This guy is really a blessing. It's nice to watch someone who really knows what he is doing.

I have an '89 Iroc-Z with the L98 engine. I had the same problem and it turned out to be faulty injectors. There was way too much resistance for these things to fire. I got a fresh batch from injector connection and never had start issues since. Great video on how to diagnose a no start condition on an L98!

It is good to see there are still technicians in the trade,and not just all parts changers.Outstanding video,i have the same year car.

Eric deserves a beer and a handshake (actually an elbow bump during the corona pandemic) for the time and effort he puts in to his videos. He shows you how to go about things right, armed with knowledge and excellent equipment to logically approach the diagnosis. Fantastic presentation and explanation of how to go about tracing out the problem. You da man. Hope you’re staying safe and healthy in NY state

32:55 that's cool how the fuel pressure reacts basically instantaneously with the throttle. Awesome video and diagnostic process! I've been learning a massive amount from your huge library of videos! I also love how even your videos from 7 years ago are still just as valuable and fun to watch as your currents ones!

I worked in a GMC dealership in the early nineties, worked on a ton of these tpi injection systems. Replaced a lot of injectors. One big issue these had was when ethanol fuel came out. Fue would flow over the windings to keep the injectors cool. High concentration of ethanol would strip the insulation from the copper windings shorting the injectors. Gm even had a technical service bulletin on the problem

Watching Eric always reminds me of how many tools I DON'T have.

Second video I watched of this guy .... damn, he knows what he is doing and knows how to use his diagnostic equipment....he had my attention every moment - nothing boring here !!!! I would change all the injectors to be 100% I cured the problem. Very well done - didn't change a dozen parts to eventually solve the problem !!!! Great narrating too !!!!

With a resistance reading that high, it's a wonder that the ECU didn't get fried from too much current draw! You are an amazing diagnostician.

Eric, love your videos. You are THE perfect mechanic. Master of mechanical AND electrical / electronic, computer and old school analogue. Great deductive and reasoning process of thought. Articulate and humorous, you put together a great video, a feat in itself. Do I sound like a fan ? You bet !

I'm amazed you had a touch screen scan tool that supported OBD1. To me, OBD1 is sitting in a broken car in the garage with my dad as he clicked the key on and off for the secret handshake, then counting the lights flashing to get the code. Fond memory I think of every time I have to fumble with a code reader (especially before I owned one)...

This is the best freakin channel on youtube that helps you learn how to make a variety of repairs along with what tools to use and how to use them!! Thank you SMA, my favorite channel.

Eric: There's a cop. Also Eric: Give er' the beans! Again also Eric: OOOOHHHHH BABYYYYY! It's like my V-TECH! 😂

Love the diagnosis videos. You have a great logical process of diagnosing and its very entertaining and educational as a DIYer to watch a pro at work. Great video Eric!

It’s rare that I watch a 55 minute video but this level of troubleshooting, knowing waveforms and having the right tools makes him a credit to his profession. This is a very cool video and explained in a form that is understandable. Bravo Zulu sir... I will keep watching.

This exact thing happened to my 91 olds Cutlass. The mechanic didn't believe me until it left him stranded on lunch. He kept throwing parts at it, coil packs, ecm, all while trying to charge me and not solving the problem. Needless to say, this issue dissolved a long relationship i had with this mechanic. I appreciate your sense of diagnostics. You do a great job! Thank you for these videos!

Suggestion for Part 2, add some 80's hairband music like Whitesnake or Poison and you'll be all set!

You are a great diagnostician. The number of times you rechecked to confirm the car is not starting was remarkable. And yet, that's just what diagnosis of complex systems needs.

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. ..

Eric, you are one lucky guy. Mrs. O helps around the shop, books you good meals, and has a sense of humor like you! One lucky man.

From my experience, a single shorted injector on a bank-fired PFI system will pull the entire bank down and prevent it from firing. Quite common on OBD I GMs. Interestingly, those Multec I fuel injectors that GM used, the coil is actually exposed to fuel ; they use the fuel to cool the coils. Allowing fuel to sit for a long time, or even using harsh injector cleaners, can eat through the insulating varnish on the coil wires and short the injector. Luckily, whether by design or the limitations of the technology of the day, the injector drivers on these GM PFI systems are built like brick shithouses, and usually survive a shorted injector or two. Certainly can't say the same for these new SFI systems! Awesome video, Eric! Great diagnostics and good process!

Eric, Thanks for taking the time out of your busy days to make these Very interesting videos.!!! I myself is from a long line of auto Mechanic's from Shade tree to Professional... And every time i watch your video's i find them very interesting and your very thorough with your diagnosis... Thanks Again.!!! Ky Ridge Runner...

LOVE the scenery of you town. Reminds of Mayberry, Andy, Opie, and Barney when I was a kid.

I always want to own this model of Corvette as a collector car. This video taught me about this model year with common engine problems to look out for. I like the diagnostic tools and your trouble shooting method and approach. Thanks for posting!

Another excellent detailed video! The 89 Corvette used the Multec injectors (Gray colored body). The injector coils were exposed to the fuel. Eventually the insulation of the coil winding's erodes and short out. One bad injector can cause problems for the other three injectors on that bank.

This is one of the few I wouldn’t be able to figure out. I’ve watched a ton of your videos and try to figure out in the beginning. I wouldn’t even know where to start. It takes a real expert. You would definitely be my mechanic.

Sticking that badge on that valve cover tells me you also do what I do when I find loose change in a customer's car, goes into a zip-lock bag and put where the owner can find it. That also applies to anything else found in places where things get lost. You have integrity Eric.

As a technician, I really appreciate his approach, and I actually learned something useful from him. Worth subscribing if you're a young tech starting into this I think. Keep your mind and eyes open kids, you'll learn a thing or two.

I love the look of the 1980's corvettes even though a lot of people probably like the 60's and 70's ones

These are some of the best repair videos I've ever seen. Your one smart guy. Thanks for the posts. Keep up the good work.

I have a 1989 Ford Bronco XLT with EFI. Has a 5.0L V8. I bought it as a plow truck. I live in Taxachusetts. I had the issue of no start when hot. Spark plugs had a gap so huge. I changed the spark plugs, wires, cap, rotor, ignition switch, motor control unit, starter motor, ignition control valve, EGR valve, EGR valve sensor and wires, yanked off the throttle body and cleaned it and inside the intake, Throttle position sensor, Intake air pressure sensor, coolant temperature sensor, MAF sensor, just a lot of stuff and all of it looked like it was good to change it anyway even if it wasn't the issue. I finally changed the ignition coil and the wires and connector that came from it and that is what fixed my issue. The gasket that kept the rain out from under the hood was gone so after a rain, water dripped onto the coil and the bracket it was on. The bracket was rusty and the wires and connector were nasty looking. I am not sure if it was that or the coil wire itself, but after I changed the coil and wires the no start when hot was fixed. Like I said, all that other stuff needed to be changed weather it was working or not and only a few things were expensive but not so much money it was ridiculous. The plow lights had butt splice connectors on it and it was all a mess so I yanked all that off and redid it. The high beam switch on the floor that you step on for high beams had no wires to them and when I found them they were all twisted together and the ends were stripped and twisted together, power and ground wires all twisted together and taped. So of course I made that all neat and put in a new switch and had to replace the headlights because the high beam was blown out on both. timing may be off because it was loose as hell and you could move it by hand easily, but I played it by ear and now it stars and idles fine, but i didn't do it with a timing light. I replaced all the brake lines and the parking brake cables are new. I replaced the calipers, rotors, brake hardware in the drums. The ABS light was on and rear brakes were disconnected, but it wasn't the sensor. The guy wired the plow lights in the fuse where the ABS goes so the light was on. I redid it all to factory and the ABS light went off and everything works. I had to replace one of the rear axles, the bearing and seal and when you do that the Diff cover has to come off so I changed the fluid and cleaned off the rust and painted the cover orange. I am not a mechanic and all the stuff I did was from watching people like you do it on youtube. I did not have a check engine light come on but the vehicle didn't run for shit, so don't say "read the codes and go from there" because there was no codes. If it had a carburetor It probably would still be running good and I wouldn't be for sale. I hate computers and they do not belong in cars. Easiest vehicle I ever owned was a 1969 Malibu with a 230 cubic inch inline six with a one barrel carburetor on it.

Had an 86 Corvette about 12 yrs ago set a 34 MAF code when driving. Ran the usual tests and found nothing. Measured the resistance of the injectors and 5 were shorted. Replaced them and fixed the car. You never forget the ones that test you.

I think this was one of your best yet.....glad you didn't have to get towed for the test romp......

Great trouble shooting Eric. It pays to have the right tools on hand. I appreciate you explaining so much. I know that takes valuable time from your work.

I was ecstatic that you have the same labscope I have. You showed me more features I didn't know how to access. Great video, Boss!! Thank you!!

I can appreciate professionalism and the way you explain things. Most DYI videos the guys talk down to us as though we don't know a damn thing. But you speak as though we are one of the guys. Because you have to have some knowledge to even be interested enough to even watch videos like this. Thank you for sharing your experience and knowledge.

you deserve Great praise for your workmanship!

This one is amazing! Thank you for going the extra mile!

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.

Thanks for an informative and entertaining video Eric. You are an awesome mechanic and a person who is fun to watch while you work!

Thats really a nice tool to be able to trigger each injector individually.

Your camera work and videos just keep getting better and better. I don't even want to think how many hours it takes to do a video suitable for uploading. Keep'em coming and thanks.

My 88 GTA (which sits) had this same problem....With pretty much the same identical issue....When she warms up she falls on her face... Spark is good, fuel delivery is great at first..dudes even dropped a new distributer in it... Still nothing... That is, until I saw this video...This boy is a rocket scientist !! mine was a bad injector driver due to jacked injectors from sitting... I give you a mega thumbs up with a bell !

“Take my word for it” ……you are the only mechanic that I would !

good job I have done 3 or 4 of them ,injectors all go to he'll on that car and the water pumps to. very well done Eric.

"Whoa, we're at nine hundred and eighty-three thousand RPMs. That's really zingin'"

Eric you have a gift So many times I’ve seen people on KZfaq and shut them off immediately because they’re not going anywhere or getting there very slowly you do a wonderful job I’m 65 years old still work on cars once in a while you inspire me to keep working good job

I really enjoyed that vid, I'm a 60 year old shade tree drag racer trying to keep up with the newer tech. You sure have the gift of teaching, was able to keep up with a bit of your coaxing. Thank you so much will watch part 2 the conclusion.

Wow, that's a mechanic ! Good job, Eric !!!

Nice diagnostic Eric with the Multec injectors. Very common problem with the older injectors shorting. As one viewer mentioned, best to replace them all. Keep up the good work...

GREAT Job Eric , Me worked at a GM Dealers for many years , its a common Problem on those's Port fuel cars. Just a simple ohms reading will tell ya what the deal is. If you have good fuel and Pressure. Another Problem with those's is the Intake gasket, they suck oil in from the bottom part of the gasket, and the intake valve is blocked from carbon build up , and not letting the fuel to reach the combustion chamber, And/or the valve seals. Your lucky living in a small town , no Traffic , for a good road test as well !! Keep the videos coming Eric , Love your dogs as well !!

I apologize if this has already been said, I don't want to search through nearly 800 comments. If you pause the video at 45:48 you can actually see the mechanical opening of the injector. That small little drop in the middle of the current ramp is actually the injector opening. You don't see that small little drop in the bad injector because the injector is unable to pull enough amps to lift the pintle off its seat in the injector. The reason you are getting too low of an ohms reading is because the injector is shorted internally. Since it is shorted the voltage is taking the path of least resistance and bypassing most of the injector coil, that is why the ohms is low. I really enjoy your videos. Keep up the great work.

I respect you and your work. I hope to be a great tech like you

Hi Eric, you live in a lovely area you lucky thing. Love the vids. WhitwellMike

Brother I want to thank you for helping I just bought a 92 that sat for 5 years bought it from a good friends shop after he put a fuel pump in I put a new optispark in had good spark still didn’t start oh yea the waterpump was leaking on old one started to go crazy I had no idea ,,,,then this vid yeeeehaaaaa tytytyt for setting me on pace 😉👍👍👍👍👍👍started right up

Eric O, I just watched all of your videos. this is far way the best vid I've watched. I'm a mechanic myself. but I've learned tons of diagnosing methods, thanks for your teaching how to diagnose etc, keep it coming! I'll keep on watching!

Thank you, Eric My car had the same problem, now she runs GREAT. Bill

OH MY GOD ERIC I MADE THAT TOOL! WOW GOOD OLE KAL EQUIP! Thanks

All this info and being able to sit in..sooo invaluable. This vid in particular helped me diagnose bad injectors. Ran rough once warm then awful on hot start...no power. Replaced and now runs well. Thank you for the guidance. Respect for all you do

I saw part 2 first. Listening to the bushing of this one, same symptoms exactly. Thanks so much. I'll do some diagnosis myself. Love your videos!

I’ve been watching your videos for a while. You seem to be very thorough, we need more mechanics like this. New sub here, keep the quality videos rolling. Best of luck in all your endeavors!

Well done Eric. I'd like to see some more OBD1 work. Great video and sound.

Really awesome seeing your analytical diagnostic skills in action.

Excellent diagnostic! Thanks for the good and bad injector graphs that is really helpful!

Great Video! Hardcore...., you have excellent command of electronic diagnostics...., two thumbs up!

Now I understand injectors...another fine video, my friend.

Great in-depth technical info, as well as diagnostic approach and conclusion. Very informative. Keep up the great work. We'll done!

I am a professional mechanic(8 years) but I have to say I learn a lot from you when you work on these older vehicles. Thank you. I’ve been spoiled by modern vehicles and their more modern computers giving me all the information I ask. It’s nice to see someone teach me to use noid lights in this day and age.

Man I hate when your videos end. Seriously I watched this and it felt like about 10 minutes. Keep it up brother! Love the long vids!

You'll probably never read this but anyway.... Don't forget, the higher the heat the higher the resistance; and vise-versa. Higher the resistance, higher the heat. That's why you read less than 2 ohms and later you read 8. The coil was cooling down. Learned that on F-15's 30 yrs ago and Ohm's law has worked for me every time. Learned a lot watching your channel, so keep it up ol' boy!

This is one of the best videos I’ve seen. It also hits close to home with my new project ‘87 Corvette in my garage! Just getting into the old-school OBD1 and looking for suggestions on my error for the MAF burn-off error. New relays and I can see the actual wire glowing after a shut off. Thanks for your great content!

Those older-style injectors were never meant to have 10% ethanol-laden gasoline sit inside them and heat soak for prolonged periods. If you think about it- an injector is a type of electric (stepper) motor. If any (even low a voltage) electric motor is kept from moving, or a "drag" or "load" on it's rotor- it will build up heat, and (especially in the small windings of these) become weak, and eventually burn out. The gumming properties of the ethanol build up, shorten the throw of the pintle, then this weakens and burns out the coils. Also- given the hygroscopic nature of ethanol (why it's not used in aircraft) I'll bet the insides are also rusty. Eric- after replacement of these- could you please autopsy the weak units and show us- to confirm or dispel these ideas? Thank you so much!

i really appreciate you taking the time out to do this video. if you think that scope software is a mess. you don't want to use the pc version

Good videos, I’ve been addicted to watching the last couple days. Thanks for the good info

Wow, you really know your stuff. Im an electrician and you were in our upper profession, as a mechanic. I know guys that been in my profession for decades and would be clueless. Your customers are blessed

I always look forward to your videos during the week. Love anything with wheels. You should do another day in the shop video.

I love it when you do the brake cleaner thing. lol

I have had 3 or 4 0f these and the antitheft systems are a big problem with the same symptoms your having, glad you got this one fixed. but you always do...

Can't wait for Part II. I always learn a lot watching these vids. You must have a ton of money spent on tools. Great job. Thanks.

Loved the music when the brake cleaner came out.

Fantastic diagnostic thought process and a new back up to the Verus when it craps out again :) the best part of the whole vid was the scenic drive just awesome scenery and the best part was when you drove past Opie Taylor's house, next time could you drive past Aunt Bees place.

This "old car" as you put it- shares many of the same parts as my '89 Reatta. Even though mine is a DIS ignition and also has MPFI- I can tell that engine is in a serious need of a *complete* tune up. The spark was intermittent and the wrong color (weak) which with HEI usually (mostly when hot) points to a dying ignition module (the dielectric grease usually dries up, then unit gets hot & fries).The injectors are gummed up (thanks corn-based alcohol). They used to make a product and procedure called *"Hot Shot"*. It was a can of concentrated cleaner, with an incorporated hanger-wire and hose, with a Schrader valve end. You attach it to the fuel rail, hang up the can upside down, disconnect the fuel pump (fuse or electrical plug) and run the engine- revving a few times- until the can was empty.They also make a similar tool- it's a refillable can (container) that uses shop air and your choice of cleaners (Seafoam is great here, btw). Also on this system- holding the accelerator floored while cranking- *shuts off the injectors* (in case it's flooded).That injector pulse on the noid light wasn't very bright, either. Depending on the location of a C-4s' ECM (under hood?) I can imagine their Quad-driver circuit(s) are weak and/or failing. I loved the drama over the BPC.

Howdy Erick, I recently had same problem with my 94 Vette. I watched your video and I thought my prob might be same as yours ended to be. I purchased new injectors from corvette mods, rep,aced and didn’t fix my problem. So, I ordered new optispark and water pump , I took old parts off with no problems. My 94 is very clean .did not show signs of oil and or water on optispark, I replaced both seals as well on timing cover, installed new distributor abs water pump, I also went through harness checking possible brittle wires and connectors. Ended up running new grounds from battery to injector rail ground point and body to block. Cleaned throttle body, already replaced icm, solenoid and the easy stuff a few months ago. I’m pleased to say your video helped me learn my C4 in more ways than most. After I put er all back together with new optispark, she purrs and runs great now. I’ve had her about 14 mos. hadn’t put 100 miles on her before she started the engine stall stuff. I believe my problem may have been related to insufficient grounding and or the Optispark replacement . Havnt found a for sure fix for similar problem. Thought I would share my results. Thanks for tutorials. HaulinAss Transport 1.

Hey Eric nice diag! When you called me up to share your findings on the Vette, I was surprised that you've never run across the shorted Multec I injectors on late 80s-early 90s GM cars... "That's because they're all in the CRUSHER" hahaha priceless! The MaxiScope looks pretty cool. Don't worry though, they will never get around to fixing the glitches...I've tries contacting overseas-based companies like Autel and OWON about their software and have gotten nowhere.

8:53 That view is amazing!

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

Appreciate the way you run through your diagnostic tool and how you explain what you're doing. Broke my next seven years ago so I've been out of the loop for a long time. But basically I was just a Master Mechanic and medium heavy truck for Cemex. Anyway buddy of mine in Manassas has a collection of Corvettes so I try and pick up on all the Corvette videos I come across. Coming across your page and the way you explain not just this car but all your other cars is very helpful and educational. If you've got some mechanic who's on the border of being a competent mechanic and a master or really good mechanic your page and the way you go about Diagnostics and explaining what you're doing could really help some younger guy who's on his way up on the talent ladder. Anyways, keep up the good work brother, please don't take it as an insult when I say it's very entertaining to watch how you go about doing things. I mean that in only the most positive way.

Holy cow! Thank you for bringing us along on this one. That was some Nth level diagnosing Eric! It is going to be cool seeing part II! For that engine, wouldn't typical Fuel PSI be in the 50 - 60 range? Or being multi-port injected, 30-40 psi is acceptable? Keep up the good work, and thank you again for posting this video!

Favorite part of the video was the road test when you said oh great there's a cop haha

Nice! I have been chasing what I thought was a heat soak issue on my Malibu ski boat which has port FI for about 3 years now. All the basics have always checked good such as fuel pressure, spark, and power to the injectors. I have never thought to check resistance on the injectors when it is acting up. Love the videos!

Very interesting diagnosis, straight to the point and thorough. I wish you were my mechanic.👍👍👍

Thanks for the vid!. from the get go I thought it was a bad plug or fuel pump. I own a 1985 but runs good. I'd go ahead and replace all the injectors.

Nice roads man

Thanks for the vid. One of the best. Keep it down to earth with the explanations, I even liked your lunch break segment.

Love watching your channel I do the same thing but on a smaller scale with a multimeter and a AutoZone scan tool my customers love that I can diagnose their car without guessing. I like your channel because there's no BS just facts you rock

thank you. i learned a lot on testing.you da mam.

Parents gave me a 89 vette. Did the same exact thing and ended up doing a ohm test right away and it was my 3 rear injectors on the right side bank of the engine. When it wouldnt start i would unplug those 3 crank it and it would fire right up. Plug them back in and tried to start wouldn't even try to start. From what i read that body style vette it was a common issue with the injectors.

Another excellent video sir. Thank you again Jim

I don't know exactly where you live, but I like seeing Old Glory flying in front of so many homes!

I like how you spend a lot of time diagnosing, some mechanics would just throw parts on it until it's fixed lol which is bad. I like your multimeter I've never seen one like that, you need to do a toolbox tour one day :-)