last time out wheelin truck acted up and died like 2x

limped it home from the bush found the short but now have found it is like it is running on 4 cyl's
4.6 19197 128.000km
what I found IAC valve closed circut no resistance period
Iat sensor working
CHT/ECT sensor closed no resistance cold or hot
CTS sensor for dash gauge reads 5.13 ohms cold
when plugged in gauge swings to full hot key on
EGR vac reg no resistance closed circut

pcm is not throwing any codes period
scanned it many times
aside from replacing defective sensors
rough idle no power , wants to idle @300-450 in gear
700 in p or n

any wisdom or input would be great
thx

 

Your CHT sensor is indicating an engine over heating situation and the PCM is setting a failsafe cooling mode. The engine runs on 4 cylinders. Unplug the sensor to confirm.

.

 

thanks for the input will replace sensor as i have literally everything torn down
good time to change the plugs now much easier with stuff out of the way.
what about my Iac valve?
and egr vac reg

 

When the engine goes into failsafe cooling I believe that the EGR is turned off so that no exhaust gases get into the engine. It is hard enough to run on 4 cylinders adding EGR would make it even harder to run. Have you run it with the CHT unplugged?

Regards

Jean Marc Chartier

PS. I will check the schematics to see if any of these sensors share a common power source. Most sensors share a 5 volt lead and actuators like the EGR solenoid use 12 volts.

 

changed the CHT and IAC Valve today runs the same still pooched no power
runs smooth but no torque
still not setting any dtc codes
got a yellow emmissions light.
plugs are good proper voltage to all sensors
tranny fluid full and clean
temp gauge working now with the new CTS i put in as well
was full hot before unless i unplugged the CTS