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Thread: Is this injectors?

  1. #1
    Join Date
    Feb 2004
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    Columbia, SC
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    Default Is this injectors?

    Need some diagnosis help. Think I have some dirty and/or failing injectors but want to make sure before I drop the $.

    I had a fuel contamination issue I discussed previously with the "coating" inside my tank breaking down. Here's what I did. Replaced tank with good clean used tank - new sending unit with new strainer, flushed and blew out the lines from front to back - pickup and return lines, replaced complete filter housing assembly, and replaced the lift pump since it was weak under load according to the fuel pressure gauge.

    Here are my symptoms:

    Hard start when cold - this has been going on for a month or so. Turns over strong and it is trying to start but takes a while. Seems to be dumping fuel in because it really belches gray/black smoke when it finally starts. When it's warm - starting is better but not like it has been. Also have to "clear it out" by hitting the throttle as it wants to spit and sputter some after start up.

    Has been driving ok around town - throttle response has not been the crispest, but ok.

    Took a 4 hr one-way trip to NC this weekend. On Friday - noticed some slight surging and bucking trying to hold steady throttle going down the interstate. Coming home last night - the surging and bucking was much worse. Also noticed the boost gauge going up and down as the engine surged. Does ok under load, but it does not like light steady throttle.

    My thought is that I have an injector or mutliple injectors that got trash from the contamination in the tank. I'm thinking they are squirting rather than spraying causing the hard start and the surging. The injectors are 2-3 years old and probably have 30-40K miles on them so they "shouldn't" be worn out. They were new Bosch units from Heath.

    2 questions:

    Does this sound like an injector issue?

    Can they be taken apart and cleaned?

    Thanks as always for your input!
    96 K2500 Suburban /300+K miles /Relocated PMD /Turbo-Master /4" Exhaust (LOVE IT!) /Amsoil in Engine and trans with Amsoil remote bypass filter / Max-E-Tork ECU / Kennedy Fan upgrade / Bilsteins

  2. #2
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    Default

    Sounds a lot like you could have air in the system.

    Connect a small clear plastic tube to the fuel return line on the injector pump.

    Run the rig and see if you are getting bubbles traveling through.

    If need be, loop the clear tube up past a wiper and then back under the hood.

    Air bubbles will really mess things up.

    Can cause hard starting, stumbling, soft throttle and all that you have described.

    How many miles on the rig.

    Yesss the injectors can be repaired, but this is a task best left to the specialty shops that do injectors and pumps

    Hard starting can be due to bad glow plugs too

    when was the fuel filter last changed ???

    You have symptoms that can be related to several items.

    Any codes popping up ???


    When was the PMD last changed out ???


    Keep us in the loop


    Missy
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  3. #3
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    Feb 2004
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    Default

    Robyn - Whole fuel filter housing and filter just changed last week when I did the whole system clean out thing.

    Glow plugs are less than a year old - quick heats from Kennedy. Put 4 AC Delcos in on the driver side last week just to see if they changed anything. It didn't. Checked the glows using the old batter cables and they glowed pretty quick.

    Miles just hit 300K

    Check engine light has never come on but have not pulled codes yet.

    PMD change out has been a while - have a Heath remote mounted unit. I do have another one I can swap out that came on my last IP. Should I swap that out to eliminate it as a possibility?

    Thanks
    96 K2500 Suburban /300+K miles /Relocated PMD /Turbo-Master /4" Exhaust (LOVE IT!) /Amsoil in Engine and trans with Amsoil remote bypass filter / Max-E-Tork ECU / Kennedy Fan upgrade / Bilsteins

  4. #4
    Join Date
    Feb 2004
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    Columbia, SC
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    Default Update

    Pulled codes - have a misc unrelated trans code but also have a new one:

    P0004 Fuel Volume Regulator Control Circuit High

    Anybody help with this one?

    Also - I did connect some clear tubing on the return line. I've got bubbles. Are there supposed to be no bubbles at all? Didn't show many going steady down the interstate but there were a few. Shows more with start and stop driving.

    It is running like total crap now.

    Help. Have a trip coming up soon and really need the big rig running.
    96 K2500 Suburban /300+K miles /Relocated PMD /Turbo-Master /4" Exhaust (LOVE IT!) /Amsoil in Engine and trans with Amsoil remote bypass filter / Max-E-Tork ECU / Kennedy Fan upgrade / Bilsteins

  5. #5
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    Default

    Any air in the system is a bad thing.
    '94 GMC 6.5TD K1500 4L80E 2-Door Yukon SLE 221K
    '93 Chevrolet 6.5TD K2500HD NV4500 Std. Cab Longbed 187K
    '85 Toyota 22R RN60 4x4 Std. Cab Shortbed 178K (Currently retired for rebuild)
    Diesel Page Member #2423

  6. #6
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    Air is getting in somewhere prior to the lift pump on the frame.

    Sort that out and repair as needed.

    There should be ZERO Bubbles streaming through.

    Likely a tank pickup tube connection or a hose between the tank and the lift pump.

    Keep us posted

    Missy
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  7. #7
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    Default

    OK - thanks. I'll check that out. I did just replace the sending unit so maybe it's something with those connections. Weird part is that it was doing this before I changed the sending unit. Do you typlically use teflon tape on those connections and the lift pump connections?

    Thanks
    96 K2500 Suburban /300+K miles /Relocated PMD /Turbo-Master /4" Exhaust (LOVE IT!) /Amsoil in Engine and trans with Amsoil remote bypass filter / Max-E-Tork ECU / Kennedy Fan upgrade / Bilsteins

  8. #8
    Join Date
    Apr 2010
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    Default

    I just chased down some odd behaviuor to my Heath pmd relocater.

    I had a tcc code, fuel trim too short and cruise control wasn't working.

    Turned out to be a big blob of green corrosion hiding under the resistor in the pmd.

    Cleaned it up and everything was good again.

    Probably not your problem, but it's "no cost" to check.....

  9. #9
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    Default Update

    OK - I had the clear tubing plumbed in the wrong spot. Put it on the return out of the pump and looped it - NO bubbles at all.

    Also swapped out my PMD with an extra I had - no change.

    The IP was replaced approx 2 years ago and I've had a couple of them fail and this does not seem to be exhibiting the same characteristics.

    Has this pretty much narrowed it down to injectors?

    Hard start, kicking and surging going down the road, terrible throttle response at this point.

    Thanks!
    96 K2500 Suburban /300+K miles /Relocated PMD /Turbo-Master /4" Exhaust (LOVE IT!) /Amsoil in Engine and trans with Amsoil remote bypass filter / Max-E-Tork ECU / Kennedy Fan upgrade / Bilsteins

  10. #10
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    Arrow

    It could also be a fuel quality issue. If you haven't done something to be SURE you are supplying fresh, clean #2 Diesel, do so. A bunch of gas or some other non-Diesel contaminant can also cause your issues.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  11. #11
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    DMAX - after dealing with the fuel contamination issue already and replacing the tank, filter, blowing out lines, etc. I'm getting fuel from hi-volume truck stop type gas stations. Staying away from the mom and pop. Short of sampling the fuel - not sure what else to do on a regular basis.

    I have new injectors arriving tomorrow so we'll see. Just hope I haven't wasted the $.
    96 K2500 Suburban /300+K miles /Relocated PMD /Turbo-Master /4" Exhaust (LOVE IT!) /Amsoil in Engine and trans with Amsoil remote bypass filter / Max-E-Tork ECU / Kennedy Fan upgrade / Bilsteins

  12. #12
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    UPDATE - new injectors installed tonight. Truck is running much better but still not 100%. If I start from a dead stop it seems to "bog" some until about 2500 rpm and then it really hauls. It's pulling ok up until 2500 but then it really takes off until it shifts. It does the same thing after each shift.

    Runs pretty good down the highway - still seems to be surging very slightly.

    Not sure on the starting yet. The new injectors took a while to bleed of course and a couple of starts after that took longer than normal and still had to hit the throttle to clear it out.

    Any thoughts?

    Thanks
    96 K2500 Suburban /300+K miles /Relocated PMD /Turbo-Master /4" Exhaust (LOVE IT!) /Amsoil in Engine and trans with Amsoil remote bypass filter / Max-E-Tork ECU / Kennedy Fan upgrade / Bilsteins

  13. #13
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    Air filter? Collapsed intake plumbing?
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  14. #14
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    Default

    Dmax - just put AFE air intake on so that's not it. Could a worn timing chain cause the hard start and/or delayed response under load? Truck just hit 300K and orginal chain as far as I know.

    Was thinking of going with gears to replace - thoughts?

    Thanks
    96 K2500 Suburban /300+K miles /Relocated PMD /Turbo-Master /4" Exhaust (LOVE IT!) /Amsoil in Engine and trans with Amsoil remote bypass filter / Max-E-Tork ECU / Kennedy Fan upgrade / Bilsteins

  15. #15
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    Timing chain could, but not overnight. It would be a degradation over time, and goes mostly unnoticed. At the same time, it's way overdue at 300K. You may have a culmination of issues that came to a head all at once. If injectors helped, a timing set will probably help more. Tackle them one at a time. It runs, albeit less than ideal, but it runs. Without getting hands on, it's difficult to say.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  16. #16
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    Quote Originally Posted by 65-f100 View Post
    Replaced tank with good clean used tank - new sending unit with new strainer, flushed and blew out the lines from front to back - pickup and return lines

    replaced complete filter housing assembly

    replaced the lift pump since it was weak under load according to the fuel pressure gauge

    The injectors are 2-3 years old and probably have 30-40K miles on them so they "shouldn't" be worn out. They were new Bosch units from Heath.
    Quote Originally Posted by 65-f100 View Post
    Whole fuel filter housing and filter just changed last week when I did the whole system clean out thing.

    Glow plugs are less than a year old - quick heats from Kennedy. Put 4 AC Delcos in on the driver side last week just to see if they changed anything. It didn't. Checked the glows using the old batter cables and they glowed pretty quick.

    PMD change out has been a while - have a Heath remote mounted unit. I do have another one I can swap out that came on my last IP. Should I swap that out to eliminate it as a possibility?
    Quote Originally Posted by 65-f100 View Post
    I did just replace the sending unit so maybe it's something with those connections.
    Quote Originally Posted by 65-f100 View Post
    just put AFE air intake on so that's not it
    I've tried to break out all the replacements you've already made from your posts. Seems like you recently did an awful lot of work - new fuel tank, sending unit, and lines; new filter housing; new lift pump; new air intake. Fairly recent glow plugs, PMD, and injectors (even before the latest new injectors).

    Were these issues prior to all of this replacement? Or after? What was the reason for all the replacement? You discussed the fuel tank coating "contamination" but did you have all these symptoms before or after you discovered that?

    It just seems like people are shooting in the dark with suggestions without seeing the whole picture and timeline. Also that since so many changes were made in a short period of time that opens up the possibility of something being connected wrong or something being disturbed while doing all the other work. Sort of like a recent electrical problem a friend had where a light wouldn't work so he replaced first one switch, then the other (3-way switch circuit), then the breaker - only to find that the recently replaced lightbulb had already burned out... Then had problems because he had connected up the switches wrong while he was replacing them...
    '94 GMC 6.5TD K1500 4L80E 2-Door Yukon SLE 221K
    '93 Chevrolet 6.5TD K2500HD NV4500 Std. Cab Longbed 187K
    '85 Toyota 22R RN60 4x4 Std. Cab Shortbed 178K (Currently retired for rebuild)
    Diesel Page Member #2423

  17. #17
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    Have you seen this:
    http://www.thedieselpageforums.com/t...=39850&page=12

    Sounds like the same sort of problems I was having, as was this guy. You replaced your sending unit and sock too... just sayin.

  18. #18
    Join Date
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    Columbia, SC
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    Default

    OK to recap.

    I've noticed slight "bumping" going down the road for a while - very slight. (Thinking back - this is why I suspect the timing chain may be part of the equation)

    Approx. 3 months ago I started having the hard start issues but was still running "normal" at that point . Just took a long time to start and belched when it did. Also had to start "clearing" it with the throttle right after start up to get it to idle normally.

    The fuel contamination issued occurred after this - Memorial Day weekend - and that is when the real bucking and missing started. That is what led to replacing the tank, sending unit and filter housing as well as flushing all the lines. While diagnosing all of that - I tested the lift pump pressure and found it dropping to 0 under load - that is why I replaced it. Just FYI - the sending unit and fuel filter housing were both new Delco units. I had read the same post about the sock/strainer issue and that convinced me to go the Delco route.

    After checking for air in the return line and finding 0 bubbles - my next logical step was the injectors. These are new Delphi units by the way - not low-buck remans.

    I can hold the throttle steady at 2000 rpm so I "think" the IP is ok.

    Are there other tests I can do to check it? What about the fuel solenoid? I read some other posts about it

    Would the optic sensor play any role hear? Can it get dirty? Wondering if some of the trash from the fuel contamination may have gotten past the filter.

    Would the timing chain or optic sensor attribute to a hard start?

    Just scratching my head a little. Appreciate the input as always. It's at least driveable now but would really like to get it right.
    96 K2500 Suburban /300+K miles /Relocated PMD /Turbo-Master /4" Exhaust (LOVE IT!) /Amsoil in Engine and trans with Amsoil remote bypass filter / Max-E-Tork ECU / Kennedy Fan upgrade / Bilsteins

  19. #19
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    Feb 2004
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    Columbia, SC
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    Latest update - wife driving it on a 4 hour trip. Called about 2.5 hrs into the trip and said it's bucking again. My thought is that the timing chain is very sloppy causing it to jump and buck under steady throttle. It does ok under load because of the additional load and tension on it.

    Does this make sense?

    I'm just at a loss over what else it might be.
    96 K2500 Suburban /300+K miles /Relocated PMD /Turbo-Master /4" Exhaust (LOVE IT!) /Amsoil in Engine and trans with Amsoil remote bypass filter / Max-E-Tork ECU / Kennedy Fan upgrade / Bilsteins

  20. #20
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    Apr 2010
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    Does the PCM have any active or stored trouble codes?

    There can be codes present that do not illuminate the cel.

    The p0004 is a red herring I'm thinking. Here's some support for that hypothesis : http://engine-codes.com/p0004.html

    If there are codes, clear them (after recording them) and then see what codes return after running it again.

    Timing chain seems unlikely to me. Improbable, but not impossible...
    Last edited by greatwhite; 06-29-2012 at 15:47.
    1998 k2500

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