Let's have a look at this old 1989 Chevrolet C-4 Corvette with the 5.7 Port F.I. engine and see why the heck this thing will not start when the engine gets up to temperature. It starts out running OK but then takes a turn for the worse.

48 thoughts on “Chevy corvette – no start when hot the diagnosis”
  1. Avataaar/Circle Created with python_avatars tube-dude says:

    Just subscribed yesterday. Really liking your YT!

  2. Avataaar/Circle Created with python_avatars Mike Nomath says:

    Instantly recognized the symptom. It's a bad pickup coil in the distributor. They fail a lot!

  3. Avataaar/Circle Created with python_avatars James Price says:

    MY FIRST VIDEO.. i feel so special………..:)

  4. Avataaar/Circle Created with python_avatars NunyaBusiness says:

    How much is one of these diagnostic handhelds? Having this data would make troubleshooting so much easier.

  5. Avataaar/Circle Created with python_avatars Alan Rose says:

    Or the new fuel eats the seals…

  6. Avataaar/Circle Created with python_avatars Madeinusa says:

    You're a great technician no question about it. But frankly you're wasting your time on this old motor with old wiring harness old fuel pump old injectors hold everything including OBD1. PITCH and SELL the customer a new motor new wiring harness OBD2 new fuel pump new everything car will go another 200,000 miles you got to pitch these customers bro the cars going to break down again on him. You know its true. DO EVERYTHING RIGHT THE FIRST TIME FOR HIM. CHA CHING

  7. Avataaar/Circle Created with python_avatars Antonio Cobb says:

    I sprayed starter fluid in it and still just turning over like it wanna start but let it sit for couple hours and it starts back up

  8. Avataaar/Circle Created with python_avatars Antonio Cobb says:

    South main auto repair I have a 97 trans am that start up and run awhile then when I shut it off it want crank back up I change optics spark coil ignition module fuel pump and filter I'm at a stand still I don't know what to do about it can you please help me out

  9. Avataaar/Circle Created with python_avatars charles stacey lindsey sr says:

    Vacuum leak check fuel pressure regulator,and return fuel to tank

  10. Avataaar/Circle Created with python_avatars charles stacey lindsey sr says:

    Vapor locking ,cool down she cranks back up

  11. Avataaar/Circle Created with python_avatars Nahim Ibrahim says:

    A true pro at work! Excellent video!

  12. Avataaar/Circle Created with python_avatars Chris Bentley says:

    Wow, that's a beautiful Car. Must be great to have the money that you can just drive it 400 miles a year to Walmart and back. I bet it hasn't got the old Rust Belt issue underneath. The servents probably wipe it down and valet it after each spin around the block. Not envious much lol. Good luck to him. But at least he knows where the best mechanic/technician is in Town. You want it fixed properly and not be ripped off by some cowboy hitting it with the parts bomb then bring it to Eric O. Still a beautiful Car in excellent hands. Must be a dream to drive. But if I did live on that side of the pond then I would drive across Country/State to have either Eric O, Ray or Ivan to fix it for me. There are probably many more out there but these three are the guys I'd trust with my Car even if it isn't as beautiful as this one.

  13. Avataaar/Circle Created with python_avatars Reg Peeler says:

    Hey there. Having this issue with 64 impala. 283 engine rockchester carb. You mentioned that you going to do a part 2 to see if fixed. Did the owner ever comment or bring back to let you do part 2?

  14. Avataaar/Circle Created with python_avatars Fred Sorrell says:

    Its spark

  15. Avataaar/Circle Created with python_avatars John K says:

    My Avalanche had exact same problem and Chevy could not figure it out and would send it back to me every time and tell me they could not find anything. With only a few thousand miles left on the warranty it started to miss fire while I was on the road, I punched it something blew hard, limped it into the dealership that night threw my keys in the drop box with a note, I think you can find the problem now, they had to redo the whole top side of the engine.

  16. Avataaar/Circle Created with python_avatars Bob Wright says:

    You know the day's turning to shit for ya when the Kentucky tune-up fails to do the trick.

  17. Avataaar/Circle Created with python_avatars Artemio Panganiban says:

    Do you have any idea what spare parts from other vehicles brand or model fit to my 2005 Dodge grand caravan sxt vin# 1D4GP24R25B225906 thanks. Like front mounting, air filter, rack and pinion, etc i am a filipino doing diy to my vehicle Dodge. Keep safe and stay healthy.

  18. Avataaar/Circle Created with python_avatars Artemio Panganiban says:

    How can i check the problem is when i turning the signal to right it okey but when i turning to left it same the right is flashing but the hazzard is okey and i could not able to see the problem, what would i do, can you send me the diagram of 2005 dodge grand caravan signal light electrical outline thanks.

  19. Avataaar/Circle Created with python_avatars chris cash says:

    I'm no computer wizard but my experience with Chevy small blocks has always been boiling fuel like vapor lock and shorting out hot coils meaning temperature hot not fire hot . I can not wait to see your findings ,To see how bad my guess is . Great video you got me hooked on your work . Thanks

  20. Avataaar/Circle Created with python_avatars Mechanicsville804 says:

    Great work and pretty dog!
    John 3:16
    For God so loved the world that he gave his only begotten Son that whosoever believeth in Him shall not perish but have everlasting life.

  21. Avataaar/Circle Created with python_avatars 79tazman says:

    on older FI cars it's good to pop the injectors out and get new ones or send them away and get them professionally redone and cleaned especially on cars that get more sit time then run time. I deal with lot's of FI cars that have sat for a long time and 99% of the time it's the fuel tank and injectors that need to be cleaned for it to run great and I kind of guessed as soon as you said don't run when hot and runs like poop after it does run it was the injectors. I bet that 30 year old car has never had those injectors professionally cleaned or replaced.

  22. Avataaar/Circle Created with python_avatars mrmusic248 says:

    Can we clone this guy into a super race of honest, competent auto mechanics ??
    I've watched "Mr. O" for years, and he has saved me loads of cash by showing how easy some of these repairs are, and which ones I better not try to do in my driveway/garaage.
    The fact that he's a stand-up husband & Father, just adds to his integrity.

  23. Avataaar/Circle Created with python_avatars 3dvorator says:

    a good set of bosch III 22 lbs and your good to go…

  24. Avataaar/Circle Created with python_avatars Klaus Schreyer says:

    You don't need to hook up Scopes to Injectors actually pulse Noide light is good enough Stephenscope good tool listen to injector clicking no clickie no workie when Engine running also check ECM Electrical signal to injector Noide light should flash while engine is running. ECM Controls Injector Electrical Signal on Negative Side Positive side is Fused on in Crank and On key position.ive seen 4-5 injectors fail causing no start because Resistance was to low shutting down Driver's in ECM which is Fail safe so don't burn up ECM Board even though GM had issues with ECMs too those years. Also Check Fuel Pressure with Engine running should be More than 40 lbs rev engine pressure should increase 5 lbs or more. Rest Pressure test turn off engine look at Fuel pressure gauge Pressure should not drop for at least 20-30 min very little if pressure drops fast may have Faulty Check valve in fuel pump or hose between Fuel pump and Sending unit may have split or hole or Leaking Injector or faulty pressure regulator.takes a expert like me to figure that out. Some insight of how system works and Diagnosis

  25. Avataaar/Circle Created with python_avatars Klaus Schreyer says:

    Check your injector resistance cold and hot with VOM 2.0 ohms to low shut down ECM Injector Drivers. Saw a lot of Fuel Injector Problems on Tune ports back 80s and 90s Replace all injectors it's a lot of work removing upper plenum and Runners to get to the Injectors.

  26. Avataaar/Circle Created with python_avatars Klaus Schreyer says:

    Let me guess Fuel injector resistance to Low shutting off ECM Driver's or Fuel pump problem

  27. Avataaar/Circle Created with python_avatars T Smith says:

    I had a Honda car they did the same exact thing it was vapor locked

  28. Avataaar/Circle Created with python_avatars Blake Harvey says:

    what oscilloscope software are you using? Does Autel ever specify a name and version?

  29. Avataaar/Circle Created with python_avatars Jamie Comer says:

    @South Main Auto Repair LLC awesome job, just figured out how to use analog amp meter to read voltage, next will be digital, gas soak is junk, just like the oil bath for wheel bearings on tractors and trailers instead of old school grease

  30. Avataaar/Circle Created with python_avatars Nate Davis says:

    Im pretty surprised at how sophisticated OBD1 was.

  31. Avataaar/Circle Created with python_avatars Bobby says:

    Cool, watching this video today and going to part two……….Dec. 25 / 2021

  32. Avataaar/Circle Created with python_avatars Mike Copenhaver says:

    75 Torino 302 no start when hot. Weak Springs on weights in distributor, wouldnโ€™t retard.

  33. Avataaar/Circle Created with python_avatars Mike Copenhaver says:

    I Believe I have hauled Potatoes Past Your Shop

  34. Avataaar/Circle Created with python_avatars John Scavarda says:

    Spectacular video. Most interesting. Love this stuff. Thanks for sharing.

  35. Avataaar/Circle Created with python_avatars Heyyy says:

    This comment will probably be wasted because it's a 6 year old video and Mr. O won't see it, but…
    When you apply a voltage across an inductance, the current ramps up slowly, but when you apply a voltage across a resistance, the current shoots up to its final value immediately. On the scope this appears as two curved lines, one ramping up and then one decaying to zero for an inductance whereas for a resistance you get a square with a vertical line on switch on followed by a horizontal line and then another vertical line at switch off.
    An inductor is anything with a coil such as a motor, solenoid or fuel injector. A resistance is things like connectors and short circuited coils.
    So the good injector was recognizable by the curved lines on the scope and the bad injector was recognizable by the straight lines.
    This is a useful way to distinguish, when the current drawn by a shorted coil is close to the current drawn by a good coil. (A high resistance short.)

  36. Avataaar/Circle Created with python_avatars grabir01 says:

    opti

  37. Avataaar/Circle Created with python_avatars Dalton says:

    Another quality interpretation of how not to throw parts at the problem, as so many inept garages do.. Keep plowing deep S.M.A.P. ..

  38. Avataaar/Circle Created with python_avatars slayer 1 says:

    Is it me or does it sound like he's just having massive fun that day ๐Ÿ˜Ž just having a rocking good time LOL

  39. Avataaar/Circle Created with python_avatars Herman Rogers says:

    All new spark plugs fuel filter fuel pump

  40. Avataaar/Circle Created with python_avatars Herman Rogers says:

    If it was my car I would start buying new parts until I solved the problem case closed thatโ€™s a nice car and it needs a lot or he will be back in the shop after a few thousand miles

  41. Avataaar/Circle Created with python_avatars Jim Thompson says:

    gm quit building good cars @ tks in 1974 vega first 3.8 401 cady bad junk trans. they need to sell cow poop or water melons get out of auto industry!!!!

  42. Avataaar/Circle Created with python_avatars William Roberts says:

    I worked at the dealership and old gas will cause injection to stick. When thereโ€™s no fuel on the inlet what is there beaks down and sticks injector.

  43. Avataaar/Circle Created with python_avatars Kerry Mills says:

    Typical of the C4, replace the injectors.

  44. Avataaar/Circle Created with python_avatars J Kaehler says:

    I'm jumping the gun on what I think is wrong with it before watching the video. And what I think is since it's hot and runs crappy and then cools down and runs fine sounds like an EVAP issue we shall see.

  45. Avataaar/Circle Created with python_avatars 1Who GotAway says:

    I had some cool packs go bad >>> and once it was warmed up it would fire ๐Ÿ™‚ BUT only when it was cold >>> only thing I can think of boss >>> PEACE to you and yours man good luck wit that one

  46. Avataaar/Circle Created with python_avatars Cow Girls Can! says:

    What about the yuck at the bottom of the fuel tank having condensation in it and that expanding rapidly inside of the injector cuz of its inherent heat that could mess up multiple injectors at the same time from running out of gas right?

  47. Avataaar/Circle Created with python_avatars Alberto Sierra says:

    Fuel filter maybe lets see

  48. Avataaar/Circle Created with python_avatars pleasecho2 says:

    Wouldn't you be tempted to tear the old parts down autopsy?

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