Ok a quick question: Black smoke at full throttle intermittent and MAF sensor code P0101 and EGR code 403. The truck has 250000Kms. Any help would be appriciated. Also we cleaned the MAF but the symptoms are still there. Nick

Do you still have the OEM vacuum controlled watsgate on your turbo? Edited by: Juancho

Yes I do. Thanks

Does the second solenoid on the bank (egr vent) have a "T" that goes to the EGR and Baro?


This controls the EGR cycle and is the most likely place to cause problems. look for a leaky line between EGR and Baro.


make sure your pulling a vacuum at the turbo and EGR.Edited by: quantum mechanic

Yup, it hat the "T".

Make sure you have Vacuum on the turbo and "T". Pull the line off and check it at idle. Turbo should have 15" Hg and "T" ~20"Edited by: quantum mechanic

can't do that on the trucks with MAF sensors, any attempt to disable EGR system will really upset them. check all vacuum lines for cracks, check EGR valve operation by unplugging the line to it at idle, should be a definite popping closed sound. Check air filter.

PCM sets EGR at instances of extended deceleration, as on freeway off-ramp - reduces combustion temps


PCM senses EGR vacuum via tubing to sensor on firewall.


Check vacuum with a 'tee' - 25" at pump, 0" at EGR.


Vacuum at EGR at idle indicates leakiing EGR Solenoid.


Second EGR solenoid is Vent - vents vacuum at PCM command to release EGR valve


Could be engine harness connections\grounds.


Try another MAF, or try that MAF on another truck