1999 K1500 Suburban Vortec 5.7 Problems

Discussion in 'Engine & Drivetrain' started by shovenose, Dec 28, 2016.

  1. shovenose

    shovenose Well-Known Member

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    About a month ago I was having a problem where on the first cold start drive in the morning the truck would not run well. Basically it would shift badly and seemingly have no power to move forward though the engine would somewhat rev, so I thought it was a failing transmission and had the transmission fluid+filter changed. It still did it, so I added K&W TransX and the issue seemed to get much better. The truck did still seem slightly slower in the morning than what I deemed to be normal but I didn't think much of it up until now.

    Last week the water pump went out. It pissed coolant everywhere, but the failure seemed to happen as I was just arriving at my destination so I don't think it overheated - the gauge never went above normal. I had it towed to the shop and the water pump replaced twice (the first one was defective).

    Well, I don't know if that has anything to do with it, but worth mentioning, because ever since my issue has come back and it's worse than ever. When the truck is cold in the morning it just falls flat on its face when I try to merge into traffic from my parking lot. By the time I get to work it's warmed up and it runs better but still not like I would expect. It seems a bit down on power, and it intermittently idles really low/rough to the point at which I thought it would stall out (but it didn't).

    While I know the MIL works as it shows up when the key is turned on, it's never gone on by itself. I have a reasonably advanced Bosch scantool. All modules show no codes of any type. Everything looks to be alright, but my coolant temp seemed to hang at 194 when the truck warmed up. I change the coolant temp sensor (the one at the front where the thermostat is) and now it actually fluctuates, but it's still in the range of 19x-20x when warmed up. Fuel trims are close to +10 at most times. I checked the throttle position sensor, and while it seems alright, there were some small dips in the graph, so I have a new one ready to put in tomorrow. The other thing the "CMP Retard" ranges between -11 and -10. I've heard that anything outside of +/-11 will set a code but that the real spec is +/-2. Could that cause my problem, or do I just have a host of issues all coming together to make my 'burb run like a turd? bad tps, bad timing, bad ect, bad transmission...

    Thank you for any advice/suggestions on what to check and how to proceed.
     
  2. MRRSM

    MRRSM Gold Supporter

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    If other people were accessing this engine... it might be that somebody nudged the Distributor out of place if the Hold Down Fastener was a bit loose after so many years of operation. This information when applied with your Bosch Scan Tool might be the first place to sort out the Camshaft Retardation that would definitely rob the engine of the power it should be making. These Distributors are not that expensive now if the idea leads you to want to replace it...and this following information comes from Justanswers.com. You will need a "Buddy" to help you when you are doing the Diagnosis to work the Gas Pedal and keep the Engine running above 1,000 RPM:

    TEST PROCEDURE

    The distributor may need adjusting to prevent crossfire. To insure proper alignment of the distributor, perform the following:
    1. With the ignition OFF, connect the scan tool.
    2. Start the engine. Allow the engine to idle until the engine reaches normal operating temperature. IMPORTANT: Cam Retard Offset reading will not be accurate below 1,000 RPM .
    3. Increase engine speed to 1,000 RPM while performing the following steps.
    4. Use the scan tool in order to monitor the Cam Retard Offset.
    5. If the Cam Retard indicates a value of 0 degrees , the distributor is properly adjusted.
    6. If the Cam Retard does not indicate 0 degrees , the distributor must be adjusted.
    ADJUSTING PROCEDURE
    1. With the engine OFF, slightly loosen the distributor hold down bolt. IMPORTANT: Cam Retard Offset reading will not be accurate below 1,000 RPM .
    2. Start the engine and raise the engine speed to 1,000 RPM .
    3. Use the scan tool in order to monitor the Cam Retard Offset.
    4. Rotate the distributor as follows:
      • To compensate for a negative reading, rotate the distributor in the counterclockwise direction.
      • To compensate for a positive reading, rotate the distributor in the clockwise direction.
    1. Repeat step 4 until 0 degrees is obtained.
    2. Turn OFF the ignition. NOTE: Refer to Fastener Notice in Cautions and Notices.
    3. Tighten the distributor hold-down bolt. Tighten Tighten the bolt to 3 N.m (25 lb ft) .
    4. Start the engine.
    5. Raise the engine speed to 1,000 RPM and view the Camshaft Retard Offset.
    Good Luck! ;>)
     
    Last edited: Dec 28, 2016
  3. gmcman

    gmcman Well-Known Member

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    I would check your fuel filter, fuel trims of +10 show its trying to add more fuel than what it should normally deliver. Could be other issues but I would start there...if you haven't changed it in the last year then definitely change it to remove that variable.

    Check your air filter as well as your intake tract for any rodent nest if you let it sit for long periods.

    I would also make sure your cat isn't plugged up.

    One other thing to check, place shifter in 2nd and see if it takes off the same as in D or 1. I'm not 100% sure but that vintage may allow for a takeoff from a standstill in 2nd gear when the selector is placed in 2nd, like most later models.
     
  4. littleblazer

    littleblazer Gold Supporter

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    Do you have access to a tech 2? Ours had a similar issue where the torque converter was dropping out. There is a service bay test built into the tech 2 to check for that issue if you have access. Otherwise disregard the test. Our problem was that the valve cover leaked and ran oil into the bell housing can messed it up that way. Sometimes it would be fine then OD would drop out at 80 and all of a sudden you're spinning 4k. When it lost OD shifts would become erratic and sometimes it would hold gears at low speeds making it feel like a sled.

    The other issue it had which was way back at 80k... (it was a new 00 bought in 01 so... 2003-2004 it was?) If you would punch it out it would sometimes have no power. Actually a lot of times. Just needed a tuneup, plugs wires cap and rotor.
     
  5. shovenose

    shovenose Well-Known Member

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    I don't have a tech2 :'( but my Bosch scantool has all sorts of transmission, torque converter, etc. readings if you tell me what to look for I can provide that :biggrin: When I'm on the highway and truck is warmed up I can go 95mph no problem though and rpms are normal so OD is working OK. Though, I tried putting in it 3, it still doesn't feel right at slower speeds, lacking power and shifting at weird times. That's why I was suspecting the TPS (will change that today).

    I do have a new fuel filter somewhere around here so I really should put that on since I have no idea when it was last changed and that's free since I already have it. Just depends on how easy it is.

    The dealership where I bought it this year, they apparently replaced the catalytic converters. I know this because they were complaining I was beating them up on the price too much after they put all this money into it lol.

    Next time I have a 2nd person I'll play with the distributor and fix the cmp retard. I still want to know if that alone could cause the issues I'm having though? I don't know if I caused it when I did plugs/wires/cap/rotor soon after acquiring it. I used ACDelco or Delphi cap and rotor (don't remember), OmniSpark plug wires (generic stuff from O'Reilly), and ACDelco plugs.
     
    Last edited: Dec 28, 2016
  6. gmcman

    gmcman Well-Known Member

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    3rd is the same as 1st or D from a standstill, 2nd is different. See if it takes off the same in 2nd as the other gears.

    If you can do about 70 mph until the 1st shift.....then it's taking off in 2nd.
     
  7. littleblazer

    littleblazer Gold Supporter

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    If it has it it should be labeled p1870 test or something like that. The code itself is for slipping and shifting errors iirc.

    Edit: of there is an issue with the cap rotor dist. And such you would've had the issue from the second it was replaced unless it somehow moved itself. Just throwing it out there. If you could throw up torque it should show advance all over the place and it should be something like 14 I believe?
     
  8. shovenose

    shovenose Well-Known Member

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    Spark advance and cmp retard are different right???
     
  9. gmcman

    gmcman Well-Known Member

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    Don you have a vacuum leak? Check brake booster for leak. Just throwing out ideas.
     
  10. MRRSM

    MRRSM Gold Supporter

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    "Spark advance and cmp retard are different right??"

    Yes... When Gasoline Vapors mixed with Ambient Air are ignited inside the cylinders of your engine... the combustible mixture does NOT instantaneously "explode" as many people might imagine the process to be. Rather... as the piston rises up inside the cylinder on its Compression Stroke and begins to "Squeeze the Hell out of the Fuel-Air Mixture"... The Spark needed to ignite the event is set to go off at the proper Crankshaft Angle "BTDC" (Before Top Dead Center) so that the controlled burning necessary to make power sort of gets an "early start". Here is a video that provides a look directly into a Simple 4 Stroke Engine that shows the Flame Propagation during the Ignition-Power Stroke... watch how it literally burns in an orderly manner when the piston approaches Top Dead Center:



    This process has been called "Spark Advance" and becomes very important as the engine RPM increases and Volumetric Efficiency declines. Your engine requires a "0" degree set up for retarding this process and since your present readings are showing a (-) Negative 10-11 Degrees... the "Early Burn" necessary to ensure complete combustion of the Fuel-Air Mixture is being delayed long enough to prevent all of the Fuel-Air Mixture from delivering Full Power at the completion of the Power Stroke.

    Advancing the timing in an engine depends upon many factors that will be different for any number of reasons... but generally... they all benefit from having the Spark Advanced at the precise position in the engine design to ensure that when piston arrives at TDC... every last bit of energy has been extracted from nearly complete combustion so that the Power Stroke that follows on is as good as it can get.

    Even though your Distributor is an updated version of the Old Vacuum or Centrifugal Weights used to accomplish this "advancement" and now probably relies upon using "The Hall Effect and Square Wave Electronic Circuit" to initiate the Spark Events... Nonetheless, the Camshaft Helical Gear driving the Rotor under the Distributor Cap has to be set in the right place or the problem with Advance or Retard of the Timing will persist.

    The actions described above in the Instructions for Testing and Adjustment directly relate to the information shown to you on your Bosch Hardware and Tinkering with the Rotation of the Body of the Distributor while observing the "CMP Retard Ranges" will allow you to bring them back in line to "0" once again. There may be other issues that are compounding this problem as mentioned by the other Contributing Members... but as you investigate each one to your satisfaction... changing one variable at a time is the best way to make your approach; regardless of the order you choose to follow in getting to the bottom of all the possible causal problem(s) suggested above.

    For Anyone interested in delving more completely into this subject:

    Even though this Video Topic covers Knock Sensors... Brian from Briansmobile1 Youtube Channel ... puts on a "Mini-Motor Clinic" that goes a long way with more complete explanations about the Engine Combustion Dynamics that are important to understand:

     
    Last edited: Jan 21, 2017
    shovenose likes this.
  11. shovenose

    shovenose Well-Known Member

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    Alright, so I checked codes and there was a TPS code this time around so a new BWD part from O'Reilly (made in the USA which is cool) and that's done.

    Also, I adjusted the distributor from -11 to 0 cmp retard. Initial impressions are it runs a little smoother, sounds smoother, and seems to have a bit more get up and go. I didn't have time yet to change the fuel filter yet. It'll be interesting to see where the fuel trims land because I cleared codes so I'm going to give it some time to figure itself out.
     
  12. shovenose

    shovenose Well-Known Member

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    Alright so it's still grumpy in the morning on a cold start. Shifts and drives better than before when warmed up though so the stuff I did was worth something. Still intending to change fuel filter and air filter soon. I also should clean the throttle body and iac properly (when I changed distributor cap and rotor I cleaned as much of the throttle plate as possible without removing the throttle body from the engine and it was really nasty) and check for vacuum leaks with some sort of spray.

    After I do those things what's the next thing to check? Fuel pressure? The intake gasket is seeping coolant out the front but so the logical thing would be to do intake gasket and while I'm there a new upgraded fuel injector spider but that's pretty expensive.
     
  13. MRRSM

    MRRSM Gold Supporter

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    The Age-Old problem of the GM V-8 Engines in their Truck Line Series suffering with "Leaking Coolant around the Intake Manifold" is a familiar issue; with a design flaw that invariably will rear its ugly head over time. But speaking more towards your immediate symptoms is the idea that if Coolant can migrate OUT of from around the Intake Manifold Gaskets as they break down and fail... Air can also be sucked right back in and ruin the balance of the Fuel Air being drawn in and bypassing the Throttle Body and Fuel Controls to keep things in proper balance.

    Worse yet... if you have any leaking Coolant migrating into the Oil Stream or having the presence of Oil Droplets floating around on top of the Coolant under your Radiator Cap or filling up the Coolant Reservoir, this puts a greater sense of urgency for you to get this repair done as soon as possible. This site will give you the History of the Problem and offers a solution in the form of using the Updated, Modified Intake Manifold Gaskets for similar vehicles ... and the Generic "How-To" which might help you with how the repair should be done. However... the Service Manual for your 1999 Suburban Vortec 5.7L Engine is the Bible... and should be followed; Chapter and Verse on how to properly do the job:

    http://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/coolant-leaking-from-intake-manifold-gaskets
     

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