Ive been fighting a boost loss problem if you check out the other threads I have posted I have disabled the high pressure relief valve, tried two different lift pumps. The problem Im having now is you shut the truck off for five minutes hop in it and it will run right up to 37-38 lbs of boost, drive it for about 15 min. and you will hit a grade and the egts will go up but the boost stays right at 20-21 lbs.Put your foot in it and you cant get it any higher than 24. I have a edge and have taken it off had it checked and put it back on. I haul a lot and I have to get this figured out, I have not ordered my rail pressure guage but I will in the short future. Im leaving in the morning and thought if anyone had any ideas Id like to hear them. I think it is electrical somewhere but unsure where to start I have already replaced the temp/ boost sensor.

 

i dont know much about them, but is it possible that your wastegate is sticking open when the underhood temps go up. or maybe something is wrong with the electronic actuator.

I dont know, im just trying to put out some ideas..

 

I think you have a hole in a rubber boot somewhere. When it warms up, it leaks.

Make a boost leak finder like this:

take the air filter ducting off the turbo, put the leak detector on, put some air to it, and spray around all areas that you think might leak with some soapy water, and it will bubble, problem hopefully solved. it has worked for me in the past, boost leaks can be very frustrating, hope this helps

 

Ive already pressurized the system with a deal like that and really could not find anything but the truck was not at temp when I tried it.

 

check all rubber hoses(wastegate, intercooler, and air horn) and also the gasket between the air heater grid, etc. There has gotta be a leak somewhere, you can 't make boost one minute, and then a significant drop in boost the next, just my opinion

 

Went out and pressurized it again and found a pin hole in the intercooler. Hope that is it.

 

no very unlikely (I know its not a freightliner)but spec on a freightliner is 5psi loss in 15 seconds for detroit diesel engines (I know its not a detroit) but would not go out and drop a grand on a new CAC unless you need a good excuse to calm the wife down if im not mistaken on the literature on cummins is 5 psi drop at the charge air cooler in 20 sec and same with CAT would sure hate to see you get stuck at the dealership for $ for them to tell you that leak is not enough to warrent a swap of a warranty part just my .02

are you checking it with a manual guage or through the edge product not familure with the edge product you use if it reads boost sounds like a wastegate problem

 

You were correct borrowed a intercooler today and same stuff, went through 5 gallons of soapy water trying to find something else leaking and cant find anything.

 

Disabled waistgate and went out and beat on it for 20 minutes straight. No Problems it is running much better now instead of telling the wife I need a new intercooler I can tell her I need a new turbo instead!!! The stocker has 156K on it so I really cant complain it has some end play in it so I think it is time to look for a replacement instead of putting a new waste gate in it, or the electronic actuators. Thanks for your help now I can hook up and take off. Ill just have to watch the boost guage.

 

Wardy, check for end play on a cold soaked turbo, then again at full operating temp, Cummins allows a small amount of end play cold, zero end play hot.


Tim

 

Where in ohio are ya ?

 

Risingsun about 40 miles south of Toledo.