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No fuel

Discussion in 'GM Powertrain' started by k.daddy1, Mar 4, 2011.

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  1. k.daddy1

    k.daddy1 New Member 100 Posts

    I have a 98 silverado 1500 with a 5.7. The other day, the truck wouldn't start, found I didn't have no spark. Replaced the ignition module and all was fine till yesterday. The truck will crank over and as soon as I let the key go, it will chug over 2 or 3 times then quits. pulled several plugs to check for spark. I have spark, but all the plugs are dry, even from all the cranking. I have 55 psi at the schrader fitting on the fuel line behind the air box.Left it set over night with the fuel pressure gauge hooked up. Started back on the truck this evening, the gauge was still showing pressure. Checked every plug wire with the plug installed in the boots. I have spark at all cylinders, but no fuel is coming from the injectors. Is there a way to check the injector module or could there be something else causing none of the injectors to spray any fuel? I've checked all the fuses,don't know where to go next. I appreciate any help. I'm too broke to pay anyone fix it, so I'm hoping you guys can point me in the right direction.
  2. MrShorty

    MrShorty Moderator 1000 Posts 100 Posts

    I would probably start by checking the wiring to the injectors (a wiring diagram, even the one in Chiltons will be helpful). My wiring diagram shows a common power supply to all injectors, so I'd probably start there - make sure the injectors are getting power.
  3. k.daddy1

    k.daddy1 New Member 100 Posts

    Mr. Shorty, If I understand this book right, I'll have to crank the engine to put power to the fuel injector module to make the injectors pulse. Is that correct?
  4. Lil_Red_Chevy

    Lil_Red_Chevy New Member

    maybe this article about control of fuel mixture will help you get in the right direction http://en.wikipedia.org/wiki/Engine_control_unit
    ie you may have a bad sensor. also most dealers, atleast by me, have a tech2 diagnostic tool and should scan your truck for free. If you can figure out away to have that tech2 brought to you. my dealer has done that for me before

    also here is some other possibilities:
    air intake duct leak
    vaccum leak
    put a automotive stethscope and listen to see if the injectors click while cranking if they do thats good also a screw driver will work in place of the stethoscope just put the tip on the injector and listen to the handle
    the other thing you could try is a injector test light
    hope any of that helps
  5. k.daddy1

    k.daddy1 New Member 100 Posts

    Another question, Can the throttle position sensor or the coolant temperature sensor cause the fuel injectors not to spray?
  6. Lil_Red_Chevy

    Lil_Red_Chevy New Member

    check your oil pressure sensor first, it will only allow fuel once oil pressure reaches a certain point so that could have crapped out. your ignition and fuel injection timing are dependent on throttle position. so, I could see that as a possiblity however, you did say you were getting spark.I wouldn't think its your coolant temp sensor because that only affects your ignition and fuel injection after the initial start up (i think). The coolant temp sensor is supposed to play with your ignition and fuel so that you dont have to let the engine warm up to get immediate performance. this guy wrote an article on coolant temp sensors http://www.asashop.org/autoinc/may98/techtotech.htm . without a scan tool my suggestion is the same as mr.shorty just work your way back. I took a look at my diagrham for my 04 1500 and the wires from the injectors go straight to the fuses and to the pcm. if your fuses are ok then either something, like an oil pressure sensor, is not properly communicating with your pcm or theres an issue with your pcm itself.

    ---------- Post added at 09:29 PM ---------- Previous post was at 09:15 PM ----------

    if it makes you feel any better I just changed the fluid in my transfer case like two days ago and now my 4wd doesn't work :)
  7. k.daddy1

    k.daddy1 New Member 100 Posts

    Yes I am getting spark now.Two weeks ago, the truck done the same thing, but it didn't have spark. I replaced the ignition module and the truck started and has run fine. I pulled the truck in to replace the u-joint. After I replaced the u-joint it would not start again, check the spark, it has spark on all 8 cylinders, but the plugs are dry. It does have oil pressure while cranking, up to 10psi, but won't start. I can dump some gas in the TB, it will chug over 2-3 times then die. The fuel pump has been replaced 8-9 months ago. I'm just stumped. I have a code scanner but doesn't show any codes.
  8. MrShorty

    MrShorty Moderator 1000 Posts 100 Posts

    The PCM should have power whenever the key is on. Yes you will need to crank the engine to see if the PCM is commanding the injectors to "pulse."
  9. Lil_Red_Chevy

    Lil_Red_Chevy New Member

    well you could of knocked into something while you were under there with that u-joint. you may already know this but make sure you measure your oil psi with a mechanical gauge. the gauge in your dash isnt a good indicator of actual oil psi. and make sure everything is tight like your oil pressure sending unit/switch. the only thing i can think of at this point is a problem associated with your oil pressure electrical system. I have a feeling you'll figure it out if you just take your time with it. so git-r-done.
  10. k.daddy1

    k.daddy1 New Member 100 Posts

    Here's where I'm at so far. I have replaced the Ignition module X2, coil, plugs, cap, button, distributor, ECT, TPS, done a noid test on the injectors. I have power to the injectors, power to the ignition module. I have spark, and smells of raw gas in the intake. The plugs have a little gas on them, but this darned thing will not start or run. It will crank over as pretty as you please, and as soon as I let off the key, the motor will chug 2-3 times then quit. It has 57 PSI of fuel pressure to the injector module, it also has approx 10-15 psi oil pressure while cranking (according to direct pressure gauge), but it will not hit a lick. What effect does the crank position sensor play into this scenario? This is on a 98 chevy 1500 with 176k miles. Pull the codes and it show P1351, but everything that has been replaced should've corrected this code.

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