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Discussion Starter #1
working on a friends truck. completely all stock 2005 lly with 165,000 miles.

fuel filter, intake filter are good. truck reads p0101, p0102, p0229, p0401,p0404.

I drove the truck, very sluggish an smokey. No power, so i plugged in my cts and reading no boost. deleted all the codes and watched the readings on the mass air flow sensor an seems to functioning fine. watched the map sensor and got zero boost. truck had very good oil pressure, so i am guessing that the actuator is working because it is ran off from oil pressure.

Any other things i should check before before i change the vane position sensor?
 

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Drivers side lower boos tube. Take it off and check it. There was a 05 LLY at the company I used to work for that had the same problems and I checked it but didnt feel any holes. When we had a change to pull it off, there was about a 1" gash in the bottom of it.
 

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Drivers side lower boos tube. Take it off and check it. There was a 05 LLY at the company I used to work for that had the same problems and I checked it but didnt feel any holes. When we had a change to pull it off, there was about a 1" gash in the bottom of it.
Isn't the stock boost gauge before the intercooler?
 

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Isn't the stock boost gauge before the intercooler?
Dont know, but that 05 was reading low or no boost too. If there is an opening in the system, there isnt gonna be any boost anywhere.
 

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Discussion Starter #5
low boost code would make sense for the egr an maf because the engine is not sucking the air it is suppose to and the turbo is not working right allowing the egr to not get the correct flow through it right? and if that drive side intercooler tube specs out to be okay then what should i turn too? are these vanse sensors known to go?
 

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Yeah thats where I would go then. MAF and Vaine Sensor would be next. Maybe someone else would chime in here.
 

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Discussion Starter #7
alright thanks goose. appreciate the help
 

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The "stock" boost readings (on your CTS reading through the OBD2 port) comes from the MAF sensor. So technically yes the stock boost gauge is before the intercooler...........way before the intercooler.
 

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And how exactly does a maf sensor read boost? The maf sensor is on the intake tube which is constantly under "vacuum". There is no boost sensor pre intercooler. The MAP SENSOR is just north of the y bridge..that is where boost is read from. IT IS POST INTERCOOLER.

MAF=MASS AIR FLOW. Senses the amount of air COMING into the engine through the filter.
MAP=MANIFOLD ABSOLUTE PRESSURE. Senses the amount of air GOING into the engine.

These 2 sensors are used in conjunction with each other to monitor and control many aspects of the engine and its performance.
 

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Edit: Damn you beat me to it.


MAF = Mass Air Flow

It measures the amount of air coming in, not a pressure reading. Not a boost gauge or sensor. It's actually a special type of resistor called an "anemometer" that varies resistance with temperature change. The more cold air that is pulled past it, the colder it gets, therefore allowing more voltage through. The ECM thus relates that to more fuel must be added.

MAP= Manifold Absolute Pressure

Pressure is even in the name. So is manifold (which is after the intercooler). I think we have a winner.

Please refrain from posting total nonsense in the future.
 

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can you see what vane position is?
 

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Discussion Starter #13
im sure i can on the edge cs. i will check the intercooler tubes an the vane position. if the tubes are good and getting zero vane postion. i am going to say its the vane postion sensor that is bad.
 

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Edit: Damn you beat me to it.


MAF = Mass Air Flow

It measures the amount of air coming in, not a pressure reading. Not a boost gauge or sensor. It's actually a special type of resistor called an "anemometer" that varies resistance with temperature change. The more cold air that is pulled by it, the colder it gets, therefore allowing more voltage through. The ECM thus relates that to more fuel must be added.

MAP= Manifold Absolute Pressure

Pressure is even in the name. So is manifold (which is after the intercooler). I think we have a winner.

Please refrain from posting total nonsense in the future.
:rofl and i was just about to bust your balls for saying exactly what mike said, until i saw you edited it
 

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well if your vane positiond doesnt change, it could also be the actuator or the vanes are siezed up
 

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Discussion Starter #16
good point dirty maxx. ill let u guys no this weekend
 

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And how exactly does a maf sensor read boost? The maf sensor is on the intake tube which is constantly under "vacuum". There is no boost sensor pre intercooler. The MAP SENSOR is just north of the y bridge..that is where boost is read from. IT IS POST INTERCOOLER.

MAF=MASS AIR FLOW. Senses the amount of air COMING into the engine through the filter.
MAP=MANIFOLD ABSOLUTE PRESSURE. Senses the amount of air GOING into the engine.

These 2 sensors are used in conjunction with each other to monitor and control many aspects of the engine and its performance.
Edit: Damn you beat me to it.


MAF = Mass Air Flow

It measures the amount of air coming in, not a pressure reading. Not a boost gauge or sensor. It's actually a special type of resistor called an "anemometer" that varies resistance with temperature change. The more cold air that is pulled past it, the colder it gets, therefore allowing more voltage through. The ECM thus relates that to more fuel must be added.

MAP= Manifold Absolute Pressure

Pressure is even in the name. So is manifold (which is after the intercooler). I think we have a winner.

Please refrain from posting total nonsense in the future.
Woah Calm down Dudes! Sorry , My bad! I was also talking with someone about having his MAF rescaled after going to a LBZ CAI in his LLY and got my wires crossed is all.
 

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The EGR could be stuck open-!
 
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