PSD 'sounds' / questions / observations

SHINTON

SHINTON

Well-Known Member
Joined
Mar 17, 2005
Location
Triad area of NC
Ok, driving the new to me PSD (7.3) 2002 Excursion and wanted to ask about a few sounds I am hearing, etc.

First....when letting off gas and / or then applying brakes, I am getting a sound like pressure is being let off on an air tank if you will. I figure it is a pressure valve of some sort? Normal I guess?

My turbo was making an awful whistle, but then it made a huge POW..and then no power...(yikes...) Called Slim and he tells me to look at the intercooler pipes and sure enough the 'cool' side had blown off the intercooler, guess I didn't tighten those down good enough. (Pulled intercooler, had oil in it from rollover) Whistle is now gone/reduced/changed so it must have been leaking air/causing that whistle.

Hmm...drivethru guys had hard time hearing my order last night..HEH...

Final thought/question...right now I am registering about 15.1 mpg "average" but that has been all over the place since I reset it, etc. I am really trying to make myself stay under 2000 rpm and not spool up off every light, etc (aka RICH...heh) But I betting the diesel in the tank is at least 6 months old or more...had a full tank. I have burned off almost a 1/4 tank...should I try to burn most of it off so I can fill with fresh?

Sam...PSD newbie...Hinton
 
Couple crappy cell phone pix
 

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SHINTON said:
Ok, driving the new to me PSD (7.3) 2002 Excursion and wanted to ask about a few sounds I am hearing, etc.

First....when letting off gas and / or then applying brakes, I am getting a sound like pressure is being let off on an air tank if you will. I figure it is a pressure valve of some sort? Normal I guess?
Click to expand...

no experience with a PSD specifically...

but a lot of turbocharger and supercharger setups have a blow-off valve...

when you let off the gas, it releases the pressure so you're not slamming all that forced induction into throttle body butterflies, etc...

others have a bypass valve (my custom supercharged Dodge Ram - gas engine was designed this way) that routed the air back to the intake side of the blower unit...


Greg
 
bigwaylon said:
when you let off the gas, it releases the pressure so you're not slamming all that forced induction into throttle body butterflies, etc...
Click to expand...

No throttle body in a diesel. ;)

Sam, you may be heaing the hydroboost brakes doing their thing, or you might just be hearing the turbo spool down, but neither one should be very loud.. But, your PSD's turbo is RIGHT behind the center of the dash...

I'd run some Power Service or Stanadyne additive for the next few tanks, and maybe change the fuel filter after 2-3 tanks.. But your milage sounds about right for that tank... :flipoff2:

And what's wrong with a little smoke? :D
 
fuel

Time should not affect the fuel. I would do as Rich suggested, change the fuel filter, add a can of injector cleaner at your next fill, whick I would do soon. The mpg sounds about right for a 7.3. I would figure it with miles and gallons, not from the trip computer.
 
The trip computer is notoriously off by about 10 percent and it is not in our favor. I average about the same mpg in 99.5 while unloaded. I dont here anything like that noise when i let off the brakes, i would suspect the vac. pump may be leaking. Heck yeah, that turbo makes all sorts of great noises, sounds like a 747 taking off when your in it. Try an aftermarket chip, that will increase your mpg and the power is undeniable, you wont believe the gains, the tuner of choice is a guy named jody doin under the name DP TUNER.
check this site for everything powerstroke, great tech help/info!!!! great forums.
www.thedieselstop.com
 
SHINTON said:
Final thought/question...right now I am registering about 15.1 mpg "average" but that has been all over the place since I reset it, etc. I am really trying to make myself stay under 2000 rpm and not spool up off every light, etc (aka RICH...heh) But I betting the diesel in the tank is at least 6 months old or more...had a full tank. I have burned off almost a 1/4 tank...should I try to burn most of it off so I can fill with fresh?
Click to expand...

Hang on.... so you haven't even filled it up yet? You're just counting on what the thing on the dash tells you? That's pissing in the wind. Wait until you burn through a few tanks, then tell us what kind of economy you're seeing.
 
Basing MPG on two things....one is the idiot gauge on the console, other is guessing about 1/4 tank (11ish gal) used and 150-170ish miles driven. I will keep close check on this with a mileage log.

The PSSSSSSSSSSSSSSSSH sound is when letting off gas (not brake), and WWildman called this morning to say it was the "waste gate" / bleedoff value as I suspected. Turbo DOES get loud, like you said I could almost reach it by hand if the dash wasn't in the way.

Ok...will look at the fuel stuff for the next tank...I will be driving 3-400 miles this weekend so that should burn off what is in there.

As for smoke...got ON it with wife following in the convertible...she says "it is still smoking some honey..." HEH...really?

Sam
 
SHINTON said:
The PSSSSSSSSSSSSSSSSH sound is when letting off gas (not brake), and WWildman called this morning to say it was the "waste gate" / bleedoff value as I suspected. Turbo DOES get loud, like you said I could almost reach it by hand if the dash wasn't in the way.
Click to expand...

My wastegate actuator is blown out (the diaphragm is torn), and it was louder than when I capped it off. What's happening with mine (and maybe yours too), is when the turbo spools, some of that air is going right out the diaphragm, and sounds just like turbo whistle, just louder.

Be glad it's not stuck open... what a slug that would be!
 
SHINTON said:
The PSSSSSSSSSSSSSSSSH sound is when letting off gas (not brake), and WWildman called this morning to say it was the "waste gate" / bleedoff value as I suspected. Turbo DOES get loud, like you said I could almost reach it by hand if the dash wasn't in the way.
Click to expand...


I prefer the term "Dam Gate" :D
 
Rich said:
No throttle body in a diesel. ;)
Click to expand...


thanks...never even dealt with one...

I knew both S/C's and turbos on the gassers could have them, but wasn't sure on the diesels...

do they not have blow-off valves of any kind? or is that how the wastegate also works?

Greg
 
Sorry to be the bearer of bad news, Sam, but that's the I'm gonna blow up any second sound. Your Excursion is no good.

I'll be happy to take that clunker off your hands for a small fee. :)
 
I've seen a couple of pictures of using them (blow-off valves) as a kind of "intake wastegate" to prevent overboost conditions, but it's rare.

The wastegate works just like on a normal turbo setup, bypassing the turbine to control the speed, and thereby boost.

The only reason you need a bypass (blow-off) valve on a gasser is because of that shockwave when you snap the thottle shut, right? With a diesel, the go-pedal only controls the amount of fuel injected (They don't run "stoich", "rich", or "lean"), and the more fuel, the more heat, which spins the turbo.. the intake tract is otherwise wide open.

Some turbos can "bark" when you let off fast, because the turbo slows down so fast from the driving gases going away quickly, but there isn't much that can be done about that..

The lack of a throttle body is also why boost gauges for a diesel don't have a side for vacuum. :)

Some turbos also don't have a wastegate at all (mostly commercial apps). Boost is controlled by housing size, and fueling level.

I won't even go into the compound turbos.. They're complex, but really interesting if you're a motorhead.

I love nailing the loud pedal, blowing some soot, and watching the boost gauge wrap around to 38psi.. Makes my gasser buddies freak when they see that...

OT, but some new Bimmer's don't have throttle bodies either.. the amount of air going in is regulated by the amount of valve opening.. technology is cool.. (till it breaks - BigWoody's shop is guaranted to stay in business.. :D )
 
BoltOnJohn said:
Sorry to be the bearer of bad news, Sam, but that's the I'm gonna blow up any second sound. Your Excursion is no good.

I'll be happy to take that clunker off your hands for a small fee. :)
Click to expand...


A small fee??? Heck I'll be generous and give ya a couple hundred and come and pick it up..... :D
 
That bark is the compressor surging. This happens when you go from high flow through the compressor to a sudden decrease in flow. Over the long haul, excessive compressor surging can lead to premature failure.
 
NC_Mog said:
That bark is the compressor surging. This happens when you go from high flow through the compressor to a sudden decrease in flow. Over the long haul, excessive compressor surging can lead to premature failure.
Click to expand...

Ssshhh.. don't tell my stock turbo with 231,000 miles.. :D

HX-35's are pretty tough.. HX-40 wouldn't like it much at all.
 
SHINTON said:
Basing MPG on two things....one is the idiot gauge on the console, other is guessing about 1/4 tank (11ish gal) used and 150-170ish miles driven. I will keep close check on this with a mileage log.

The PSSSSSSSSSSSSSSSSH sound is when letting off gas (not brake), and WWildman called this morning to say it was the "waste gate" / bleedoff value as I suspected. Turbo DOES get loud, like you said I could almost reach it by hand if the dash wasn't in the way.

Ok...will look at the fuel stuff for the next tank...I will be driving 3-400 miles this weekend so that should burn off what is in there.

As for smoke...got ON it with wife following in the convertible...she says "it is still smoking some honey..." HEH...really?

Sam
Click to expand...

It's the turbo spooling down you should hear mine with the ATS intake way loud.
I would change the filter pronto it's cheap and really easy. Be carefull the
O-ring is in the right place and only screw it hand tight that's all it needs.
Othersie it will spit fuel all over when you crank it:)


Good luck.
 
Rich said:
With a diesel, the go-pedal only controls the amount of fuel injected (They don't run "stoich", "rich", or "lean"), and the more fuel, the more heat, which spins the turbo.. the intake tract is otherwise wide open.
:D )
Click to expand...

Whats fun is starting a diesel with the intake removed, those watching who have no idea how a diesel works are quite amused. ( easy to do on a 6.5 TD) just be damn sure you don't have a fuel leak anywhere near the open ports.

If you have ever heard a runaway diesel, it is a sound you never want to hear again !!!

Kevin
 
like someone said, www.thedieselstop.com is the place for stroke info. Also, will confirm what someone said about the waste gate sound of 'blow off' when you release the throttle.

You actually want the turbo to whine, that's a good sign. Can't really hear it with the stock air box. Tymar intake setup is awesome. Adds 4-5 lbs boost by just getting more air in. Also you need to get the air out. Down pipe and 4-5 inch exhaust pipe really wake up the 7.3. Chip it, Tymar intake, pipe, and guages. Must have guages, even in stock trim.

Shannon
 
Well i started having trouble w/ my work 7.3 f-450 on the way to the CNC show.. Blew smoke,no power but the problems came and went. Everybody said either waste gate or fuel filter.

Well 2 new injectors and a rebuilt manual tranny later I say DONT DIAGNOSE (sp?) IF YOU ARENT A DOCTOR. Or maybe i should rephrase that. DONT LISTEN TO PEOPLE THAT ARE TRING TO HELP which are usually friends. :flipoff2:

Oh total bill: $6000 est.
 
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