Page 1 of 1

NO INJECTOR PULSE FROM ECU 4G64

Posted: Wed Mar 10, 2010 9:59 am
by Yokohama
I have a 1990 USA spec L300 with 4G64. I have replaced the injectors and revamped the fuel system because the rust and stuff in the system. I had not tried to start it until now. I checked spark and fuel pressure (about 53 PSI engine not running). It will attempt to run when some carb cleaner is sprayed in the crossover pipe.
I got out my oscilloscope and unplugged the ECU harness-to-injector harness connector that is over the engine. I tested each pin (as I do not have a pin out) while turning over the engine. Each pin would indicate a positive 12 V when not turning over, but would only drop a few volts at most.

My conclusion is the ECU is not grounding the injectors to provide the negative necessary to pulse the injectors. Could this be the ECU? Maybe the AFM is bad? Thoughts?

Thank you.

Re: NO INJECTOR PULSE FROM ECU 4G64

Posted: Sun Mar 14, 2010 10:44 am
by Yokohama
I found the codes. It has a diagnostic port above the fuses; it gave the code for bad ECU.

I found that the ECU suffers from similar capacitor leakage to the DSM's ECU. I either have to repair my ECU or find another one.