LBZ: Turbo cycling/fluxuating at idle

[tinman22]

my truck has recently had the same thing happening. usually happens after the truck is warmed up and started and driven a few miles. I have 2 codes pending one is I think P0125 coolant temp below thermostat control usually sets the check engine light after its partally warmed up... about 5 minutes of driving. and a code for drivers door ajar circut low voltage... I think that one is due to the alarm. perhaps a broken wire from tapping in...
havent had a chance to chase the coolant code.

 

[lotsofmiles]

mine just started doing this the last trip.

does it warm or cold. in park or in drive with the brake on.

ugggg I know something has changed. I just dont understand why I can hear it in the exhaust, see it on the snow gauge but it doesnt show on the log or on the banks 6gun display.

 

[lotsofmiles]

logged it again. log and banks display stay level, but I'm thinking they're reading off the same electronic sensor, right? But the snow gauge is an air line tapped into the intake and displaying what it actually is doing, not what a sensor says its doing .

So, is my vane sensor going out?

and/or

Is there another sensor that controls/reads boost?

 

[lotsofmiles]

Now it has stopped doing it. Smooth idle just like normal.
2500 miles this week, and it didnt do it once.

 

[tinman22]

possibly sun spots or something? mine hasnt done the cycling thing in over a month.

 

[coldLBZ]

FWIW my truck was doing this too when I had a P0098 code. The wires going to the intake air temp sensor broke. The vains would cycle off and on like you're describing, but then they would stay closed like it was trying to spool up. I don't have a boost guage so I can't help you there.

 

[lotsofmiles]

I got a suspicion that my finger stick needs to come out.
the other day, pulling away from a stop light with a trailer, truck threw a CEL. 1st time in a LONG time, cant even remember the last time.

anyway, it had no power, and I was trying to go uphill away from the light. checked the code on the 6gun, a maf code & a egr code, and 1 other I didnt see. Just saw the maf and egr, hit clear codes, cel went off power came back and its been fine since.

I think something is going bad in the stick area. So I'm going to pull it off, turn it off with efi and see what happens.

 

[770JOHNNYW]

ive got an lly doing this...had a po2563 in it and under/overboost codes. scanning with tech 2 boost jumps all over. vanes don't want to follow desired. no power at all.

 

[lotsofmiles]

Mine has never done it again.

 

[770JOHNNYW]

I'm getting heavy grey maybe blue smoke but have zero shaft play. I'm wondering if the vanes are stuck but I can't figure why the boost is bouncing around anyone seen a map sensor cause this?