Still having issues communicating with the ECU. I have tried multiple scan tools, triple checked every wire, confirmed all grounds are good, replaced the ECU and looked at wiring diagrams until I can see them in my sleep. I just can't figure it out.
The engine side of the harness is 100% original (other than extending the wires for the rear O2 sensor). Engine is a dual coil from a 98. The only connectors I modified are as follows:
1K2 #6 Ground to #5 pin on D7 (data link)
#8 12v ignition
#16 12v ignition
E5 #2 12v Battery
#4 Check engine light
#8 Speed sensor
#12 12v ignition
#19 SIL to #7 pin on D7
#22 12v ignition
D7 #4 Ground
#5 Ground pin #6 1K2
#7 SIL from #19 on E5
#16 12v Battery
I am not running any "factory" gauges and have the fuel pump controlled on its own circuit outside of the ECU. I want to run an ELM327 to a cheap Android phone to monitor the coolant temp, voltage and tach, therefore I really want to figure out why I have no communication with the ECU. I have pretty much eliminated everything I can think of with no success. The truck will start and run fine. It does have a slight stumble off idle but I think it has more to do with the lack of any stored data in the ECU than anything else. I'd know more if I could monitor the data. Does anyone have any idea what I am overlooking?
