Hey there, I am having an issue with my car and it is posted in the TPI section. I tried to hook up a Snap On scanner to it and for some reason it jsut keeps coming back saying that it is not connected. Is there anything special that I need to do in order for it to connect to the ECM? Or should it be plug and play. The reason I ask is because some aldl cables on the net have a 10k resistor built in them for tpi cars, does the snap on have that as well? Or am I completely missing something. Thanks in advance

 

What year is your car and which ECM is being used?

RBob.

 

Right now it is an 86 and the ECM ends in 7165. The chip that is in it is ABXX from an 88 5.7L that I changed to have 24# injectors.

 

OK, that ECM requires the 10K resistor to start the scanning. Once data is being received it is best to remove the 10K. The reason is that it changes the way the ECM runs the engine.

The '86-'89 MAF TPI ECMs can run at two different scanning speeds. There is the 160 rate and the 8192 rate. The 160 rate is usually easy to connect. Although the amount of data is limited.

The 8192 rate is more difficult to connect at but offers much more data. Well worth it if that speed is reliable.

RBob.

 

Where do I put the 10k resistor, across A and B?

 

Yes.

RBob.

 

Thanks i will try that tonight and see what I get.

 

OK, i tested with the 10K resistor and still nothing. Still says that it is disconnected and will not interface with the computer. Not sure why it is not. I made sure that pin A on the aldl is ground, pin B is the diagnostic on the ecm and pin E is the serial data to the ecm. Anything else that I can try? Should I go and buy a connector for the car to interface it with my laptop?

 

To add to this problem, I have another post in the TPI section with what the car is doing. If anyone can help me out with why the iac wants to let more air in, and why the maf is having a low voltage at the ecm would be great