Lost some boost

[Desert Wrench]

I have lost boost pressure and I can't find the culprit. Stock I had 18psi. I added Superchip 1705, and could get 23-24psi. I installed a Wicked Wheel and a 6637 AF, took a spin and only could get 15psi. I have removed, inspected, and pressure checked all boots, hoses, intercooler, autometer gauge and tubing, wastegate actuator etc. I put the stock wheel back in and still can't get over 15psi. I have the IAH delete, HPX, and the tank to pump hose mod. The truck runs well and have seen no unusual smoke. Fresh fuel filter and 2000 miles on oil. I have just about narrowed it down to the turbo. I disconnected the pressure line to the actuator and wired the wastegate closed. Still no difference. Does anybody have an idea?

'99.5 F250 SC, auto,54K, Autometer triple pod.

 

[95_stroker]

This all came about when you did the WW and filter install?

 

[Desert Wrench]

I didn't notice until I did the WW. I normally don't see how far it will go unless I have made a change to something. So, I can't say this is when it happened, it is when I first noticed it. The last time I can remember checking the max boost was about 3 mos ago. I haven't noticed any irregularities in performance. On a recent roundtrip to Rockwall, TX (800 miles), I got 20mpg going 70mph (2100 RPM), up from 18 I got stock. I never really had to get on the pedal hard, but when passing or going up hill I would see 5-8 psi of boost and normal exhaust temps.

 

[95_stroker]

With the WW and new filter can you hear your turbo spooling better? On your trip to Rockwall, was that before or after the WW install?

 

[whatabudro]

Not meant as an insult, just want to rule out the obvious:

Still running the 1705? Turn it back stock, then reinstall. You may find that you turned it back stock some months back and forgot to put the program back on. Your boost numbers are made with a stock truck.

You may have also not gotten your intercooler boots back on all the way. I would bet that the lower y-pipe boots are leaking making you lose boost. They usually have the most oil (NO CCV) and are only clamped with worm gear clamps. You can find all your leaks easily with a setup like this:

Regulate your air compressor down to 20 psi, open the valve slowly, and do not leave it on more than a few seconds because the engine is not running and there is no fresh oil making it to the turbo bearings.

 

[Desert Wrench]

The trip was with the stock wheel back in it. When the WW was installed, I didn't really hear the wheel unless I really got into it. When I pressure checked my intercooler, I disconnected the pipes from the compressor discharge and the y-pipe inlet, put a 3" plug in one boot and a 3" plug with a fitting w/gauge on the other boot. I slowly pressured it up to 25 psi and shut the supply valve. I watched it for several minutes and saw no bleed off. About the superchip. I usually run on the middle. This weekend I set it back to stock and test drove. Nothing over 15. I then reset it to the high-perf setting, same results. It is back in the middle(performance tow) setting. When I put the stock wheel back on, I checked the turbo shaft for looseness and shaft end play. I didn't use indicators, but I could feel clearance, but not see if move. No indications of rubs or seal leaks. The best that I can tell, there isn't any vibration either.
Is there any chance that there is something wrong with the waste gate internally? What about the EBPV? I checked to see if is was stuck, and I can move it.

 

[whatabudro]

I was saying you should presure check your entire system with all intercooler tubes and boots and turbo in place. The WW does make more whistle, but only under a heavy foot like you said, thats not its intention. It's clear the WW and filter are not the problem since its happening now with both compressor wheels. The problem started when you put them on yes, but here is what I'm saying. What else did you do to the truck right then? Well you had to remove the intercooler pipes and y-pipe to be able to put on the wheel. If you did not get everything lined up when you did it, then there's your problem. The way you pressure checked you only verified the IC does not have a leak. The only way to verify there are no leaks is to install a setup like I posted earlier into the intake system. Once you find your leak your problem will be fixed.

 

[Desert Wrench]

Okay, I will try it the way you described. I will post my results after another painful trip under the hood. Thanks for all input.

 

[MUDWHISTLE]

I wouldn't rule out the waste gate. just a thought.

 

[whatabudro]

I wouldn't rule out the waste gate. just a thought.

I would think that would be easy to rule out. It's no more than a flapper on tied to the actuator. You could just pop the hood and tell.