Hello to all, I am a newbie here with a newly purchased '02 2500 Ram CTD with 108,000 miles. As far as I know, there are no mods other than a new 4" exhaust with glasspak muffler. The truck runs great but I noticed a problem. I have a scanpro onboard OBD II scanner that says the truck has 29 lbs of boost at idle, and goes up to 36 at 2,000 RPM. I believe the wastegate is stuck in a closed position, and when I tried to move the wastgate rod it seems to be frozen. Is this the reason for the high psi? What is the manifold pressure supposed to be normally? What can I do to free the wastegate? Or do I need to replace the turbo? Thanks to you all.

 

At idle you should have 0psi of boost, even flooring it in neutral or park, you won't see hardly any boost.

You have a bad MAP sensor, not a stuck wastegate.


phox

 

if you cant move the wastegate rod then it is frozen and is a common issue, even with that stuck shut you should not have more than about 5-10 psi and wot during no load rev. i would change the map sensor we went through this with a buddy of mine on his 01. however the map sensor reads 14.7 at idle or with engine off that is normal it will always read at one atmosphere hints the name (manifold absolute pressure)

 

Thanks
I will try changing the MAP sensor first. How do I remedy the seized wastegate?

 

I doubt the wastegate is siezed, you usually can't move it by hand. You need to apply a little air pressure to the actuator, 25-30 psi should be enough. Use a valve so you can control it.

 

No way I can apply any compressed air to it, I have the turbo with the little elbow that runs from the housing into the wastegate actuator. I will install the MAP sensor and take it from there. The truck seems to run normal with no black smoke and plenty of power, but the scan tool telling me that its running 37 PSI at 2000 RPM has me a bit worried.

 

I don't think a stock engine would be able to dump in enough fuel to make 37 psi , wait , i know it couldn't! I have a few bombs , and i still can't get over 34psi.

All stock i could get just over 20 lbs of boost.

 

Went to the local dealer and he quoted a price of $177.00 for the MAP. After they applied smelling salts and picked me off of the floor, I asked for a blowup. Despite his claims, the printout does NOT appear to show an '02 engine, IMHO. Also, his computer called it the turbo boost sensor and it is shown istalled in the rear at a 45 degree angle, nowhere near the one on my truck, which is between two allen plugs just above the LP. So tomorrow I will call another dealer and see if their parts guy is a bit more sharper. Any help here with a part number would be greatly appreciated.

 

Check with a Cummins shop - the mopar number is 5017791-AA. This may be the Cummins number 3348747.
Jack

 

The other thing to check is the electrical connection on the MAP - On a trip I was setting an overboost code and running awful. When I got home I pushed all the wires into the connector and pushed the connector on to the MAP and before I could get into the dealership the codes cleared and it was back to running like it should.
Jack

 

I had the same problem on a customer's CTD (MJ 02) and found out hte hard way that this truck reported 28 psi with the engine standing still and increased from there with the normal rate. After changing the sensor the values reported by the OBD2 scanner remained the same and the truck did not set an overboost code.
Applying "boost" with a sensor fooler ( a device that will feed out the output of a sensor and can be regulated by a potentiometer- cool diagnostic tool) I was able to raise the boost reading on the OBD2 up to over 50psi before I got an overboost code so IMO there is something in the software of this truck that gives a garbled readout on the OBD2.
To eliminate the WG from your calculation it must be said that at idle there is no way to have enough fuel to spool the turbo to 29 psi. Get a readout with the engine not running.
The preload on the wastegate is rather high so you will not be able to move it by hand. You can check it by removing the turbo inlet pipe and the turbo outlet to intercooler pipe, plugging the latter and applying regulated shop air to the turbo inlet ( there are pipe plugs of just the right size to mount on the turbo inlet, drill a hole and install a tire valve- good tool to search for boost leaks too)- the wastegate should move at about 20 psi, do not go over 30 psi.

HTH

AlpineRAM

 

Thanks AlpineRAM
Your answer makes the most sense- the truck seems to run normally and there is no code thrown for the MAP. So I would just be throwing my money away on a new MAP only to discover the numbers would still be high. I will therefore invest in a mechanical boost meter, including a pyro and fuel pressure. I am now debating between a Juice with attitude, or a Smarty. My first step of course is to upgrade the LP. Maybe the Smarty will eliminate the software glitch. And because the truck does run like it should with no black smoke (and the turbo spools like it should) I will assume the wastegate is normal, too. Thanks again

 

I hope I could help- If you want to upgrade a good and reasonable sequence would be:

Gauges (Fuel Pressure, Pyro, Tranny Temp!)
Take care of the tranny (depending on how far you wanna go )
Then some fuel and air for good measure.

HTH

AlpineRAM