NO BOOST

[axe]

Posting for a friend. 14 month old turbo was slobbering oil. Dripping out of hoses on turbo side. Intake side showed just a residue. He says it wasn't boosting but 10-12 lbs. @m*m^2 and boost pyro gauges. Replaced turbo, had calibrated and says it will not boost. I told him to check sensor on intake. Its 09 Pete CM 871. Any ideals. CAC was leaking, pressure tested system after replacing CAC and no leaks. Thanks in advance for any help or things to look at

[Brock]

Tell him to pressure test pre turbo and pressure it all up, if leave the intake piping on, won't hurt anything as there will be exhaust valves open, just don't crank up the psi.

If no boost leak, check around exhaust manifold for soot marks.

Maybe first before all that, tell him to crawl under and shine a flashlight to the back of the engine and see if there is soot from the egr crossover tube. I know the document says you don't need to worry about blocking it but mine blew out back there and killed my boost so I blocked it off.

[Brock]

The rubber boot between my egr valve and venturi blew also causing no boost.

[Rawze]

(11-03-2017 )axe Wrote:  Posting for a friend. 14 month old turbo was slobbering oil. Dripping out of hoses on turbo side. Intake side showed just a residue. He says it wasn't boosting but 10-12 lbs. @m*m^2 and boost pyro gauges. Replaced turbo, had calibrated and says it will not boost. I told him to check sensor on intake. Its 09 Pete CM 871. Any ideals. CAC was leaking, pressure tested system after replacing CAC and no leaks. Thanks in advance for any help or things to look at

As far as turbo slobber goes.... When the engine re-programming was done .. Did they ensure there was not a vacuum at idle in the intake? - Remove the IMAP sensor and feel if there is positive pressure at the hole where the sensor goes. There should be slight positive pressure. If not, then have the turbo adjusted up at idle until it is.

As far as no boost, either there is a derate, or there is a boost leak problem, or the turbo was not programmed for proper boost levels. Take your pick.

Lastly, everyone seems to claim they have MM programming these days but unless it was done by one of the well known guys on here, it may not be correct. there is no cookie cutter solution to proper re-programming a de-mandated truck.

i recomend he goes to Unilevers, gearhead, or Mr.hag if he is unsure of what he has, or can't figure it out.

[axe]

(11-03-2017 )Rawze Wrote:  

(11-03-2017 )axe Wrote:  Posting for a friend. 14 month old turbo was slobbering oil. Dripping out of hoses on turbo side. Intake side showed just a residue. He says it wasn't boosting but 10-12 lbs. @m*m^2 and boost pyro gauges. Replaced turbo, had calibrated and says it will not boost. I told him to check sensor on intake. Its 09 Pete CM 871. Any ideals. CAC was leaking, pressure tested system after replacing CAC and no leaks. Thanks in advance for any help or things to look at

As far as turbo slobber goes.... When the engine re-programming was done .. Did they ensure there was not a vacuum at idle in the intake? - Remove the IMAP sensor and feel if there is positive pressure at the hole where the sensor goes. There should be slight positive pressure. If not, then have the turbo adjusted up at idle until it is.

As far as no boost, either there is a derate, or there is a boost leak problem, or the turbo was not programmed for proper boost levels. Take your pick.

Lastly, everyone seems to claim they have MM programming these days but unless it was done by one of the well known guys on here, it may not be correct. there is no cookie cutter solution to proper re-programming a de-mandated truck.

i recomend he goes to Unilevers, gearhead, or Mr.hag if he is unsure of what he has, or can't figure it out.

You programmed the truck. Took pipe loose from turbo outlet and it will blow the hat off your head. No vacumn at idle. When he first noticed slobbering, replaced hoses on turbo side and cleaned it all up. Drove it 1400 miles home and oil was puddled up in new hoses, so he opted for new turbo. He tested entire system for leaks, you showed him how when he was there. That leaves derate. Could it derate with no check engine light on?

[Rawze]

(11-03-2017 )axe Wrote:  You programmed the truck. Took pipe loose from turbo outlet and it will blow the hat off your head. No vacumn at idle. When he first noticed slobbering, replaced hoses on turbo side and cleaned it all up. Drove it 1400 miles home and oil was puddled up in new hoses, so he opted for new turbo. He tested entire system for leaks, you showed him how when he was there. That leaves derate. Could it derate with no check engine light on?

yup, there are silent derates that protect the engine that can throw no codes sometimes on the 871. I would suggest he take it to one of the guys mentioned and have it looked at before jumping to conclusions though. could be a lot of different things.

[Rawze]

Also, you did not mention how low the boost is and/or how +when it got that way.

[Mr Hagg]

Axe does your friend ever come through GA. or will the truck make it? There are many reasons why you have low boost. Would love to take a look at it to see what it may be. ANd how long ago was it done. May things have changed over the past few years. and like mention before could be egr tube leaking if it was dont along time ago. Or as Rawze mention may be in some sort of silent derate...Just the other day we have a truck that the wiring got on the exhaust pipe after the guy had a clutch put in and who ever did it left the wires loose and it burnt into the 5 volt wire and caused it to through a few odd codes..

[smorgan87]

Ive got an issue with boost too on my 871. Topping out at around 34psi and only achieves that sometimes. Usually around 30-32. It started when i changed the imap and backpsi sensors as well as updating to @m*m^2 from mm1. Installed egr plates with no change. Upped the turbo tables. No change.