2001 3.4 with PO300,PO301 and PO171 codes

My 2001 3.4 with auto started running rough. I found packrat damage causing a dead short on the #1 injector leads, which I repaired. Now I have these codes and a rough running truck. A local shop recommended ECM replacement but I wanted to post here before going that route.

Any help is greatly appreciated. Jim

 

300 and 301 is misfire. the other a lean o2 sensor. So the injector may not be injecting. ( pretty much a 100% )

I would double check that the wires are repaired and fully plugged in before you go ecm route as that will be pricey. Check that get you voltage across the plug with the engine running.

 

Thx 95v6mt
What should I read across the plug? Volts, ohms ??
Also can I self check the actual injector?

 

Volts, it will be pulsating as it tries to fire the injector. If you use a digital meter just set it on low range 20 volts max or so. But you would honestly be better in this case with a cheap analog meter, as it will react better. Even a 12 volt tester, the ones with the little light bulb would work well.

https://www.youtube.com/watch?v=pzeOz-seIQE

I believe most injectors are 5 volts.

Yes there is youtube vids for checking the injectors,that is a ohm reading. check them all, if one is out of the range of the others it has issues. you can do this in the truck.

https://www.youtube.com/watch?v=wi90kx32c10

lastly
https://www.youtube.com/watch?v=tA_E6X4ISgQ

 

Update.
I put a cheapo test light on the #1 injector leads and saw faint pulsing, I checked it against #3 injector leads which pulsed brighter. I rechecked the wiring splices and they appear good. I tested upstream of the splice point and got the same results.

Since I had prepaid NEAT Computers (Ebay vendor) for a ECM rebuid, I pulled the ECM and shipped it off. They called me and said the ECM bench checked fine and refused to charge me, even for return shipping. Fully refunded my $$, that's a rare company these days.

So, I reinstalled the ECM and cleaned the mass air sensor with CRC electronics cleaner. It still idles rough and the CEL came on after a few miles. The truck shakes pretty bad at 1500-2000 rpm but feels normal at higher rpm/speed. A scanner shows 301 and 306 codes.

Any suggestions? I ordered a new Denso MAF and I'm hoping that helps.

Thanks, Jim

 

code 301 and 306 are misfire in cyinder 1 and 6. check for the pulse on 6.
edit

okay our ecm switches the ground. 1 and 6 share nothing but power in, they share with all the cylinders.

the switching is done a single injector by its self. i think you have aharness issue.

send me a pm with an email address i have some info for you