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TBI Help

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by jc71355, Oct 11, 2002.

  1. jc71355

    jc71355 1/2 ton status

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    I drove to school this morning, about 15 minutes, and my blazer ran fine. Took care of business, about 30 minutes, and started to leave. Drove probably a quarter to half a mile, still in the parking lot, and the blazer died. If it stubled it was very little because I didn't feel it. I pulled into a parking spot and tried to start it again. Took longer to start and when it did it stubled and died again (Almost like you took the gas away from it). Let it sit for about 5 minutes and tried again. This time it ran normally. Well I immediatly headed for my house so that I would not be left anywhere. I got home, put it in park, and the idle was high. Ran lke it does when you first start them in the morning. It Idle'd high about a week ago but After I killed it and started it up again it ran normally. Temp was up and normal and it has a new thermostat, plugs, wires, cap, rotor, and fuel filter. Anybody know what could be my problem? /forums/images/graemlins/1zhelp.gif

    TIA,
    James
     
  2. smack

    smack 1/2 ton status

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    Provided you're not getting an error codes (check engine) I'd say there's a very good chance you have a bad distributor module. These things are heat sensitive and the usual malady is when it gets hot it fails and usually that failure is fuel-related. Wait 'till it's cold, run it 'till it dies, then see if you're getting a fuel spray in the TBI. If not, have someone crank it for you while you listen out back under the tank for the sound of the fuel pump working. If it is, then chances are it's your module (but also check for a clogged fuel filter).
     
  3. RedBrute

    RedBrute 1/2 ton status

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    Had a similar problem with my '87. The "dying" problem turned out to be a fuel pump on it's way out. I could get it to start by pounding the bottom of the fuel tank square in the center with my fist. Did this for a week till I ran the tank near empty. The high idle may be a faulty coolant sensor, computer thinks the engine is cold and keeps the idle up. Thats a guess on the idle deal however. If it is the pump, buy the best you can afford, this is not a job you wanna do twice. /forums/images/graemlins/grin.gif
     
  4. jc71355

    jc71355 1/2 ton status

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    Thanks ya'll. My first thought was fuel pump b/c the way it started and died again (burning what's left in the lines). But when it started and ran I figured it had to be something else. It makes sense that could be the temp sensor. Does Anybody Know if AUTOZONE loans a fuel pressure guage? That should diagnose a pump problem right?

    TIA,
    James /forums/images/graemlins/k5.gif
     
  5. azblazor

    azblazor 1/2 ton status Premium Member

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    Statistically the most common failure on TBI engines is the fuel pump, the next highest is the coil. I have owned several TBI trucks - the only time any of them have ever quite driving on me was a bad fuel pump. Fuel pumps can be very erratic before complete failure. I have nursed one for 70 miles on the highway between first stalling symptom and complete failure.
     
  6. Steve_87K5

    Steve_87K5 1/2 ton status

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    Mine's got nearly 300k miles on it and I have gone through 1 coil and 2 fuel pumps, 1 coolant sensor and reman injectors. My bad fuel pumps had same symptoms as you describe. Bad Coolant sensor, it ran like choke was on full. I changed to a Mallory 4060FI fuel pump mounted on frame rail. No pump in tank anymore. The Mallory eats motor brushes but otherwise a very stout pump. You can tell a lot about fuel system by sound of the Mallory pump, like if injectors are leaky.
     
  7. jc71355

    jc71355 1/2 ton status

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    Thank Ya'll /forums/images/graemlins/thumb.gif. Looks like I'll be changing a fuel pump when I run this tank out... If the pump last that long /forums/images/graemlins/tongue.gif
     
  8. azblazor

    azblazor 1/2 ton status Premium Member

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    How much did the Mallory 4060FI cost you? I've been through a couple of Holly's and now have a Walbro.
     

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