U have mastered the art of the cliffhanger. I really like the way u use your Verus. Watching u helps me. I wonder what Diagnose Dan thinks. Maybe he will start doing cliffhangers. I hope not. Great vid!!
Nice, really appreciate the tip on the CKP Variation Relearn, very cool! I also like the tips to check Amp pid for O2's, very convenient and nice that they give this to us. I have just made doing that CKP Variation Relearn & Idle Relearn a part of my routine after I do any cleaning of the throttle bodies, doing induction services, or just scheduled spark plug replacement on all of these GM trucks. Nice to know that key information you mentioned, I never new that about the correlation between CMP & CKP gradually getting off from factory and it throwing false misfire counters...so awesome, thanks for sharing this with us Ivan!!! As always, a VERY informative video, explanation, and diagnosis of the problem. I cannot wait for the follow up on this truck! Thanks for everything you do and hope you have a great day!
I was getting weird misfire readings on my bi-directional scan tool. I didn’t trust it because it was always 2 misfires and it was on random cylinders at random times. I even hooked up my HP Tuners to see if it was getting different readings. It appears the the crank position relearn has fixed it. Fuel composition isn’t getting out of wack, no misfires registering and the mpg took a jump. 👍👍 Great video.
Interesting Dionostic: check that belt, make sure it's tight, check the wires from the battery positive and negative & the WIRES at the ALTERNATOR, you never know it could be Rats eating up at the wires you have to do a VISUAL CHECK, make sure they're tight make sure there's no corrosion or rust or oil in the way, you need a clean connection and tight, just check everything alternator related, and this could be a long shot, but the DASH - INSTRUMENT CLUSTER could have a short in it too GM known for that Issue, just ask ERIC-O, lololo, can't wait for part 2, the suspense is killing me!!!!
Ivan the up shift in manual low is a programmed feature to keep the engine from over reving. If the PCM see's engine speed above 25 mph it will override engine braking in manual low & up shift to second.The other problems yes bad 02 sensors, check the alternator voltage output with a meter & amps at the rpm it occurs if it matches the gauge alternator problem if not sounds like a gauge issue.
More checks first please...before you condemn the alternator. (I would be willing to bet you don’t change it yet) can’t wait for part 2. A very interesting problem. Thanks for sharing it with us
Okay, that's a weird one! The fact that it happens right at the same spot every time strikes me as being a programming thing, rather than a mechanical failure. Belt slippage would vary depending on load, not necessarily RPM. Same could be said for a failing diode pack. After verifying no TSBs and design function, I'd want to current-load the alternator to see if a heavier load changes the point at which it cuts out. If it does, I'd suspect a ground issue or failing alternator. If not, I'd verify signal with a scope to make sure I could trust my scan tool, quick visual inspection of the belt, pulleys and tensioner, and call the alternator. I'm currently going through ADAS training, and am learning very quickly to distrust scantools even more than I did before. I think I'm developing paranoia... LOL
5 лет назад
He has a scope in the VERUS, just throw leads on it. Scopes rule.
I almost bet that Alternator is designed to go on a Diesel. Most Diesel's red line at 3k or 3500.. So this thing is set up to put out more current at lower RPM's. Maybe it's just a slightly different voltage regulator built onto it.
Great presentation! Check for loose and VD test grounds and power in engine bay. Alternator brushes, diodes, voltage regulator,and commutation is toasty? Check for AC ripple in the electrical before diagnosis! I bet the the ign coils are not getting enough current on the primary at high rpm. Running a car with ripple can destroy sensors, modules, even your catalytic converters. I will only use brand new Genuine OEM Delco alternators on GM’s for this reason. Please tell me that alternator is genuine and not lifetime guaranteed Chinese junk from the 3 brick and mortar community polluters. Check AC ripple while driving the truck under a load with air conditioning, headlights, windshield wipers.....ON
I almost bet that Alternator is designed to go on a Diesel. Most Diesel's red line at 3k or 3500.. So this thing is set up to put out more current at lower RPM's. Maybe it's just a slightly different voltage regulator built onto it.
I had a pretty bad misfire last week. I got home and hooked up my scan tool. It was showing thousands of misfires on cylinder 3. I swapped plugs and coils. The misfire stayed on 3. I swapped the wires between 1 & 3. Misfire moved to one. I went out and bought a new set of Delco wires. Felt like misfire was completely gone. Truck was smoother and more power. I hooked up my scan tool again just for giggles. I noticed not it would show 2 misfires on random cylinders at random times. I started wondering if it could be an O2 sensor getting weak, but not throwing a code. I figured my upstream O2 sensors are 14yrs old and have 143k miles on them so I would just replace them anyway. A pair of Denso O2 sensors were relatively cheap and I really like Denso so I bought them. I haven’t installed them yet because I am going to do them when I put the new brakes on this weekend. I did do the crank position relearn. It smoothed out the engine even more and now I don’t see any misfires at all and my fuel trims stopped jumping all over. Now the only move from 0 to 1 or -1. I am just happy it’s not fuel or compression related. 😂😂
This is interesting. Possible alternator with brushes not getting contact at high rpm, marginal battery, belt tensioner/belt issue, possibilities are endless, LOL. I remember Eric O. did a video with the body ground between the engine and body going bad but don't remember what the truck was doing. That CKP variation learn was interesting, back when I worked for a GM division we only did crank relearns if the PCM was replaced or crank sensor changed or a different engine was installed. Strange. Electrical gremlins are always fun, haha.
Ivan, just for grins pull the end cover and check the brushes. I bet they are worn out and harmonics cause them to loose contact with the slip rings. Replaced brushes in my Delphi alternator.
Load up the parts Cannon! Replace the alternator. If that doesn't work, it HAS to be the PCM! That's what ALL of the guys on the forums are saying! If not the PCM, run ground wires from every location you can think of! LoL 😂 Waiting for part 2!
My 04 is the same way. It started just happening @ over 70. And only when not on the throttle. Like when it goes down hill or levels after a slight climb. Now.... it does it at 65.
The misfires might be from the bad o2 sensors. That I have seen before. You are correct, replace both upstream o2 sensors. Crank/cam sync might not be doing it. 2 years ago I had my alternator do the same thing. Rpm rise, alternator turned off. That was a bad voltage regulator, where it was at full field at idle and the car turned off the alternator
Amazing fix for that fake p0300! That voltage drop when accelerating is interesting, check if the alternator pulley is a clutch pulley or a overrunning pulley because that is the exact failure symptoms when they fail
@17:00 voltage regulator in the alternator is bad. Can be replaced by taking the alt apart and doing some soldering but it is usually easier to just replace the alternator.
Yeah I have that experience with my oxygen sensors on my 07 Toyota sienna. Too bad they don’t sell them two for one sales! I would’ve bought both now I got to save up some money for the other one. But I’m used to the money light and the other ones on so will wait for a while.
I had the same problem with mine last year. There are three banks (name?) in the alternator that control voltages at specific rpms so amperage does not overload. Mine had a bad third and caused the same to happen at 3600 rpm or so. All lights dimmed and voltage dropped to 10-11. Changed alternator and fixed.
Hi Ivan, Very interesting video again, particually the ckp relearn. Never heard of it before. Also the part of the alternator, curious for part 2. Nice job again. Greetings Hans
On my 15 Sonic and 14 Sierra at high rpms the a/c clutch will not engage, I still haven't figured out if it's the computer saying "all hands to the engine" or if maybe the compressor isn't designed to spin that fast. Now on the Sierra if there's no high load on the alternator the ECM will command it down to a low state and the only way to keep it at a high state is to have the headlights on or have it in tow mode but in that video you have the headlights on so.......... yeah and there's really no manual mode for GM pick up Transmissions either
Very cool case study Odd that the alternator loses voltage at higher RPM, Kind of the opposite of my alternator Experiences, can’t wait to see what you find out
Plug the adapter from the power probe into the power outlet and use the your meter with the snapon banana jack leads. Watch voltage on the meter while you accelerate
I did my own research for fun and one guy found it was a bad diode in the voltage regulator. We all know the faster an alternator spins, the more "raw" voltage it produces, and that voltage has to be regulated down to 14 V. Apparently the diode breaks down at whatever raw voltage is produced at 3000 RPM and the regulator detects this and shuts down the field coil. One could replace the alternator (if the regulator is built in) and fix the problem and never discover the cause.
@@PineHollowAutoDiagnostics I almost bet that Alternator is designed to go on a Diesel. Most Diesel's red line at 3k or 3500.. So this thing is set up to put out more current at lower RPM's, but then it will over-voltage if you over-rev it's rating. Maybe it's just a slightly different voltage regulator built onto it than the gasser version. Not real sure. The cutoff being at that precise RPM range is just screaming pre-programming rather than a failure IMO.
First thought was belt slippage at the alternator ... but not like that, consistently at 31-3200 rpm - that's interesting! Strange failure there. I'll be looking for part 2 as I go through my 200 email notifications, HAHAHA!
My company Chevrolet Van did the same thing the alternator would shut off under hard acceleration and high RPMs. It had a vortec engine and it I believe it was 6 l
Ooow that alternator is odd, almost a harmonic effect, vibration on the brushes or plug connections. I really don't have a clue, unless it's a odd belt/pulley effect. You have/had a good one there lol.
I wonder if the smart charger drops out when you're calling for acceleration, so that there is no extra mechanical alternator load on the engine when you're looking for acceleration.... Maybe service data would tell a story.
I just bought a 2009 GMC Sierra I have a misfire on cylinder 4 I've checked the lifters I've replaced the coil wires plugs I cleaned the injector I can't figure it out could it be an O2 sensor or could the cam need recalibrated what do you think I'm not paying a garage $100 $200 to diagnose something for me unless I have no other option usually I can figure these things out thank you for your time
Belt temsion problem... maybe, but why would the PWM signal to the alternator drop out? -broken wire and worn engine mounts allow the engine to pull on the harness just hard enough at about 3500rpm to open the circuit?
My guess: the alternator brushes or slip rings are excessively worn and not making good contact at higher RPM's. If you replace it, buy a new OEM GM alternator from an online source, if possible. Brand new 2005 Chevy GM alternators are available online way cheaper than reman units from auto parts stores.
That's a gm thing. It won't let you hold 1st without changing programming or a trans valve body mod. Won't let you take off in 2nd either like Ford does for poor traction conditions. And now we wait for part 2 grrr. LOL
My Chevy shifts too haha also running into po300 and misfires on cylinder 2 and 7 changed plugs,wires and coils so gonna check these o2 sensors ,would be nice buy computer like yours to see trims and stuff lol
Probably bad coils on the cylinders that are misfiring. I had the exact same thing a few months ago. I put two new coils on cylinder 1 and 3. They misfired in the 20 thousand times range.
Fun fact: Selecting manual 2 or 1 is for engine braking only. If you have it selected as such and accel above 3500, it will upshift! You cannot hold the trans in gear like you could on older models while accelerating, beyond a certain rpm/load. Again, 2nd and 1st are for decell, not accell.
Actually 2nd is for starting out in second or torque reduction. This is ideal for low traction situations. It is essentially a VERY basic traction control method. Selecting 1st performs exactly the way you described though. These are traits of the 4L60E and 4L80E ever since their introduction in 1993.
@@jbernfield2612 You're right about 2nd depending on calibration. I should've added that. Some models will not start out in 2nd in manual 2. I've driven 100s of them and it seems based on GVWR . Anyways, let's see what Ivan finds! :)
My 03 gets a random misfire code every once in a while. Replaced all coils, plugs, wires, injectors, 02's, mas,ect... It will randomly pop up and go away. I never heard about adjusting the crankshaft sencor. So since i don't have a computer can i just replace the sencors
I noticed that truck has low miles for that year, he probably doesn't drive it that much, so it's making it very nice and comfy for RODENTS those little BUGGERS, CHECK for Rat 🐀 droppings, I can bet you for sure!!!
I almost bet that Alternator is designed to go on a Diesel. Most Diesel's red line at 3k or 3500.. So this thing is set up to put out more current at lower RPM's. Maybe it's just a slightly different voltage regulator built onto it.
i had same problem with my old ford explorer. stepped on gas to raise the rpm voltage drops to 11v but at idle voltage went up to 12v. was the alternator
I know that some Isuzus will cut the alternator at WOT but never seen anything drop out at a specific rpm. The up shifting in 1st and 2nd is weird. My Volvo will up shift in manual mode if you get near redline supposedly. I've never been brave enough to try it.
Reminds me of when I complained to the dealer of wind noise from side windows. Happens when I hit 100mph. He wasn’t very helpful, but Acura redesigned the Integra to have framed side windows 2 years later. You’re welcome. BTW, if you run all accessories does the RPM it happens at drop?
Mine is the same way. Mine was fine untill I bought a rebuilt cluster. Must be my stepper motor. I know it will react to loss of pressure because I lossened the wire at the sending unit, so I'll live with it.
Ivan, don`t believe it is alternator, my Chevy S10 4.3l v6 does same thing, I replaced alternator and did same thing, almost appears to be heat related at times, If you resolve this, I might find cause on my truck also.
Is the oil pressure supposed to be that high? Mine runs up to 3/4 of the gauge when cold, but only when I'm pressing the gas. It sits a bit over the half while idle.
It may be a component in the alternators charging voltage regulator failing into a short or open circuit state. If it were a mechanical belt slip I would not expect as much dip in voltage. That's my preliminary guess. Any takers ?
hello i have a 2001 gmc sierra 1500 5.3 misfire cylinder one i have replaced coils injectors found bothe lifters on cylinder one they were bleeding down so i did heads and replaced all lifters still cylinder one misfire compression test is fine leak down test is fine looking for ideas
Hey broo! Have a Q Have a Honda pilot 2003 3.5 Only 2 Oxigen sensors Engine cold just ignition key on.My scanner shows This Volts readings on those O2 sensors. Bank 1 S1 1.275V Bank 1 S2. 0.035V Is this a normal reading??? Thanks in advance for your time🕛
