First off the P1211 is a very common code for a PDS with a chip. It is saying that the HPOP is unable to maintain the pressure that the chip is calling for....

The low boost code can be caused by a few things... First off crawl under the truck and look at the up pipes to the turbo. If they are leaking badly you will see lots of black soot around them at the top...

Next you need to build your own or buy a boost leak detector. Here is the Dieselsite version:



You remove the air filter and plug that in, pressure up the system and check for leaks...

If you have no exhaust leaks up to the turbo, and no boost leaks, then the turbo is no good...

Good luck!
Bob

 

How bad of shape would you guys say that wheel is in? Makes me want to go look at mine now......been awhile since I inspected it! And I ran the K & N drop-in filter for forever!

 

Mr. Bob,

Is the system supposed to maintain pressure or do I just crank up the flow to maintain pressure while I look for leaks? How much pressure should I test with?

Thanks for the advice and especially a photo, I can make one of those with parts on hand.

John

 

I think he said 25 PSI .. its in a previous post on this thread !

 

Put it in the inlet of the turbo and apply between 10 - 20 psi from an air compressor (with regulator) If you can't hear the leak try spraying soapy water around any connections.

 

Try this!
I bought my first 7.3 a year ago. It obviously didn't have right power. After MUCH checking, some one suggested I change the MAP, and that solved the problem. My understanding is that the MAP senses the boost and allows the computer to add fuel accordingly, which of course adds boost! With no added fuel you will get no added boost.
Anyway, why not try it? Just swap MAP's with a friend to see if it makes a difference. It only takes 3 minutes. If your MAP is bad, you and your friend will both know it!
It sure fixed mine. Best $90 I've spent on it, and it is lifetime guranty at O'reily's!

 

I checked the up-pipes, yes they are both leaking at the top judging by the black soot streaks. I'm not sure how much they are leaking but they are leaking. No leaks from the bottom connections.

I pressurized the intake to 15 PSI and found no leaks on the IC pipes or connectors, but I did find air leakng from the MAP sensor. Is this normal?

So I disconnected the MAP sensor just for a test drive to see what happens, the system definitely noticed since the check engine light came one. But it runs EXACTLY the same as it does with the MAP sensor plugged in. What SHOULD it do with the sensor disconnected?

Thanks for the advice, I'll keep chipping away until I get this thing running right!

John

 

Where was the leak at the sensor? Was it in the hose or at the sensor? Either way the leak should be fixed.

If you unplugged the electrical connector on the MAP then the PCM is supposed to assume default readings, which means it would have ignored your leak if that was the problem.

I'd guess it's time to play with the up-pipes. I'll look through the manual and see if I can find any other ideas.

 

The MAP sensor seemed to be leaking at the seems of the plastic case. The hose is new, I changed it when I added the boost gauge last week.

I'll se if I can find a new MAP sensor tomorrow, my local AutoZone doesn't carry them, special order only.

Thanks,
John

 

Sounds like you'll have it fixed when you put in that new MAP.. Good work on tracking the problem down !!!!

 

would low boost result in not as definate and loud whistle?

 

Well I replaced the MAP sensor with one from NAPA on my way home from work. $105 with tax! ouch!

In any case I can't really tell if there's a difference or not. I haven't towed my trailer yet, but getting on an up hill highway ramp with the pedal to the floor I got about 11 lbs at 3000 RPM. Is this similar to what others are getting?


QUICK EDIT --- Every time I read about someone installing a 6637 they talk about the great sound the turbo makes. When I installed mine I didn't hear ANY difference.. Maybe my turbo is dead?

 

That one look pretty bad almost like it was run with no filter


if the boost is low it won't hardly whistle

how much boost are you making between 1800 and about 2300 at full throttle?
I really don't think you will get a lot of whistle with the shape the turbo is in

 

Ray,

The boost is low between 1800-2300, like 5-6 psi, even with my foot to the floor. It doesn't climb to 10 psi until aroun 3k.

I'm really trying to get this resolved. The truck has little blow-by, starts right up, does not smoke etc. I think the engine is in OK shape, but the low boost / low power makes it a lawn ornament. I'll have to get my Dodge ready for the Pocono500 next weekend, there's no way I can tow 100's of miles with this one yet.

Thanks for any and all advice.

John

 

for sure you need a new compressor wheel and with 155k miles it could probly use bushings also,some have put more miles on without bushings being bad but mine were gone at 55k
with the shape the wheel is in hard to say if compressor housing is scored or not
only other thing I read you haven't addressed is up pipes but think turbo is biggest culprit
one other thing I had early on was a plugged muffler,thinking that could br why turbo died so early

I really don't like to send anyone after expensive repairs without seeing problem first hand