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EFI ?? Please Help

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by JF 89K5, Jun 7, 2001.

  1. JF 89K5

    JF 89K5 Registered Member

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    Here's a brief explanation. Ran great for a 3.5 hour drive, tried to start 2 days later, turns over but won't start. Replaced fuel filter, still nothing. Next day try to start it, fires right up, drive it , runs good w/ a little hesitation at times. Today drove it to work, dies on the way in, and limps the rest of the way to work, now it won't start. I had someone turn it over while I watched for gas and it is barley dripping out of the injecters.

    I know it might be the fuel pump, but when I changed the filter I turned the key with the filter off and it seemed to have good pressure. Are there any fuel cut-off lines/or fuses in the engine compartment? I already checked the other fuses. Any other ideas?

    Thanks for any replys

    JF
     
  2. lvmyK5

    lvmyK5 Registered Member

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    I had the exact same thing happen to mine 87w/tbi and after replacing a number of componants under the hood I finally found out it was the fuel pump

    You can never tell how deep it is untill your in the middle of it and usually thats to late
     
  3. SummitXMK

    SummitXMK 1/2 ton status

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    I concur it is the fuel pump. I had a 88 tbi and I though that since it was still running crappy it couldn't be the fuel pump. After replacing almost 300$ worth of sensors and selenoids I check actual fuel pressure with a gage and it was below what the service manual said. Chaged the fuel pump and WALLAAA Runs like a dream.

    78K5 Cheyenne
     
  4. 90K5

    90K5 1/2 ton status

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    Could also be the ignition module or pick up coil

    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>
     
  5. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Any more updates?
    IF you get it started again, you should be able to hear the pump if it is working. Sounds like a beehive. Screwdriver test can also help - put a long screwdriver to the tank (while the truck is running) and put the plastic end against your ear. You should hear a pretty strong buzz.
    And another option but wait for confirmation from the Chevy Mechanics before you try this:
    There is also a test lead under the hood. I think it should be right over your AC box. Check a Chevy manual to be sure. Run power to it with a line open (away from sparks).

    Dave

    "Visualize Whirled Peas"
     
  6. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    Its the fuel pump. I GAR-ONNN-TEE!!! Change the thing, and you will be happy you did.

    <font color=red> Check out my truck @ </font color=red>
    <A target="_blank" HREF=http://24.10.209.54/bigolk5.htm>http://24.10.209.54/bigolk5.htm</A> [​IMG]
     
  7. CaptCrunch

    CaptCrunch 1/2 ton status

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    when it doesn't start is it getting fuel out the injectors? Does the fuel piump kick on? Will it start if you spray carb spray in it? It sounds alot like an ignition module to me, but it could also be a fuel pump...or a bad ground... or even a malifunctioning relay... I have seen it all. First thing I would try when it doesn't start is see if it runs on carb spray by spraying it in the TBI unit. If it starts it is in the fuel system... if it doesn't it is most likely a ignition problem... but check to see if the injectors are spraying... if they aren't it could be a computer or wiring problem. Feel free to pm me w/ any questions you may have and I'll try and guide you through no start trouble shooting.

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <A target="_blank" HREF=http://www.geocities.com/milnerlives_2000/blazer.htm>http://www.geocities.com/milnerlives_2000/blazer.htm</A>
     
  8. JF 89K5

    JF 89K5 Registered Member

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    Thanks for all the replys everyone,

    When I changed the fuel filter I turned the key with the filter off and watched fuel shoot a strong stream out of the line.

    However with a new filter in and having someone turn the key I watched the injecters and it just had small drips coming out of them. Also normally by turning the key forward, but not turning it over it should spray a squirt of gas from the injecters and it's not doing that at all.

    Is there another fuel filter besides the one on the frame rail?
    It seems like if I'm getting good pressure at the fuel filter, that something is happening between there and when it comes out of the injecters that is causing it to just drip out.

    I won't be able to work on it till after work today, so I guess I'll just sit here and wait till I can go work on my blaz and keep surfin CK5 :)

    JF
     
  9. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Only one filter that I know of but there is a screen on the base of the fuel pump - no help there.
    OK - sounds like the pump is still spinning but delivering LOW pressure. Broken impeler blades maybe.
    Still sounds like fuel pump. If you need to be absolutely sure (eliminate fuel pump or not) before you pull the tank and replace the pump, take it to a shop that has an inline fuel pressure gauge (if you can get it there). Or ask the guy if he'll do a house call on his way home for a fee and pizza and beer.

    Dave

    "Visualize Whirled Peas"
     
  10. JF 89K5

    JF 89K5 Registered Member

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    Thanks, I'll see what I can do, damn I just replaced the fuel pump 2 yrs. ago, pain in the a$$ with tow package and skidplate.
     
  11. Blazer1970

    Blazer1970 1/2 ton status

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    The fuel pump on my neigbor's '88 died a slow death exactly like that.

    Tim

    70 Blazer CST 4X4 350 SM465 NP205
    87 Burb 4X4 350
    01 GMC 2500HD 4X4 Duramax/Allison
     
  12. newyorkin

    newyorkin 1 ton status

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    I would almost definately agree; fuel pump. I've done it quite a few times in my chevy's, all with identical symptoms. Sometimes it works, sometimes it doesn't. Sometimes when it does work, it pumps too low pressure.

    Also, this may sound very dumb, but make sure the filter is in the correct flow direction.

    I did two on my camaro within 2 years of each other, using only NEW Delco pumps. 2nd pump finally bought the farm right around the first gas crunch when I started putting cheap crap in... 45 miles from home/tools/family/etc...

    Good luck with it!!

    Ratch
    **<A target="_blank" HREF=http://k5.8m.com>http://k5.8m.com</A> What more is there to life?**<P ID="edit"><FONT SIZE=-1>Edited by newyorkin on 06/08/01 11:30 AM (server time).</FONT></P>
     
  13. WOODYJ

    WOODYJ 1/2 ton status

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    I vote for the bad fuel pump answer to your problem. It seems that the fuel pumps get worn a little and they will give you all kinds fo false readings. I have been down the road replacing all the sensors, etc. Cost a he__ of allot of money. Slipped a new fuel pump on and can't get the damn thing to die!!

    k5woody I Don't Understand The Jeep Thing Either!!!
     
  14. JF 89K5

    JF 89K5 Registered Member

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    Re: EFI ?? I feel stupid!!

    Well turns out I was out of go go juice, thats right, no gas!! In my defense though, I still don't understand how it didn't start one day and then started the next and then drove 25 miles to work? But anyway, filled it with gas and it works great now! Drove it on a 6 hour round trip to Salt Lake City this weekend and it ran like a champ, just kept gas in it :)

    Thanks for everyone's help,

    JF
     
  15. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Re: EFI ?? I feel stupid!!

    Have you run it to low/no fuel? As the fuel pump died, mine ran at full but started crappin as the tank emptied..... Be prepared just in case.
    Hope that is your fix tho - DOH!

    Dave

    "Visualize Whirled Peas"
     
  16. elkboy

    elkboy 1/2 ton status

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    Sounds really familure, my fuel pump died kinda like that last week. Looked like it was getting enough fuel, but it wasn't. In tank pumps suck !!!

    <font color=red> Elkboy </font color=red> 82 K5 fuel injected H.O.305, TH350/205, 14bolt/10bolt and 39.5 TSL's.
     

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