rexset

Yes
But if ypu buy an american speedo , it shows 290km/h
I think that they combine the 2 of them

DaleClark

iTrader: (55)

Hey Howard -

That sounds like the speedo is dying. I haven't totally cracked how to fix bad speedometers, supposedly the capacitors go bad and replacing them goes a long way, but it's fiddly work to get in there and fix.

It's really hard to say with that module, it might be outputting a signal the stock speedo doesn't like. Only way to test it I can think of is to swap clusters around with another car and see if the problem stays with the car or the cluster.

Dale

DaleClark

iTrader: (55)

I'm not sure on changing the KPH faces to higher-reading faces if that calibration would throw the odometer off. There must be a way to do it as the 300 KPH speedos were very common and popular in the aftermarket in Japan.

You'd have to test over a known length of road. I have a loop near my house that comes out to exactly 1 mile, I use that when I'm testing speedometer and odometer stuff.

Dale

hickman

Hey guys,
I have a question. Anyone know where to get a replacement variable resistor for the spedo? :S Long story short, I broke mine. Now my spedo just sits at 290KP/H (lol). I removed mine from the cluster and was able to ger a ohms reading sweep from about 10K-160K (from ground to one pin, 3rd pin mirrored 2nd (not ground) pin). Can anyone else conform this, or better let me know where I could get one? I was thinking about this too and it does not even have to fit on the spedo board, it can be mounted elsewhere in the cluster and run wires from the board to it (also, may make adjusting it easer depending on where you mount it ). Any insight would be great guys,
Thanks,

Jay
P.S. I have my cluster in so i can track KM. And since removing the resistor, my "Intermediate" function for my wipers don't work. any idea if it runs that through the speed sensors/cluster spedo? or did I maybe hit it while installing the cluster? :S

davesan1

iTrader: (4)

Dale-

Thought you might be able to throw some light on my problem, see below:

3rd gen, '93.

Everything all OK over the past few years. Then car off the road for approx 2 months (I was out of town). On returning and starting the car, neither the speedometer or the tachometer worked (both at zero). Tried disconnecting and reconnecting the battery but did not fix. Fuses OK. Wiring not been touched or changed since car was last on road.

Bought a used (but believed OK) center control panel and replaced the old one. On start-up and driving, both meters seemed OK (no longer at zero). Car ran OK but I didn't check if the tacho and speedo were accurate at that point. However after a few miles both meters started moving up and down suddenly and seemingly independently, despite constant engine RPM and car speed. A few minutes later, both meters went down to zero and stayed there.

Stopped car, turned ignition off then restarted and drove the car. Both meters still at zero. Stopped, the car, disconnected battery, waited a while for engine/engine compartment to cool down a little, reconnected the battery and started and drove the car. Now both meters are "working" but Tacho. is too low (approx 50% low) and speedo. is too high, (approx 60% too high).

Tacho. appears to run non-linear with actual RPM (accurate at idle but flattens off significantly above 2000-3000-RPM) Speedo. seems linear with car speed but reading is much too high - gives reading of 110 MPH at actual car speed of approx. 75 MPH

Any ideas?

Thanks

Dave

davesan1

iTrader: (4)

Dale and all others -wondered if anyone could help me with the below strange problem - I'm baffled as to what went wrong!
3rd gen, '93.
Everything all OK with car over the past few years. Then car off the road for approx 2 months (I was out of town). On returning and starting and driving the car, neither the speedometer nor the tachometer worked (both at zero). Tried disconnecting and reconnecting the battery but did not fix. Fuses OK. Wiring not been touched or changed since car was last on road.
Bought a used (but believed OK) center control panel and replaced the old one. On start-up and driving, both meters seemed OK (no longer at zero). Car ran OK but I didn't check if the tacho and speedo were accurate at that point. However after a few miles both meters started moving up and down intermittently and seemingly independently, despite constant engine RPM and car speed. A few minutes later, both meters went down to zero and stayed there.
Stopped car, turned ignition off then restarted and drove the car. Both meters still at zero. Stopped, the car, disconnected battery, waited a while for engine/engine compartment to cool down a little, reconnected the battery and started and drove the car. Now both meters are "working" but Tacho. is too low (approx 50% low) and speedo. is too high, (approx 60% too high).
Tacho. appears to run non-linear with actual RPM (accurate at idle but flattens off significantly above 2000-3000-RPM) Speedo. seems linear with car speed but reading is much too high - gives reading of 110 MPH at actual car speed of approx. 75 MPH.
Go figure!
Any help would be most appreciated. Thanks - Dave

Wolf_

Good thread!!

have the JDM cluster to 180km/h and planning to have a friend make a new dial that reads 280+ atleast and recalibrate the speedo after it

but really never got the answer if the Odo is affected or if it follows with the calibration or not?
anyone that have tried this that can tell me what happens? =)

breakfast

iTrader: (4)

To my fellow cavemen who while drilling an access hole for the potentiometer ended up breaking it: I'm looking into what a replacement would be, so far I've been running with a 10k pot. and it seems to basically be a poor conversion to MPH lol. Its about 2mph off at 40mph (based on my power fc and a local police speedtrap) Adjustments don't seem to make a difference, so with my limited understanding of electronics the pot. might just be acting as a regular resistor for all values in its range of adjustment? Will update as I swap in another.

breakfast

iTrader: (4)

Swapped in a 1k pot. and no change. I'm going to decrease again and see what happens, will report back with findings.

Mr rx-7 tt

iTrader: (5)

My Speedo is stock and I run 275/40/17's. A while back my speedo went nuts, reading 85 when I was going 60. Still haven't fixed it but then again haven't driven the car for years. Sits under a cover cover...I'm thinking it's the speedo sensor on the tranny.

breakfast

iTrader: (4)

The replacement is a 200kohm pot.

I was initially unable to get a good reading off the one I broke, but after some creative soldering I got good contact and was able to figure it out. Ordered this on digikey, it fits perfectly on the circuit board and seems to give a good wide range of adjustment. I'm now able to run with my kph speedo calibrated to mph

nitewing117

iTrader: (6)

1 year bump. I just picked up a JDM cluster and came across this thread. Does anyone have any updates about it's effect on the odometer?

Since the cluster is 0-180kph, would this potentiometer adjustment allow me to treat the cluster as 0-180 mph? It would be great if I could just use the existing JDM face markings as "MPH" and ignore the kph text (e.g., treat the 60kph mark as 60mph, 70kph as 70mph, etc.) without negatively affecting the odo.

DaleClark

iTrader: (55)

Your question should be covered either in this thread or in another of my threads. But, it is just as you say - the speedo has KPH printed on it, but the number corresponds to MPH and the odometer properly displays miles. And counts up the mileage accordingly.

Dale

psyposa

Some updates for this question?
I wanna do the same mod like Markus1981.

DaleClark

iTrader: (55)

Not sure if if affects the odometer. I have a one mile loop from my house, around the block, and to a stop sign that I test to see if the odometer is doing what it should.

You would need to test this yourself to be sure.

Dale

existanzrx7

iTrader: (8)

Nice write up. Thanks day for another one

psyposa

Alright, thought there are some references now.
I will try that.

cib24

Has anyone ever noticed that if you adjust the screw that it might make your mph read correctly but then the trip computer counts the miles covered too fast or too slow?

afgmoto1978

iTrader: (6)

This is awesome!

Slides

Thanks for sharing this. Changing final drive in mine so need to adjust it.

Ceylon

iTrader: (3)

Bumping this one up with some added info that I've discovered today.

So I was browsing the EPC for gearbox bearings and noticed there were two part numbers for speed sensors, one for the 4.3 rear end, one for the 4.1 rear end. So perhaps the calibration on the cluster was less utilized from factory.

I happen to have an RZ and a normal gearbox, both of which are currently out of my cars, so I thought I'd pull the speed sensors to compare. The sensor is actually the same, just the plastic gears are different, RZ has 24 teeth, normal has 23 teeth and they're interchangeable. The gear on the output shaft is the same for both sensors, so it's an easy swap from underneath should you want to change it out.

Part numbers are:
RZ/RS/SR 4.3: R50717400B
Normal 4.1: R50517400B

RZ on the left, normal on the right:

Ceylon

iTrader: (3)

Just to add, assuming the signal from the speed sensor with a 23 tooth gear reads accurately with a 4.1 rear end. Simply changing this plastic gear to a 24 tooth gear will make a mechanical calibration change to match a 4.28 rear end, near enough to the optional 4.3 final drive on some JDM models without calibrating the speedo .

I'm running a 4.44 rx8 crown and pinon, so it wont be plug and play accurate for me, but it'll get it closer than if I ran the 23 tooth speed sensor before I correct it with the speedo adjustments. Now if somehow you could offset the speed sensor shaft and run a 25 tooth gear, that'd read accurate for a 4.45 rear end, would be a cool option for guys running the rx8 crown and pinions.

Have we discovered if calibrating the speedo also adjusts the way the odo clocks up miles yet or not yet? I have a hunch that it doesn't.

DaleClark

iTrader: (55)

As far as I can tell doing the speedo calibration it seems the odometer reads and records properly.

Dale

Ceylon

iTrader: (3)

I'll take a look at the speedo board and try to work it out. If the calibration corrects the odo also, I'm not sure how the 300kmh gauges can read accurate on the odo as they're just swapped faces onto a JDM 180kmh board that have been re-calibrated to read accurately. This is why I was thinking the signal used for clocking up the odo must be taken prior to that calibration. It would also make sense as to why they changed the speed sensor, otherwise they'd just use a different speedo calibration for 4.3 equipped models and keep the speed sensor the same.

DaleClark

iTrader: (55)

It may be it was just cheaper to make a $1 plastic gear than have 2 different calibrated speedometers on the line. Especially for a "special" model that they probably didn't make many of.

Also, I know there was a Mazdaspeed or something offering of the 4:30 gears, they could sell the gears with that speedo gear and make it a relatively easy install.

Dale