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Thread: Injectors

  1. #1
    Join Date
    Jul 2001
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    Greensboro, NC USA
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    64

    Default Injectors

    I replaced all the injectors on my 6.5L Chevy two weeks ago. My electric fuel pump worked well in priming them and I didn't have any problem starting it. They still run a little rough at the stoplight though. After two weeks of driving, would they still need to be bled? Thanks.
    \'83 Chev 4x4 Suburban; 3/4 ton; <BR>6.5L non turbo; replaced the original 6.2L with new GM motor<BR>4:10 gear<BR>new 700R4 trans <BR>B&M Deep Trans Pan<BR>Autometer Trans Temp Gauge<BR>Rear Heater & A/C

  2. #2
    Join Date
    Mar 2000
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    South Central Pennsylvania, USA
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    Default

    Unless air is leaking into the system, I’d see no reason to need to bleed the injectors after the initial start-up.
    '94 GMC 6.5TD K1500 4L80E 2-Door Yukon SLE 221K
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    Diesel Page Member #2423

  3. #3
    Join Date
    Mar 2000
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    Loyal WI US
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    10,792

    Default

    As stated above no need to bleed, but there are plenty of suspect quality (cheap) injectors out there.
    Kennedy Diesel-owner
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  4. #4
    Join Date
    Jul 2001
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    Greensboro, NC USA
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    Default

    I'm still having problems with starting that I hope someone can help me with. I've replaced the mechanical fuel pump with the Kennedy electric lift pump setup, replaced the injectors (Kennedy) and the glow plugs (Kennedy Quick Heats). I have a manual switch for the GPs to give more glow time but it still is hard to start and white smoke belches out when it catches. But no more smoke afterward. It idles a little rough but revs up quite nicely. It runs pretty good around town and on the highway, but I can tell from the sound that it's not the way that it used to be.
    Is there any conclusive tests that I can perform to zero in on the problem rather than throwing parts at it. I also put a clear fuel line on the return line. No bubbles.
    Thanks for any suggestions.
    My specs are shown along with my signon bio.
    \'83 Chev 4x4 Suburban; 3/4 ton; <BR>6.5L non turbo; replaced the original 6.2L with new GM motor<BR>4:10 gear<BR>new 700R4 trans <BR>B&M Deep Trans Pan<BR>Autometer Trans Temp Gauge<BR>Rear Heater & A/C

  5. #5
    Join Date
    Jul 2001
    Location
    Greensboro, NC USA
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    64

    Default

    I must also add that it sputters and shakes a lot at first unless I rev it for a few seconds until it catches up. This happens especially after sitting for 2-3 hours.
    My fuel pressure is 3 lbs at idle.
    \'83 Chev 4x4 Suburban; 3/4 ton; <BR>6.5L non turbo; replaced the original 6.2L with new GM motor<BR>4:10 gear<BR>new 700R4 trans <BR>B&M Deep Trans Pan<BR>Autometer Trans Temp Gauge<BR>Rear Heater & A/C

  6. #6
    Join Date
    Oct 2001
    Location
    Granby, Missouri, USA
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    3,081

    Default

    Have you checked timing and the timing chain? If timing was a bit retarded, it could cause your symptoms.

    Casey
    1995 K1500 Tahoe 2 door, 6.5LTD, 4L80E, NP241, 3.42's, 285/75R16 BFG K02's; 1997 506 block; Kennedy OPS harness, gauges, Quick Heat plugs, and TD-Max chip; Dtech FSD on FSD Cooler; vacuum pump deleted, HX35 turbo, Turbo Master, 3.5" Kennedy exhaust, F code intake; dual t/stats, HO water pump, Champion radiator; Racor fuel filter

  7. #7
    Join Date
    Dec 2003
    Location
    Yukon Canada
    Posts
    1,612

    Default

    My Guess is an air leak into the fuel system.
    What filter are you using? Large rectangle on the firewall?

    My 90 6.2 started like that after i got it on the road.Turned out one of the plugs on the filter base was almost corroded through.Wouldn't leak fuel but would suck in air when it wasn't running.It was the rectangle one on the firewall.
    I ended up pressurizing the system and found the leak then.
    90 Chev 3500 c/c 4x4,6.2na,400 auto,4:10 gears.DSG Timing gears,main girdle, isspro tach, pyro,boost,oil and trany temp.Dual Tstats, High volume peninsular pump,on shelf, Custom turbo and intercooler 85%complete. Change of plans for the dually, it's going to get a Cummins. Both trucks are Blue 90 4x4 crews

  8. #8
    Join Date
    Jul 2001
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    Greensboro, NC USA
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    Default

    Casey,
    I haven't checked the timing because I don't know anyone that has the diesel timing equipment.
    Yukon. I have previously been chasing the air in the system theory as you suggested. Thanks Yukon! But to no success! I made and used "the gutted out filler cap." However, I can't get the system to hold much pressure. I will set my air compressor regulator to 10 lbs and fill the fuel tank and system with my air chuck. I would think that if you then unscrew the filler cap, you would hear the pressure escaping. But I don't! Am I doing something wrong. I didn't see (or hear) any leaks but then again I don't think it holding much pressure. I don't want to rupture anything by putting in too much pressure.
    The funny thing is, that I don't see any air bubbles in the clear fuel line. All my instincts tell me that I've got air in the system but I just can't seem to get an indication of "where".
    Any other suggestions would be appreciated.
    Thanks.
    \'83 Chev 4x4 Suburban; 3/4 ton; <BR>6.5L non turbo; replaced the original 6.2L with new GM motor<BR>4:10 gear<BR>new 700R4 trans <BR>B&M Deep Trans Pan<BR>Autometer Trans Temp Gauge<BR>Rear Heater & A/C

  9. #9
    Join Date
    Feb 2012
    Location
    Pauline, SC
    Posts
    618

    Default

    Have you tested the glow system to make sure all are working, the white smoke leads toward unburnt fuel.... that will cause the motor to stumble..
    1993 Chevy K3500

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  10. #10
    Join Date
    Apr 2001
    Location
    CA
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    13,573

    Arrow

    Also check the HPCA (Housing Pressure Cold Advance - Very important for MFI systems). Make sure it is connected, and getting power. If it isn't powered, or has failed, (relative) cold starts can be difficult, rough, and smokey.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  11. #11
    Join Date
    Jul 2001
    Location
    Greensboro, NC USA
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    Default

    I think I finally got my answer. About a week ago, after I stopped at a little market, it wouldn't start again. Turns over ok, but never catches. I'm getting fuel to the injector pump and the glow plugs are fine. I had it towed home. Last weekend, I removed the oil filler tube so that I could see the injector pump end that runs off the camshaft gear. I could see it turning. I hope that, that rules out a timing chain issue.
    Soooo, does this basically say that the injector pump has failed and it's time to remove for a rebuild? Is there anything else that I can test to be sure that it's the injector pump?
    Thanks for any suggestions and/or replies.
    \'83 Chev 4x4 Suburban; 3/4 ton; <BR>6.5L non turbo; replaced the original 6.2L with new GM motor<BR>4:10 gear<BR>new 700R4 trans <BR>B&M Deep Trans Pan<BR>Autometer Trans Temp Gauge<BR>Rear Heater & A/C

  12. #12
    Join Date
    Feb 2012
    Location
    Pauline, SC
    Posts
    618

    Default

    I didn't read every word in this thread again so I'll ask....

    When it won't start have you tried pouring cold water on the pump??

    If it starts when cold water is poured on it then it's time for another pump...
    1993 Chevy K3500

    owner - Twisted Steel Performance

    porting, ceramic & powder coating

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  13. #13
    Join Date
    Apr 2001
    Location
    Newberg Oregon
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    Default

    Another test is to dump a gallon of 30W motor oil in the tank (Mix with some diesel first)

    This will add lubricity and THICKEN the mix some.

    If the hot start issue is better then the IP is worn out and needs a rebuild.

    A good rebuild requires a head and rotor replacement.

    What happens is the plungers and their bores wear out to the point that once they heat up they leak enough that they can't build pressure.

    As mentioned COLD WATER ON THE IP can cool things enough that it will start.

    If you can spin the engine fast enough (Stick shift being towed/pushed) it would likely start.


    Give the oil a shot.

    Robyn
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
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