You Won't BELIEVE why this Volvo Doesn't Start... (Part 2: XC90 Long Crank/Stall)

[@PK-yf4ho]

I cannot thank Ivan enough to fix this car and gave it a new life. The days of not knowing when/whether it would start were gone. It was embarrassing to keep cranking while at a gas station or anywhere else for 5+ minutes without success. I wish I had sent the car to PHD 3 years ago. I think very few mechanics have the patience, skill and talent to handle tough-to-fix cars. Ivan is definitely one of those.

[@dans_Learning_Curve]

You're lucky to be close enough to send it to him! Did you find him via KZbin?

[@JD-iu3vi]

Or friends that have Volvo knowledge.

[@PK-yf4ho]

@@dans_Learning_Curve Yes. We are almost 200 miles apart but well worth it.

[@PK-yf4ho]

​@@JD-iu3vithat actually showed one of the most precious and rare attributes of being a mechanic - honesty - by telling you how things were actually fixed

[@JasonLee-lv7tm]

Very few mechanics are able to diagnose performance problems with cars. The reality is there aren’t many quality mechanics

[@marknaravas318]

Ivan, if there’s only one thing I ever learned from watching you, is to CLEAN THE GROUNDS!

[@kerrylewis2581]

I am glad there will be a part three. I thought there is probably more mistakes made by the previous mechanic.

[@johnnyblue4799]

I'm not! I want everything in one video. I hate waiting another day!

[@kerrylewis2581]

@@johnnyblue4799 At least he doesn't make us wait a week

[@johnnyblue4799]

@@kerrylewis2581 I'd riot next to his shop! :)))

[@calholli]

@@johnnyblue4799 He doesn't always fix it in one day.

[@johnnyblue4799]

@@calholli Nope, but the repairs are done by the time he uploads the first video. If he says "yesterday this car was towed in" it means yesterday when he shoots the video, not when he uploads! :)

[@htownblue11]

Crazy how sensitive some components can be to ground current flow. Nicely done Ivan.

[@vpimike2646]

Poor grounding is always a lurking problem, especially up there in the rust belt. Thanks for the lesson, Ivan. Love your channel! 👍

[@Land2020-w6w]

Ivan, you definately a Master Tech and has so much patience. Excellent video and learned so much from your previous videos. Plase keep it up. Absolute genius.

[@lifelong5425]

Many would throw parts in...many would call it a bust, no fix.......This proves the need for thinking outside the box...ground control to Major Ivan...well done

[@generaldisarray]

Great diag and partial fix Ivan. One quick, cheap, and not so dirty way to test for a bad or inconsistent ground connections between the engine block, or transmission case, and body is to take a bog standard jump lead, clip one end to a clean spot on the engine/transmission and clip the other end to a clean bolt on the body, or even directly to the battery negative terminal. If that works you can chase down where the ground straps are and clean/replace them, or even add some more if desired.

[@PineHollowAutoDiagnostics]

Usually yes, but this was a very special case that I can't quite explain haha

[@deepsquat600]

You guys remember the one that SEMA auto had a while back where one of those particular ground straps on I don't know what vehicle it was had broken h was causing strange issues

[@generaldisarray]

@@PineHollowAutoDiagnostics very true. Given the modern car is basically a computer, or 3, on wheels, and computers are known for their serious dislike of power fluctuations, most "weird" issues, from a Christmas tree dash to the all light bingo of the flashing rear lights, or rapid indicator flashing, is usually down to bad grounds or power connections, which are always a pain in the ass to track down.

[@deepsquat600]

@@generaldisarray A3? I know mine only has one but hasn't even come across like a BMW that had like 12 different modules?

[@generaldisarray]

@@deepsquat600 and they seem to put all the modules/computers in the most idiotic places where moisture, etc is most likely to get into them

[@ApexHotShot]

Ivan, you impress with each diagnosis and repair. I really like that you typically wrap up with careful thinking … like a lessons learned session. Also, I would never have thought to epoxy that broken holder for the crank position sensor but it makes sense and saves your customer the cost of a replacement and the time to source one. Thanks for bringing us along for the ride.

[@petepeabody8905]

So the initial look saw no hacks jobs like the other Volvo, but it was even worse when it's not obvious. It took time and all is well. Great job Ivan I enjoyed this journey

[@dans_Learning_Curve]

How true!!

[@JamesAgans]

I am 78 years old. I learned when I was around 12 that good grounds mean everything when you are dealing with a mere 12 volts. Resistance can defeat 12 volts, and newer cars use a lousy 5 volts for a ref voltage. I remove and clean the ground straps on my trucks every year. I coat them with anti-seize and tighten them securely.

[@mattbrown5511]

It is nice that your friend could give you some insight to the cause of the problems plaguing the Volvo. Now, I hope the owner will address the rest of the issues caused by the former work done to the vehicle.

[@timjackson1904]

Talking earths reminded me of a mistake I made replacing the starter on my Metro (UK). All ok till I went out in the evening with the headlights on. Next thing I know, the throttle pedal gets sticky so without thinking, I gave it a tap with my foot to rev it. The pedal went to the floor and stayed there, the car accelerated of down the road at full throttle, eventually I stood on the brakes but it still kept going. Just before I ran off the road at a corner, I turned off the ignition and just ran up the verge a bit as the steering lock came on!. After changing my trousers, I found that I had not connected the starter earth causing the current to flow up the throttle cable. OK till I turned the headlights on, causing it to get so hot the cover melted seizing the cable at full throttle. Could have quite serious but now an amusing story for the lads. Enjoy lol.

[@PineHollowAutoDiagnostics]

Can you just shift to neutral to stop the acceleration? 😁

[@timjackson1904]

@@PineHollowAutoDiagnostics I remember dipping the clutch and it sounded like the engine would explode causing a bit of a panic, so then the not to effectual braking with the clutch engaged, then the 'just turn it off idea'. Its a lot easier to think straight when your not in a panic lol! I think it played on my mind that the wife had totaled our main car with weeks till insurance payout and the metro was all we could afford so I couldnt afford to 'break' it and the runaway engine noise sounded terminal and expensive.

[@mazdaman1286]

Quite common on European cars, the ground cable goes from battery earth to the body then continues onto the transmission or engine block. This is a failure point because the engine rocks and gradually the strands in the cable by its fixing start to break (Audi VW group, Peugeot Citroen Renault and Nissan ). In virtually every case I had to deal with a new battery had been fitted. On my own Citroen as a precaution I installed a cable from the battery to the cylinder head and one to the body , I did notice the lights were brighter.. Also Volvo were close to Renault and shared some parts. It was quite common to have bad crank sensors , easy to diagnose as there was no rev counter flicker, so much so many kept a spare sensor and 10mm spanner in the glove box !!

[@dougkubash8673]

I wrenched for 45 yrs. plus and learned you can't take nothing for granted. Who would have thought the starter cranks over fine but it still wasn't a good enough ground! Good job!!

[@caseypowell9030]

As a subscriber i dont know why u dont get a million views i remember seeing you on SMA 8 yrs ago good work

[@jamesglynn1267]

Spent countless hours chasing the hard starting issue. Diagnosis here was spot on for my issues. Re-torque transmission to block bolts; Wire brush block to chassis ground cable; and replacement of deteriorated split wiring looms. Note: symptoms appeared six years and 20K miles after complete engine rebuild and replacement. Would have never thought to check transmission mounting bolts as a possible cause for this issue.

[@scottleary6055]

Ivan, I have a 2004 Volvo V 70, a few years ago I had a cranking starting issue. I searched it, and finally came across to one Internet conversation that said the starter when it wears out, starts to draw more amperage and interferes with the crank sensor wire, I replaced the starter and all the problems were fixed. Anyhow the crank sensor wire is very close to the starter and the electronic interference causes crank issues. The ground for the starter and shielding for the crank wire is important. You stumbled on some thing that not many people know about at all, very good diagnosing skills you have.

[@luckyguy600]

You are a 'tenacious kind of guy'. Many, and that includes me, would have given up a long time before we went that far. You're a good technician. Two thumbs up.

[@faxmen09]

Maddening! I'm sure owner paid good $$$$ to get the rear main seal fixed, only to have a half-assed repair. Bolts left off bell housing causing other issues. smh. Fortunate to have other Volvo there and helpful to have friend to drop some valuable tsb knowledge on you. Kudos to the commenter on first vid mentioning ground contacts. I'll be checking next one. Seems you may have a Va. Volvo diagnosis/repair pipeline going. 😀

[@ashercohen4739]

Ivan, thank you for sharing the entire diagnostic process with me. I am learning a lot from you.

[@thePoconoPatriot]

👍 you confirmed what I suspected! I have 2 - 2004 S60 2.5T AWD with a crank no start! When I did 1st inspection, both had a broken crank sensor bracket. And 1 failed the ohm test. After watching this video, I checked the grounds & guess what! Both were severely corroded! Thank you! I'm 70 & have been a mechanic since I was 14. And I have always went after a grounding problem, except this time! I blame it on old age! 😂

[@petergondolier4088]

For all the DIY mechanics out there, the first thing I do when I get a new/used vehicle is locate ALL the grounds I can get to. Remove them, clean to nice clean metal, lube the connectors and the body grounds, bolts, etc., with NO-OX-ID and re-attach. Unless the cables snap off, or are cut off, you've eliminated any grounding problems forever. When you replace starters, etc, use the NO-OX-ID on all those connections as well.

[@Hybriddiag]

Ivan! As working in automation industry from long time and plc programmer i noticed proximity sensor is mounted in a plastic housing instead of metal..as i know these sensors if you mount it in a electrically noisy environment it gose nuts even small magnetic field disturb its performance thats why 3 wire proximity switch is better and most use that now.cheers waiting for final results

[@JoseSilveira-newhandleforYT]

The rabbit hole of bad power grounds, but this was very elaborate, because the sensor was right in the middle of the ground path. Great job, Ivan! Now on to problem #2 - start/stall. It sounds like fuel thirsty but, who knows - you always surprise me with odd causes :-)

[@jennieroque169]

My wife's 2004 Volvo XC90 has been having the same issue you've discussed.... you provided an excellent detailed approach to diagnostics. Thank you so very much! ROCK ROQUÉ

[@jamesbruno5896]

Had a Subaru setting a code for the upstream 02 sensor which the dealer replaced. Car ended up here & i found both engine to subframe grounds rotted off. Replaced both grounds & the O2 sensor cleared! Nice diag Ivan I feel your pain!

[@mph5896]

I just pulled a 2.5 for a rear main and torque converter seal. Both of those grounds crumbled when touched.

[@PineHollowAutoDiagnostics]

Those little braided straps? They are pretty useless lol I just pull off the remains. How does that have anything to do with the oxygen sensor? 🤔

[@ПутьДиагноста]

Wow) the extra injectors pulse surprised me, never seen that before (diesel engine -yes, gasoline- no). It’s good to know. That’s why PHAD is my favorite yt channel. Free awesome knowledge, who wouldn’t like to get it?

[@nabeeljacksonrhoda6480]

I've got similar signal codes from the crank sensor and coil packs when I purchased it. Currently tracing all wires from sensors to the ecu to check for continuity issues. But this video was helpful to add some depth to the task and avoid missing important checks, especially the ground wires. Much respect from Cape Town, South Africa

[@davidturner4639]

Good hunting Ivan! I often will add additional grounds, especially with trunk mounted battery, on older vehicles (Miatas).

[@tracydiller9378]

Great video Ivan as always, it's good to have people in the industry that we can talk to. Todays vehicles are so complex that even the simple bad ground can cause so many issues. Going to watch part 3 .

[@PineHollowAutoDiagnostics]

This was by far not a "simple" bad ground 😉

[@tracydiller9378]

@@PineHollowAutoDiagnostics 100% agree was much more but that ground did not help.😁

[@fredsalter1915]

Powers and GROUNDS 🙂 Great vid, Ivan!!

[@wrarraven]

Great video! I think I'm experiencing the same issue with my xc90, and your reasoning is very helpful. Would you mind sharing the oscilloscope channel to sensor setup so I can compare what I'm seeing? I'm new to this, need a little bit of help!

[@robc3056]

Morning dude ! Good old fashioned sunday morning entertainment good to see someone whos walks the walk..

[@DuaneDonaldson]

I have watched all your videos since last December, you live in a salt state or heavy corrosion area, I don't remember you ever adding any redundant grounds or jumper cables from the battery GND to the engine block for example, maybe you have? I lived in Japan for 20 years and repaired many ground problems with an EARTHING KIT and found the problem by jumping the engine to the battery or body/chassis and the Tokyo area is more famous for salt sea air and surface corrosion. Throwing on a set of jumper cables is one of my first steps. Thank you for the hundreds of awesome videos, hope to meet you when I move back to the USA someday in the near future, currently in the Philippines. Out of 200 technician/diagnostician (no DIYers) Channels, you are my #1, cheers.

[@stelvioc3691]

21:55 cost-cutting in the assembly plant, planned obsolesence or money-making strategy via spare parts?

[@jeffryblackmon4846]

Grounds, and electrical connections in general, seem more important with all the computers nowadays. Great work, Ivan!!

[@zackarymcclain164]

Thanks for the shoutout Ivan. I’m a Volvo fanatic and I’m glad I could help. Awesome video!

[@PineHollowAutoDiagnostics]

I still want scope proof of why the ECM wasn't happy with the original CKP signal 😂

[@zackarymcclain164]

@@PineHollowAutoDiagnostics test it out

[@major__kong]

Interesting. Reminds me of an exhaust gas temperature (EGT) sensor in an airplane that works on millivolts like a flame sensor in a furnace. If you have a bad ground anywhere near that thing, it will let you know. I wonder in modern cars with all the electronics if checking and cleaning grounds goes near the top of the diag tree.

[@PineHollowAutoDiagnostics]

It's crazy that the ground checked out fine, but improving the ground fixed the car 😂

[@oscillation_overthruster]

Ivan, your channel and your humility are infectious. I came across an s80 with the t6. And as it came out of your mouth about the tsb, I went "oh, yeah..I remember that." I had the same symptoms. However, I gave up on it because I didn't want to reseat the transmission which is what the tsb says to do. And, I'll be damned to find you discovered it was just the shitty ground wire connections. I didn't fix it and donated the car. Arrgh I with I had it back now. It was mad fast when it worked.

[@diablo7322000]

There's an old TSB about this, I couldn't find it on VIDA, but its there. EDIT: never mind, just read the video description and got to 16:45.

[@joepalovick1915]

Great case study Ivan. I really enjoy watching you apply engineering logic and principles in your work. It’s fantastic. I’m guessing very few auto techs would be able to track down a bad ground like you did even if you got a tip from a friend.

[@zoobydoo2518]

Great diag. Supports importance of good grounding with all the electronics on new cars. 1 volt drop on ground during crank was a clue. Wonder what that would have been if scope ground was at Battery? Ivan usually shoots for less than 1/2 volt ground drop. Adding another ground strap to engine bolt may be beneficial to prevent future problems when age and corrosion come to call again. Maybe also check ground wire to ECM ground point from body and ground at Battery to body. Can’t wait for part #3.

[@EngineerLewis]

Great video Ivan and I have already checked my Volvo 3.0 -ve straps! All good thankfully and no bolts missing from my bell housing! 👍

[@dans_Learning_Curve]

How many miles on your car? How close to Ivan do you live?! LoL 😅

[@EngineerLewis]

@@dans_Learning_Curve mine has just 130,000 miles but I live in the UK so too far away from Ivan . 🤣

[@isalmankhan1]

First of all congratulations, you fixed it, this is a totally surprising one where any part can be replaced easily, bcuz of no service info😇 Great work as usual BRO😍

[@cliff499]

As a tech myself. Mostly ford. I really enjoy your videos. Please please keep filming !!! We need you !!

[@mikechiodetti4482]

Ground problems. Good old ground problems! Throw in electronics with a "sensitive" ground point or "must see this absolute no-higher ground point"(such as no higher above ground than 10mv) and here we go with "not-so-fancy" brackets allowing extra micro volt and micro amp drops, all equaling a long crank/hard start. Where others would have quit, YOU are persistent! Very Good Fix Ivan, Very Good Fix ! ! ! I need to make a diagnostic chart for a hard or no start, using this video's steps. I've only seen a few like this at work before retirement, but when dealing with milivolts, miliamps, micro volts and micro amps, every electrical connection is on the list of potential problems. ESPECIALLY DURING CRANKING! My apology for the long comment.

[@Desire_of_Ages]

What would happened if you just bypass the crankshaft position sensor?

[@stevex3976]

Ground is ground the world around....except when it isn't ground! Great job.

[@Ram14250]

Your Mastery of skill in diagnosing is mind blowing! You are a master diagnostic super hero!

[@Sandmansa]

Nice find Ivan. I'm shocked that this is not a TSB. Because it happens A LOT. If you separate the engine from the trans, you absolutely have to clean the mating surfaces before you put them back together. And securing all the case bolts is necessary. All the engine electronics get the bulk of the ground through that mating surface. Sure, there are a couple of support grounds from the valve cover to the body, but they are not enough to overcome the draw from the starter. I've spent nearly 13 years working on nothing but those Volvo's. So if you need a spot of advice, I believe I can be of help. The last issue has to be one of 2 things. Either the MAS is bad. Which is kind of rare. Or there is a massive air leak somewhere after the MAS housing, to the throttle body. Most likely, one of the boost hoses have come off or has broken. I'm really looking forward to part three. You're in my wheelhouse now and this is great stuff for me. Thanks for sharing Ivan.

[@deepsquat600]

Not that I would have ever found this... My 2010 Yamaha fjr1300. As a known similar problem to such an extent that the previous owner to me had the entire wiring harness rebuilt ... My bike has like 7 known ground places that you have really have to watch out for corrosion... I also used to own a 91 Corvette... It was also known for a few suddenly had problems with the engine not starting you had to really take a look at the ground first.... Again I would never offend the problem you did on the Volvo even with this information in the back of my head. Awesome job my friend

[@AP9311]

Well, it wouldn't be PHAD if there's part 3, lol. Interesting diagnosis! Bad ground! Not bolting up all the parts back in is sloppy work!! Great to see it fired right up! Awesome part 2!! Great video Ivan!

[@metoon3092]

A wise -old- young Russian gentleman once had a KZbin channel, and he often said *Powers and Grounds* . Hmm, who could that be. 😆 - I'm enjoying this one Ivan. Good Job!

[@robertheim352]

Thanks Ivan, another good example of logical circuit analysis. Two symptoms pointed toward that degrading circuit (aka ground): 1. The problem degraded with time, 2. the problem changed with temperature of the engine. (These are small signal sensors, so the signal strength seen at the computer was degrading by means of common mode noise.) When the customer paid for an oil seal and received the car with an issue ( long crank time before start ) they should have insisted on analysis. Of course, with the sloppy work that you found I expect the customer may have not received any satisfaction.

[@dustcommander100]

Great work, including knowing who to chat with and the need for more info! Think about this: in our daily lives, what do we interface with that is more complicated than a vehicle? Computers and cell phones operate in much more ideal conditions, and don't interface with anything mechanical!

[@billziegmond4943]

Great diagnostic. You called me the regional Saturn Astra tech. I think you have become the regional Volvo tech.

[@davidcraven277]

Years ago we had a 4.6 in a mustang come in after an engine install we found the wiring for the can link to close to the alternator moved to the correct routing and ran fine

[@LesReeves]

Eric O is really good with finding ground problems but I think even this one would have had him stumped.Cheers. It will be good to see what is stopping it idle now.

[@wallace3953]

Also, pls think about Installing some "Ground Strap" connectors between the engine and the transmission housing....amybe a few more locations....You Decide! You never quit, you always WIN!!!

[@fwgmills]

That has to be the most humbling diag ever! Great job!

[@WECB640]

Ivan, I see this issue becoming more commonplace as auto technology advances. Noise on the line is corrupting the data feeding into the ECU. It becomes worse when the impedance for the data inputs at the ECU are higher. Ferrite beads, twisted pair and bypass capacitors are often not designed into the circuit due to profit margins. That starter is producing a ton of noise from the brushes arcing and Volvo is relying solely on the ground connection to shunt that noise. I might suggest a ground strap between the transmission and the engine and also a 0.1uF capacitor right at the positive connection of the starter and the other capacitor lead connected to a ground bold (again at the starter) to give that noise a dead short. This will keep the noise from propagating through the data lines. It forms a RC type low pass filter. Without that capacitor (actually should be one inside the starter....but that's another story), it is up to the very low impedance of the ground connection to provide an easy path for the noise to go to ground an not to the ECU. The problem is, even if there is a low DC ohmic value on the ground, there is generally higher ohmic value at RF (noise) due to wire length (inductance). This was a GREAT video series. Wishing you continued success. 😎👍

[@ghettsumm7949]

I was wondering if you could add a separate ground strap between the engine and transmission to insure the ground connection? I'm always learning from you Ivan.

[@russellhltn1396]

I'd think using a jumper cable to add a temporary ground for diagnostic purposes would have helped.

[@JD-iu3vi]

Even NEC requires bonding jumpers on everything to insure a complete ground path. I would add more grounds jumpers to make sure there is a good path all the way from the battery.

[@Garth2011]

Its always convenient when you have the right tool in stock to make a job go smoothly like the pilot brush and ratcheting end wrench. That pilot brush might just be the norm when cars come in for repairs...first thing, clean up those grounds once determined by visual inspection. Time for an oil and filter change and maybe a fresh tank of gas. Tire pressures likely need looked into.

[@urishaham2544]

I'd definitely torque to spec all accessible bellhousing bolts, given that some were missing altogether... Great work and diagnosis!

[@Nemesis-yn5wv]

I have seen a bad ground cable/connection or even a failing starter motor cause a long crank and or not start on volvos. But I have never seen missing eng/trans bolts and poor contacts causing it so that’s a first for me. I’ll keep it in mind when doing things like clutches or diagnostics 👍.

[@glenntownend9047]

Hey. I love your videos. I live in Cyprus but am from UK. I had years repairing tvs in my shop. You are very patient guy. I had so many sleepless nights thinking about issues I left in the shop which I could not diagnose. You are clever man. I wish I had your patience. Customer is always right 😂

[@a_w_bukhari7579]

A PHAD morning video is always entertaining. Thanks Ivan.

[@davide.s.9880]

Well SMA worked on a 2018 GM truck with all sorts of problems. Turned out that a breaded ground strap from body to frame corroded so bad it didn't have enough ground. Replaced it with a battery ground cable and it fixed everything. So I'm not suprised this one is having problems because of a ground.

[@ccmoos]

This is one of your best finds, I was so incredibly curious to see this part 2.

[@JoelAutomotiveInaction]

At minute 6:29 I see Ivan you had the ckp sensor inside a magnet tray, that is very danger for the sensor I have seen it multiple times before whem you place them near to any magnet devise , the magnet on the sensor can chage polarity and give you inverted sigal messing with the computer clock programming. Nice case study thanks for sharing 6:29 g 👍

[@paulmuff9883]

I don’t know about this engine but earlier I think in part one you mentioned about crankshaft oil seal, when I bought my Volvo with a D5 engine my mate who’s a Volvo tech/ manager told me to be very careful with the oil level and told me NEVER fill beyond the full mark infact a little below is best because you’ll blow oil seal’s if you do 😱

[@PineHollowAutoDiagnostics]

Interesting...

[@secretsquirrel9722]

I suppose I shouldn't be. But I'm amazed at just how many cars you repair that come down to almost criminal work from another shop/mechanic!

[@newjerseybill3521]

It would have been interesting to put the scope between the engine block and chassis ground, see what voltage drop / noise developed there in addition to transmission to chassis.

[@mcdk72]

Your patience is extraordinary.

[@PineHollowAutoDiagnostics]

This one really tested my patience haha

[@mcdk72]

@@PineHollowAutoDiagnostics 👍🙂

[@Ianf1x]

I would add another earth from main earth to bell housing with jump lead. Bad maf can also make car run poor . I know you're a top notch tech .But I like to add a comment every now and then.😁

[@zoobydoo2518]

I agree adding another ground strap to trans / block bolt could prevent future problems when age and more corrosion happens.

[@carguy0000]

I had all sorts of different issues with my 2006 P.T. Cruiser ended up being a bad ground >> one bolt with all the connectors located under the battery tray on the fender well > I added extra ground cables i purchased on eBay >> been perfect ever since ...

[@huntnfishnuts5880]

It’s nice to have a known good signal for scope work, more so when your working on something unfamiliar.

[@Mr2004MCSS]

Definitely an interesting case study and shows the importance of good grounds. I bought a couple of those pilot brushes after your other video where you used one and have already used it a couple of times. It works great and I highly recommend getting one. I recently used it to clean up the ground connection on my flat bed trailer and now the lights work as they should.

[@windward2818]

The 2.5 VDC bias voltage means the VRS zero cross detect circuit uses a virtual ground at 2.5 VDC (which is one half the 5 VDC supply). This is done to avoid having +/- power supplies on the VRS conditioning and detect circuit. However, after designing several versions of this interface circuit on the bench, I really like the split supply versions because they also support a bi-voltage noise blanker (+/- comparator supply with symmetric hysteresis) which I think is a much better approach. Meaning, the VRS is an AC signal sensor (voltage above and below ground) and it makes more sense to condition the input with an AC type interface circuit. To verify engine positional inputs you should look at both the CNK and the CAM. If the vehicle has variable CAM timing then look at the base or reference CAM signal as a base line. I think the MAF sensor is critical for the cold start strategy. The ECM might use a MAF multiplier based on engine coolant temperature for enrichment during cold start. To not have a dedicated starter return ground wire going back to the battery in the trunk is just crazy. You cannot rely on a chassis return for starter currents. I have never seen this in a post 1990 vehicle with the battery in the trunk. In fact this is one of the very first thing harness engineers (usually as a starting intern before graduation) learn when they start working at the OEM. That is, always establish how load return current flows, especially for heavy loads like the starter, and if you use the chassis as return you essentially do not know the return path, or if the return path is even stable when the body flexes. In fact in moving a battery from under hood to the trunk the starter power feed and return are usually 1 AWG copper. High stranded welding cable is very popular. But, you can also use high stranded tinned marine wire, which is more corrosion resistant. For electrical noise you would want to run the red power feed and the black return next to each other. That is, minimize the circuit loop area. The question I like to ask is why is the unitized steel body shell considered an adequate ground? Steel as compared to copper is not a good conductor, especially for a starter current return. If you modulate the reference ground because of a high common ground impedance (bad connections) and high currents (starter) you will not be able to pick out the CNK signal from the common mode noise. This is why it is crazy to not have a dedicated starter return cable to the battery in the trunk. A good test would be to temporaraly add a large 1 AWG cable from the point on the chassis under hood to the point on the chassis near the battery NEG, essentially shunting out the steel unitized body.

[@PineHollowAutoDiagnostics]

I've never seen a dedicated ground return cable on any vehicle with the battery in the trunk... 🤔

[@windward2818]

@@PineHollowAutoDiagnostics Ivan, I misspoke, of course for production vehicles you are correct. When I commented I was thinking about the aftermarket retrofit kits. That is to address hard starts during winter the kit would provide a large ground wire which essentially bypasses the chassis. What is interesting is if you compare the resistivity of steel as compared to copper, or tinned copper if we look at lugs, because relatively speaking steel is not that great a conductor. Also, interesting is if you look closely at the chassis design try to imagine where the return current actually flows, and ask how does the current make it back to the battery NEG during cranking, what is the actual resistivity?

[@keltecshooter]

This is like the Nissan Maximas , don't remember the years but the fix was to remove transmission and clean both mounting surfaces.

[@LeverPhile]

Is that all? Yikes ...

[@baxrok2.]

My early Mazda's also have that low voltage signal on the cam and crank sensors. Thanks Ivan!

[@ALEX-xd7ko]

I had a similar fight with a Nissan recently. Would loose signal to the back half of the truck . All grounds looked good all grounds passed load tests, but during cranking when i couldn't catch it on my testing equipment i would loose ground . Spent an entire day chasing it then just decided to run a battery ground back to the f.p ground and walaa . Runs like a champ. Ive now built an 8ag 15ft jumper to test with lol.

[@lauriaboone845]

Even I as a woman know to stop when the temp gauge acts wonky. I had a leak in the coolant reservoir and found it quickly cause my temp gauge started dancing around, never to the point of overheating. I pulled off at the next exit and put some water in. As they didn’t have antifreeze. I know water is better than nothing. When running low. I made it back home and found micro cracks in the reservoir.

[@davidhollfelder9940]

Maybe I’d run a #4 wire from the engine block to the batt neg, bonded to the trans and body along the way.

[@Uticagreens]

I had a similar ground happen with a 03 Ram that had a Daimler PCB. The grounds had to be impeccable for it to start. The least bit of corrosion and it failed to start. Cleaned the main Ground from frame to engine block . . . and BINGO it started and ran like new.

[@michaeljohnson1006]

I like the sound of the good old volvo 2.5 5 cylinder engine. My dad had one in his Renault safrane it was 170 bhp none turbo but went well. I had an intermittent fault crank sensor on a 2.0l hdi Peugeot 406. You could move the body of the sensor and get the resistance to change when you measured it with an ohm meter. But the fault code was crank and cam sensor so I just replaced both with genuine Peugeot ones they were about £50 for both and it's just not worth getting stranded. The good thing was the fault appeared on the drive on starting than goodness.

[@mrjsv4935]

Interesting case, nice to see the ground fixed but I guess there's more problems.

[@ehsnils]

Ground faults are always interesting. I once encountered that on a car of a friend - turning left caused it to misfire and eventually it also misfired when running. When I connected test probes it started to behave correctly and I finally isolated that to bad grounding of engine ECU.

[@goodtimejohnny8972]

I suspect the engine needs to be removed again. The carrier plate is probably installed incorrectly after the rear main replacement. All bell housing bolts need to be installed and torqued to specification. Also check the vacuum hose routing to the TCV. Since that rear main seal job seems to be when the problem started I think you need to do the job again to find all of the problems caused by the seal installation. Especially since adding a bell housing bolt in part 2 helped. 😢

[@GregoryGlessnerViolin]

Keep calm, and check your powers and grounds. 👑

[@calvinogada3480]

Loyal fun and student from Kenya Your videos educate me alot

[@thomasjensen5237]

Good morning all. Great video as always

[@johnthompson1453]

I looked at a UK Rover 213 with slow electric windows and slow starter even with a new battery. It turned out to be the engine earth connection to the bell housing, the bolt was extremely tight but corroded.

[@voffchik26]

Had the same issue with my Xc70 It wasn't a ground cable that caused the issue. It was the missing bolt. In my case all bolts were there but not tight enough. Added extra 30lbs to all of them and cured the car

[@jamesanderson2176]

Where did you take your scope ground? With ground issues, if your scope ground wasn't electrically close to the computer ground, it may not have been seeing what you were.

[@williegillie5712]

I see your having some fun Ivan. It would suck if the job was easy. I can count on both hands the cars I thought I was done with weren’t done with me yet. It’ll be interesting to see what ya find next episode of PHAD👍

[@chriscrusader5412]

Scanner Danner always says "Check your basics". Fuel, spark, ground and what else?

[@jerryking2418]

Another genius diagnostic. Kudos.

[@ryno6101]

Question….what brand of scanner did you use on that OBD1 red pickup ? I like what it’s functions are.😊 thanks 1991 Chevy about a year ago 3 years ago Christmas time