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Why would an 89 TBI run rich? Just looking for out loud thinking...

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Kyle89K5, Apr 7, 2004.

  1. Kyle89K5

    Kyle89K5 1/2 ton status

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    My 89 runs rich. All the time. At idle, when the motor is warmed up, it will flood itself. When it's cold, it will do it if I'm not careful about how much gas I give it taking off. My thoughts so far are
    O2 sensor. haven't replaced this one in about 2 years
    Injectors. To my knowledge have NEVER been replaced
    TBI unit. Rebuilt this about 4 years ago
    TPS. Replaced it about 2 years ago, but I'm not sold that it's not a problem.

    Any other thoughts? The motor itself has about 8k miles on it. I've replaced all the other sensors within the last 12 months. The motor is about as stock as you can get one, save for a K&N Filter and no convertor on the exhaust.

    An example of how this thing goes. You start it in the morning to warm up and it starts up great. After it warms up, it will flood itself out. When you re-start it, you can smell the gas, and a hard rap on the throttle will blow enough out to power a Honda for 3 weeks. With all this going on, my miliage sucks and the power is AWFUL. I'm big enough to admit, that try as I might, a Dodge Caravan blew me away in a race to the onramp. It's not running so rich as to start tearing up the motor, but it's getting old, REAL old. I don't ask much, I just want it to run!!!

    TIA

    KP
     
  2. 4xcrazy

    4xcrazy 3/4 ton status

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    No check engine light? no codes? /forums/images/graemlins/dunno.gif
     
  3. Kyle89K5

    Kyle89K5 1/2 ton status

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    About every two months I get a Rich condition something or other like that kinda maybe.

    Maybe I'm wrong on the actual words /forums/images/graemlins/grin.gif
     
  4. 4xcrazy

    4xcrazy 3/4 ton status

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    I'd replace the o2 sensor first then go from there, and let us know.
     
  5. Kyle89K5

    Kyle89K5 1/2 ton status

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    That's my first plan of attack, but I"m dreading it more than rebuilding the TBI again. The wire for my O2 sensor got caught/crimped/cut when the tranny was reinstalled many moons ago. I need to re-wire that part, and I hate wiring more than I hate ricers...
     
  6. k20

    k20 3/4 ton status

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    [ QUOTE ]
    I hate wiring more than I have ricers...

    [/ QUOTE ] You have a ricer? BAN HIM! haha. j/k
     
  7. Kyle89K5

    Kyle89K5 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    I hate wiring more than I have ricers...

    [/ QUOTE ] You have a ricer? BAN HIM! haha. j/k

    [/ QUOTE ]

    WHOOPS!!! /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif

    I will say this though, I drive a Jeep most of the time /forums/images/graemlins/grin.gif /forums/images/graemlins/whistling.gif
     
  8. k20

    k20 3/4 ton status

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    haha, I agree with the others, start w/ the O2 and go from there. Could it possibly be a weak ignition and not necesarily the tbi running rich? Maybe an ignition module?
     
  9. fortcollinsram

    fortcollinsram 1/2 ton status

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    I vote O2 sensor (just replace it it is only like $18) and if that doesn't fix it, look into the MAP sensor or a vacuum leak...

    Chirs
     
  10. Kyle89K5

    Kyle89K5 1/2 ton status

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    The ignition system is entirely new, top down no change. nothing /forums/images/graemlins/frown.gif

    I'm thinking the o2 looks like my start...
     
  11. RedBrute

    RedBrute 1/2 ton status

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    It might be there is a problem with the fuel pressure regulator. if it doesn't send the excess fuel back to the tank via the return line, the fuel has got to go somewhere. Maybe try blowing low pressure air, 10 - 15 psi back thru the return line. maybe line is plugged or kinked if it's not a bad regulator. /forums/images/graemlins/dunno.gif
     
  12. Thunder

    Thunder 3/4 ton status

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    Have you replaced your coolant temp sensor? It may be bad and telling the ECM that your engine is not warmed up. When it acually is at operating temp. This will cause a very rich mixture. Also the over rich mixture prolly has ruined your O2 sensor. If both are bad the computer will go to bypass mode The engine will run pretty bad with low power and usually run pretty rich when in bypass or limp home mode.
    Check the codes or Better yet put it on a scanner. It would really help to know what the ECM is seeing.
     
  13. Kyle89K5

    Kyle89K5 1/2 ton status

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    Hadn't thought of the FPR, I'll pull the lines and blow them out, won't hurt nothing.


    As for the coolent sensor, yep, changed that one too. My thinking though is that when I first got this motor in, it was running rich, as in fuel washed the pistons and took out the bottom end of the motor. (This is the part where I should get by tail kicked) I never cahnged to o2 sensor after I got rid of that motor. Would an o2 sensor that was gone, toast, carboned over cause it to run this much like crap, while never throwing a code?
     
  14. Fubeca

    Fubeca 1/2 ton status

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    Before you spend too much money re-replacing sensors you might want to subscribe to http://www.alldatadiy.com/ They have all the diagnostic charts to help you figure out what is really wrong. Good Luck /forums/images/graemlins/smile.gif
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    I'm going to second hooking up a scanner to it. New parts don't = properly working parts. If you don't know what your O2 is doing, what your ECM thinks coolant temp is, and what your TPS thinks throttle position is, you really have no idea what is going on.
     
  16. Kyle89K5

    Kyle89K5 1/2 ton status

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    I can't find my WinALDL cable, so I'm a little at a loss. As soon as I find it or chunk up the money for a new one, then I will for SURE know. As for the o2 sensor, I think I got more life out of it that I should have. Like the title says though, I'm looking for thinking out loud ideas. At one point, I replaced every sensor on my truck, including the ECM, only to find a bad ground /forums/images/graemlins/rolleyes.gif I try not get into the sensor war anymore /forums/images/graemlins/grin.gif
     
  17. K5Jimmy

    K5Jimmy 1/2 ton status

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    Don't waste your money on cheap....buy an ACDelco...'bout $40....fawkin' Bosch cost me about $200 when it was all said and done...
     
  18. dyeager535

    dyeager535 1 ton status Premium Member

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    I made a cable from a computer cable I had laying around and about $2 in parts from Radio Shack, it really wasn't that difficult, and cost almost nothing. Can't guarantee mine works yet, just that I made it. lol

    Of course, right after you make one, you'll find the one you "lost" /forums/images/graemlins/smile.gif
     
  19. BurbinOR

    BurbinOR 3/4 ton status

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    [ QUOTE ]
    Would an o2 sensor that was gone, toast, carboned over cause it to run this much like crap, while never throwing a code?

    [/ QUOTE ]

    Yes.

    If you're keeping this rig, get a scanner...........you'll be able to see what is going on without throwing parts and money at it.
     
  20. Kyle89K5

    Kyle89K5 1/2 ton status

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    [ QUOTE ]
    I made a cable from a computer cable I had laying around and about $2 in parts from Radio Shack, it really wasn't that difficult, and cost almost nothing. Can't guarantee mine works yet, just that I made it. lol

    Of course, right after you make one, you'll find the one you "lost" /forums/images/graemlins/smile.gif

    [/ QUOTE ]

    That's what I did. Cost me a few bucks more cause I bought a new iron to put it all together with, but that's the cable I can't find /forums/images/graemlins/mad.gif

    Like I said, BurbinOR, I'm in no mood to toss money at this thing, it's just a matter of thinking out loud for things that are on my list anywho.

    BTW, do I plan on keeping it? I named my SON Blazer Scott after this rig for gawds sake, I better keep it /forums/images/graemlins/yikes.gif or my wife will SKIN ME!!!! /forums/images/graemlins/peace.gif
     

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