Have you ever wanted to own an electric car? or have you ever wanted to drive a Porsche 911? I wanted both, so I decided to build one. This blog is here to document my journey as I convert a 2002 Porsche 911/996 Carrera 2 from a gas guzzler to a completely electric vehicle - not a hybrid!

Monday, August 27, 2012

Transmission Frustrations!

So its been 4 days and I've been feverishly working all angles of attack to break down the problem of why the transmission does not spin the wheels when the DC motor is running.  Here is what I know so far and some things I have tried....

1) When the motor spins, the transmission sounds like it is spinning -- there is mechanical noise coming from it.
2) When I apply an RPM input to the ECU, I hear what I believe are a few solenoids that click into place in the transmission.
3) When I take the car out of Park and put into D, R, or Manual,  the transmission responds with a few clicks which I assume are solenoids changing states.
4) If I put into Manual and use the paddle shifters to shift up, it moves into 2nd,3rd, 4th, etc, and there are clicks from the transmission with each change. At no point do the wheels spin.
5) While in Park, if you try to manually rotate both wheels at the same time and same direction, they do not spin. If you put in Neutral, they do spin.  If you put it into gear, say 1st -- if you manually spin one wheel the other spins in the opposite direction.
6) I've drained the transmission fluid and refilled and topped off with new fluid.  -- No change in behavior.
7) I've fixed most ODB2 error codes
a. Engine temperature now reports properly
b. Engine RPM now reports a constant 700RPM which is the idle speed of the stock gas engine as well as the new DC motor controller.
c. I've fixed 4 of the Throttle Valve input errors except P0638-- this one specifically indicates the valve is not opening the amount that is requested by the ECU.  With some more time I should be able to fix this one.
8) There is still an Engine Oil level and Generator indicator lights on in the console.

My next step is to work through the entire Transmission Diagnostics repair manual which will hopefully help me narrow down if one of the solenoids or pressure regulators are misbehaving.

Any feedback is greatly appreciated.  I'll post some pictures soon.

1 comment:

  1. Hey Kurt,

    I'm reading your blog with interest. I have purchased a 2000 Boxster with a no engine, and a tiptronic transmission. I especially like your analysis of the inputs required fro the TCU. Since your conversion, have you encountered any easier or off-the-shelf way to send the engine RPM and load data to the TCU? Also, where did you get the transmission manual?


    (ps - Here's my Porsche 914 EV - 914electric.wordpress.com)