Hello y'all very helpful people.
As some of you know, my PSD died from a heart attack in March.
I finally got it resurrected, with a completely overhauled engine, new pumps, etc. It was quite a challenge since I had no experience whatsoever doing this kind of jobs.
The truck is running, it pulls the boat but it has low power. The boost is really low, sometimes just 3 or 4 psi on acceleration, just once going up a hill, with a 5000 lb trailer, after I downshifted to 4th, I got 9psi, I used to have much higher. Mileage is aweful. It shows no trouble codes. This is an early 99 model.
I can't find any leaks on the pipes to the intercooler or from it. I put the bigger donuts on the uppipes and see no leaks there. The turbo has no play and seems to spin freely. The wastegate is all the way to the driver's side, which I think is closed. I even turned in the turnbuckle to make it more difficult to open it to the pressure line. No trouble codes reported. What else could it be?
Also, a couple or unrelated questions. I have Diesel 15W40 oil, is that the one I should use in the break in period? When should I do the first oil change?
Thank you,
Alejandro

 

How do the fans on the turbo look?

 

Hello edub, thanks for your fast reply.
They look OK on the intake side, I can't see the exhaust ones.

 

did you use any parts off the old engine to make the new one run? Perhaps the ecm is wrong for the engine you now have and that would make a difference - but I dont know how much difference.
Are you getting full fuel pressure? Is the HPOP full of oil? Are filters ok? Is there a kink/hole in the boost guage line? Is the aftercooler ok? When you look into the intake side of the turbo at idle, is the turbo spinning? Does it infact spool up when the accelerator is depressed?
So many questions and so little time. Hope this helps you out.

 

Check you line going to your map sensor. see if its attached. Maybe your MAP isnt seeing any boost. Just an idea??

 

Hello, thank you for all your suggestions.
I checked the turbo, the inake fan baldes look OK, the turbo spins easy. When I start the engine, it starts spinning right away. When I stop the engine, it spins fine for a few seconds. So I don't think I have a problem in the turbo.
I have a westach gauge that I t'ed into the hose to the MAP sensor. I disconnected the hose coming from the intake and blew into it, I found I have a 2 psi lung capacity, (pretty weak, I think I need to get in better shape, go up to 5 miles runs, 3 is not doing it). I put the compressor with the compressor gauge indicating 20 psi, the gauge indicated 20 psi. So it works fine.
I read 0 to 1 psi while driving it normally. If I try to accelerate hard, I can get it to almost 7 psi. If I am pulling something heavy, I can get it to 10 for a few seconds. I have teh diablo connected in diagnostics mode, at idle it reads about 100 kpa, which is normal 0 boost, under acceleration it reads about 130 kpa, and I was able to get it to almost 160 kpa once. Seems like the MAP sensor works too, reads something similar to what my boost gauge does.
I bought a plunger, put a hole in the middle and put the compressor at 20 psi into the intake, I could not hear any major leaks, I didn't have the plunger well sealed, but the boost gauge moved. All the blue connections of the intercooler pipes seem to be OK.
I put the plunger in my exhaust, compressor at 60 psi, I could not find any leaks in the up-pipes or anywhere around (I assembled all these with the engine in the stand, so I had a good chance to put them right, and I put the chevy style xl donuts).
Any other ideas of what to check? I am getting very frustrated. I haven't had my truck running well since February, I rebuilt all the engine, spent a lot of money at the dealer and they didn't find anything, etc.
Anybody knows how to get Diablo Predator to show the backpressure sensor reading? I think if I could get this reading it would help me a lot.
One thing that came to my mind while typing this is that my egt's are getting to almost 800 on acceleration, and run around 500 while pulling. Is this high?
I am going to check the BPV in case it is stuck closed, but any other hint would be very welcome.
Sincerely,
Al

 

no actually your egts are pretty low. i think you have a fuel problem. fuel= more power, egt's and boost. seems like you are barely getting any. not to familiar with the new 7.3's but if you have a schraeder valve on it take a fuel psi reading at idle.

 

Make sure your EPV is connected so that it opens up when your engine warms up. It it isn't connected and stays close you will get low boost.

 

Hello, thank you for your replies.
I have not checked the fuel pressure. Where can I fit a fuel pressure gauge?
I should add, in case it matters, I'm getting horrible mileage according to the computer, about 9 mpg, half of what I used to get.
Thanks again,
Al

 

Hello, well, I connected a pressure gauge, as soon as the pump starts, it pumps up to about 53psi. once the truck starts, it gets up to around 58. it sometimes got to 60. Once, under acceleration it got down to 48, otherwise it never came below 50. But, I didn't try it pulling or over 40 mph. Are these readings normal? if they are low, should I check the pressure regulator first? and then the pump? I just put a new fuel filter, even though the old one had less than 300 miles, just in case, it made no difference. I still have low boost. This morning, pulling 5000 lbs, I floored it in OD, and I got the boost to 10 psi finally and the egt to almost 1000, I think this is way too low. I have the wastegate disconnected. If it is not the fuel pressure, what else could it be? Does the wastegate ever fail to close all the way? The turbo spins freely. I am clueless about what it could be. Any help would be inmensly appreciated.

 

The fuel pressure should stay the same at all times. It is not controlled by the ECM at all. The pumps are more than able to keep up with demand and maintain pressure when they are in good shape with a good air free fuel supply.

 

Hello, thank you for your fast reply. You think I can have a pressure regulator problem? I have a new filter, so that's not restricting. What should normal pressure be?
Thank you,
Al

 

Wastegate all the way to the pass side is wide open dump...not good. Troy

 

Hello, thank you for your reply. The wastegate lever is all the way to the driver's side. so it should be closed. Could it happen that the lever is all the way to the passenger side and it is still partially opened? Or mechanically that is impossible?
What should the fuel pressure be?
Thanks again,
Al

 

You're earlier post says it all. You need to maintain that 60 psi fuel pressure AT ALL TIMES or you are going to lose serious HP.