mmasse

I am having problems getting the RPM on the G2X data logger. I tried different sources for the signal, cable on tachometer and directly on the tach pin on the DME connector, both got the same result:

Here is the situation. If I disconnect the tapped wire from the Tach, I will get signal in the G2X, but as soon as i connect the Tachometer again, I loose the signal on the G2X. It seem that there is a problem for both devices to work at the same time.

But even if I disconnect the tapped wire from the Tachomenter and get a signal on the G2x, when I pass the 3400 RPM the G2X start showing very strange info. It goes donw to numbers like 100 or below. Any idea what can be happening?

I contacted racepak and the gave me the following answer:

"The problem appears to be the draw created by one or the other systems which accounts for one or the other dropping out. The data going crazy when you rev the motor indicates the tach signal is actually not correct for the G2X. What you will probably need to do is (this is a coilpak or coil on plug vehicle..correct?) is purchase a GMR sensor and PWR / RPM cable. This is the best way to get a clean signal...as long as it is a coilpak or coil on plug vehicle."

So, before buying anything I would like to check here, because I read different post of people connecting the G2X directly to the OBDII connector.

Btw, my car is an European '97 993 Vario, therefore is OBD1. Is this a coilpak vehicle???

Thanks in advance for your help

Mario

Mark in Baltimore

Try posting your question to the racing board, PM APKhaos aka Tony Kelly ro email Kary at http://group9motorsports.com, a Rennlist sponsor.

Good luck!

TheOtherEric

I was told by Chris Brown, who was a seller of data loggers for a while, that OBD won't give you a good enough RPM signal since it's not updated enough. On my DL90/DL1, for a time I had tried using a wire attached around a spark plug wire. I never could get a usable signal, and it also caused some strange noises thru the radio!! It was very odd. I solved my problems by tapping into the wire going into the ECU under the drivers seat...haven't had any more issues with my DL1.

JasonAndreas

Porsche's have an undocumented/non-standard "non-obd2" RPM signal on the diagnostic (OBD1 & OBD2) connector at pin 9 that should work.

Jeff96-993

Your car is not a coil-pack vehicle, but it sounds from the others responses that there are solutions. Good luck!

kary993

I am not sure but if your car is a 97 then it is OBD2 not OBD1.

Secondly, is this car a stock Row 993? Or are there modifications to motor or wiring?

I have both a wire to my tach and a wire to the coils in rear. Both work however I have found the wiring to the coils in back are more accurate (+_200 RPM).

Also please read manual as it describes the signal the G2X is looking for. Sounds like your signal is not correct for the G2X to get an irratic RPM reading like you have.

mmasse

Thanks for your replies.

Kary, my car in in fact a 97 993, but it is OBD1. Euro cars for this year are OBD1...

Can you please explain how to wire to the coil. Is it just a cable to the + terminal on one coil?? I just read the G2X manual and it says to "NOT connect the RPM input directly to any part of the coils, since this will damage the data logger tachometer input". Did you use any kind of interface?
Thanks in advance for you help