99 loss of boost and white smoke

[PowerSToKed]

99 F450 Wrecker while driving WOT at times boost drops from 8 psi to 2 psi and starts blowing white smoke, the truck is straight drive and the concern is present coming through the gears if winding out that gear and goes away when shifting to the next gear until your at wot. I took a couple recordings during the concern - concern is only present around 2500 rpm, ICP holds steady around 2400 to 2600 psi, ipr is 33%, just driving the truck and not monitoring pids it feels like fuel pressure or an fuel inlet restriction - but with these issues your boost is always still present, the air filter is clean, the map sensor and hose are ok (i robbed them off my personal truck that has no problems and concern is still present), p1247 was stored in memory, the wot boost (9psi max) seems to be low when the concern is not present... I'm not sure on this one any help will be greatly appreciated

[Bruce Amacker]

99 F450 Wrecker while driving WOT at times boost drops from 8 psi to 2 psi and starts blowing white smoke, the truck is straight drive and the concern is present coming through the gears if winding out that gear and goes away when shifting to the next gear until your at wot. I took a couple recordings during the concern - concern is only present around 2500 rpm, ICP holds steady around 2400 to 2600 psi, ipr is 33%, just driving the truck and not monitoring pids it feels like fuel pressure or an fuel inlet restriction - but with these issues your boost is always still present,

 

Sorry, sir, you are incorrect. If your FP goes away so does your boost, immediately.

 

 

the air filter is clean, the map sensor and hose are ok (i robbed them off my personal truck that has no problems and concern is still present), p1247 was stored in memory, the wot boost (9psi max) seems to be low when the concern is not present... I'm not sure on this one any help will be greatly appreciated

8PSI is waaaay low for that engine, this sounds like a textbook case of fuel starvation, check it at both heads if the first one shows OK. The screens in the tank or a bad pump are on the top of the hit list.

 

Good Luck!

 

[Fredsvt]

As Bruce said, start at the supply end. Is the filter housing all corroded and stained inside?

 

Does it act like a gas engine with bad secondary ignition, along with a lot of blue/white smoke if you rev it in neutral as it goes through the 2000~2800 rpm range?

Is it much worse when cold?

 

I've had several that have had tank/pump/filter issues that damage the injectors and they run like I described. They actually start cold fairly easy, but have no power, build little boost, and smoke quite badly until hot.

[Matt Saunoras]

that last fuel starved 7.3 i had ran fine with no load on the engine. i putted around town with no problem at all. went to run up a long hill and it fell on it's face within a 1/4 mile, eventually stalling altogether. i agree with no fuel = no boost.

[Jim Warman]

Like Bruce says.... 8 PSI is way low. A decent 7.3 will make at least 15 PSI - 17 PSI is real nice.

 

If you can't make 15 you have a problem... and this is why you get the big bucks....

 

Go to section 4 in your PC/ED and refer to "performance diagnostics". Start at the beginning.... do NOT assume anything.

[Bruce Amacker]

The 99.5 Diag sheet says 15psi minimum, a buddy of mine has a stock 2000 7.3 with a boost gauge on the dash and makes 25+ at WOT.

 

[Jim Warman]

Yes to the 15 PSI... 17ish PSI is what I used to see the most of on decent trucks... 19ish PSI the odd time.... 25+PSI with a stock turbo and no power adders? This is something I would like to see for myself....

[Fredsvt]

Make sure the wastegate solenoid is not allowing boost to get to the actuator prematurely. I've had a couple that have gone bad and they run like pigs as they can't build proper boost with the wastgate open.