Loss of power when hot.

[matuva]

Talk with a 1997 6.5 owner in the week-end.

He is complaining about a loss of power when hot. He says the rig pushes strong when cold.

Couldn't connect my laptop yet to see if any DTCs are stored in the PCM, and other than that, he couldn't describe me any other problem.

The rig runs fine, just he says he is loosing power when hot. Starts fine when hot, so I don't think the IP is concerned.
Turbo actuator seems to work fine.

Worn turbo may be? gap in the turbo shaft beyond specs when hot so loosing boost?

What do you think?

 

[matuva]

Forgot to add:

no MIL on
LP test to be performed to get sure it works
stock boost actuator, so I believe no overboost
doesn't look like defueling...

 

[Crankme69]

Plugged or restricted exhaust?

 

[matuva]

Must check, but IIRC, it is a straight pipe

 

[jmiller]

Check the vaccumm pump, to make sure its ok. If your laptop can log data, take it for a drive. Record iat, boost, boost command, app. Make sure the Turbo is not deboosting. If commanded to deboost, iat would be high. Like 230 or hotter.

If commanding boost, but not building, solenoid could be sticking when hot.

I just replaced my solenoid for not building boost.

 

[Turbine Doc]

High IAT & defueling possibly, neither of which will set a code, do you have any method of verifying IAT while driving to see if true high IAT vs. one in error ? To check for defuel command what happens for high IAT once seen @ PCM max fuel rate will be limited to 50mm fuel, once vehicle is shut down this resets and acts fine until the high IAT is observed again. You have to be viewing with a bi-D scanner what the max fuel rate on a WOT commanded is to actually see this happening, if IAT sensor has failed high you would see this on scanner as well.

 

[Joey D]

High IAT & defueling possibly, neither of which will set a code, do you have any method of verifying IAT while driving to see if true high IAT vs. one in error ? To check for defuel command what happens for high IAT once seen @ PCM max fuel rate will be limited to 50mm fuel, once vehicle is shut down this resets and acts fine until the high IAT is observed again. You have to be viewing with a bi-D scanner what the max fuel rate on a WOT commanded is to actually see this happening, if IAT sensor has failed high you would see this on scanner as well.

At what IAT does the computer cut the fuel back?

 

[Turbine Doc]

I've never been able to capture the exact point due to refresh rate of my MT2500 nor have I read any text defining it; but 275 ish sustained for 5+ sec or so is when I've seen the defuel happen, I think it is a ramped feature vs finite setting based on X time over X IAT temp and it defuels, or if quickly hitting a peak of X IAT 275+F it does an immediate defuel, just like with an overboost situation that can't be corrected with opening of a WG.

 

[Joey D]

I can feel the power drop on my truck hammering on it. The IAT hit 260 plus. This is when it's hot out and the a/c is on but not even towing.