Timing won't fully retard... ECU?

[Nick_4567]

I know what I am doing for the most part but this one has me confused and pissed as all hell. My 1990 GSX has been sitting for almost three years and I finally got around to rebuilding it. The problem is that when I went for the initial start up I was unable to retard my timing to 5 BTDC. Basically where the CPS sat before the rebuild my timing is off the charts probably in the area of 30 BTDC. Obviously it goes without saying that it doesn't exactly run smooth. I know my valve timing is correct along with my CPS, and Power Transistor module and coils being good. My thought is that my ECU is bad but it doesn't make sense because it was working fine before the rebuild. Any thoughts?

By the way anyone have the readable voltage inputs and outputs for the ECU along with wire code? My book is Crap!!

 

[scott90gsx420]

Have you adjusted your CAS(cam angle sensor)?? Thats what it sounds like too me.. If so then your probably right about your ecu but i would think its the CAS position long before a fried ecu..

The CAS is how you adjust your initial ignition timing and set it too 5*tdc.. Set your base timing to TDC then ground the plug on the back of the intake right under the throttle body to the firewall..This make it so the ecu doesn't further advance timing and leaves it at 5* of advance..

Loosen the CAS bolts just enough to turn it and turn it clockwise with the way the motor spins to retard timing and counterclockwise opposite of how the motor spins to advance it..
Hope this helps man..

 

[91stocker]

Dude dont you know, you never go full retard.

Sorry had to...

 

[Nick_4567]

CPS or cam positioning sensor is the same as CAS or cam angle sensor... right.

Also, I understand that you don't fully retard your timing but when you are setting base timing you adjust the CPS to 5 BTDC but the most I can get out of it is probably 15 BTDC fully retarded; either my ecu is retarded or I am just need to figure out witch... nice!

Basically I am wanting to know if anyone has ever heard of this happening and what the symptoms associated with it were. As far as the ecu input/outputs go that would help a lot.

hopping it's not the ecu...

 

[scott90gsx420]

Did you ground the plug so the ecu cant further advance timing??? If not the ecu will continue to advance it man.. Also if your idle isn't set to 750 or within 100rpm of it that will mess things up too.

 

[Nick_4567]

That's all good...

 

[Nick_4567]

Did you ground the plug so the ecu cant further advance timing??? If not the ecu will continue to advance it man.. Also if your idle isn't set to 750 or within 100rpm of it that will mess things up too.

I grounded the plug but doesn't the fact that the timing is off the charts advanced; outside the spectrum of limits for this ecu?