2011 Tacoma 2.7 engine

We have a 2020 Tacoma crewcab,my wifes ride,i bought a 2011 Tacoma crew cab, with a new short block and cylinder head in the bed of the truck,previous owner and friend gave up on finishing the job,i assembled the engine,installed it,after going to hell and back with it,DO NOT buy one of those after market new heads,replaced cylinder head,truck runs great,working in my spaer time only took 6 months.My problem,have repaired cars all my life,mostly a GM guy,my Tacome runs great,unplug my scan tool,engine dies,won`t restart,plug scan tool back in,fires right up,no codes,but with scan toll unplugged,my coils are`nt firing,have 12 volts to all 4,but not being pulsed almost like crank signal lost,problem is,when plug in scanner to check,it runs perfect,anyone in the universe ever heard of this,it was a basket case,but i`ve checked all of my grounds etc.

 

Your almost certainly missing the ground at EH, when a scan tool is plugged in they jump Pin 4 (Chassis Ground) and Pin 5 (Sensor Ground) of the DLC together which is allowing the truck to run with the scanner connected.

 

I was waiting on you.
(Didn’t we just go through this not long ago)

 

Yea on a 1st gen.

 

Yeah, I was going to post the diagram. But seen you in here.
So I took the easy route, I let you do the work

Thanks for helping man

 

Thank you for this detailed info,i wanted to believe someone had this happen before,is the ground supposed to attach to back of cylinder head area?

 

There should be 2 grounds on the back of the head with multiple wires going to them.