1999 Dodge Ram 5.9 Diesel Whistle under acceleration- not a turbo whistle.

[bobbyboy35]

Have owned this truck since new. 104000 miles now. This noise has been around for a couple of years. It reminds me of electrical feed back on a cheap stereo without a filter. Am quite sure it is not electrical as far as sound system. Sure coming from under hood. Occurs under acceleration. I say it whistles it could be considered a howl. connections between air box and turbo are tight. Any ideas? Fuel injection, lift pump, replaced at approx. 85-90,000 miles. at same time technitions tightened all intercooler couplings and powerwashed the cooler and radiator. Don't recall the noise at that time although I asked why I only get 10-12 mpg on the hwy, no trailer at 65-70 mph. Looking fwd to any educated ideas thoughts or experience's. thank's to all!

[2.2 Straight six]

sounds like a boost leak somewhere. check and tighten all hoses and connections between the turbo and intake manifold.

[samdodge]

I had this problem in my 1999 Dodge Diesel a couple of years ago. It drove me crazy. I used a stethoscope and listened for the noise. I found the noise in the heater core inlet and outlet hoses at the firewall. I flipped the hoses around and the noise disappeared. Not to worry I replaced the turbo first because the dealer said it was going bad and causing the noise. I was not happy when the noise was still there and I just spent $800 for new turbo.

[Chris Stewart]

Have you removed the silencer ring off the turbo or changed the air filter lately/not changed the air filter in a long time?
Have you installed a lift pump fuel pressure gauge?

[samdodge]

I have replaced the original air filter a couple of months after I bought the truck in 99 with a K&N air filter. What a difference! I clean it periodically. I have not removed the ring on the turbo because I do not know what advantages there are? I have not placed a fuel pressure guage permanantly. I have checked the pressure and it is around 10 pounds. I know this is important to know the fuel pressure. I talked to Cummins and they rarely have a fuel pump go bad even though it pulls fuel as much as it pushes it. You should be able to tell if the fuel pressure is not up to pressure if the truck hesitates a little going up hills. I have placed an Edge Chip in the truck and it adds about 90 hp and about 165 ft pounds. May help gas mileage if you could keep your foot out of it. I only get 20 miles a gallon and I am happy with that.

[Chris Stewart]

Congrats on going this far in your Dodge.
Because the Injector Pump(IP) is lubed & cooled by fuel, the performance of the lift pump needs to be adequate to handle that cooling & lubrication chore.
I changed my lift pump & relocated it to the frame rail just in front of the fuel tank after I found the old pump would only build 7 psi @ wide open throttle(WOT).
.

[fffdavis]

Just fixed a loud whistle on a 98. The whistle was only noticeable during acceleration. What we found was the intake manifold gasket was blown due to a loose bolt under the throttle linkage bracket. Took some soapy water and poured on it while idling and found it. Maybe this will help.

[Chris Stewart]

Thanks for the info...A fellow found an excessive 20 spi boost leak with 2 of those intake bolts missing recently on another site.