1st Generation Dodge Cummins 89-93 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with Rotary Injection Pumps

Boost question...

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  #1  
Old 01-14-2013, 08:44 PM
Cree's Avatar
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Default Boost question...

So I finally got the Pyrometer and the Boost gauges hooked up, and I noticed when I get into the throttle, I build boost steadily ... to a point. As the engine defuels, I see a drop in boost pressure. Since I haven't really messed with the new VE pump yet, I'm wondering if I'm just running out of fuel, which slows the flow of exhaust, which slows down the turbo, which lowers boost? I still have to turn up my fuel, and put my trusty "366" spring in, but I'm just wondering if I'm thinking this through properly. If not, and I'm leaking through a boot somewhere, it sorta changes the purchase plans in the Cummins budget this month and puts boots over tint and puts me cleaning up the intercooler pipes. I'm am running the stock H1 and for now, stock exhaust. Over the next few months, I am going to a 4 inch straight pipe, so that should spool quicker. Right now I'm still fixing what the previous owner ignored...

So, long story short, should I see a drop in boost as the stock pump runs out of fuel/RPM?

Thanks-
Chris
 
  #2  
Old 01-15-2013, 10:17 AM
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Exactly, as fuel drops of so will boost
 
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Old 01-15-2013, 01:02 PM
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AS BlackDuck said....to get boost, you have to have exhaust gas to drive the turbo, exhaust gas is made by burning fuel. Loosing boost pressure is cause by 2 things usually, 1 is running out of fuel, or a blown boot on one if your intercooler tubes.... or a seeping intake plate gasket....

---AutoMerged DoublePost---

Go to our sticky section on turning up your pump....
 

Last edited by Screamin' Metal; 01-15-2013 at 01:02 PM. Reason: Automerged Doublepost
  #4  
Old 01-15-2013, 04:52 PM
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Just so it's been said: Don't get all wrapped-up in thinking high boost equals high power.
 
  #5  
Old 01-15-2013, 08:52 PM
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No, I'm just trying to make sure I understood boost and its relation to fuel. I have too much other stuff to fix from the previous owner (like brakes and steering) before I mess with the go-pedal. It ain't got to start, but it has to stop or turn. Figure I'll get them right then move on to stomping ricers. Thanks for the help, guys.

And if anyone reading this hasn't A.) changed or checked the oil in the Getrag, do that. I overfilled yesterday with some 5W-30 and the difference is amazing. Quieter, smoother, and of course the previous owner had 80 weight... B.) Switch your headlights to relayed circuits and C.) changed out the bushings in the doors. Got all that done this week, and it was a great day off!
 
  #6  
Old 01-16-2013, 12:33 AM
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Your probably hitting the govenor where it starts to defuel. my ppump does it like normal cuz I dont have a gsk in it. It will pull like crazy till 2500 n drop on its face.
 
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