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Boost issue

4K views 20 replies 6 participants last post by  southend 
#1 ·
So a while back I had a "Turbo Underboost" code and took apart the turbo and cleaned the living s**t out of it, like I mean it was pitted bad and the vanes were stuck hard, but I followed the DIY that I was linked to here (DTS Articles - Turbocharger Reconditioning) and everything ran perfect for a few months.

But now it seems that the truck has lost a lot of bottom end power almost like not building enough boost low range but as soon as I pass 2000rpm all the freakin boost in the world is contained within the truck and it spools and all the power is ready at the pedal.

I did NOT change the unison ring when I cleaned the turbo as none of the slots were 'ovaled' or worn, I cleaned around the actuator that runs the unison ring as best I could making sure it was free to turn.

Could my vanes be stuck again? are there tests to I can do to make sure the actuator is actually moving? and lastly any good sources for new or re-man'd turbos? and are there any aftermarket turbos that I can slap on without an additional tune, even if there are no power gains but reliability or ball bearing that spool faster?

Any input is greatly appreciated since this is my daily driver/work horse.
Thanks in advance.
 
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#2 ·
You need to update your sig, what year is your truck? You may need to google the turbo relearn procedure. Maybe you have an exhaust leak.

Sent from my phone that somebody didn't help me get.
 
#3 ·
sorry it's an 06 bone stock, and do I still have to do the relearn if I'm using the same actuator? I checked for exhaust leaks at the V-bands and Y-pipe under the truck. Also checked over all silicone couplers last night, no leaks.
 
#4 ·
Unplug the VGT plug and see if the tone of the engine changes, that will tell you if the ring and vanes are moving. With the connector plugged in the vanes should be in the closed position while at idle, so lots of backpressure which will result in a very deep exhaust note.

I find that the more you drive the truck after cleaning the better it will get. The PCM needs to relearn VGT duty cycle.
 
#5 ·
this may be a dumb question, but do I disconnect it as the truck is running? or run with it plugged, listen, shut off, unplug, start again and listen again?

and found a write up on how to do VGT relearn,

The low power and lag problem could be a result of the sevice "Tech" not performing the VGT re-learn strategy after flashing the computer. Here is the strategy you can perform it.

KAM (keep-alive-memory) reset & VGT learn procedure

1. Drive the truck until the engine and transmission have reached normal operating temperature.
(The VGT learn procedure requires that the oil and coolant temperatures be at normal operating temperature)

2. Flash truck back to stock (Only need to do this if running a tuner or module)

3. Turn on the headlights

4. Disconnect both batteries

5. Short out + to - battery cables to each other (Make sure both batteries are disconnected before doing this).

6. Let truck sit like this for 10-minutes

7. Turn off the headlights.

8. Re-connect batteries

9. Cycle the key to the run position twice. Pause in the “ON” position each time until the wait to start lamp goes out (minimum 5-seconds) and pause in the “OFF” position each time for 10-seconds to be sure the PCM has "gone to sleep".

10. Start the truck and let it idle for a minimum of 5-minutes at normal operating temperature. This allows the PCM to learn the EGR valve closed position value. Also you will likely hear the turbo pitch change several times during this period as the PCM learns the necessary duty cycles for accurate VGT control.

11. Complete the road test Drive Cycle:
15 miles of mixed driving (*should* be enough in most cases) to allow the PCM to "re-learn" its adaptive strategy.

Note: Anytime the batteries are disconnected, the PCM will throw the P1000 code until the “Drive Cycle” is completed.


As for the Tow/Haul mode, the transmission must re-learn your driving style and loads hauled again as this was cleared when the truck was re-flashed.
this actually makes a lot of sense since I the truck was on a EDGE programmer "Hardcore" tune before the turbo 'stuck' and after I cleaned it I didn't do a relearn.

Will keep this thread updated, as this seems to be a common issue.

Thanks for the help in advance.
 
#6 ·
Just at idle.

Sent from my phone that somebody didn't help me get.
 
#7 ·
an 06 does not need a vain position relearn procedure. That is only for 03 and early 04 with the inferred EBP strategy.

If your turbo center housing is pitted you're in for problems in the long run. You may never be able to effectively clean it. I bet your turbo is stuck again
 
#9 ·
Can't the unison ring be replaced?

Sent from my phone that somebody didn't help me get.
 
#10 ·
yes but the unison ring is stainless and doesn't get rusted up. the main problem with the ring is wear in the cam slot and vary rarely it can end up cracked from being frozen to the center housing.

The turbo center housing is cast on the exhaust side and is prone to rusting up causing more problems than coking alone. rust cannot be cleaned from the center housing, it will just reform again.

The best fight against rust is to not make short cool trips and not let the exhaust stay cold enough for moisture to collect.
 
#11 · (Edited)
yes but the housing where the fins or vanes sit on is pitted and basically the soot and crap sit in there and prevent the fins from moving. Even if I change the uni ring it won't change much if anything at all. At least on mine, it was pretty f**king pitted, took me a whole night of grinding to get it flat enough that the fins glided across but the surface was still rough.

Here's a picture before I cleaned it, fins were cleaned but I was afraid that I would forget how they went back in so I reassembled it and took a photo before I forgot.



You can see the pitting clearly and how they might affect the fins.

Most of the pitting was gone when I was done, but the ones on the edge were harder to get to because I had to try to get the bit under the edge of the housing.


*Actually in hindsight, now that I'm looking at the picture again. I should've just replaced it...
 
#12 ·
Gotcha. Mazesecond, had a turbo from an 05 for cheap. He replaced his with an 03'. Give him a pm, or check out the for sale section.

Sent from my phone that somebody didn't help me get.
 
#13 ·
The center housing is the wheel side of the turbo. It can be either flat or if it's a reman it may have a dished design where the unison ring sits. That's where the rust causes a problem. The turbine housing is what you have pictured. That can always be blasted to clean it.
 
#15 ·
Hehe......the benefit is the whistle. Most especially if you have removed the cat.

Sent from my phone that somebody didn't help me get.
 
#16 ·
I cant get over how rusty the whole thing is?? Not a California/ envirement
 
#17 ·
Hey guys, not to hijack the post buy i have a related question.
The other day while climbing a large hill, my VGT plug became disconnected. The truck instantly was affected and started blowing black smoke. I yanked it off to the side of the road and fixed the issue. Would this have any adverse affects on my rig? I also got the P0046 code.
 
#18 ·
You should be fine, clear the code, carry on.

Sent from my phone that somebody didn't help me get.
 
#20 ·
I know it's been a while since I posted the thread originally, but I had to put a hold on it since we had gone to SEMA for work and we have just been swamped since. Today is the first day I finally get a chance to post what progress I had made.

So first off, the truck is fixed and everything runs well, hauls like a champ and power out the wazoo again. The issue? Thermostat stuck open. Yep. Truck wasn't reaching OT so was running in limp mode so to speak. But all is good now, and in case you're all wondering, I didn't figure it out, brought it to Ford and hooked up Modus to it. On cold temps all parameters were in spec other than the engine temp, they let it run outside and it never hit OT so couldn't run other tests. Swapped it out and it ran perfectly, did all the other tests and it passed all of them. The only issue he said was my FICM is starting to look weak on cold temps (39v at cold), enough still start the truck somehow (min. is 48v iirc) and at OT the FICM is at 55v so it's still strong but may be on it's way out...

So to end on a good note, my turbo is still holding up after I cleaned the **** out of it and it didn't cost me my unborn child to fix the truck. Today is gonna be a good day.
 
#21 ·
Thats an interesting update, thanks. You need a monitor.

Sent from my phone that somebody didn't help me get.
 
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