Boost leak? I can't tell....

[Robert6401]

Hey guys,

I just got back from a week long trip down to Florida pulling the 5th wheel. This was my first time towing since I installed the PHP chip and I am very happy with what I gained. I did end up with some sort of problem though and I'm hoping y'all can help me figure it out.

On the way out of town last week I noticed some increased noise coming from the engine bay but the truck seemed to run fine. I was able to pull all the way down to Florida in OD no problem and was getting about 20psi of boost going up some hills holding just under 70mph, not really trying to get any more. I noticed that around 15psi the turbo seemed to have a pronounced flutter to it rather than just the normal high-pitched whistle, but once it got above 15psi it went away.

Well, we got down to Florida and I didn't drive much while I was there but the little bit I did drive the noise from the engine bay seemed to get a bit louder. The best way I can describe this noise is like a throaty exhaust sound like you would hear from a gasser.

Then, finally, I was able to tell that there is definitely something wrong on the way home yesterday when I could only get about 15psi of boost, the EGTs were a little higher, and the truck definitely felt like it had less power. The condition also seemed to get worse throughout the 9 hour drive.

Of course I have heard of many people on here having boost leaks, but I wasn't sure if it was normal for it to start out small and just get worse and worse like mine did?

Also, if y'all do think it's a boost leak, I need some specifics on where to look because I glanced around a bit last night and didn't see anything I could pin-point as being loose.

Thanks a bunch!

[907DAVE]

Check your up pipes for leaks, sounds more like a exhaust leak than a boost leak. Boost leaks will produce more of a high pitched squealing, or a loud hissing sound.

Good Luck

[Robert6401]

If it is an exhaust leak? Is there anything I can do besides replacing the up-pipes? Those puppies are expensive.

[cleatus12r]

Actually, the Ford replacements will run you about $100 in parts. The labor is pretty intense (turbo r&r at 1.8 hours plus the time to do the pipes).

Originally Posted by Bob

I noticed that around 15psi the turbo seemed to have a pronounced flutter to it rather than just the normal high-pitched whistle, but once it got above 15psi it went away.

That's turbo surge and it's very bad for the turbo. Just sayin'.

[Robert6401]

Cody, I was able to get what I thought was turbo surge around 25psi just playing around in the perf tune, but it was more of a *chirp chirp* sound. The sound I was getting at 15psi was more like the sound you would hear if you blew into a table fan. Why would the turbo surge at 15psi? Isn't that really low psi for it to do that?

[Robert6401]

YouTube - 7.3 powerstroke turbo surge, turbo stall, compressor surge, or normal wastegate blowoff???

This is the closest sound I could find to what I was hearing at 15psi. Go to the 1:00 mark like he says in his description.