I converted my camaro iroc-z from its 870 ecm to a 165 ecm from an 87. Everything works fine except I cannot get any signal or data from the aldl plug under the dash. I am confused why it is not working. Car runs good without problems. Any ideas why it will not work. Scanner says no signal from ecm. Thanks

 

160 baud ALDL is still on pin E of the ALDL connector. If you have a 10K resistor between pins A & B, then it is 8192 baud on pin M. In stock installations pins E & M are wired together and go to the same pin on the ECM.

Note that the '7165 ECMs are known for bad ALDL serial data.

RBob.

 

Hmm okay thanks. It must be the computer or something else just wanted to make sure it wasnt something I did wrong. Ill just have to try the 10k ohm resistor again to reconfirm the problem. Pin m and e should show 5v when transmitting signal right?

 

When transmitting the voltage will fluctuate some, say between 2 and 3 volts. Note that just at key-on, engine-off pin E should have 160 bard data on it.

RBob.

 

I've been having trouble connecting to my 165 as well. My COM to USB adapter has a little switch on it. Is that the 10k resistor mode?

 

The switch it the 10k mode once connection is made you can flip it the other way. You will see the mil light go on in 10k mode , knock retard is disabled and the rpm will go to around 800 rpm.