1997 7.3 Does not seem to be making boost

[DudeManScott]

My 7.3 does not seem to be making boost, however....

When I remove the intake I can see the turbo wheel spinning, It is also solid and has no play to it so that seems fine (looks like it may have been rebuilt)

When I remove the Y pipe going into the motor it does seem like it is pushing air into where the intake would be.

There is no damage to the Y pipe or red hoses but when I hook up a boost gauge I get nothing. I had the boost gauge hooked up while driving around and it did no budge.

In the images you can see the test gauge is hooked up to where a boost gauge would go, but when I was actually testing for boost while driving it around I removed the hose with the T and directly connected the gauge to the motor.

http://imgur.com/a/V8rkv

 

[Chris2590]

Do you know how to make a boost leak tester? Is it down on power and feel like it's not making any boost?


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[Chris2590]

One of these can be your best friend lol. And they're easy and cheap to make.


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[DudeManScott]

I honestly do not know if it is low on power as I just got this truck a few days ago and this is my first diesel, but I will have to try making a boost leak tester.

Do you hook that to the intake side of the turbo and leave the output of the turbo going to the motor?

How do you test for leaks? soapy water or just feeling?

 

[DudeManScott]

I am just lost as to where these turbos could even leak.

I ran it with no intake on so nothing there and then the turbo is just outputting into the Y pipe and straight into the motor so where could the issue be?

 

[Magnum PD]

Still have the o ring on the Y pipe?

Exhuast leak from up pipes?

 

[bens]

Up pipes could be leaking, and you have to be under a load to build boost

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[Chris2590]

Honestly anywhere. There is a compressor housing o ring that goes in between the compressor housing and the Y pipe that are known to leak. The boots on the y pipes leading to the plenum, the turbo itself, the map sensor line, map sensor.. that's just the intake side. You could also have an exhaust leak anywhere robbing boost pressure and power. The only way I know how to check for that is to look for soot marks though.
As for making a leak tester I just drill ahold in a pvc cap and put some red rtv around a valve stem and pop it in. Then it goes into that black intake boot and put a good quality hose clamp on it. If you have an air compressor with a regulator use that. You don't want to put too much air pressure into it. And made sure if your ccv valve isn't hooked up. Then just like you said spray soapy water all over and listen closely. Sometimes it takes a lot of patience. Hope this helps. It looks like you do have that gauge hooked up right but were you really putting your foot down while driving? To see any boost especially if the truck is a manual you'd really have to hammer down. Keep in mind you have to be driving under load. At idle you won't see any boost.


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[LowFlying7Three]

Check the hose going from the intake plenum to the boost psi sensor. Mine dry rotted and split a few years ago.

 

[Chris2590]

That's what I like about this page. If someone has a problem or is new and just wants to learn everyone chimes right in with ideas and helps. There is little to no bashing.


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[DudeManScott]

by boost psi sensor are you referring to the MAP sensor?

 

[DudeManScott]

Yeah I appreciate the no hate haha. I have a lot of experience with cars but never diesels, and not a bunch with turbo issues. Just want to get this thing running solid.

http://imgur.com/a/hLhTt

 

[LowFlying7Three]

Yeah, that's the one, mounted up near the hood line on the right side (passenger side) of the firewall.:thumbsup:

I try to help when I can. Been doing this stuff for years, it's what pays the bills

 

[Chris2590]

Man that looks good. I wish mine was a crew cab -.-
Is it a short bed? I can't tell from the picture.


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[DudeManScott]

Man that looks good. I wish mine was a crew cab -.-
Is it a short bed? I can't tell from the picture.


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Yeup short bed 4x4. Pretty tough to find from my experience

 

[Chris2590]

Nice. Yeah I've only seen a few obs ccsbs where I live.


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[DudeManScott]

any suggestions for stores to look at to find a valve stem? Just checked home depot with no luck

 

[DudeManScott]

How much PSI should you pump into the system when testing for leaks?

 

[Chris2590]

I think I got a pack of two for cheap at ace hardware. Probably just 10-15 psi to start with and then listen for air hissing out or bubbles. I would think a shrader valve would work too.


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[DudeManScott]

Could an exhaust manifold leak cause no boost? I looked at one of the manifolds this morning and it looks like one of the end bolts had its head broken off

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