Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Failed inspection - EGR related problem ****passed****

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 90K5, Apr 11, 2002.

  1. 90K5

    90K5 1/2 ton status

    Joined:
    Jun 1, 2000
    Posts:
    3,719
    Likes Received:
    0
    Location:
    Lubbock, TX
    I failed my emissions inspection, the Hydrocarbon count was 377, max to pass is 220. Cehck engine light still comes on, but no codes. I took out the EGR valve and started the truck, and it sounded like a real bad exhaust leak, so the passages in the intake and heads aren't blocked, the diaphram on the valve is good...stays up if I push the plunger up and hold finger over vacuum port. I took off the EGR vacuum selinoid and sprayed some brake cleaner thru it just to make sure the vent wasn't plugged, and its ok. Replaced the PCV valve on the inspector's advice...probably needed a new one anyway. What am I missing?
     
  2. pr1aw

    pr1aw 1/2 ton status

    Joined:
    Sep 17, 2000
    Posts:
    144
    Likes Received:
    0
    Location:
    San Diego CA
    Re: Failed inspection - EGR related problem

    I'd check first if you are firing on all cylinders or do a good tune-up (Hydrocarbons). EGR will usually cause high NOX. High Hydros are unburnt gasses comming out of the cylinders. Also check your O2 sensor to make sure working correctly. Probably want to do that first. If you have one.
     
  3. 90K5

    90K5 1/2 ton status

    Joined:
    Jun 1, 2000
    Posts:
    3,719
    Likes Received:
    0
    Location:
    Lubbock, TX
    Re: Failed inspection - EGR related problem

    Actually have a pretty recent tune up. Plugs are about a month old, so is the O2 sensor. wires a few months old, cap maybe a year old. The exhaust has smelled richer than normal for a while, so its not really a new problem. Any more ideas?
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,975
    Likes Received:
    189
    Location:
    Roy WA
    Re: Failed inspection - EGR related problem

    Well, I would say that it wouldn't hurt to pull the cap and ake sure all the terminals are still tight, and that the contacts inside are all still nice and clean, and that the rotor is good. It's easy, and free, and definitely won't hurt a thing.

    How about the cat converter? Cat converter can make a big difference in HC apparently, as long as it is hot. (run hard right before testing)

    "My '80 Cutlass with the 455 has passed the test today. I'll post the failed
    test and the passed test sheets on my web page. this car is running cleaner
    than any new car that I know of! No Carbon Monoxides; Standard: 3.00%
    Reading 0.00; Hydrocarbons; Standard: 300 PPM Reading 26 PPM, Carbon Dioxide:
    9.53%. That is darn good for a 461,10-1 comp, with no EGR valve, headers,
    MSD, 650cfm Holley, only emission equipment is the dual Catalytic converters
    with the air pump attached.
    It's amazing what a lot of expensive and rare metals can do."

    If the exhaust is actually rich, the O2 sensor should be seeing that.
     
  5. 90K5

    90K5 1/2 ton status

    Joined:
    Jun 1, 2000
    Posts:
    3,719
    Likes Received:
    0
    Location:
    Lubbock, TX
    Re: Failed inspection - EGR related problem

    My cat is fairly new also, I think I got it in October of 00, maybe 99, so its seen an inspection before
     
  6. 90K5

    90K5 1/2 ton status

    Joined:
    Jun 1, 2000
    Posts:
    3,719
    Likes Received:
    0
    Location:
    Lubbock, TX
    Re: Failed inspection - EGR related problem

    My cat is fairly new also, I think I got it in October of 00, maybe 99, so its seen an inspection before
    its running on all cylinders, I'm almost positive of that, I'll check anyway though. The idle is a little rougher than usual, TBI's aren't usually that good, but it definately needs help I think. Also, I can now hear a sucking sound under the hood now when its on, and I don't think its coming from the air filter...
     
  7. Nrose07

    Nrose07 1/2 ton status

    Joined:
    Mar 29, 2000
    Posts:
    267
    Likes Received:
    0
    Location:
    Salem ,Or
    Re: Failed inspection - EGR related problem

    What octane gas were you running? A high quality low octane gas is best. Lower the octane the quicker it burns and the less that goes out your exhaust.
     
  8. 90K5

    90K5 1/2 ton status

    Joined:
    Jun 1, 2000
    Posts:
    3,719
    Likes Received:
    0
    Location:
    Lubbock, TX
    Re: Failed inspection - EGR related problem

    I always try to run Chevron 87 octane. I've heard several times that Chevron and Mobil are the best brands, and cheap stuff like Race Trac and QT is the stuff to avoid.
     
  9. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

    Joined:
    Dec 14, 2001
    Posts:
    22,059
    Likes Received:
    69
    Location:
    Pleasanton, CA.
    Re: Failed inspection - EGR related problem

    If you removed the EGR valve from the engine and started it and it idled then your manifold is blocked somewhere. With the EGR valve off you should have such a big vacuum leak that the truck won't idle. One port of the manifold is for exhaust and the other for intake, without the valve the intake side is a very large vacuum leak. You should try to blow through the ports and make sure that when you blow through one of them you should hear it coming out the throttle body.
     
  10. chris672

    chris672 1/2 ton status

    Joined:
    Jan 25, 2002
    Posts:
    554
    Likes Received:
    0
    Location:
    LODI, CA
    Re: Failed inspection - EGR related problem

    My neighbor works at a smog shop and he said that you can lower your HC's by changing your oil but I dont think it will help you get down to where you need to be but it might help.
     
  11. Stoopalini

    Stoopalini 1/2 ton status

    Joined:
    Oct 17, 2000
    Posts:
    999
    Likes Received:
    0
    Location:
    Austin, Texas
    Re: Failed inspection - EGR related problem

    <blockquote><font class="small">In reply to:</font><hr>

    Also, I can now hear a sucking sound under the hood now when its on, and I don't think its coming from the air filter...

    <hr></blockquote>

    Sounds like you have a vaccuum leak somewhere. If you do have a vaccuum leak, the ECM could be richening up the mixture to compensate.

    I would start replacing vaccuum lines, and also check the TBI - Intake seal for leaks.

    Good Luck,

    Thomas.
     
  12. thebigdaddyof2

    thebigdaddyof2 1/2 ton status

    Joined:
    Dec 28, 2000
    Posts:
    2,053
    Likes Received:
    0
    Location:
    St. Louis, Missouri
    Re: Failed inspection - EGR related problem

    Just like Stoop said, you may have several vac line leaks. Also, be sure to check the TBI bolts for proper torque. My buddy Shagz burb wouldn't pass emissions and also had the EGR code. EGR valve was fine. Found the TBI bolts were only a little loose. Fixed 3 vac leaks. Due to the sometimes erratic idle, we replaced the IAC (idle air control) solenoid valve, just on suspicion. Then we cleared the codes. BAM, perfect idle, no codes, passes emissions and generally runs a hell of a lot better. Good luck.
     
  13. ftn96

    ftn96 1/2 ton status

    Joined:
    Sep 26, 2000
    Posts:
    3,238
    Likes Received:
    0
    Location:
    Nashville Tn
    Re: Failed inspection - EGR related problem

    I dont understand how you can have a check engine light and not have no codes. How are you checking for codes?
    But like someone else said, it sounds like your O2 is not regulating the Air/fuel mixture correctly. You may have a boat load of carbon built up in the motor that needs to come out.
    I would get the motor hot, then drain the oil, and replace the oil filter with a new one, prefilled with oil, then put 4 quarts of kerosene in the motor. Let it idle for a about 30 minutes or so. Then drain the "crap" out. Replace the oil filter with a new one, new oil and see how it runs then. I've seen miracles happen from doing this same process.
    One thing I can tell you is that aluminum intakes are notorious for carbon build up. Something about aluminum and carbon.
    Also, when you had the EGR valve out, did you look down into the intake whole where the EGR plunger goes? If it had lots of carbon in there, you need to clean that up. Dis-lodged carbon can cause all sorts of problems.
    Also, check your timing, this can cause some problemos. I just had to replace the entire distributor on mine.
     
  14. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    Re: Failed inspection - EGR related problem

    No, not kerosene in the crankcase!!!

    Maybe 2-3 qts. ATF to 2-3 qts. oil, but NOT KEROSENE! It's too thin to lubricate a running engine!
     
  15. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Joined:
    Dec 16, 2000
    Posts:
    1,669
    Likes Received:
    0
    Location:
    Sioux City, IA, USA
    Re: Failed inspection - EGR related problem

    I was wondering that too! The light HAS to come on because their is a code. Look below your break release handle for the diagnostic port. With the ignition off, take a paper clip and jump the two upper right ports. Then turn the ignition to the run position. Your light should blink once, pause, then twice real fast. It will do that three times and then begin to read off your codes.
     
  16. 90K5

    90K5 1/2 ton status

    Joined:
    Jun 1, 2000
    Posts:
    3,719
    Likes Received:
    0
    Location:
    Lubbock, TX
    Re: Failed inspection - EGR related problem

    As I've said a few times in this thread, I know how to check the codes, but for some reason it goes off randomly also, and the code seems to be erased when I turn off the truck. I also did get a really bad idle with the EGR off, sounded like an air compressor almost, so the passages are fine. I'll look for vac leaks and then try the IAC
     
  17. 90K5

    90K5 1/2 ton status

    Joined:
    Jun 1, 2000
    Posts:
    3,719
    Likes Received:
    0
    Location:
    Lubbock, TX
    Re: Failed inspection - EGR related problem

    Any more comments on kerosene or ATF?
     
  18. scavenger

    scavenger 1/2 ton status

    Joined:
    Mar 31, 2000
    Posts:
    111
    Likes Received:
    0
    Location:
    Southern Wisconsin
    Re: Failed inspection - EGR related problem

    The problem you are having appears to be very similar to the symptoms our 1989 Astro Van was having. In the end (after changing several parts) it turned out to be a bad knock sensor. We were having a a strong smell of unburned gas (at times), and the check engine light would come on when we attempted to pass a vehicle, or go up a very steep hill. The light would then stay on until we shut it off. If we started it back up a minute later the check engine light would not be on. Maybe someone on here can tell you a way to bypass or check the knock sensor before buying a new one. Hate to see you spend more money on something you don't need........been there, done that....Pat
     
  19. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,975
    Likes Received:
    189
    Location:
    Roy WA
    Re: Failed inspection - EGR related problem

    You mentioned rough idle, heres something I got today from another list, not sure if its applicable:

    "It stands for (I)dle (A)ir (C)ontrol, its the big square 4 wire plug on the throttle body itself. It will "unthread" from the throttle body, its common for the passages in the TB to get "coked" up and cause idle problems. As long as the TB itself is not worn out, carb cleaner will clean it right up. Bill


    I replaced this today along with a rebuilt delco 78 amp alternator (the Camaro MPI alt wasn't in stock) and it runs SWEEET. has just a slight drop in volts in idle but it is still right around 13 with the stereo on. I must thank everybody who helped me narrow this problem down. now I don't have to drive with both feet. The only thing left to do is get a new windshield. and eventually a V8, but I gotta blow this 4.3 up first. Thanks again. you guys probably saved me a few hundred bucks by not bringing it to the Goodwrench guys."

    What RPM did you fail HC at? Idle? I still don't see how the O2 sensor isn't seeing this, but I'm not sure if the O2 sees a rich condition for too long, if it will trigger the light.

    I've said it numerous times to numerous people, get a $150 scanner, and see whats actually going on. You'll be able to SEE whats going on, not guessing. You'll see if your exhaust is rich, you'll see your knock count, and all real time. You can leave it hooked up while you drive to monitor as well.

    This is the one I've got, again from another e-mail, with a link:
    "I bought a refurbished Auto Xray a while back
    &gt; &gt; for $95 shipped. The company is www.Autocheckup.com.
    &gt; &gt; It will work on all OBD1 vehicles with the proper
    &gt; &gt; cable."

    I paid like $130 off Ebay, and got all the cables for Ford, GM, and Chrysler. OBD1 covers up to '95 on GM IIRC, (which includes TPI, TBI, and CCC) and I've already used it on 3 different vehicles. It is excellent.

    Add up the costs so far, and potential cost of replacing suspect parts, compare to the $100-$150 you can get a used or refurbed unit for. You can always use it and re-sell it. My opinion of course.
     
  20. pr1aw

    pr1aw 1/2 ton status

    Joined:
    Sep 17, 2000
    Posts:
    144
    Likes Received:
    0
    Location:
    San Diego CA
    Re: Failed inspection - EGR related problem

    I replaced a CAT 1 year and the next had to replace again. Under warranty my work. Made the difference. I was over by 200 ppm. It was a Pep Girl cat. I passed after replacement.
     

Share This Page