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TBI starts like a carb'd engine.....help?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BLzr4x4ngkid, Mar 27, 2001.

  1. BLzr4x4ngkid

    BLzr4x4ngkid 1/2 ton status

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    TBI starts like a carb\'d engine.....help?

    This has been going on for about a week now. When I got to start my truck I am having to keep my foot on the gas and sometimes I even have to pump it. I don't know how much good that does except maybe flood it, but it works. The other thing is, normally I can just reach in there, turn the key on, then start it without problem. Now, with all this other stuff going on, it won't even stay running unless you keep the gas on it. Then when it starts to warm up, it'll keep running. It also idles really low and I think the alternator is going out too. Please help?

    A friend told me to check the fuel filter, then the O2 sensor, and maybe even the fuel pump. I think since I did put some 100LL into my truck, that maybe the sensor is bunged. Also, it tends to idle rough too.



    "Don't hit me with them negative waves so early in the morning." Odd Ball--Kelly's Hereos
     
  2. muddin4fun

    muddin4fun 3/4 ton status

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    Re: TBI starts like a carb\'d engine.....help?

    I would also check for any leaks in the fuel lines. This is just a guess, maybe the pressure isn't where it should be. Also, Check for gasket leaks around the TB carb looking thing. Its the carb gasket on mine but mine is only carborated. Don't know what it's called on a TBI. I ain't no help! I'm gonna shut up now!

    [​IMG]


    <A target="_blank" HREF=http://muddin4fun.coloradok5.com>http://muddin4fun.coloradok5.com</A>
     
  3. 90K5

    90K5 1/2 ton status

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    Re: TBI starts like a carb\'d engine.....help?

    I'd check the fuel filter, the TBI to intake gasket and the TBI to air filter gasket.

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  4. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    Re: TBI starts like a carb\'d engine.....help?

    Hey don't be knockin' the carbs, they may not have the performance of the fuel injection but what good is it when it doesnt cooperate half the time, lo, j/k. You might wanna get some new injectors. They could not being delivering enough fuel and you have to pump the heck out of it just to get enough gas to start it. Whatever it is it sounds like you're not getting enough fuel. Just follow the lines from the pump all the way to the throttle body.

    [​IMG]
     
  5. extremeblazer

    extremeblazer 1/2 ton status

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    Re: TBI starts like a carb\'d engine.....help?

    I had the same problem w/ my 89 K1500. It ended up being the ect(engine coolant temp sensor). I think it cost around $5.00. It definitely wouldn't be the o2 sensor because that should have a 1 wire o2 which only works when the ecm goes into closed loop which would be around engine operating temp. The thing w/the ect is that it might tell the ecm that the engine is at say 60 degrees when really it is around 40 or so depending on what region of the country you live in. This in turn would make the engine not receive as much fuel on start up. I would still check the fuel filter and they should be replaced every 15k miles or so. Don't forget that there is also a filter in the tank. You might also have an injector problem. A good way to check those is to take off the air filter, let the engine run and look at the spray pattern w/ a timing light. You can also check the TBI gasket by letting the engine run and spray carb cleaner around the base. If the RPM's change then the gasket is bad. The IAC(Idle Air Controler) might be bad as well. You can take this out and see how dirty it is. It might just need to be cleaned. Could have carbon deposits around it. This would make the engine not start good and have poor idle if it is not in the correct position which if read on a scanner should be between 15-30 if i am not mistaken.
     
  6. pcorssmit

    pcorssmit 1/2 ton status

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    Re: TBI starts like a carb\'d engine.....help?

    You mentioned your alternator may be going bad. Low voltage can cause a number of problems, including the ones you described. If it is going out, you need to fix it anyway, and this would be a good starting point.

    As mentioned above, the O2 sensor has nothing to do with starting or cold idleing. It is also very unlikely that the fuel strainer in the tank is causing the problem.

    Are you getting any codes on the computer?

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  7. rampage

    rampage 1/2 ton status

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    Re: TBI starts like a carb\'d engine.....help?

    When I had a plugged fuel filter it gave code 43 (or maybe 44). It does sound like a plugged gas line though. Before replacing expensive parts it might be worth a shot to dump some fuel injector cleaner in your gas tank and see how it runs after a few days.
     
  8. Twiz

    Twiz 1/2 ton status

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    Re: TBI starts like a carb\'d engine.....help?

    The last three or so replys sound O.K. to me (not to say the others aren't good), I'am not sure with this one. I can tell you that the E.C.M. should shut off fuel supply to the injectors when the throttle is held to W.O.T. during cranking. Like the old carbs, this helps clear a flooded condition. Also if the battery goes below a set voltage the E.C.M. may "forget" how to run (they are "learning" how to idle, etc.) so it culd cause a porb. like this, but it should get better after you drive it for awile. Try starting it however works. Then hold the throttle at about 1/4, then back off slowly. If the engine starts to idle ok then I would guess its a batt. prob. Eather way I would check battery alt first, then go from there.

    Just trying to help,

    Twiztid

    <P ID="edit"><FONT SIZE=-1>Edited by Twiztid on 03/28/01 05:12 PM (server time).</FONT></P>
     

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