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

Low Power, Fuel Mileage Drop - Help Please

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  #31  
Old 10-16-2011, 03:00 AM
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Default Well, That Really Narrows It Down, Then!

Originally Posted by jwirth
That guessing you call it is from the Chrysler service manual smartass.
Yeah, I'm guessing maybe somebody swapped the injector lines around while it was parked at the Dairy Queen. Yeah, that sounds like a good possibility.

Reading (or cutting and pasting from) a service manual and troubleshooting an engine problem are two possibly related, but quite different things.
 

Last edited by NadirPoint; 10-16-2011 at 03:40 AM.
  #32  
Old 10-16-2011, 07:30 AM
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Default Low Power, Fuel Mileage Drop - Help Please

Never tried turned it into a pissing match. Purpose of the site is to help and educate and discredit if needed .Feel privileged.... I'm paying my student loans and you're getting it for free, and don't even start the "bc I didnt go to college it must mean I don't know anything" rant. I know what I know bc I cared to listen and put my opinions aside when they were wrong... Btw he said he had 15psi fuel pressure awhile ago so arguing was pointless, was meerely trying to educate. But Black smoke high fuel pressure VS black smoke low fuel pressure, that's your statment in simple terms. If that's the case... Why pressure feed the injector pump at all... Must be the millions of dollars of diesel R&D was all wasted on nothing, bc you're pretty much saying a diesel doesn't operate the way the law of diesel physics states it should. Guess common rail technology is a bust too.


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---AutoMerged DoublePost---

Originally Posted by jwirth
you 2 can have a pissing contest all you want. my lift pump went out and blow BLACK smoke low rpm's. white smoke at HIGH 3000 rpm's. and lost power. And retarded time well cause black smoke, high egt's, and high boost. Don't believe me retard your pump 1/4 or more and see what happens. It will even smoke at idle. retarded that far. And pop pressure is around 3550
EXACTLY! Lift pump went out... black smoke low rpms, white smoke high rpms. At high rpms your truck was using more fuel than the lift pump could supply... Sounds like low fuel pressure to me... Which you stated creating what color emissions again? White? Hmmm Btw educate me on what color smoke it is that's emitting for your pipe with 1/4" pump retard? At that level of retardation (no pun intended) Its smoking at idle bc it's unburnt fuel, injecting after peak cylinder temp ontop of decreasing burn time. That'd be RAW fuel with a white haze. Most of these old girls haze at idle even at stock timing levels . Just the nature of the VE. Oh and Watson... You've contradicted yourself and even proved yourself wrong with the random bits and pieces of logic intertwined with the
 

Last edited by tower_ofpower; 10-16-2011 at 07:30 AM. Reason: Automerged Doublepost
  #33  
Old 10-16-2011, 05:25 PM
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If anything low fuel pressure would cause retarded time with white smoke. Also if the tip was blown off an injector wouldn't that more likely cause white smoke since there is no way it could burn all the fuel being dumped into the cylinder

---AutoMerged DoublePost---

Ok you have black smoke at all rpms right. Does it haze at idle if not then i would say most likely not fuel related. Im not ruling out the injector tip being blown off like tower of power said but typically an extreme excess or restriction of fuel will have whit smoke. Every time I have seen an injector tip blown off it pours white to a grayish smoke...but then again I have not seen everything.
 

Last edited by cumminskid92; 10-16-2011 at 05:25 PM. Reason: Automerged Doublepost
  #34  
Old 10-16-2011, 05:40 PM
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Smile Update on Issue

Just an update to what I have done so far...

Had replaced air filter and fuel filters, looked for boost but have not taken a boost reading...How much boost should I have for 1992 Dodge?

Fuel Pressure to Injector pump right at 15psi, can bring up to 20 psi if recommended...??

Removed Injectors - No Blown Tip, a little carbon on the tips of each one...Can I use a steel wool or something to clean the ends off without plugging the holes?

Have to get a compression gauge to check cylinder compression so won't have until tomorrow, couldn't find any part stores that loaned a compression gauge that went high enough for Diesel Engines. Hopefully no bad valves or pistons since I drove it so long this way....didn't have much choice at the time...

If I don't find anything after all that I may have to ask for more help....some of the troubleshooting was beyond my limited mechanical inclination at the moment.

Thanks to everyone helping so far...
 
  #35  
Old 10-16-2011, 05:56 PM
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i know my truck stock only had at best 12-14 psi of boost, also you don't want the fuel pressure past where it is you could damage the injection pump
 
  #36  
Old 10-16-2011, 06:48 PM
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Originally Posted by regor
i know my truck stock only had at best 12-14 psi of boost, also you don't want the fuel pressure past where it is you could damage the injection pump
X2
 
  #37  
Old 10-16-2011, 07:30 PM
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Default Low Power, Fuel Mileage Drop - Help Please

You're right, was only taking the excessive black smoke into consideration at road speed, not idle. It does make sense for it to pour white smoke at idle with a blown tip. Ontop of a dead-ish cylinder. Should notice an off engine noise at the same time. All of which; hasn't been the complaint. If the injectors are out it could be worth your time to have the pop pressures tested and spray pattern observed.


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  #38  
Old 10-17-2011, 06:21 AM
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I would definitely have the injectors checked. Don't use steel wool. Use a brass brush and solvent. Steel wool could possibly mess up spray pattern
 
  #39  
Old 10-17-2011, 06:06 PM
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Sounds retarded. as in timing retarded. Check your regulator valve o rings in the pump. if they are blown. you will have no case pressure since regulator lets all vane pump fuel go out return = no pressure to barrel or timing piston and no advance= no power , more smoke, more EGT.

Look for any fuel on the pump, but it can also leak internally.
 

Last edited by 6btDakota; 10-17-2011 at 06:09 PM.
  #40  
Old 10-17-2011, 09:20 PM
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Default Fuel Pump Regulator

Originally Posted by 6btDakota
Sounds retarded. as in timing retarded. Check your regulator valve o rings in the pump. if they are blown. you will have no case pressure since regulator lets all vane pump fuel go out return = no pressure to barrel or timing piston and no advance= no power , more smoke, more EGT.

Look for any fuel on the pump, but it can also leak internally.
I hate to ask but is there someplace that shows how to check or test for the regulater valve o-ring? How do I know they are blown or not?
 
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