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Were havin' FUN now. . .

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Noiseydiesel, Oct 7, 2019.

  1. Noiseydiesel

    Noiseydiesel Full Access Member

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    Took the '94 idi Turbo dually for a ride today. After extended driving, I got down to idle speed and had a rough idle. I gave it some fuel and it smoothed out. Sounds like time for an Injection Pump. No?
    I did pick up a trailer with a 18K capacity, the trailer only weighs about 4K. Then the wife drooled all over a 5 year old Kawazaki Mule side by side. That came home on top of the trailer and a few hills were a bit much for the truck. Another possible indicator of a failing pump.

    So the next project might be replacing the pump.
    Uh, How?
     
  2. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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  3. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    Before you go about replacing the pump, try advancing the timing a little bit. As pumps wear, the timing retards. This may get you by for a while yet if your pump isn't wore out. It's also best to replace the pump and injectors as a set. They usually wear at about the same rate. You could put a new pump on it and still have a poor performing engine. Also, send Russ (Typ4) a PM. He's in Newburg OR (I think). If he's close by, he may be willing to help you out. These aren't hard to change out once you've done it, but if you're uncomfortable with it, then a little guidance won't hurt.
     
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  4. Noiseydiesel

    Noiseydiesel Full Access Member

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    I did the injectors a few weeks ago, just before it went off to Diamond Eye exhaust as a test mule. Speaking of which, the exhaust kits should soon be available. At that time I also noticed a rough idle condition and didn't have enough drive time on it to narrow it down. I have driven it around now long enough with enough drive cycles to have it pretty well narrowed down.
    As for the pump, I should take a trip tomorrow and see about picking up a core from another 7.3 idi turbo.
    As for the rebuilt pump, I will start doing price checking. Unless I increase the size of the intake, I cannot justify increasing the pump size. More fuel with the same air flow is counter productive. Beyond that is the limitation of the 4.10 rear axle gear ratio of a dually. It will only spin up so far. So spending $900 on an injection pump is a bit overkill. Kind of reminds me of some people thinking that going from a 650 CFM carb to a 750 CFM carb would make their gas engine go faster without reworking the engine to accept more fuel flow.
     
  5. chillman88

    chillman88 Supporting Member Supporting Member

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    Not necessarily... Really depends on your EGTs. Not that I would jump way up to a big pump but you should see decent gains going to a slightly larger pump. Personally I think I will be looking at a 90cc pump after I get my turbo on.

    I think Wes said the stock pump maxed out is only something like 75cc? Especially with your bigger, better flowing exhaust you're able to flow more so you should still be able to keep EGTs in check.

    You technically DID increase the air flow. By increasing the exhaust size that previously WAS a restriction you have allowed the turbo to spool faster IF it's given a little more fuel.

    Not telling you what to do, just trying to make sure you make an informed decision.

    Just make sure you read the hall of shame and avoid all but the good vendors. If you don't know who does reliable pumps just ask, stay away from Advance, Auto Zone, O'Reillys etc...
     
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  6. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    Your gear ratio won't affect top engine RPMs. That's limited by the governor.
     
  7. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    I can clean up 150+cc with the same turbo as your truck has, if you are used to gas terms, these engines run very lean with the factory fuel settings. There’s quite a bit of room to increase fuel delivery and still maintain a stoichiometric fuel ratio since with a turbo diesel, more combustion equals more airflow until the turbo’s compressor runs out of airflow.
     
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  8. Oledirtypearl86

    Oledirtypearl86 Full Access Member

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    More fuel =more boost
     
  9. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

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    One other thing to check out before condemning the pump is the fuel supply to the pump. I have had rough idle and poor performance result from a failing lift pump. Even if it turns out to be the injection pump you wouldn’t want to install a fresh injection pump without verifying fuel volume and pressure.
     
  10. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

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    One more thing to check.....if your last dynamic timing setting was done with your old injectors and you installed fresh injectors it is very likely your timing moved a significant amount.
     
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  11. bbjordan

    bbjordan Snow Monkey

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    Not to sound like an ass, but have you replaced the fuel filter lately?

    As was said before, check/advance the timing.
     
  12. Noiseydiesel

    Noiseydiesel Full Access Member

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    Lift pump is about. . . 4 months old,
    fuel filter is under 1,000 miles on it,
    Injectors were done about a month ago,
    Air filter about 4 months ago,
    Problem only exists when engine has been driven 30 minutes plus.
    Advancing timing is a good band aid.
    I currently do not have an EGT gauge set up and Diamond Eye kinda forgot to weld in a bung for the probe when they did my exhaust.
    I do have a pillar gauge set I was looking to install, so far with water temp, oil pressure and trans temp. Those gauges are already waiting for an install. The 4th hole will find a pyrometer in it.
    All of that is a "round tuit" project.
    I get to do the pump, now it seems, the question will be price and quality.
    I considered a larger pump but the local Ar-a-gun state legislation is already considering outlawing older diesels and driving down the road belching out black smoke just adds fuel to the fire.
    I found I can do that without much problem just by letting that dually drop into overdrive at 30 MPH and backing off the throttle slightly.
    Great for passing bicycles on the back county roads.
    Unincorporated county roads in the state of Ar-a-gun, where the speed limit is 55 MPH unless otherwise posted.
    Truck weighs how much and goes how fast?
    Bicycle is what? Speed is how much?
    6/1 ratio? 10/1?
    Add riding away from the edge, a curvy road, blind corners, riding side by side. . .
    I did find a you tube video on replacing that pump.
    Pulling it is easy enough, Tightening fuel lines at the proper angle before installation could be fun.
     
  13. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

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    Even though lift pump is new verify pressure and flow.

    On putting the lines on the pump I have never had an issue. Don’t remove the clamps that keep them in groups of 4. Snug down the lines gently to the pump while helping them find their happy spot. Works for me many times.
     

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