I have an 06 w zero boost. I have traced it back to the MAP is not moving. We cleaned turbo out and the vanes were stuck. it was good thing. i can command the vgt up to 85% and i can hear the pitch change. not sure it was the whooosh i was expecting but it does change. i have tried a couple of MAFs and they are reading 14.4 engine off and like 14.3 at idle. the EBP is reading pretty close engine off and in the 15s at idle. I can pull off the MAF tube which is brand new and put my finger on it and feel some additional pressure in the line - you can feel a little positive pressure.

the motor sounds great. I know the difference between the sound when they aren't running so well. throttle response is good - just no boost at the cluster and no change in the MAP.

question is - assume throttle translated to fuel is dependent on MAP. No map, and the throttle response might be higher based on throttle, but not pumping fuel like it would if MAP showed boost?

the real question is what is throwing off the MAF? it has 5v reference voltage. it reads like 2.6 psi if i unplug it entirely. I don't see any issues w the wiring across the top of the motor but I will test it next.

 

Went back thru it again and actually, the MAP tube has a slight vac on it. its sucking at idle. pulled the egr valve out cleaned it. pulled the cold said cac tube off and its pushing air, but obviously not sufficient air.

just rebuilt this turbo and the vanes were struck. everything new except the housing. the wheel is turning, its pushing air.

what am i missing? anybody?

 

So we’re on the same page

MAF in Not a pressure sensor
it is a volume of air sensor it is unable to report pressure

MAP & EBP are your pressure sensor

just because you command VGT to control turbo doesn’t mean it moves as it has no position sensor built in to verify

 

Have you read the tech turbo guide in the tech folder very handy


Any codes

 

tks - i do get that. when i took out the turbo, the fins were stuck. actually once we took off the unison ring, the little actuator wouldn't move it was so clogged up w soot. cleaning it up, it moved quite easily by hand. for good measure we took out the vgt and test it. you can hear and see it moving.

re-read that initial post and i don't know why i kept typing MAF, but all the MAFs are MAPs. it would appear that i have negative air pressure at the manifold at idle. i verified it by pulling a piece of string off my shirt and holding it up to the MAP tube. it sucks it in.

I did find an air leak where the exhaust back pressure runs into the egr. going to remove turbo and whatever else necessary to get that leak stopped. i know any leak at any of the exhaust connections can cause no boost, but i guess i was surprised it can actually cause negative manifold pressure?

 

A 2006 turbo control is heavily reliant on EBP

MAP for that year is mainly used for the gauge at cluster


common issue seen here is
since the turbo has been removed and reinstalled
start the truck let it idle and feel around the up pipe to turbo connection and at flex joints it cannot leak and is a pain to get to seal if not done in right tighten sequence


if you pull the EBP make sure to clear the tube between the EBP sensor and Exhaust manifold weed eater line works here

 

first thing i did was check the tubes and lines. they clean. has to be this back pressure line to egr connection. there is soot all around the clamp and i think its causing another issue we've been having w this truck. hot no start and i replaced the hpop stc fitting w that causes hot no start issues not long ago. the soot is being blown on the heat shield right next to the ipr. appears to be blowing hot exhaust gasses on the ipr. it was a hot no start and letting it sit for 10-15 mins, it would start no issues. guessing it was getting that ipr pretty darn hot w what . . 400 degree exhaust gas blowing across it.

 

You shouldn’t have any soot on the IPR area it’s leaking exhaust

if it leaks here no boost

you Can use some string or rag to check if it gets blown around the exhaust joints

 

Not sure which area you are referring to, but I assume this is the up-pipes. You don't want any soot leakage out of these, anything lost here is less energy going to the turbo. Get all leaks fixed.

-Make sure the up-pipe connection to the turbo is lined up correctly. It needs to be VERY close before you tighten the clamp. If misaligned loosen the up-pipes so you can get it into a good position.
-Check the bellows, they like to break over time.
-If you took apart the header-to-uppipe connections double check those. They can be a PITA to get put back together due to the tight clearances (especially driver side).
-Check the connection from the passenger up-pipe to the EGR cooler. that should also be very closely lined up before you tighten down the clamp

Good luck

 

Boost is back! Not really sure what it was that did the trick b/c I wanted the thing running so I did things i could think of that might be the culprit.

Removed the turbo and check the exhaust to egr connection which is where we spotted soot. Not like i took the clamp off and went aha! it may have been a 1/16 askew and somebody left off the egr bolt to the manifold and it needed some help to perfectly align it all. Reinstall turbo carefully two guys watching both sides tightening clamps a little at a time so we didn't end up w a leak there. I pushed shop air to the map tube and nipple to the manifold even though i had already done it once. Even though i was getting solid readings from the ebp sensor, i removed and shot shop air down the tube just to make sure b/c so many people that's the culprit. Last thing, I reset the pcm adaptive tables.

somewhere therein, the boost is back. guessing ebp tube or air leak. didnt have to go after the up pipes fortunately
onto the next adventure . .