E40 / LS2 DBW issues
Thread Starter
TECH Fanatic
Joined: May 2010
Posts: 1,081
Likes: 8
From: Atlanta, Ga
E40 / LS2 DBW issues I am trying to trouble shoot the DBW in an E40 system. At idle or even static both the Yellow (TB pin A) from PCM pin BLACK60 and Brown (TB pin B) from PCM pin BLACK 63 show constant 12V. Cycling the pedal does nothing. I see the 5V on the Purple (TB pin D) PCM pin BLACK 31 and LT BLUE/BLACK (TB pin E). These do not change voltage as the pedal cycles, but do change as the throttle plate is manually moved. I have tested the pedal sensor and it seems to be functioning correctly. If I remove the yellow wire from the TB and quickly ground the terminal the throttle blade does open for a moment. Any ideas?
On The Tree
Joined: Sep 2012
Posts: 134
Likes: 0
From: New Taxes York
The only thing I can think off off the top of my head is that the connector at the pedal isn't seated all the way.
Or the pedal is bad.
Do you have the schematics for the LS2 and E40? I can send you all of them, but mine are for the GTO and Corvette, not the TBSS.
Or the pedal is bad.
Do you have the schematics for the LS2 and E40? I can send you all of them, but mine are for the GTO and Corvette, not the TBSS.
Last edited by HwyStarJoe; Apr 5, 2014 at 01:31 PM.
Thread Starter
TECH Fanatic
Joined: May 2010
Posts: 1,081
Likes: 8
From: Atlanta, Ga
Let's see how good my memory is.
I did determine that I had the 2 TAC wires to the TB backwards (gold blade LS3). I also found that my low ref was not correct. I was working with several wiring diagrams and a stock truck harness. Once I got that sorted out it worked like a champ.
It seemed that initially everything was good. That did not last long. The engine started to run extremely rich. No DTC's though.
Another trip back to the tuner.
He had set the ECU to not show several faults even though thy were present.
I figured out that the MAF was showing WOT. Traced the issue to a poor connection at the ECU connector. While at the tuner, he set up a more gradual fuel curve that really helped overall driveability and even makes it easier to send the rear tires up in smoke any time I want.
A negative side effect is that I killed the DS O2 in the process.
If anyone was following the original posts you will all remember that this adventure was all a by product of rebuilding my dash. Again, nothing another $1000.00 can't cure.
I did determine that I had the 2 TAC wires to the TB backwards (gold blade LS3). I also found that my low ref was not correct. I was working with several wiring diagrams and a stock truck harness. Once I got that sorted out it worked like a champ.
It seemed that initially everything was good. That did not last long. The engine started to run extremely rich. No DTC's though.
Another trip back to the tuner.
He had set the ECU to not show several faults even though thy were present.
I figured out that the MAF was showing WOT. Traced the issue to a poor connection at the ECU connector. While at the tuner, he set up a more gradual fuel curve that really helped overall driveability and even makes it easier to send the rear tires up in smoke any time I want.
A negative side effect is that I killed the DS O2 in the process.
If anyone was following the original posts you will all remember that this adventure was all a by product of rebuilding my dash. Again, nothing another $1000.00 can't cure.
