Greetings, I've discovered an unbelievably strange problem with my car this weekend. It's a 99 JDM car, speedo has been converted to MPH as its now in the UK. BUT, I noticed this weekend on my 'private test track' that the speedo gets to 129mph the starts reading backwards to 128,127,126 etc etc but the revs appear to still be rising on the rev counter but very slowly.

Not sure if it could be that the car still has the JDM speed limiter on it but is expect that to just hold one speed rather than go up and start coming back down slowly or if it could be an issue with the cluster itself?

Please dear god help, this is driving me insane.

 

Sounds like it has a speed limiter defencer. These stop the speedo rising just below the 180 km/h JDM limiter. Sounds like yours is part of the MPH adjustment. Normally the speed limiter defencers only change the ECU speed feed so the speedometer keeps rising.

 

Any way I can change this? It's both shit and annoying.

 

PS

Just checked the ECU there is no SLD that I can see either attached to or near to the ECU any other ideas?

 

Is it clutch slip?

 

Nope.

 

Get a GPS out and confirm what is actually happening with your speed.

 

The revs are still increasing even with the speedo reading down, and can tell the car is going faster, wind noise is enough to tell that. Going try GPS it at some point to see though, can't this week as I'm working nights.

 

I have seen this before, but at a speed of 40 or so.

Lose ground wire on the back of the head.

 

Still have this problem as I've not had a huge amount of time to do anything recently. How the hell do you check the ground wire on the back of the head?? I can't even get my hand to it let alone see enough to get a spanner or anything on to it?