Low Boost Pressure, Turbo Replaced

canonoch1 · **Joined:** Sun Mar 10, 2013 2:59 am **Posts:** 77

yep unfortunately this country boy has over extended his wallet after knocking my marble shelf down :BANANA:

. so boost gauge will e on next month budget.

but i am happier with it. thanks to everyone for their input here. i'll add as i progress though the fine tuning of this project

Smacker · **Posted:** Wed Jan 14, 2015 10:16 pm

Sorry a little late to this thread, but i also had the mind boggling p0299 that would not go away! Not sure if you modified your exhaust system? But i found out that a new turbo will not boost correctly with a plugged catalytic converter. Open it up and you may be surprised!!

WWDiesel · **Posted:** Thu Jan 15, 2015 3:34 pm

P0299 code
AS a warning or heads up to others who have capped off their EGR tube at the valve/cooler end when removing or disabling the EGR system or installing the Weeks 101 kit:
Let me share what happened to my CRD this past weekend!
Cranked CRD around 6 am the morning to go work, temperatures were ~25F, had Jeep plugged into timer set to come on at 4 am.
Jeep fired right up as normal, after a short warm up time to allow all fluids to get flowing, pulled out of car garage and started down driveway. As soon as I pulled out onto road and started accelerating, lost power and DTC light came on. I could tell I had lost some boost so I figured maybe I had blown off a boost connector hose somewhere?
It was still dark so I could not see behind me. Drove on to work with very low power when accelerating.
Plugged in code reader and only code I had was the P0299 (low boost pressure) Opened hood and checked all hoses, found no problems. Drove it home that evening, lots of black smoke behind me when trying to accelerate! Babied it all the way home and got it in the shop and discovered I had blown off the end of the EGR pipe. See pictures. Pipe was also cracked for about one inch down its length from where it blew the cap to one side.
This tube comes off the end of the exhaust manifold at the No. 4 cylinder BEFORE the turbo, so it is under pressure at all times when exhaust is being pushed against the turbo wheel. Made a solid metal cap and capped the exhaust manifold fitting at the exhaust manifold using the OEM clamp.
Do not know how long this thing has been leaking with the cracked pipe? Jeep seems to have a lot more power now, back to where it was back in the summer. I thought the less power was due to cold weather and winter fuel?
Note: I am running a Stage IV Hot tune by Yeti and it probably has more boost than stock. Got to get a boost gauge on it!!!!

flman · **Posted:** Thu Jan 15, 2015 3:52 pm

When I did my delete I did not even plate off the end of that pipe, I just cut it about and inch away from where it mounts to the manifold, pinched it, and welded it shut.

thermorex · **Posted:** Thu Jan 15, 2015 4:31 pm

WWDiesel wrote:

P0299 code
AS a warning or heads up to others who have capped off their EGR tube at the valve/cooler end when removing or disabling the EGR system or installing the Weeks 101 kit:
Let me share what happened to my CRD this past weekend!
Cranked CRD around 6 am the morning to go work, temperatures were ~25F, had Jeep plugged into timer set to come on at 4 am.
Jeep fired right up as normal, after a short warm up time to allow all fluids to get flowing, pulled out of car garage and started down driveway. As soon as I pulled out onto road and started accelerating, lost power and DTC light came on. I could tell I had lost some boost so I figured maybe I had blown off a boost connector hose somewhere?
It was still dark so I could not see behind me. Drove on to work with very low power when accelerating.
Plugged in code reader and only code I had was the P0299 (low boost pressure) Opened hood and checked all hoses, found no problems. Drove it home that evening, lots of black smoke behind me when trying to accelerate! Babied it all the way home and got it in the shop and discovered I had blown off the end of the EGR pipe. See pictures. Pipe was also cracked for about one inch down its length from where it blew the cap to one side.
This tube comes off the end of the exhaust manifold at the No. 4 cylinder BEFORE the turbo, so it is under pressure at all times when exhaust is being pushed against the turbo wheel. Made a solid metal cap and capped the exhaust manifold fitting at the exhaust manifold using the OEM clamp.
Do not know how long this thing has been leaking with the cracked pipe? Jeep seems to have a lot more power now, back to where it was back in the summer. I thought the less power was due to cold weather and winter fuel?
Note: I am running a Stage IV Hot tune by Yeti and it probably has more boost than stock. Got to get a boost gauge on it!!!!

So yours broke when it enters the EGR unit from the manifold? I think weeks kit comes with block off plate for the EGR outlet, is that so?

Never mind, I know now. Its the egr end of the connecting tube from the exhaust manifold to egr. I think I'll also weld it shut as flman did when I'll replace the turbo... it is weird though, as this should break even with egr enabled. I wonder if it is not just a case of bad luck... Anyways, I think some soot should be visible if it starts breaking.

papaindigo · **Posted:** Thu Jan 15, 2015 4:41 pm

I recall occasional reports of losing that pipe. Based on your images it does not appear to be particularly robust but being that it's attached directly to the exhaust manifold pre-turbo I wouldn't think it would be subject to much pressure. With EGR closed the only pressure would be from the exhaust toward the EGR. With the EGR open this tube would be just a pass thru.

I suspect just normal engine vibration could simply wear out that joint.

I do find it a bit odd that you don't report any excess noise. I would have thought that with a hole in the exhaust manifold, so to speak, that exhaust noise would have been pretty loud.

thermorex · **Posted:** Thu Jan 15, 2015 4:46 pm

papaindigo wrote:

I recall occasional reports of losing that pipe. Based on your images it does not appear to be particularly robust but being that it's attached directly to the exhaust manifold pre-turbo I wouldn't think it would be subject to much pressure. With EGR closed the only pressure would be from the exhaust toward the EGR. With the EGR open this tube would be just a pass thru.

I suspect just normal engine vibration could simply wear out that joint.

I do find it a bit odd that you don't report any excess noise. I would have thought that with a hole in the exhaust manifold, so to speak, that exhaust noise would have been pretty loud.

I agree, shouldn't be much pressure in that pipe as it is just normal exhaust, even in the propeller side of the turbo is not more pressure than what exhaust the engine spits out.

WWDiesel · **Posted:** Thu Jan 15, 2015 4:59 pm

thermorex wrote:

papaindigo wrote:

I recall occasional reports of losing that pipe. Based on your images it does not appear to be particularly robust but being that it's attached directly to the exhaust manifold pre-turbo I wouldn't think it would be subject to much pressure. With EGR closed the only pressure would be from the exhaust toward the EGR. With the EGR open this tube would be just a pass thru.

I suspect just normal engine vibration could simply wear out that joint.

I do find it a bit odd that you don't report any excess noise. I would have thought that with a hole in the exhaust manifold, so to speak, that exhaust noise would have been pretty loud.

I agree, shouldn't be much pressure in that pipe as it is just normal exhaust, even in the propeller side of the turbo is not more pressure than what exhaust the engine spits out.

My best explanation is that when that tube blew open, all the exhaust pressure went out the path of least resistance, the open tube, instead of going through the turbo to make boost. And yes, I could hear an exhaust leak when I opened the hood. Was not that loud inside the cab....

gmctd · **Posted:** Thu Jan 15, 2015 5:25 pm

Yeh, but that exhaust pressure in the manifold is left-over combustion pressure and heat augmented by Boost pressure - I had MAP (pre and post CAC) gages + EGBP pre and post turbine gages on my truck during my early R&D on the Diesel Page forum, along with switchable IAT pre and post CAC and switchable EGT pre and post turbine, switch was selected to cause least voltage-drop amongst EGT dual thermocouple probe wiring - may still be some pics, over there - that multi-function monitor panel still resides in-place in the big GMC, out there in the yard

If no exhaust heat and pressure energy, ur turbo would have a difficult time keeping up with even the normally-displaced CFM of the engine

However, that silver-soldered(?) rupture appears to have been caused by torsional stress resulting from casual manipulation of the tubing whilst reworking amongst various componentry at the other end, on the other side of the engine from the exh manifold

flman · **Posted:** Thu Jan 15, 2015 6:52 pm

WWDiesel wrote:

My best explanation is that when that tube blew open, all the exhaust pressure went out the path of least resistance, the open tube, instead of going through the turbo to make boost. And yes, I could hear an exhaust leak when I opened the hood. Was not that loud inside the cab....

Also consider that pipe is usually attached to the EGR crap, so it is pretty rigid under those circumstances, it would have to bend the SS pipe to blow the end off under those circumstances.

WWDiesel · **Posted:** Thu Jan 15, 2015 9:19 pm

gmctd wrote:

However, that silver-soldered(?) rupture appears to have been caused by torsional stress resulting from casual manipulation of the tubing whilst reworking amongst various componentry at the other end, on the other side of the engine from the exh manifold

Yep! Could not stain the strain; no matter, its all gone now!
My post was to let others know that if they have their EGR tube just hanging out there capped off and not connected to anything anymore, it could crack or open up on the end as it did on mine.... :wink:

lacabrera · **Posted:** Tue Mar 03, 2015 12:30 pm

Not sure if its been mentioned earlier on previous posts, but my catalytic converter was restricting exhausts flow and pressurising, preventing turbo boost. De-cated mine made a whole lot of difference to turbo boost.

Low Boost Pressure, Turbo Replaced

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