Ahtasham

Hi, I have just installed the Pioneer AVG-VDP1 to my pioneer P6850DVD in my Evo VIII (Jap Spec)

The problem is that my RPM signal is not getting calibrated properly with the tachometer signal from the pioneer VDP1 unit. And without the RPM calibration this thing doesnt work

Does anyone here has one of these? The unit is getting the RPM signal from the battery power wires ... probably the problem lies there (I think). When I turn off other electical components like the turbo timer, it does effect the RPM signal.

Any ideas ???

Ahtasham

Come on guys ..... anyone ??? someone must be knowing ..... ????

White_CT9A

The AVG-VDP1 does not use the signal from the tachometer to see what RPM the engine is running at. It measures the voltage to calibrate the RPM.

Unfortunately for the unit, the EVO uses an electric fan, and that jacks up the voltage signal from when you calibrated it.

Just sit at idle and look at RPM gauge on the VDP1. When you hear the fan turn on the RPM jumps all the way up to around 12,000 rpms. Same thing happens when you turn on the AC.

Don't know if you can fix, if you do find a way please let me know, I'm having the problem.

Ahtasham

Yes you are right about the voltage thing.

I tried connecting the VDP unit directly to the battery. After that the tachometer reading on it became pretty stable but still not stable enough to stay at one place to calibrate the system ....

Did you (White_CT9A) find out anything that might help ???

Cambo

Hi Guys,

I've sorted it out for my setup and presumably yours!!!

What I've done is taken a power feed from the battery and the coil and fed that into the unit's constant power wire and acc power wire and used some diodes to prevent the unit and the coil running all the time and damaging them or draining your battery. On my car I get no random changes in rpm at all, I have noticed a small jump when I turn on my zeon headlights about 200-400 rpm for around 10 seconds (till the lights warm up).

This should work on ALL cars not just EVO's.

DOWNSIDES
~~~~~~~~~~
1) - The battery voltage will appear lower by 0.7V to the unit, so the battery gauge will be off by 0.7V in the VDP (Big deal).
2) - The unit will not run with the accessories on, you need to have the motor running or ignition switch on (Sigh but I'd rather have the unit accurate than have it run on acc).

GUIDE
~~~~~~
You need to buy a couple of diodes that can handle 12V DC 1-2A, and a fuse and holder, some wire and insulation tape and conduit to make it look purddy. You'll need a soldering iron, wire stripper, wire cutters and a voltage meter or test light. For those that don't know what a diode does in it's simplest form it is a one way flow valve for current.

Disclaimer: This is the internet so there are no comebacks if this helps you then great, if not then don't complain to me, if you don't know what you are doing then get someone to help or take it to someone that can do the work for you.

1) Run a small gauge power wire from the battery to near the back of the VPD unit's constant power supply. Put a fuse in it near the battery terminal.
2) Run a wire from the power side of one of the coils (yellow with Red tracer if I recall right on an Evo7) to near the back of the VPD unit, don't cut the coil wire just remove some of the insulation and solder your new wire to it (don't be a tight a$rse and use a knife buy a proper wire stripper).
3) At the VDP end of the battery wire solder the diode on in a manner that the current cannot flow back to the battery (this is simple to check with a voltage meter, one direction you'll have 12V, the other direction almost none).
4) At the VDP end of the coil wire solder the diode on so that current can flow from the coil (and not the other way around).
5) Now solder the free ends of both diodes to the constant pwr wire on the back of the VDP.
6) Connect the VDP acc wire to the coil wire BEFORE the diode. This allows the unit to switch on when the motor is running, and get a good signal for the rpm.

Testing
1) With the power off and key out of the ignition check the voltage at the coil, if you wired the diodes in correctly it should be 0V, if not it will read 12V.
2) The VDP const voltage/battery wire should read 12V
3) The VDP acc wire should read 0V when the ignition is off and 12V when the ignition is on and the engine is running. (NOTE it will be 0V on accessories).


I hope that helps someone out there with this problem.

Cam.