How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Daniel Wilson Your Own Question
Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 5552
Experience:  Owner at DJ Wilson
Type Your Medium and Heavy Trucks Question Here...
Daniel Wilson is online now
A new question is answered every 9 seconds

2007 ISX CM871 high exhaust temp and black smoke when foot

This answer was rated:

2007 ISX CM871 high exhaust temp and black smoke when foot in throttle. Truck seems to be down on power some. May not be but I don't think it has the power it should. Can I get some trouble shooting help?

Hi my name is***** will be glad to try to help. What fault codes are logged in the ECM memory?

Customer: replied 1 month ago.
No fault codes

thanks for the update. Check for air restrictions and for any leaks in the turbo intake piping and manifold gaskets, CAC cooler. Check the turbo for problems as well and the actuator for proper operation. Check for exhaust restrictions as well. If okay I recommend checking the ECM software calibration and having the ECM software updated as ECM calibration and software issues can cause these symptoms if no mechanical problems are found. Let me know

Customer: replied 1 month ago.
I did find that the exhaust gasket between the egr valve and the manifold is leaking. I also found that were the egr valve and cooler connect the flange is completely broken and the egr valve is disconnected. I asked the driver about this and he said it has been disconnected since he got the truck several years ago. There is no exhaust leaking from the flange. Could the exhaust leak cause low boost? I'm thinking yes but not 100%. When I drive the truck the most boost it makes is 10psi

Thanks for the update. I agree not 100% but if you have insite try re-calibrating the turbo actuator and check it for proper operation. this is a variable turbo and could have an actuator problem or excessive carbon buildup in the turbo vanes. Check for that. Im logging out got the night but we can follow up as needed.

Customer: replied 28 days ago.
Do u know what amount of boost is normal to build when driving. 10psi is the max we are making. And exhaust temps are still high

Max Boost Pressure 35 PSI
Max Exhaust Gas Flow 3625 cfm (102 m3/min)
Max Exhaust Temp 900-950 degrees F
Combustion Air 1470 cfm (41 m3/min)
Cooling System Air Flow 25000 cfm (707 m3/min)

Customer: replied 22 days ago.
I should be seeing 35 psi at WOT

WOT under a load such as puling a hill etc.

Customer: replied 22 days ago.
Ok. But bobtail and wot what would u expect

You still should be able to obtain full boost and even 25 or better

Customer: replied 22 days ago.
Ok. Just wanted to make sure I’m on the right track. Still can’t get over 10psi boost

Even driving under a load such as pulling a hill? That is low

Sounds like the turbo vanes might be sticking or some actuator problems, possible faulty turbo. The VNT turbo is variable and if the vanes are carbined or soot plugged the turbo can not reach max boost.

Customer: replied 22 days ago.
This turbo is a new one but maybe it’s defective

Was it recalibrated with Insite software after installation? If not, it has to be on this engine.

Customer: replied 21 days ago.
It was not calibrated. Didn’t know it needed to be. I have a Peterbilt tech come look at it and he said it did not have a actuator. When he said that I thought there wasn’t any calibration...

A non VNT turbo? has there been any modifications on this such as EGR delete, etc?

Customer: replied 21 days ago.
No mods...
Customer: replied 21 days ago.
Man mine doesn’t have this type of actuator. It is done with air

What is the complete model and serial number from the engine tag?

Customer: replied 21 days ago.
Serial number is *****

Check that the actuator lever on the turbo will move and is not sticking and there is no leaks in the actuator or problems. Click here for some FYI

Air actuator

Customer: replied 21 days ago.
No leaks but I will check to make sure it’s moving in the morning

Let me know

Daniel Wilson and other Medium and Heavy Trucks Specialists are ready to help you
Customer: replied 20 days ago.
we found a missing plug on the bottom of the head that goes into the intake side. Plugged it and all is good

thanks for the update and glad you got this resolved. Pleasure to help