I first noticed a strange sound when I bought my toy hauler and towed it home to the coast from Calgary over the Rockies. Sounded sort of like an old speedometer cable going bad, mixed with a vacuum leak. It would only happen for 10-15 seconds at a time, when pulling up a big hill between the speeds of 70-100km/h.

Over the next several trips with the trailer in tow the sound increased in volume, range of speeds and duration.

In the last two weeks I've also started having a power issue. The truck seems a bit sluggish when it's on its own. Can't hear the sound. Starts fine. However, when pulling the trailer I have a hard time accelerating past 25km/h on a hill and 80km/h on the flat (yes I'm Canadian). The sound still only happens when going uphill... and many times it won't make the sound.

I've been to several shops and chatted with several mechanics. We've ruled out the turbo, intercooler, exhaust system is clear, CAT is fine, injector pump pressure is good, manifold gasket is new, fuel filter changed, transmission and torque converter are good...

The loss of power issue isn't happening all the time, seems pretty normal with daily driving, just a bit sluggish maybe. The harder I push it, the more I notice the power problem. With the trailer on, it's painful! But the sound only happens when pulling at max capacity with my 16000lbs load.

So now I'm wondering if the lift pump in the tank is going or is clogged, or if the flow is restricted in the fuel line (this would cause the loss of power?), and as a result I'm not getting enough fuel to the high pressure injector pump which is causing it to make the sound I'm hearing (?).


That's my best guess right now. I'm no mechanic. I've only had the truck for 6 months.

I'm stumped. As are my mechanic friends.

Any suggestions or ideas would be much appreciated!

 

Do you have a boost gauge? Have you very carefully checked every turbo boot for damage or loose clamps??

 

I don't have a boost gauge. But did go for a drive with a diagnostic computer and the readings for the boost were good. Up to 40 pounds when pulling hard with the trailer. Have checked all the boots and clamps well. Replaced one clamp. Have had the turbo inspected twice in the last month.

 

Check your fuel pressures to make sure you have enough fuel. Also, check the oil for diesel, you may have a loose fuel tube at the injector and losing diesel in the valve cover. I've heard of these making noise and loss of power.

 

Any way to check the transmission? After re-reading I wonder if it is a trans issue since there are no signs coming from the tailpipe regarding fueling or compression issues.....

Kurt

 

make a pressure fitting to go over the turbo inlet that can accept an air hose, pressuriize the system with air and listen or spray down the air intake areas with soapy water, especially the bottom of the intake manifold. you might have a boost leak.
9 use a pvc pipe pipe cap fernco fitting.