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(When Good Chevy's Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 88K5Rhododendron, Oct 15, 2000.

  1. 88K5Rhododendron

    88K5Rhododendron Registered Member

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    (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    If you all saw my earlier post... This is just a continuation... but I wanna describe my problem more intricately this time. Here it is folks:

    - An 88 350 TBI...

    - When I first purchased it there were some idling problems.. only in that it would idle extremely low and sound like it was planning on dying... but never would... this was an intermitent problem... could at times make cold starts very difficult... Ran the scan code checker... returned 33 and 45... 33 is MAF or MAP... I don't know about 45...

    - Last nite on my to a friends I let off the gas to turn left onto the service road from the highway... and my car died in the middle of the highway. I cranked it back up by giving it lots o gas and crossed the highway... but naturally I was going too fast to make a 180 degree turn and so I hit the brakes which had gone no-power... and then my steering locked up and I ended up gunning it through a fishtail to get going the way i wanted to... not fun... so I went down this teeny gravel road on-and-off power brakes/steering and called my dad... I was convinced that I could get her home like this... and I did... we checked the codes again and still 33 and 45 were returned... So we just planned to buy a new MAP sensor today...

    - So this morning I went out to see if it would start correctly under a cold start... It cranked rite up... but was misfiring like no other! And to add to it... The fuel was clearly incredibly rich as the exhaust smelled like pure gas.... I pushed the pedal down and it revved up but no matter how high I revved it it wouldn't stop misfiring... So I checked all my plug wires and made sure the distrib. cap wasn't cracked (as was previously suggested)... and saw nothing wrong... so i turned it off and figured I'd wait for dad to get back from town with a new MAP sensor...

    - Installed the sensor and re-checked the tubes... Everything looked good... so I started it up... same problems...
    I am stumped! Buck to the first person who gets it!

    Here are the symptoms outlined:

    - Misfires
    - Gas in exhaust
    - erradic idle
    - loss of brakes and steering (when warm)
    - Not the MAP sensor!

    (Engine is very stock! 350 TBI)

    Anything is greatly appreciated at this point!

    Thanks everyone!

    Matt


    gasoline4life! Or rocket fuel... I could see my blazer with some rockets on it... :)
     
  2. 90K5

    90K5 1/2 ton status

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    code 45= rich exhaust indication - oxygen sensor voltage stays high after one minute of engine run. (Left sensor on dual sensor engines.)

    It sounds like you might have a dead cylinder. This could just mean a bad spark plug, or it could be a lot worse. This would explain the erratic idle, the gas in the exhaust and the misfiring. I'd replace all the plugs first. Hopefully you just have one thats messed up.

    OK wheres my buck?[​IMG]

    90K5
     
  3. 88K5Rhododendron

    88K5Rhododendron Registered Member

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    Bad plugs might make sense... but the exhaust is way way richer than if just one cylinder is not firing... I mean it doesn't even smell like exhaust... it smells like gas fresh from the pump... But I am gonna go out rite now and try to isolate a cylinder if that's the prob... Keep tryin! If you do get it rite just gimmie your address and I will really mail you a buck... no joke!

    Thanks all!

    Matt

    gasoline4life! Or rocket fuel... I could see my blazer with some rockets on it... :)
     
  4. K5Jimmy

    K5Jimmy 1/2 ton status

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    Mine misfired and ran really rich when I had a bad wire...they were only 6 months old at the time, so I figured the worst...I changed several things (O2,plugs, cap, etc) before I finally changed what I thought were basically new wires...Luckily I have those lifetime warranty wires from Autozone, so it didn't cost me anything...but I spent about $75 on stuff I didn't need first...of course this story may be completely unrelated to your situation...I spent about 3 days buggin' the s*** outta people and losin' sleep...I hope you find as simple a solution as I did...Good Luck...JD
     
  5. k5king

    k5king 1/2 ton status

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    O.K. here goes,
    first it's so hard to figure out an ignition/fuel problem it's unbelievable. the only help i could offer is to tell you to do ALL the basic tune up stuff first. plugs,cap,rotor,wires... even though they look ok all plug wires have to have a certain amount of resistance in them. it's not unlikely to buy a new box of wires and have one or two that just don't have enough resistance in them to carry a charge. next would be to borrow someone elses coil and or distributor and install in your truck. this will let you know if you need to replace something in the dist. I.E., the elec. module. and last but not least check out the WHOLE fuel inj. system,,front to back and inside out.even the computer. i know this is very wide spectrum of things but there's no one way to pinpoint a problem like this. even mechanics spent countless hour's trying to figure out stuff like this. hopefully someone else has had the same problem and can help you more sorry.

    DRIVE IT LIKE YOU STOLE IT
     
  6. waxer@work

    waxer@work Registered Member

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    I put my money on a bad O2 sensor. I had the same symptoms on my car and replaced the sensor and all was fixed.
     
  7. Truckfan2

    Truckfan2 1/2 ton status

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    Mann, it sounds like you have it really bad... mine will die every now and then while going around a turn (only during warm up usually around 100 degrees) but that's all it does now... oh yeah, and a little stumble while warming up; it weird now that I think about it, the truck has more power cold and then gets crappy while warming up, then once warm it runs ok but not as great as cold. Oh, well, to your prob now. My only advice that has not been mentioned (unless I'm blind) is check your timing!! You can toy with it just a tad and see if it runs better... this is a no cost opperation if you alreay have a timing gun, if not, ask a friend to burrow one. Let me know if you try it. Later.

    Have been stuck (once) as of 8/12/00
    "(2H) Where's all the mud?.(4H)...(4L)..(4H)... oh crap"
     
  8. bablazer73

    bablazer73 1/2 ton status

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    problems like this can be very hard to pinpoint. do you have a vacuum gauge you can check your vacuum at idle with? you need to find out if you have a mechanical problem or electrcal/efi problem. map sensors use vacuum to moniter engine load. If you have a bad or weak cylinder, your vacuum will suffer and cause the map code. in effect, the map sensor will think there is more engine load than there really is and try and richen the fuel mixture. causing an oxygen sensor code!! make sure you don't have a mechanical problem before you start throwing sensors at it. Is the skip consistant? maybe to one cylinder? If it is, pull 1 wire off at a time while it's running and see if you can figure out which cylinder is causing the problem. If it's an inconsistant skip, start looking for vacuum leaks somewhere. They are not always easy to see. use propane torch, unlit and probe area's. if you have a/c, check the control switch. brake boosters, pcv valves, any or all vacuum motors. pinch of lines. These are all "low cost" ways to diagnose problems before you by expensive parts. I recently went through a similar problem with my wife's car. it has a bad tps sensor. but gave no code for that. the sensor was still within the perameters, but showed engine load at an off idle and caused oxy codes and a map code. 40.00 tps and all better! snap-on scanner 1600.00. I don't know if this long winded post helps, but good luck to you.

    your right. I don't understand the jeep thing!
     
  9. 88K5Rhododendron

    88K5Rhododendron Registered Member

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    OK here's what I have done based on ur advice:

    - I unplugged each plug wire trying to find if one was already not working.... they all appear to be firing... meaning that each time i unplugged one the condition got much worse... So no plug prolem

    - Checked the timing with the gun... lines up perfectly....

    - And as for the O2 sensor being bad... well... the computer isn't reporting it rite now.. but I have not ruled it out...

    Methinks I am gonna have it towed into the dealer tomorrow... :-(

    I am stumped... unless anyone else can think of anything I think that is all I can do...

    Thanks again

    Matt


    gasoline4life! Or rocket fuel... I could see my blazer with some rockets on it... :)
     
  10. FWP

    FWP CRS

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    Quick question, When you look down the throttle body, what do you see- a fine mist of gas?

    <font color=blue>Maverick</font color=blue> <font color=red>CH 4 or 35</font color=red>
     
  11. 88K5Rhododendron

    88K5Rhododendron Registered Member

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    FWP:

    I don't know exactly what you mean by fine mist of gas... but yesterday after I had just driven 20 miles and it started doing this... I pulled off the filter... while it was running.. and a little bit of steamish stuff was coming out of it... I noticed it but I just took it to be steam i guess...

    gasoline4life! Or rocket fuel... I could see my blazer with some rockets on it... :)
     
  12. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    If your injectors are clean and functioning properly there will be a conical mist of fuel being sprayed downward from each injector onto the throttle plates. If there is any dripping or non-symmetrical pattern happening you need your injectors cleaned. Kinda like a dirty/clogged shower head.

    One more thing you can rule out with a visual check.

    Rene

    [​IMG]
     
  13. FWP

    FWP CRS

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    Yep, that's what I meant. That strong of gas smell out the exhaust, and rough run, I would be lookin hard at what's goin in the intake.- My 2 nickels (inflation ya know)

    <font color=blue>Maverick</font color=blue> <font color=red>CH 4 or 35</font color=red>
     
  14. Gandolf

    Gandolf 1/2 ton status

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    My Nissan 280ZX, which is computerized, started running very poorly & eradic one day with some similar symptoms like you describe. I cleaned the battery connections and the ground from the wiring harness to the engine block and that cured it. I don't know if this relates to yours but it's worth a try. (and it's free) Good Luck.

    '89 K5 Silverado 4" lift w/BFG 33's
     
  15. realsquash

    realsquash 1/2 ton status

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    Re: EFI Problems (shorter subject)

    First, disconnect the battery for 10 seconds or so to clear all codes in the ECM.

    Second, check to see if your plugs are fouled. I suggest replacing them immidiately anyways. It is possible to save fouled plugs, but spring the $10 and get new ones.

    Third, measure timing with timing light. How have u been reading this? It should be 4-6 with the timing control wire diconnected (should be in the shop-manual, but it is a tan wire most likely). IF you are measureing with the timing wire connected, you should see upwards of 20 degrees at idle. Yeah, no kidding. If you don't see these, go into your shop manual and set it the right way....

    Fourth, if the timing isn't off, you need to check for a stuck fuel injector. Remove your entire air-cleaner and start the truck up. Connect your timing light to #1 (right front, remember) plug wire. With the engine running, point the light (set at 0 if adjustable) right at the fuel coming out of the injectors. You will need to get up-close and personal (be safe) so you can view the spray pattern on the throttle blades. If both injectors are not even, you have a faulty injector (or a faulty wire, but unlikely). Also try rapping on the side of the injector "pods" with a screw-driver handle or a wooden hammer handle.

    BTW, a code 45 is rich exhaust, and a 33 is a high MAP sensor reading. Logic: if you get a 33, you HAVE TO RESET THE ECM. if you didn't unhook the battery, you still don't know if you fixed the problem.

    My e-mail is realsquash@yahoo.com if you need more help. There are other things to do after you have verified these things FIRST. I've been playing with this stuff for a while now. I reprogrammed a GM ECM to run my 500 HP 454.

    Squash
    http://www.trailrunners4x4.org/users/realsquash
     
  16. craig

    craig Newbie

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    You might want to check your fuel pressure, if there is a problem with the regulator you can get problems similar to what you have.
     
  17. KrebsATM02

    KrebsATM02 1/2 ton status

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    yea fuel pressure can make alot of difference, i had a bad problem with the engine loping and it turned out that the fuel pump had got knocked loose from the pick up

    Doug Krebs
     
  18. archer

    archer 1/2 ton status

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    could be false air from a bad throttle body/intake manifold seal or rounded out butterfly pin. the large vac hose that goes into the throttle body gets clogged too and screws up timing and the computer can't negotiate the parameters.

    "who dares wins"
     
  19. 79Guy

    79Guy 1/2 ton status

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    Lots of choices. My vote would be:

    1) Bad O2 Sensor

    2) Bad ground in computer / sensor circuits. Had a similar problem once after some serious engine work. Ground strap was reconnected to a non-conductive anodized bolt. W/o a good ground, all kinds of sensors were confused.

    Also, only trust the computer so far. It is doing its best to tell you what is wrong with itself, but it can only do that so well. By the fact that anything is wrong, what it is telling you may also be wrong.

    '79 Guy
    1 Blazer - 7 Children
    http://79guy.coloradok5.com
     
  20. sosamantx

    sosamantx 1/2 ton status

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    Re: (When Good Chevy\'s Go Bad) FUEL INJECTION PROBS! HUGE PROBS! I am stumped... first one to get it rite gets a buck... :-)

    <font color=blue>Have you run a compression test? I would run a test to make sure that everything is alright, and then do as the others have said, plugs, wires, etc. What about the vacuum lines, what condition do they look to be in? Start with the basics, intake leaking/sucking air, etc., etc. Try adding a good fuel system treatment to the gas tank as well, might have some moisture in the tank, of course this would not account for the rich levels, but could have some effect. - Steve</font color=blue>

    <font color=blue>Steve Sosa a.k.a. "sosaman"</font color=blue>
    http://sosaman.home.texas.net/carpics.html
     

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