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WOW... that's all I have to say about this one. I thought it was gonna be just an other quick "lets have a look at this 02 sensor video" boy was I wrong. When I looked at the scan data we noticed more problems than just what the money light was on for! Enjoy!
--Eric O.
Disclaimer:
Due to factors beyond the control of South Main Auto Repair, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Main Auto Repair assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. South Main Auto Repair recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of South Main Auto Repair, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not South Main Auto Repair.

50 thoughts on “Engine lights and 02’s and vacuum leaks oh my!”
  1. Avataaar/Circle Created with python_avatars Kevin Rowan says:

    I've been watching your site for over a year now and am very impressed with your ability to troubleshoot and find wiring problems. I've been a farm mechanic, shade tree mechanic since 1977. I really enjoy a challenge and electrical troubleshooting is my favorite. But I get lost at times in my work. But I never give up. When it comes to watching your Shows, I love the in-depth explanations and information you pass along to us. It's greatly appreciated. You are a gifted person. I wish everyone in the automotive industry could be as and honest as you. Great job, keep up the good work.

  2. Avataaar/Circle Created with python_avatars Rod Marin says:

    Great video. Always good learning, whether it's new topic or something you'd seen before. The plus here is always a good idea to investigate to the hilt. Including matching harnesses. 😂

  3. Avataaar/Circle Created with python_avatars Doug Kelley says:

    Great video for maf vacuum leaks

  4. Avataaar/Circle Created with python_avatars corkforbrains says:

    On the slim chance that you never receive a "thank you!" for these videos, you are certainly receiving one from here! Between this video and the one that you did replacing the injectors on a C4 Corvette, I've found my way out of a pretty severe mental block and I have only you to thank for it!! Happy Easter my friend and thank you Once Again!

  5. Avataaar/Circle Created with python_avatars Jeff FromChicago says:

    Very knowledgeable

  6. Avataaar/Circle Created with python_avatars James Dvorak says:

    How is it that I don't have a test light?!? Sheesh. Thanks Eric O. for another educational and entertaining video!

  7. Avataaar/Circle Created with python_avatars Antonio Claudio Michael says:

    Surprised it didn't have a code with the vacuum leak and the Dirty maf sensor Causing the huge Fuel trim corrections making the system Rich because it was Way to Lean nice work Eric O @SouthMainAutoRepairLLC

  8. Avataaar/Circle Created with python_avatars Johnny Sechrist says:

    Had truck in the shop that the AC would work great when hood was open and didn't with it shut. Was worn out thin vacume line. Looks like a possum bag to me.

  9. Avataaar/Circle Created with python_avatars klumpy103 says:

    So am guessing that the MAF sensor wanted it rich, the vacuum leak caused it to be lean and there seems to be some sort of halfway house where it was wrong but not wrong enough to light a code…
    .Cool beans

  10. Avataaar/Circle Created with python_avatars kerzwhile says:

    BEST "free" edubacation on the planet. Everyone should throw Eric a bone! 😉

  11. Avataaar/Circle Created with python_avatars 40cleco says:

    Negative and positive "pressure" is how science defines it.

  12. Avataaar/Circle Created with python_avatars D.j. says:

    Thumbs 👍 from me!!!!

  13. Avataaar/Circle Created with python_avatars Dependable Auto Truck says:

    best explanation i have ever seen thanks good job

  14. Avataaar/Circle Created with python_avatars donald lawton says:

    I have a 96 s10 LS 4×4. Vacume leak caused 4wd failure. Replaced all vac. Lines.tested everything ,in the vacume system. While installing shift motor I discovered the transfer case was shot. And seal between trans and transfer was leaking. Installed a new case with manual shift. While moving fuel lines to hook up the shift linkage. I cut my hand on the 1/4 inch steel vac.line The floor pan seam sawed through. I missed the charcoal canister. Brain fart moment,lol!!🤪

  15. Avataaar/Circle Created with python_avatars Michael Berry says:

    2 brake cleaner climaxes, very thrilling! ( – :

  16. Avataaar/Circle Created with python_avatars martin012710 says:

    Thank you so much, every time!Watch your videos I certainly learn something new, once again thanks.

  17. Avataaar/Circle Created with python_avatars William Cantrell says:

    I enjoy and learn something from all your videos. Keep keep it up.

  18. Avataaar/Circle Created with python_avatars sheeshalready says:

    Thumbs down are either trolls or haters. Neither are worth our time. Many modern vehicles sound like there is a vacuum leak when there is not. Great job, again, on a great video of just running down a step by step process of diagnosis and repair.

  19. Avataaar/Circle Created with python_avatars Rich Hopkins says:

    New subscriber, watching and learning.
    I just watched you channel on o2 sensors and vacuum leaks.
    This was very informative and I really appreciate your video. As with all the previous videos, binge watching. I find them very educational.
    Thank you again for all you do!

  20. Avataaar/Circle Created with python_avatars LeewardStudios says:

    I don’t even like LTFT above 3%. Had 15% on wife’s Hondoo . Not a vacuum leak though, bunch of small cracks in the pipe to the throttle body, but after the MAF sensor. Smoke test didn’t find it but would cause LTFT to go up at highway speeds but also stay up, in the 8% range at idle. Only reason I found it (was underneath and in the bellows so missed it on visual) I took pipe off to clean throttle body and it cracked in half. It’s a 2006

  21. Avataaar/Circle Created with python_avatars That American says:

    Chevy Mass airflow sensor Needs replacement always..lol yeah I always try the cleaners first.

  22. Avataaar/Circle Created with python_avatars Oscar Lopez says:

    If this fixes my p0300 im going to be so angry at myself

  23. Avataaar/Circle Created with python_avatars the reptile guyz says:

    So did you fix that idler pulley or whatever else that was going wrong with the front of that engine or at least to tell the guy that it was about to throw a belt lol

  24. Avataaar/Circle Created with python_avatars John Robertson says:

    Here kitty kitty kitty……

  25. Avataaar/Circle Created with python_avatars Alan Crawford says:

    So if the damn thing grenades during your 3000 rpm testing are you responsible?

  26. Avataaar/Circle Created with python_avatars uglysteve1 says:

    As much as I enjoy your videos it’s not for me as I have hands like catcher’s mitts. My garage would be called Steve and small person.

  27. Avataaar/Circle Created with python_avatars Nelson Eichelber says:

    Great info.

  28. Avataaar/Circle Created with python_avatars Speed Ineed says:

    Best learning video You have ever recorded.Third time to watch it ,and see something new each time. Thanks!!

  29. Avataaar/Circle Created with python_avatars Alvin Brown says:

    I used to work in the field, and I've seen a bunch of these videos. And this technician is topshelf.

  30. Avataaar/Circle Created with python_avatars Alvin Brown says:

    Agreed Wyatt

  31. Avataaar/Circle Created with python_avatars Nelson Eichelber says:

    Great info

  32. Avataaar/Circle Created with python_avatars Chas Boomer says:

    Great job Mr. O! I've been trying to figure out why my 08 Chevy Uplander minivan 3.9 V6 is not getting a little better mpg than it is, about 5 to 6 mpg less than it should be. This the third one I've had it is a flexfuel this time. Oh and thank you guys for helping learn how to use my hand held scan tool even if HF it works good for what is. Uplander is a work in progress.

  33. Avataaar/Circle Created with python_avatars tv says:

    You would of verified but your not a rocket surgeon and great tenacity.

  34. Avataaar/Circle Created with python_avatars Clint T says:

    I also love the non-swear words 🤣 what the thunder ❤️.

  35. Avataaar/Circle Created with python_avatars Clint T says:

    I love that you tested the wires going to the sensor before just replacing it 👍. When I see the hose loose underneath the hood I imagine like someone trying to see if you are a scammer 🤣. Good job man 👍

  36. Avataaar/Circle Created with python_avatars Curtis Muma says:

    Too long. Sorry

  37. Avataaar/Circle Created with python_avatars c5back9 says:

    Hi Eric, My daughter’s 05 Tahoe (which she dearly loves incidentally) has a money light issue. I’ve taken it twice to a friend who operates an independent shop. They clear codes and have run smoke tests (twice) with no determination of the source of a leak which we suspect might be causing the codes. My daughter’s ex-husband being somewhat of a useless mass of carbon, tried fixing the truck himself a couple of times and ended up replacing the downstream 02 sensor, but of course he cheaped-out and bought a Chinese knock off to save about ten bucks at Auto Zone. He claimed to have had a buddy of his who knows what he’s doing diagnose the problem. That’s how he came to the conclusion that the downstream O2 sensor was the culprit. I can’t have my granddaughters out there riding in a truck with issues which might at some point cause a breakdown on I-95. Additionally the truck has failed state inspection now, and she can’t get her registration renewed until the problem is fixed. So I’m done playing around with it. I ordered new upstream and downstream O2 sensors and a new MAF and will put all three in this week, then I’ll clear the codes using my cheap tool and see what happens. I also found the vacuum leak on the truck in this video to be interesting. Given its location and fact that it’s not easily seen, it could be where the leak on the Tahoe is and might not have been detected during smoke tests. So I’ll be checking that hose on her truck for sure. If these don’t do the trick, I’m driving it to NY and leaving it with you so you can give it a try. Its only 4 or 5 hours to your lovely area and I don’t care if it takes you two weeks be able to get to it. I’ll leave it with you to get it fixed the right way. There are a few other things you might be able to help with too. Lucky for you this truck lives in a more southern state and hasn’t been exposed to the road salt you fellas suffer with up there. So rust won’t be what you typically see on NY vehicles. I’m just tired of playing around with people who are supposedly skilled and trained experts, but who don’t know much more than me (a retired old sales guy). I know these people are well intentioned but it seems to me that they don’t have the skills necessary to properly diagnose and repair these systems. The dealerships are even worse I’m afraid. They hire youngsters fresh out of tech school and then set about training them how to increase revenue for the dealership. BTW, this isn’t a rant, so please don’t mistake my attitude here and get the idea I’m a snobby jerk that you don’t want to deal with. I’ll be nice I promise. So if by chance you happen to see my comment here, you might be hearing from me in a few days. Thanks, BK.

  38. Avataaar/Circle Created with python_avatars James Koralewski says:

    Real funny reference to the Forest Gump comment "that's all I have to say about this one".

  39. Avataaar/Circle Created with python_avatars John Schultz says:

    You helped me identify a vacuum leak for my roommate I would have never found.. on that exact same truck.

  40. Avataaar/Circle Created with python_avatars William Mason says:

    Just a few idiots what is not to like

  41. Avataaar/Circle Created with python_avatars Venture Electronics says:

    For the amount you paid for that thing, It should have an auto setup for any vehicle.

  42. Avataaar/Circle Created with python_avatars lucky5wonder says:

    Thanks for explaining fuel trim, I must of read forums and watched 30 videos, and still not understanding it. Tested out your knowledge on my wj, found the leak, and now idles perfectly. Can’t thank you enough for making these videos. Great story teller and teacher, keep up the great work, thanks again bud.

  43. Avataaar/Circle Created with python_avatars Shane Harrison says:

    I remember dad haveing a fit about his wipers on his 60 willys jc5 they work great til you start moveing well dad pulled off the vacuum tank and the little check valve and tossed them although he got the jeep and they were in a box on the seat and one morning befor school I went out run new hoses and installed the check valve and vacuum can and balls and check valves for the items that needed vacuum to work properly and went washed up and took off for school

  44. Avataaar/Circle Created with python_avatars Shane Harrison says:

    Yep keeping my wieners in the ice box for now lol

  45. Avataaar/Circle Created with python_avatars twincam825 says:

    Thanks posting you have helped me fix a problem i had with my 2004 express van 6.0 lq4 i had 16 % long term fuel used a smoker i made and found
    3 vacuum leaks.

  46. Avataaar/Circle Created with python_avatars Don Munro says:

    I actually learned a lot. I've got a solus ultra but don't use it enough to be proficient with it. Thank you for the lesson. I also like how you don't just throw parts at it. You test it out then verify the repair.

  47. Avataaar/Circle Created with python_avatars Mark K says:

    I wish I lived by your shop

  48. Avataaar/Circle Created with python_avatars Mark K says:

    I know you say you’re not ASE certified etc., but you’re probably the best mechanic I’ve ever seen. I don’t take my car to the shop because I believe 95% of the mechanics are idiots, I would rather do it myself.

  49. Avataaar/Circle Created with python_avatars Steve Zickefoose says:

    I've been watching your channel for a few years. I am not an auto tech or in the auto repair industry. But after watching your videos, and especially this one, if I were young again, and was choosing a career I would want to diagnose and repair automobiles. Excellent video! Many blessings to you and your family.