7.3 Fluttering/Turbo Noise under heavy load

[boostedh22a]

I have a 2000 EX with a 7.3 in it. I recently took my first trip with a 24' enclosed trailer, and noticed something happening that is very odd. Under a load, in OD, I would heard a "fluttering" sound coming from under the hood. Almost sound like compressor surge, maybe a boost leak?? But I couldn't find any loose clamps, or problems with the couplers.

Basically what I was feeling when this noise started was lack of power. It only happens in OD, when the truck kicks down, going up a hill, it's fine, but then when it kicks into OD, I here the "fluttering" noise. I know it's normal to hear the turbo, as I have towed with other 7.3 before, but this was definitely not a normal noise, and seemed to me that it had a lack of power when this was happening?? It was definitely coming from the turbo/air intake area of the engine, as I had several passengers that confirmed as well. The only mods the truck has, is a K&N intake system.

Any ideas???

[vitalidle]

Could be turbo surge as your losing power when it happens. Do you have a boost gauge?

[strokerboy73]

waste gate?? bump

[boostedh22a]

I do not have a boost gauge installed, however I have a mechanical one just sitting around I could hook up and see what boost is doing. What is normal?? Also, where do most people "t" into for boost pressure??

I was starting to wonder about the wastegate???

Thanks for the responses so far

[boostedh22a]

The weird thing is, without a trailer hooked up, it seems completely normal. It's just that load when in OD, when this seems to occur

[vitalidle]

Yeah that is usually when it will happen or if you have a chip or tuner added to the truck. You can T into the map line for the gauge. You will see the boost gauge flutter basically the turbo is stalling and doesn't know which way to spin that is turbo surge and its very hard on the shaft and bearings, so you either need to drive through it or let off the throttle to prolong the life of your turbo. There is other fixes also.

[vitalidle]

If its not turbo surge which you will be able to tell with the gauge my next guess would be when you shift into overdrive and you have an open intake that is the excess pressure bleeding off back through the intake. With an open intake you can hear it now vs the stock closed intake you can't.

[boostedh22a]

What are some other fixes?? I towed about 50k miles across the country with a 24' enclosed trailer in 2003 with a 99 F250 7.3 TD and never had this issue.

I should also note that this trailer was empty, and I have pulled a loaded 28' trailer with the truck around town, and some highway without this happening.

[strokerboy73]

sounds like waste gate to me.

[boostedh22a]

What would be wrong with the waste gate?? If it's sticking open, I wouldn't make any power, if it's sticking closed it would over boost and I would think it would either trip a check engine light, or have some fail safe that would shut the engine down??? The truck isn't physically surging like boost is going up and down, it just overall feels like a lack of power when this is happening.

This noise is definitely coming from the air intake area. The waste gate is all on the exhaust side.

I don't know though. I have a lot of experience with turbo'd cars, but none with diesels, so they might be setup differently.