My 2001 Dodge Cummins Turbo does not come on under a load (towing my travel trailer). That is the only time I notice a power problem. With no load it performs as normal. I used to hear it cycle on whenever pulling a grade, last trip it came on one time and didn't sound as loud. I am NOT the world's worst mechanic but I probably rank in the bottem ten! I hve had the truck in the shop (not a dealer, a local diesel mechanic) for three days. He says pressures are good. He's been in contact with Cummins for help but they are slow to call him back. 130,000 miles on the truck, regularly serviced. Any suggestions appreciated!

Russ

 

Welcome.

Guages should have been installed from the factory on these trucks. You need Exhaust Temperature, boost, fuel pressure and transmission temp (if you have an automatic transmission) guages. Guages greatly help with troubleshooting and will SAVE you money. The boost guage will tell you if your turbo is working like it should. What was the boost pressure that your mechanic was seeing? We need numbers here.

Dont hold your breath - your not going to get much (if any) help from Cummins.

Has the truck been scanned with an OBDII scanner? Thats where I would start.

 

x2

 

I don't fully understand "Turbo on under load"? The turbo in these trucks spins as soon as the exhaust gas rolls past the wheel.

Get you buddy to remove the air intake housing and expose the intake side of the air comressor (inlet of the turbo). With motor off, grab the shaft of the wheel and give it a light tug and see if there is any side to side play - ie does it touch the side walls? In and out is ok for about 1 to 2 mm (3/32") max.

Next, check to make sure the exhaust manifold is not cracked - without gauges you'll see this by a huge amount of black on the manifold, the block side of the turbo and the hood as well. This is an easy fix but involves a new manifold.

Next, check that all the boots from the air compressor through the intercooler and up to the intake horn (intake manifold) are intact. This can be done by visual inspection and can also be done with warm soapy warm and an idling motor - check for bubbles.

Afer that, check for a damaged waste gate. Do a search on this site on how to build a tester for that out of PVC pipe. Use compressed air and blow at under 15 psi to a max of 25, then 26, 27 through 34 at single psi increments to see when the gate opens. Yours may be set way too low.

I would note that boost is a direct relation between air in and fuel in so if all the items related to the air side are fine than you've got a lift pump or VP44 pump problem.

Beyond that - get gauges.

Sorry man.

 

Good answer but its much easier to scan with a scanner and install a boost guage.

 

where are you located?

 

Well, if the turbo is bumbed a boost gauge won't tell him that 100% if he can't get enough load on it. Putting load on the block may be a bad thing in this case if he's got a VP44 problem - right?

I mean, don't get me wrong get it scanned and get gauges installed but if the turbo is damaged a scan won't tell you this on this model year.

Cheers.

 

Went by the mechanic's shop and he said he found a problem. Some sort of part with a weak spring that regulates what pressure turns on the turbo? (Told you I'm not a mechanic.) Says he disconnected it so it was turned on all the time and picked up 7 lbs. pressure. He's waiting for the part. Keeping my fingers crossed. Thanks for your replies.

 

A wastegate failure is VERY rare, and rarely a instant failure. It sounds like a boost leak to me.
A good scanner with Live data will show you your map signal, (same as a boost gauge) and alot of other needed information! I would be looking for a cracked manifold, leaking manifold or a busted boost hose!

 

Get your waste gate tested! ive replace multiple HX-35s with that same problem.