Engine/Transmission (1998.5 - 2002) Boost pressure question

[JMarkos]

I am trying to fix a egt problem and I think I have discovered I have a boost leak. I had always ran my guage out of a tee on the waste gate where the boost elbow goes, I see 35-38 lbs under load, even with the high egt problem. Today I drilled and tapped the intake horn and put the fitting there, now I am seeing 30 then it drops to 28.





What I don't know is how much drop should I see though the intercooler. I would think there should be some but not that much.



Also where have people had experiences with a leak such as this, and how would I go about finding it? I have tightened all the hose clamps and that didn't help.



Thanks in advance for your help.

 

[Whitmore]

I have mine drilled and tapped into the airhorn and I see 34 my set up is simular to yours

 

[Rob Thomas]

Your air horn has 2 gaskets, I'd check those.



BTW why do you guys insist on drillin' and tappin' the air horn? Just above the map sensor, there's a perfect spot for the boost tube, no drillin' and tappin' either. It's a 1/2" pipe plug, bush it down to put your fitting in. My boost gauge came with the bushing along with instructions on where to install it, don't they all?



Later, Rob

 

[Bigsaint]

Might want to check your exhaust manifold bolts, especially the ones at the rear that are the hardest to reach, seems they loosen first, at least on my truck.



Scott W.

 

[dsldoug]

jmarkos





in a stock truck you can easley see 5 psi loss/restriction across your intercooler if you were loosing 5 psi you would hear a whistle much more than that and you would hear a woosh if your egt is not any higher in good shape

 

[JMarkos]

Ok I just spent about 3 hours making a block off plate to go under the air horn and a plug that connects to the aluminum elbow at the turbo, pressurized to 34psi and guess what? No leaks, that is checking all hoses and clamps and intercooler so now what.

I would assume I can't go through the intake cause the valves would most likely be open, but I did check all the intake bolts and all were tight as well as the exhaust manifold bolts.







EDIT: I did check though the intake just to check intake gasket looked good too.