Turbo Boost Abnormally High?

[Blue05]

Noticed today while driving down the highway at about 80mph, my turbo boost was about 20psi, its normally around 8-10psi what could cause this? It wasnt really windy, but was really cold out (-30C).

[stroken04]

your turbo veins could be stuck

EDIT: are you talking about the truck in your sig or a 6.4

[Blue05]

whoops i posted in the wrong forum, can someone move this to this 6.0 problems forum for me.

[Blue05]

guess not then

[Jake]

I've got a 7.3, but my boost is higher when its cold. A number of factors play in that. Its cold, so the fluids are more viscous. The colder air will have more wind resistance. And id imagine that since the air is colder goin in, there will be more air goin out, therefore more air is going over the turbine wheel, which equals more boost.

[theonlypheonix]

Blue05 - I think I had a similar issue as you described, did you find any resolve to it?

I would question whether the cold would be related to the vanes sticking as the vanes are on the turbine side and normally operate around 800 F. Doesn't seem that the outside temp would have any bearing on the vanes sticking.

[stroken04]

Originally Posted by theonlypheonix

Blue05 - I think I had a similar issue as you described, did you find any resolve to it?

I would question whether the cold would be related to the vanes sticking as the vanes are on the turbine side and normally operate around 800 F. Doesn't seem that the outside temp would have any bearing on the vanes sticking.

How much are you boosting?

[theonlypheonix]

It was a wierd situation, boosting upwards of 30 PSI but was very unstable and it did not seem to produce any power?

The vehicle is a '05 F350 6.0L PS SB DRW stock with the exception of a Corsa 4" Cat back exhaust and a Banks tecnicooler high flow intercooler and I live near Rockford, Il. It was a little cold (-32 F real temp) when the problem first was observed this winter. This particular day the block heater had been plugged in all night so the engine would be warm for an early morning start. The engine started normal and I let it warm up for around 5 mins, drove around town for around another 20 mins. Then when I was getting onto the tollway I noted that the temp gauges were both about in their normal range. Everything appeared normal while driving for the first 15 mins at about 70 MPH, outside temp was around -8 F. If I was to be a little picky I would have said the truck seemed a little sluggish. I noticed that the boost was running about 0 - 2 PSI. This seemed a little low but I dismissed it due to the cold air temps(the air was denser because of the cold temps and therefore less boost was needed). Normal boost at speed is around 4 to 8 PSI depending on road grade and load.This is where it gets a little wierd. If I increased the RPM only 50 to 100 RPM the boost would shoot up to 25 to 30 PSI with little or no increase in acceleration or speed and would be unstable. But I had no load on the truck, there was little or no wind and yet boost was around 25 PSI even up to 30 PSI at times. Modulating the throttle the truck seemed sluggish, not its norm. It was as though somehow the truck was working against itself . If I changed the engine speed the boost would suddenly rise significantly and fall with only 50 to 100 RPM change in engine speed. The boost was nolonger proportional to the throttle as it normally would be, just very unstable. If I slowed down to 55 MPH the boost and throttle were more the norm where boost appeared proportional to throttle.

As I got closer to the Chicago area the temp warmed up to 0 F. As I got off the highway and drove through town the boost and throttle started to respond more as normal where the boost was proportional to the throttle and the truck was responsive to throttle. Later that night I left to return home near Rockford. Once again the temp had fallen to around -8 F and the same problem showed up again, lack of throttle response, unstable and much higher then normal boost pressures at speeds of 65 MPH and higher.

Initially I though it might be sticking vanes in the turbo but I did not see how it would be related to the cold temps. After all the vanes are on the turbine side and should be around 800 F. Then I was thinking that it might be related to a sticking EGR valve as these have also been known to be problematic but again because of the engine temps in this area I could not see how it could be related to outside temps. My last thoughts were that maybe the intake air would be over cooled because of the aftermarket intercooler and the high flow exhaust and the OEM controls and programming could not control everthing properly in the extreme temps. Once again after surfing this board it appears that a couple of other members have had similar issues on their stock truck even to the point that there appears to be something magical about an ouside temp above or below 0 F. So now I'm at a loss, any thoughts would be appreciated.

[AaronATX]

sorry i don't know what's happening.. but i'm fairly sure turbo boost is proportional to load, not rpm

[npccpartsman]

Take your EGR valve out and clean (with CARB cleaner not brake cleaner) it or replace it. The O-ring kit is about $8 I think. If this doesn't help or solve your problem it sounds like sticking turbo veins to me.

Blue05 On Edit: I reread your signature and see that you have an EGR delete of some kind so I'm thinking turbo veins if your boost is being weird.