I have a 1993 Toyota Camry LE, 2.2L 4 cyl, AT; i am having some strange problems with the tach and speedo.

The tach and speedo usually read wrong. For example, sometimes it says 15mph but I'm really going 35mph. or I'm going 30 and really going 35mph.
Likeiwse, the tach shows idle around 500rpm and other times, a click about 0. Very occasionally, the tach and speedo will read almost correct. Also, depending on the weather, the readings on the tach and speedo change. That is to say, a change in temperature affects how the speedo and tach operate. There are no warning lights on the dashcheck engine lights, or anything like that (although the check engine bulb could be burned out).

I've checked all fuses, checked all grounds that I can find / get to. Taken the instrument cluster out, cleaned it, put it back in...A friend suggested that I check the speed senors in the transmission. Another friend suggested I buy a salvage instrument cluster and put it in. A shop that I took it to for advice suggested perhaps that somehow the computer (ecu) needs to be reflashed or reprogrammed. In general, i suspect this is an electrical/mechanicl issue of some kind. I'm not planning to spend any more $$$ until i have some sort of idea of what i'm looking at here.

Has anyone had a problem similar to this? Does anyone have any ideas about how to troubleshoot this problem?

Thanks a lot,
Paul Motes

 

The speedo received signals from the speed sensor located on the top of the transmission differential. The sensor could have an issue. Wire color is Green/Black and Green at the meter and Light Green and Pink at the speed sensor.

The tach receives signals from the ign ignitor via a Black wire.

Given both reading seem to vary with temp there could be a bad wiring connection. Both meters receive power from the same circuit as the fuel and water temp gauges. Are these instruments working OK?

 

Thanks for the helpful information. I'll check into what ur talking about today...

As for the temp and gas gauges, they work well, all the time, no problems...
I'll make an update once I take a look at the igniter, speed sensor, etc..

Paul

 

I've checked the speed sensors - they seem to be working ok i think. My guess is that the problem must lie in the distributor / igniter / ECU and perhaps the vehicle speed meter. Now, (about 90% of the time), when I drive the car, the tach sits at nearly 0, and the speedo works very slowly (e.g. going 10 mph will actually yield about 35-40mph). I wonder if a coil is bad (haven't checked that but will next week)? I've also checked the meter and can't get it to come out of the top of the transmission.. i did take the speed sensor off (side of transmission), cleaned it up, checked the connection, and that looks fine. Both the temperature and gasoline gauges are working well and acting normal all the time. Another ideaif the vehicle speed meter affects the tach signal (which i dont know if it does), then perhaps that could solve the whole dilemma if in fact the vehicle speed meter is bad or faulty?? Last, I disconnected both the speed meter and speed sensor, and ran the car, and still had the tach problem (at idle, a hair about 0rpm)...

Any ideas? Are there are any other items in the circuit that are connected to the black wire coming from the igniter until it feeds into the computer (ECU)? (i assume that is where the signal goes, before it passes to the instrument cluster?

How can i check the igniter/distributor/coil?

I'm not sure what i'm going to do next? I don't know if it needs a salvage ecu, or a new coil, or another distributor unit or what? I'll try again to get the speed meter to come out without breaking it and take a look I don't think that will fix the tach problem thou In the end I may have to take it to someone to look at???


Thanks a bunch, Paul

PS if i can find some wiring diagrams, i'll take a look and see what i can find out....

 

The speedo sensor signal also goes to the computer to determine trans shift timing based on MPH. Is the trans working normally? Does trans shifting differant when the speedo has a problem?

Determine if the connector at the speed sensor is getting 12V at the Red/Blue wire when the ign is on.

The Black wire does not connect to the computer. The wires from the distributor and ignitor wires do and provide RPM input to the computer. Does the engine run and idle OK, if so the issue may be with the tach.

The speedo receives a signal from the speed sensor via Green/Black and Green wires. It also receives a signal from the computer by a Violet/Yellow wire.

Both instruments reciece DC power from the Gauge fuse that also powers the other gauges such as fuel and water temp. If these gauges work the the Gauge fuse is OK.

There might be a common issue with the tach and speedo in the instrument panel. A loose connection.

The AutoZone website at www.autozone.com will have wiring diagrams and info on testing the ignitor and dist. However if the engine runs OK, these parts would also appear to be OK.

 

i've done a lot of checking, measuring voltage, etc... the problem seems to be leveling out somewhat. The speed sensors check out, although i can't seem to pull or pry out the sensor that goes into the transmission housing (vss senser). not sure why. ALSO, i forgot to mention, that the car does not have original trans but a salvage trans. However, I was told that the salvage trans was supposed to match for a toyota 2.2L, and actually came off of a camry 2.2L, 1994 model.

Still, when the motor is cold, and it is cold outside, the speedo/tach are off at least 40%. once the temperature of the engine warms up (e.g. drive it on the highway for 10miles), the speedo and tach seem to get better readings (perhaps only 10-20% off) i"m calcaulating these figures by using a GPS.

I did check many of the grounds again, especially the ones that are on the back of the intake manifold, cleaned those, and secured them tightly. i need to check the ground wire that goes underneath the battery, i believehaven't looked at it.

Perhaps, this whole problem is the gauge cluster. But perhaps this is short somewhere. I fixing to give up and take it to a friend who specializes in diagnosing electrical problems...

Thanks!
Paul

 

Taking it to a shop would be a good idea or if the car runs OK wait until the spring.

The trans sensor should be held in but one bolt, it could be frozen for some reason.

 

probally really really dumb question but must ask due to simplicity yet absolute havoc it can cause, have you changed tire diameters. i know i know sorry i will shut up now lol dumb question

 

I know this is dragging old threads from the dead, but what was the solution to this problem?

My sister gave me her 1993 Camry Wagon with 160K but it's biggest issue is the problem described by the OP.

Can anyone help?

 

I am having the same problem with my 1992 camry, same with speedo and tach, plus temp and fuel are ok ...could it be the igniter? Please let me know what your cure was ...thanks,mike