.

 

So it's been a few days. I've gotten another computer from Ebay and the car still doesn't work. It stays in fourth gear, so I just put back the old one. I'm starting to think it's not the computer.

I got a Code 15 from the D4 light, which says it's a short circuited kickdown switch. My dad changed the transmission fluid(not sure how long ago) and says it's alright, but we're thinking about getting it fully flushed. Does this seem like a wise thing to do? Or is it probably time for a new car(really don't have the money though).

 

I'd pull the mainshaft speed sensor and clean the end of it - metal and "gunk" can build up on the end. Then re-install - new o-ring would be nice, check the connections and that while you are there and see what you have.

 

u just need another speed sensor ... over time either the connector pins or the rod area inside goes bad ... u can get these for like $15-$20 off ebay or amazon ... ive bought one and no issues since ... swap itin and u should be good to go