I have been having a problem with my FD (93 R1) ever since I got it over a year ago. The spedo is sometimes wrong. Sometimes its correct, sometimes its way off. Today on the way into work, it was reading 127kph. Way faster than I was actually going. I though, ohh hay, the PFC has a speed gauge. It read 97kph which I think was my actual speed. Last summer, I did some tests with a GPS unit and found the spedo to be about 10% fast. It's clear to me now that the spedo and the PFC get their speed from different places.

It's inconsistent. Sometimes it's even correct. I have witnessed it move without the car changing speeds too. Mostly on the freeway. Maintaining my speed, I will see it move from 75mph down to 68mph. The difference seems to get worse the faster I go, which makes me think it something mechanical.

I do have slightly large diameter wheels on now, but nothing that would account for 10% difference between the gauge and reality.

How does the spedo get its signal? How can I track down the part causing the problem?

 

I'm pretty sure there is only one speed sensor in the gearbox. I would assume that this is more likely to be a problem with the gauge/cluster itself.

 

Most likely a faulty gauge/cluster.

 

Can anyone think of a good way to confirm that it is the gauge cluster without swapping it out with a known good part? I'd hate to drop the money on the "new" part and not have it fix the problem.

 

I know on the gauge face itself there is a marking to calibrate the gauge. Its like "3000rpm @ 65mph" or something. I dont remember if the same marking is on the face of the kilometer gauges. I have to check with my km one to confirm. Anyone have a jdm one laying out of the cluster to help parid out?

 

i thought that too, but my gauge actually is off aswell, , but before i sent it in to rammy to get it redone because my odometer wouldnt turn on, i checked it and the GPS says i was going like 74 when i was going about 82 on the gauge. i asked him to calibrate the speedo too, short story it still does it, but the odometer works

 

Mine does the same, heard it was a bad resistor or solder on the guage

 

Sorry I didn't word that very well. It have the stock USDM 93 gauge. The PFC outputs in km so I used that unit to talk about the problem.

 

This is a common problem. ( mine does it )

Do a search on it in the 3rd gen section.

Someone here (FDNewbie I think) offers a service of rebuilding the cluster to fix this.