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4x4crazy · 12-23-2011, 10:34 PM

Ok guys. I've learned alot from this site and have given. Now I have a problem. Had my ts at a dealer getting work done. It sat for a couple weeks and when I brought it home today the turbo was not coming up to peak. I was getting about 20# of vac. And that's it. What is going on? Help!!!!

Alan24601 · 12-23-2011, 10:52 PM

Mine was loose at the exhaust manifold and would only make 15 lb boost. Check the studs.

bluepill · 12-24-2011, 10:40 AM

If you have an engine brake, I would use it a few times to excercise it.

As for the turbo, You could have a leak on the pressure side or a restriction on the suction side. Check your air intake and filter for any obstructions, including animal nests.

Good luck

lonestarace · 12-24-2011, 01:10 PM

The first place I'd look is between the turbo and the engine for a loose/broken clamp or hose.

Perry White · 12-24-2011, 01:18 PM

Might not be turbo. Check make sure no moisture in air system. Turbo actuator works off air. If you had someone with a laptop and Insite he could work it for you. Also. pull cover and look down and make sure the EGR manifold isn't rotten away at the expansion joint.

dons2346 · 12-24-2011, 02:44 PM

Turbo could be fine but you could have a leak in the charge air cooler which would show as low boost pressure. On a Cummins, you should see 24-30 pounds.

timex · 12-24-2011, 03:08 PM

I would start by changing the fuel filer. Diesel fuel can support the growth of bacteria which can plug off a filter with a black slime like substance. Low fuel pressure causes low exhaust pressure that's needed to spin the turbo to build intake pressure. Also check your air cleaner indicator.

slabman · 12-24-2011, 09:01 PM

One issue that's come up is the connection of the exhaust to the exit at the front of the turbo. The flange here can break off, leaving you with exhaust and hydrocarbons filling the engine compartment, while penetrating into the bedroom around the hatch opening-look for the soot in your carpeting.

Another poster on this board (Al_M) came up with a loss of air to the turbo due to a damaged line out of the top of the radiator which feeds the turbo. This resulted in a loss of engine power and RPM, etc. With a litle luck he'll chime in with further comment.....

Perry White · 12-26-2011, 08:51 AM

500 HP Cummins ISM should go about 36lbs boost.

J Walker · 12-29-2011, 05:42 AM

Most all turbo boost problems are caused by air leakage, so check all of the connections and the Charge Air Cooler. There have been several threads on this and recently a hose from the intake manifold to the compressor turned out to be leaking. Look for the simple stuff.

Cruzer · 12-29-2011, 06:35 AM

As the compressed air leaves the turbo it passes through the CAC (Charge Air Cooler), which is sort of an air-to-air radiator. It's purpose is to cool the intake air, which has just been heated up by the hot turbo, in order to give a more powerful blast of cool air to the engine's intale manifold.

If there are any leaks in the air intake piping (loose hose clamps or a bad hose) or any cracks or pinholes in the aluminum CAC you will loose pressure. If they are severe enough you might even be able to hear it whistle when under load, although Travel Supremes are insulated pretty good and the turbo is 45' away so you may not hear that.

B.Good · 12-29-2011, 10:55 AM

I had this same problem on an 04 500 ism wouldn't hardly get out of its way same thing it was parked for awhile I replaced the tubo actuators they sit on top of intake and just to rule out I changed the turbo boost sensor , the actuators are electric solenoids there's two they sit side by side

Perry White · 12-29-2011, 06:25 PM

Before you start throwing money at it, Spend a couple of bucks and let Cummins put the computer on it. They can exercise the turbo with the engine off and it takes all the guess work out of it. If you find a leak or something easy,go for it, but you can spend a lot of money guessing at it.

al_mers · 12-30-2011, 10:03 PM

Slabman is correct, TS welded an angle iron support member above the radiator that rested on the CAC hose. Over time it rubbed a hole in the line that bled off pressure to the turbo.
Also, had a barometric sensor go bad that signaled the ECM to reduce the turbo output to almost nothing. The result was 100 miles at 10 and 20 MPH. This particular problem does not show up in the fault codes, thus was very hard to trouble shoot. At-a-boy to Rocky Mountain Cummins in Gillette, Wy., they spent nine hours looking for the problem and only charged me for two!!
Al Mers 2007 TS Alante