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Thread: Can't Pass Emissions in NJ

  1. #1
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    Can't Pass Emissions in NJ

    Hello,

    I've tried three times to pass emissions in NJ without luck.

    1990 Chevrolet K1500 w/ 350 V8, Thottle Body.

    I'm failing low idle for hydrocarbons (not burning all fuel) at about 1000 level when typical is under ~200

    Fast idle is okay

    i've replaced the cap, rotor, plugs, and wires.

    There are no codes in the engine, when i check key on, i just get 12 (no distributor pulse) and when key is on, i get a bunch of fast blinks which doesn't stop. Hopefully i'm checking this right? I've only had experience with ODBII and not much of this ODB1

    I can't seem to find any vacuum leaks spraying around brake cleaner. About the only thing that happens is when i spray kind of near the throttle body itself it changes speed i think just because it's getting into the throttle body (air cleaner off).

    I would have expected an EGR valve to throw a code (or general emissions code).

    I've sea foam'ed the throttle body a few times (almost a whole can).

    When i removed one of the vacuum lines from something i'd call a "bulb" on the drivers side fender well, the engine sped up.

    Ideas folks? I'm kind of at a loss. I could use the "always pass" additives, or just go to a shady mechanic but really want to fix this one. Could it be the PCV valve?

    Do you have to remove the throttle body to get the EGR valve off on this engine? It's really tucked back there and i don't see how one would get a wrench on the head without either removing the throttle body or at minimum the fuel line in the back. I also notice that one of the things i'd consider where a line may go on to be blank or empty? what should all connect to the EGR in terms of lines? I see one from the carb to the valve, then the electronics. I'm still thinking the EGR should throw a code?

  2. #2
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    leolkfrm's Avatar
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    what is the engine temp? should be at least 195, if not change the t-stat
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  3. #3
    Senior Member Douglass's Avatar
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    I came across a you-tube video a while back and it was covering almost the exact problem you are describing. In this video the problem was that the fuel injectors were dripping and spraying fuel rather than just spraying. That might be worth looking at.

    Do you have to remove the throttle body to get the EGR valve off on this engine?
    On my 95 350 I was able to use a flexible ratchet wrench.

  4. #4
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    Quote Originally Posted by leolkfrm View Post
    what is the engine temp? should be at least 195, if not change the t-stat
    that was my first thoughts as well. it sounds a lot like a temp issue, maybe the cat is not reaching temp?

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    Quote Originally Posted by Douglass View Post
    I came across a you-tube video a while back and it was covering almost the exact problem you are describing. In this video the problem was that the fuel injectors were dripping and spraying fuel rather than just spraying. That might be worth looking at.

    On my 95 350 I was able to use a flexible ratchet wrench.
    I did notice the injectors were spraying okay (circular pattern). I need to check on the T-stat mentioned earlier.

  6. #6
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    here is a cheap but very useful tool OBDCOM Diagnostic Systems for ALL vehicles this will help you find the issues and under $90 for everything I have it and love it

  7. #7
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    The OBDCOM isn't going to work on the '90. If the thermostat isn't the problem, check your fuel pressure. I barely passed the last smog inspection. When I put the fuel pressure gauge on it after the test, I discovered the presure was 15.5 lbs on a stock motor. I have an adjustable pressure regulator on my '92 K1500. Either the adjustment drifted or I misadjusted it. And yes, I know, I should have checked it before the smog test.

  8. #8
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    Quote Originally Posted by darisb View Post
    The OBDCOM isn't going to work on the '90. If the thermostat isn't the problem, check your fuel pressure. I barely passed the last smog inspection. When I put the fuel pressure gauge on it after the test, I discovered the presure was 15.5 lbs on a stock motor. I have an adjustable pressure regulator on my '92 K1500. Either the adjustment drifted or I misadjusted it. And yes, I know, I should have checked it before the smog test.

    Sory My bad I didn't look close enough

  9. #9
    Senior Member gmctrucks's Avatar
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    MY bad EGR didn't throw a code and it was bad to where I couldn't pass the test as well I replaced it and she passed with flying colors.
    http://i961.photobucket.com/albums/ae98/falken86/dadnew-1.jpg

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    well... it "passed" and has a sticker, but if tested again would surely fail Hydrocarbons. The only thing that made it pass was $$$.

    I'm suspecting the fuel pressure someone noted and maybe the EGR. I replaced the thermostat and it didn't do anything. It's failing like 500% though. Could it be a timing issue such as a timing belt or maybe a bent valve? I really hate just throwing part$ at something like this.

    I don't smell rotten eggs or anything at the CAT nor would a CAT throw it this far out of spec. It should fail other stuff too. My problem is hydrocarbons at low idle.

    Anyone know how to adjust fuel pressure?

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