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  1. #21

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    I can see why you would want to check if the rotor is spinning. Before I messed with the timing at all I would check that the fuel pressure is where it needs to be. Just cause there is fuel there does not mean it has the pressure that you need.

    1995 Silverado 4x4
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    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors, http://www.gmtruckclub.com/forum/sho...5-GMC-Yukon-XL
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  2. #22
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    Quote Originally Posted by xJohnDoe001x View Post
    Yea, I was wondering about these distributor modules, are they work or don't work things with no middle area? I did replaced the distributor with a new one. The truck ran good then one morning it started for a couple of seconds then it won't start.
    since you replaced the distributor and it ran for a time it must of been installed correctly. since you feel it has good spark and fuel you may have a bad ignition module. some stores like auto zone should be able to test it.

    alternator failure causing 16volts or more will damage PCM/ ICM etc components.

    being this old wiring need be checked for damage/connectors. the other problem/failure could be fuse able links in the wiring . these hidden in the wiring loom do fail when old. this will cause erratic run failures..engine wiring harness..

    you problem is cranks good but does not run correct ?

  3. #23

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    Quote Originally Posted by j cat View Post
    since you replaced the distributor and it ran for a time it must of been installed correctly. since you feel it has good spark and fuel you may have a bad ignition module. some stores like auto zone should be able to test it.
    alternator failure causing 16volts or more will damage PCM/ ICM etc components.
    being this old wiring need be checked for damage/connectors. the other problem/failure could be fuse able links in the wiring . these hidden in the wiring loom do fail when old. this will cause erratic run failures..engine wiring harness..
    you problem is cranks good but does not run correct ?
    I am new to owning old cars with electronic ignition I was use to just turning the key and it start, I guess because it got cold it needs the gas peddle pressed while cranking which makes me think I still have a problem but it starts now.

  4. #24
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    "Old cars with electronic ignition"! HE-HE-HEEE! Anyhow, its TBI, if you have to hold the pedal for it to start, then I would look at the fuel pump or filter( filter first, its easier to change). It could be the throttle positioning sensor!

  5. #25

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    Quote Originally Posted by zuki82 View Post
    "Old cars with electronic ignition"! HE-HE-HEEE! Anyhow, its TBI, if you have to hold the pedal for it to start, then I would look at the fuel pump or filter( filter first, its easier to change). It could be the throttle positioning sensor!
    All that stuff is new, once it's started it drives nicely but I am going to reset the IAC which involves the TPS position, it's idling a bit high.

  6. #26
    Sr. Apprentice cmcolfax's Avatar
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    Quote Originally Posted by Pikey View Post
    I would consider borrowing a fuel pressure gauge from a auto parts store (free rental at most places) and see what your fuel pressure is. Just because there is fuel present in the TBI does not mean that there is enough fuel being delivered. I would not recommend it, but you could always try spraying starting fluid into the tbi and see if it runs for a few seconds on that.
    Quote Originally Posted by RayVoy View Post
    Just a little aside, you might have had a bad altenator, which caused the battery to be dead; thus, not having sufficient power to crank the engine, therefore no start. In "Joh's" case, the engine will crank. I think he is right, there is a problem with the fuel, or the spark.

    My friend, I have a ton of patience, don't take my questions as a criticism, I'm only trying to help. So, let's see what we can do to fix this.

    Let's try to narrow this down, A good way to do a quick test for fuel is to spray a little ether (starting fluid) into the throttle body. If it starts and runs for a couple of seconds, you have a fuel delivery problem. Then we need to test the relay, the pump and the filter.
    Quote Originally Posted by RayVoy View Post
    The timing is never set at TDC, it is always a few degrees retarded. check the specs.

    I'm not going to go back and look at the list of things you changed, but did you have the distributor out? Did you replace it, or remove it to inspect it? Did you have the wires off?

    If you did, you probably have the timing screwed up.

    But, even at TDC it should start. If you did any of the above, I suspect you have the plugs firing 180 degrees out of phase, ie: the plug fires on the exhaust stroke, not the compression.
    Quote Originally Posted by RayVoy View Post
    Ok @xJohnDoe001x, I did a little checking (very little, so I/we could be wrong), it appears, with an engine computer and a distributor, the mechanical timing is set to 0 (now, I don't know if that's just a mark, or if it is 0 degrees, which would be TDC). The computer then advances the timing to suit the needs of the engine.

    BTW, thanks for picking that up, I did mean "advanced"

    That post was more interested in what you had changed around the distributor; ie: had you changed the distributor, or the wires?

    Some of those types of ignition used an ignition module (someone may have talked about it earlier) maybe there is a problem there; however, checking for a spark, and having one should rule that out.
    Quote Originally Posted by 97Silveradbeast View Post
    did you get the crack and no start fixed with your truck. I have been having the same problem with my truck I changed a bunch of part hen I got a hold of a old time tech. He laughed at me and asked me if looked at the ground that is on the block that goes to the frame and he was right we fixed the breaded ground and the truck is running better then before. so just look at that.
    Quote Originally Posted by Pikey View Post
    I can see why you would want to check if the rotor is spinning. Before I messed with the timing at all I would check that the fuel pressure is where it needs to be. Just cause there is fuel there does not mean it has the pressure that you need.
    Quote Originally Posted by j cat View Post
    since you replaced the distributor and it ran for a time it must of been installed correctly. since you feel it has good spark and fuel you may have a bad ignition module. some stores like auto zone should be able to test it.

    alternator failure causing 16volts or more will damage PCM/ ICM etc components.

    being this old wiring need be checked for damage/connectors. the other problem/failure could be fuse able links in the wiring . these hidden in the wiring loom do fail when old. this will cause erratic run failures..engine wiring harness..

    you problem is cranks good but does not run correct ?
    OK, gentlemen, I am totally jumping in on this thread... Hijacking is too harsh of a word... LOL

    Been following this thread... 'cause I am having a very similar problem.

    99 Burb. K1500. LT. TBI / Vortec 5.7

    Not new to wrenching, but fairly new to Chebby's (I've been a Jeep guy for years).

    Here is where I stand...

    I've only had the truck +/- a month.

    Truck was running fine, little valve train tick that concerned me a bit, and a sketchy fuel guage, only put +/- 300 miles on it but everything seemed to run strong.

    Truck has K&N, OEM ignition with 8mm MSD wires, Flowtech shorty headers, still running both cats with a Gibson sport truck exhaust.

    Had a trusted local shop (not a parts store counter monkey) pull codes to see if anything threw a big red flag.

    This is what I got:

    P0125 - Insufficient time or tempurature for closed loop.
    P0137 - O2 Signal Low B1S1 (Lean)
    P0155 - O2 Heater Circuit B2S1
    P0430 - Catalyst Efficiency Low Bank 2 (Cats bad or not present)
    P0463 - Fuel level circuit signal high / open
    P1351 - Ignition coil 1&4 control circuit high voltage

    No idea how long ago any of them were generated.

    Ever since then it has been extremely hard to start.

    At first it was twist-fire-high idle for 3-5 seconds-idle down-shut off.

    Went thru this cycle 6-8 times to get it cold started everytime for the next coupla days.

    Then it went dead in my driveway. Twist-stumble-nothing.

    Add a shot of ether, twist-fire-vroom. Runs great until the ether burns off then dies.

    Fiddle-fawked with it for another hour, got it to sorta stay running but it was AWFUL, missing, coughing, smoking...

    Another hour, more ether, same results.

    Do the air-fuel-spark sequence... air, yes, fuel, yes... hit the shrader valve and it sprays out of the fuel rail, spark, yes... it runs on ether...

    - - - Updated - - -

    So I go back at it this morning...

    First thing I think is timing... distributor cap is a little loose, I can rotate it a coupla degrees either direction w/o loosening the hold down bolt (which BTW is a huge PITA to get at).

    Makes no difference which way turn it, still no start.

    Shot of ether, start, run, stall.

    OK, mebbe NOT timing.

    Mebbe fuel delivery. Gas guage can't be trusted and I did put +/- 400 miles on it.

    Pulled the filter, and what ran out of the lines was a nasty, rusty, fuel & water mix...

    Pulled the relay, jumped pin 30&87 to fire the pump and pump out the dirty fuel.

    No luck. Can hear the pump whirr, but nothing comes out. Battery is down to +/- 9v from all the cranking.

    Blew the lines out with some compressed air. Toward the tank and toward the engine from the fuel filter location.

    New filter, 10 gallons of fresh, clean fuel, two bottles of HEET "dry gas"...

    And we are back at square one... No start, add ether, start, run, stall...

    Shrader valve, pressure, clean fuel...

    Seems I have it narrowed down to a fuel delivery problem, between the filter and the throttle body.

    Things I am gonna check tomorrow...

    Pull the injectors out of the top of the throttle body and blow them out. Mebbe there was something in that crappy fuel that made it up there.

    fuel pressure gauge (i have one) and see what your fuel pressure is. Just because there is fuel present in the TBI does not mean that there is enough fuel being delivered.
    What should the pressure at the fuel rail be?

    asked me if looked at the ground that is on the block that goes to the frame and he was right we fixed the breaded ground and the truck is running better then before. so just look at that.
    Truck does have a fairly significant oil leak that may be coming from back of intake manifold, or RMS, or oil pan. Will check grounds.

    being this old wiring need be checked for damage/connectors. the other problem/failure could be fuse able links in the wiring . these hidden in the wiring loom do fail when old. this will cause erratic run failures..engine wiring harness..
    This will be a HUGE PITA, and require more time than I can imagine... Patience is not my strong suit.

    you may have a bad ignition module.
    Can pull this tomorrow and see if I can find one of the chain stores to test it.

    Don't want to throw parts at it or spend a lot of $$... It is s'posed to get sold this coming week... most likely to one of those "Buy-Sell-Trade" no-name lots.

    Was bought as a "build a family sized wheeler" project that I am just not gonna have the time or money for...


    PLEASE, fellas... any thoughts, ideas, suggestions, etc... I am all ears... hopefully some of you check in early on Sunday mornings... time for me to get a coupla hours sleep.

    THANK YOU!

    -cmc-

    - - - Updated - - -

    OK... so everything I read hear and some other places is pointing to either clogged / stuck injectors and / or not enough fuel pressure at the injectors.

    A quick trek out in to the ouring, freezing, sleeting, nastiness reveals +/- 50psi while cranking; with only 9-10v showing on the battery.

    (It is run down from all the cranking.)

    But I ain't hooking up my big charger in this weather...

    Really dont want to dig in to pulling the upper intake plenum anbd messing with that "spider".

    The damn truck was running fine a week ago...

    And I just need it running again.

    I am NOT throwing parts and $$ at it!!

    Any other thoughts?
    Some stuff with wheels and motors...

  7. #27

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    I think your on the right track. If it starts with a spray of either, it sounds (as you say) like a fuel problem. I think 50 lbs is a little low, but that might be due to the discharged battery. I think it should be enough to start the truck. Maybe you do have plugged injectors.

    I don't think I would worry about the O2 codes until the engine gets hot. If they are still there you might have a mixture problem. The O2 sensors are not read until they are hot.

    The other codes could indicate a throttle body problem. I think I would pull the throttle body and clean it.

    Not familiar with your year, I do not know if you have injectors in the manifold, or if the throttle body has the injectors.
    Ray

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

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  9. #28
    Sr. Apprentice cmcolfax's Avatar
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    Quote Originally Posted by RayVoy View Post
    I think your on the right track. If it starts with a spray of either, it sounds (as you say) like a fuel problem. I think 50 lbs is a little low, but that might be due to the discharged battery. I think it should be enough to start the truck. Maybe you do have plugged injectors.

    I don't think I would worry about the O2 codes until the engine gets hot. If they are still there you might have a mixture problem. The O2 sensors are not read until they are hot.

    The other codes could indicate a throttle body problem. I think I would pull the throttle body and clean it.

    Not familiar with your year, I do not know if you have injectors in the manifold, or if the throttle body has the injectors.
    Thanks Ray...

    It's a 99 so it is the Vortec, not the TBI so the injectors are in the "spider" in the upper intake plenum...
    DOn't really have the time to fawk with that, but don't have much choice I guess...

    - - - Updated - - -

    Charged battery... got 55-60psi on fuel pressure gauge at shrader valve.

    Have not pulled throttle body or plenum...

    Not a lot of time today

    And it suxors working outside alone in 38* rain...

    -cmc-

  10. #29
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    the 5.7L key on engine off psi is 62-65 psi. and the pressure should hold. when cranking the engine you should see the psi pulse as the injectors open.

    the ECT should be checked for resistance it may be open or reading too high.

    the distributor need be checked with these engines this old at over 175,000mi for bearing wear rotor at dist, wobbles ..

    using a pressure gauge with a fuel dump valve works good to dump out the fuel for a quality check.

  11. #30
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    you said you jumped the relay and could hear the pump working ,but nothing came out? If there was that much crud in the filter, then probably the sock is plugged that's on the pump itself!!!

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