1KZ-TE Black smoke and no power when warm

[lilevo]

255kms.

On cold start the truck is fine, runs flawless, no issues.

After 3-5 minutes of driving it feels like it enters limp mode. I could probably start a timer and it would happen at the same stopwatch time.

Tons of black smoke off idle, no power in any gear, some rattling/knocking off idle. The truck runs "ok" at speed and can still drive around, but low end power is significantly affected. It feels like you are starting in 3rd gear.

My gut says either timing control valve or SCV as it's such a drastic fueling issue, and it's almost a timed failure.

Need to let the truck cool completely down again before it will work properly.

-No engine codes, no trans codes, caps are all good in the ECU. Odd it would never trigger a code.
-SCV, Timing control valve, resistors on the injection pump all test in spec. Solenoids are clicking as they should. Seems odd it would be one of these since they are testing good.
-Could EGR be causing this if the above are ruled out?
-What else changes or is enabled between cold and hot transition related to timing or fueling?

 

[OM617YOTA]

Are you still getting boost?

 

[lilevo]

Yes, truck runs perfectly fine when cold. Boost, can hear the turbo, no black smoke, etc. This all happens 3-5 minutes after starting and driving the truck.

 

[gnob]

double check the ect sensor.

 

[lilevo]

double check the ect sensor.

Sensor good, 2.5V cold.

Will check when hot when I can, but truck restarts fine on hot start.

 

[gnob]

Sensor good, 2.5V cold.

Will check when hot when I can, but truck restarts fine on hot start.

ok. you need to see what it says hot. because if its stuck cold it will over fuel.
i assume you have data on a scan tool?

 

[lilevo]

ok. you need to see what it says hot. because if its stuck cold it will over fuel.
i assume you have data on a scan tool?

No don't have an OBD1 scanner. No codes either when jumping TE1/E1 so makes this troubleshooting difficult.

I can monitor the ECT with a multimeter during the drive cycle.

 

[lilevo]

ECT is fine. As soon as it hits 0.80v it goes to "limp mode" or severely rich mode. Anywhere between 2.5v and .80v and the truck drives like a dream.

Something is happening right at that point causing this. Whether it's ignoring fueling or timing advance up until that point, or?

Service manual doesn't really say what that is though. FSM says It's either a CEL or sensor out of spec or it's not.

 

[lilevo]

Problem solved. Need to disconnect the filter vacuum hose from the EGR and problem goes away. Such a simple fix.

Does this mean the EGR needs a block off or complete cleaning to restore to normal operation?

 

[gnob]

what actually operates the vacuum supply?
i would think that system is the root cause.
if the egr was actually restricted it would not cause your symptoms.
it appears its going fully open vs being modulated as it should be.
the egr is normally limited by a modulator or duty cycle solenoid.

 

[lilevo]

what actually operates the vacuum supply?
i would think that system is the root cause.
if the egr was actually restricted it would not cause your symptoms.
it appears its going fully open vs being modulated as it should be.
the egr is normally limited by a modulator or duty cycle solenoid.

There's a bunch of FSM procedures for testing the system. I'll try and narrow it down

 

[OM617YOTA]

Maybe the smooth shut down butterfly actuating when it shouldn't? Could disconnecting the EGR have created a big enough vacuum leak in that part of the system to keep the shut down butterfly from actuating?

 

[lilevo]

Problem is fixed as I just capped off the EGR solenoid and valve until a proper EGR delete can be done.

For anyone else having similar problems or issues, or can tell me exactly what failed in the EGR system let me know. My guess is the EGR valve just goes wide open once the truck is warmed up.

Here is the video: