Help RPM and Speedmeter
 

i just installed my power FC.
i have a JDM FD ...
i installed a American PFC...
i have a problem with my RPM and Speedmeter...
they both work simultaneosly like if the speedo was my RPM.
could someone know what is maybe wrong with it ?
or maybe i have to put a setting in the PFC ?

thanks.

How did you wire an American PFC into a Japanese FD?
I thought the wiring was different including the PFC connectors.

93-95 JDM cars have the same connectors as US models, minus a few wires for EGR, AWS etc. For that matter the PFC is not continent specific.

Sounds like you have a short in your instrument cluster. There are no setting is the PFC to resolve this problem.

OK thanks ...
this is the second cluster that has this sort of problem...
mine has it and my friend too...
maybe it's Missing ground somewhere ...

someone else has this problem ?
or can maybe give me more pin point to check ?

every opinion is welcome

Banzai you was right...
it had a short... ;)
thanks a lot ...

we still have this problem...
when i put the STOCK ecu it idles normal with speed meter without problem...
but as soon i change to the Power FC, i have the problem the RPM and the Speedo work like together...
any other suggestions.
thanks.

Interesting....

The speedo is not controlled by the PFC, the only link it has is via wire 1M. This is an input to the ECU, maybe your PFC is backfeeding the RPM signal through this wire.

Try cutting the 1M wire or depinning it from the connector. Leave yourself enough wire to reconnect it if you do cut it, just in case this does not solve the issue

This IS a 92-95 car correct?

^ It would be impossible to have an "American" PFC if it wasn't. Unless he is trying to wire in an earlier model PFC into a later model car, which would make no sense at all since PFC's exist for the later years and are typically much cheaper.

He has not stated if it is a new or used PFC. There have been a few bad used PFCs on the forum lately.

Is there not three interfaces from the instrument cluster to the ECM?
1. 1M the vehicle speed sensor
2. 1N milage switch
3. 2B Data Link Connector IG terminal
Seems to me, however, it's more likely a grounding issue. The ground from the cluster goes through three harness connectors (X-17, X-07, X-05 and X-14) then to the ground lug on the rear engine lifting eye. It's not unreasonable that the lack of the ground will cause the instruments to act up. X-05, X-07 and X-14 are right at the ECM location. Possibly changing the ECM / moving the wire harness is making the ground good?????

^
Technically yes. However I ruled out the Diagnostic connector since there would have to be a short that would be present with the stock ECU.

1N is the Steering Pressure sensor, could not see any way that tach readings would be making it to that pin. Again it would be present with the stock ECU, if there were some sort of short in the PS pump.

This leaves 1M, the actual speed sensor input. It is not really important to the PFC and will not stop the speedo from working if the wire is removed.

Instead of trying to confuse the OP with info that would not help him. I reduced the "possibilities" to the actual logical location for him to check.

Was there any solution with this issue?

I just installed a PowerFC in my JDM FD and I'm having a very similar issue. My speedo, tach, and temp gauges don't work with the PFC but work fine with the stock ECU.

Does this mean my PFC is bad?

I have also had people mention something about a chassis/ecu ground for the PFC but I can't find the info about it anywhere.

I usually do not get into/analyze serious problems like this, because so many times it was operator error with wiring or installation. And it can take much testing to figure it out.

Because of operator errors, some people do not want to share their fix.

After spending a few days with two other mechanics, it was resolved. Temp gauge gone bad though so I'm replacing it with an autometer model I had set aside for another car.

I don't know which one figured it out and I just hopped on a plane this afternoon so I don't know where the issue was. It's fixed n that's all I care about :)