Stalling -- No fuel to injectors

Discussion in 'General Chevy & GM Tech Questions' started by lobo93065, Aug 7, 2011.

  1. lobo93065

    lobo93065 New Member

    I have a 1994 Suburban K1500 with 5.7L engine. The engine is stalling, generally, but not always, after it has been running awhile.

    Here is what I have done and seen, in order that they occurred:

    1) A couple weeks ago, the engine was running fine until my transmission failed.
    2) I repaired the transmission
    3) Drove it home, let it sit in the driveway a few days, then tried to drive it. It stalled after driving for a short time.
    4) Replaced the fuel pump and the fuel filter.
    5) Still stalls after running the engine until it warms up.
    6) So I let it cool off awhile and then watched how the throttle body injectors were working when the engine is initially started. They are spraying just like they do when the engine is running properly.
    7) After the engine stalled, I then watched how the injectors were working while trying to restart it. Nothing was coming out. Of course it didn't start.
    8) I sprayed some starter fluid into the throttle body and tried a restart. The engine started up and the injectors started spraying like they should. Then they stopped spraying and the engine died. This only took a few seconds before it died.

    I'm pretty sure the transmission problem is just a coincidence. When the engine is running, everything is fine with the transmission in all positions (Park, Drive, Reverse, Neutral).

    The fact that the injectors don't spray when I attempt a restart tells me something is up with the fuel injection. But I'm not sure what it is, and I'm trying to avoid a shotgun solution approach (although my wife may be considering one of her own!).

    I had to have it towed home last week, and I'm afraid to drive it until I get this diagnosed and fixed. Any good ideas would be appreciated.

    Edit
    ----
    One other thing - I checked the ALDL code (flashing check engine light) and the only code is a 12.
     
    Last edited: Aug 7, 2011
  2. Chris Miller

    Chris Miller Rockstar 100 Posts

    Change the fuel pump relay.
     
  3. lobo93065

    lobo93065 New Member

    I'll try a new relay tonight. The price is pretty low, about $13. I'm not sure why it would fail after warm up, but I have seen that mentioned in at least one other place.
     
  4. Revredneck

    Revredneck Rockstar 100 Posts

    It sounds to me like you may have an ignition module or pickup failing. The computer takes its signal from the distributor. When it dies and the injectors don't squirt fuel, check to see if it has spark. If not, then you've got a primary ignition problem. HTH
    Good Luck and God Bless
     
  5. lobo93065

    lobo93065 New Member

    I'm not sure of something:
    1) If the injectors stop spraying, then the engine dies and then the spark quits.
    2) On the other hand, it the spark quits, then the engine dies and then the injectors stop spraying.

    How can I tell which is happening first?

    The ignition module, or "ignition control module" looks like a $41 part (Duralast). Does that sound right?

    What else is the pickup called? I'm trying to find that part on line, but having no luck.

    Worst cast would be to replace the fuel pressure regulator. Besides being about $110, I'm afraid the plastic case of the injectors are so brittle that I will have to replace the injectors, too.
     
  6. Chris Miller

    Chris Miller Rockstar 100 Posts

    Last edited: Aug 9, 2011
  7. lobo93065

    lobo93065 New Member

    Thanks, Chris.

    The fuel pump relay replacement didn't solv the problem. I replaced it last night and rand until the engine came to full temp and it didn't stall. I started it up again early this evening and it didn't run long before it stalled.

    I guess I'll try the stator and the ignition control module when I have the time.
     
  8. lobo93065

    lobo93065 New Member

    Still need some help with stalling engine.

    I'd like more advice, if someone can help me, and I'd like to understand the reasoning.I haven't replaced any more parts since replacing the fuel pump, fuel filter, and fuel relay. I started it up tonight and it died after about 1 minute. I started it again (it wasn't hard to restart). Then I kept the idle up at about 1500 rpm.

    It ran very smoothly for awhile, and the engine warmed up. At that point, when it had been warm for a few minutes, I accidentally let my foot off the gas and the engine died. It looked like the rpm was about 1000 rpm when it died, but I don't know how good that number is.

    I don't know enough about open loop (cold engine) and closed loop operation (warm engine) but I'm starting to think it's not a closed loop problem.

    Does anybody have any ideas that would help?
     
  9. lobo93065

    lobo93065 New Member

    Well, it's been awhile since I posted this problem. I was able to resolve the problem for a little while. I removed the ignition control module and had it tested at Autozone. It checked out okay. I noticed that the thermal grease on the bottom was dried out, so I put new thermal grease on it before I reinstalled it. At that point it ran great. I took it for a short drive and it stalled, but started right up again. I drove it around for awhile and had no problems.

    I drove it back and forth to work for a week. Naturally it stalled on the first morning drive, but after that I had not problems. I drove it around now and then after that (it's a backup vehicle) and all was good. Then a couple weeks ago it stalled and wouldn't start. I sprayed starter fluid into the throttle body and it started. I drove it home. I took it out again and the same thing happened. But it wouldn't keep running.

    I disconnected the vacuum line to the EGR valve, sprayed some starter fluid in it, and it started fine. I drove it home that way, making sure the RPM didn't get too low.

    Now I'm trying to see what's going on. It started the first time this morning, but didn't run long before it stalled again. Now I can't keep it running long at all, with the EGR valve hook up or disconnected. I couldn't even move it around in my driveway without keeping the RPM up.

    Here is what I have done:
    - Replaced fuel pump, fuel filter, fuel relay.
    - Tested and reinstalled the ignition control module.

    Earlier this year, I replaced the rotor, the distributor cap, the ignition wires, the EGR valve, the O2 sensor, the PCV valve, the catalytic converter.

    My problems started right after the transmission was overhauled, along with the cooling system to the transmission. I don't know if this is a coincidence.

    I don't see any coolant leaks. My engine oil looks perfect.

    It starts with some starter fluid, so spark appears to be okay.

    I would like to put it in open loop and see if it runs that way. I thought removing the EGR vacuum line would do that, but I'm not sure.

    It runs fine when its running down the road. Idle speed seems to be where the problem is.
     
    Last edited: Oct 1, 2011
  10. Sierraowner5.3

    Sierraowner5.3 Rockstar 3 Years 1000 Posts

    dunno what to tell ya bud. almost sounds like a wireing issue to me, but it running fine at higher RPMs dosnt make any sense if it was wiring.

    this ones a head scratcher.


    Alex
     

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