FLA997

A Racepak G2X is being installed on my car as we speak, and for some reason when we tap into the rpm pickup from the ECU or the pin behind the OEM tach in the dash, the signal is not being read on the display unit. What makes this more strange is that the tach on the dash "dies" as well.

Can anyone think of a reason why this may be occurring? The Racepak unit is not defective as it operates fine on other cars.

For what its worth, the ignition switch has been converted into a toggle on the dash, along with a master cutoff. I'm not sure if this has anything to do with the strange issue, but its the only thinkg that has changed in the dash recently.

Any help/ideas are appreciated.

Gert

From an electrical viewpoint, it looks as if the drain of the newly attached wire is too high, making the signal drop to zero.
Can't you connect it elsewhere? On the coils for example.

FLA997

Directions specifically prohibit connecting at the coils - damage will occur. The reason this is strange is that it just isnt working on MY car, which leades me to believe something has happenned when the dash and other components were taken apart and reassemebled....very strange.

TheOtherEric

Like Gert said, I'd have to think the internal impedance of your unit is too low. I've read here that some people install some form of additional impedance (resistor) in front of their data loggers so that the voltage drop is minimized. I didn't need to do that with my DL1 though.

Dumb question - are you sure you grabbed the correct wire? I've posted the colors a couple times.

FLA997

Thanks Eric,

The correct wire was used, both on my car and the other car that the unit actually operates fine on. Just doesnt make sense why it isnt picking up the signal on my car, AND it shuts down my OEM tach on the dash....but again, works fine on another car.

Gert

Try placing a 1K resistor in series with the wire to the data logger.

FLA997

Thanks Gert - i will report my findings.

Paul902

Sounds to me like your ECU is not sourcing as much current as the other ECU. Alternatively, your tach could be drawing more current than the other tach. With the additional load of the data logger it is causing both units to not function correctly. If the 1k resistor trick does not work, get an ohmmeter and measure the resistance from the input connector to ground of both the data logger and your tach, and the other tach, and report the findings.

good luck,
Paul

TheOtherEric

I'm reluctant to say this, but it's also possible the rpm sensor isn't mounted ideally, resulting in low output voltage. I say that reluctantly, because I wouldn't advise going down that path except as a last resort. (BTDT. When I played with it, I got wildly different readings from what the shop manual says to expect, yet it still works fine. So it's not painfully easy to confirm. Also not easily accessible, and possible to really botch.)

FLA997

Thanks Eric- that is enlightening. I think I am just going to use the coil pack pick-up module from Racepak and hopefully be done with it....hopefully....electrical gremlins - ugh!

Carrera Mike

Isnt there any tach signal from any of the OBD II wires?