Howdy, all!

On to my next issue to tackle on my 4run-run: A lazy speedometer.

I've searched and nothing quite matches what's going on. Sometimes, not always, when cold it takes a while for the speedometer to work. After reaching Operating Temps and running for a few minutes it works fine. There's no jumping around or anything, it just sits at zero until it warms up sometimes. It's not really loud or anything either, just lazy.

While it's sitting there at zero, the odometer still works... hmmmmm...

I haven't checked to see if I've got an electric or mechanical speedo yet. That'll give me something to do this weekend I guess.

94 4wd 5spd

Thanks for looking!
- Al

 

If your odometer still works while driving without the speedometer working, I want to say if you have a mechanical speedometer it is converted back to electrical for the ECU. Not sure what the actual gauge works off of though.

 

Yea, I dunno. I'll probably end up removing the cluster this weekend and finding some loose stuff back there. I'll confirm the speedo as mech or electrical as well.

 

You can look at the back of the transfer case to see if it's an electric or mechanical speedometer.

 

That'll save time verifying it... Anyone have an idea as to why it's not working correctly though? It's not a horrible situation, it's just annoying and Id like to fix it.

 

If the odometer works while the speedometer doesn't, then your problem is in the combo meter and not the "electronic" VSS1 or the speedometer cable. (The electronic VSS1 can give up at about 20 years old, and produce the "warm up" symptom you describe. But a failing VSS1 necessarily takes out the odo (and cruise) as well.)

What exactly is going on in your combo meter, I can't say.

 

Pardon the newb question, but from what I've read the combo meter conditions the signal from the VSS so that it can be read by the Cruise Control and the ECU. Is it a specific replaceable part?

Thanks for the help!

 

Ahhhhhhhh

Nevermind, I see.... Toyota calls Cluster the Combination Meter? It meters things, a combination of them.

 

VSS1 is either an electronic hall-effect-plus-amplifier gadget bolted into the end of the transfer case, or on earlier vehicles it's a reed switch inside the combination meter that switches based on a magnet spun by the speedo cable. In both cases, the "signal" is completely conditioned on-off, and is used by the ECU and cruise.

With the electronic unit, the combination meter converts the digital signal and drives (I believe) a stepper to display MPH. With the cable, the cable spins a magnet next to an aluminum plate, and eddy currents twist the MPH needle.

My '94 4wd has the electronic VSS1. I've never been able to figure out exactly when (or what models) the cable was used.

 

Didn't get a chance to look into it this weekend...

So then, the VSS1 is working, or starting to fail and I'm going to have to test it. AND I'll have to pull the cluster out and test whatever I can back there to find the issue. Not sure what to test in the cluster, I'll check the FSM and see what it says about it. Maybe I'll start sourcing a replacement cluster.