Rationality 2: the Mustang and the Intrepid · 2:33am Dec 27th, 2017
Y'all remember last week when we talked about rationality and circuit checks? Well, now we're going to be putting that knowledge to use! 
I didn't get really in depth in failure modes, because it depends on a lot of factors, and often times the manufacturer doesn't tell us in the aftermarket what those modes are. Sometimes we have to learn by experience. Luckily, other times the manufacturers are pretty good at it.
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What? It's a Mustang.
One thing that I like to see (and unfortunately, rarely do) is “Action taken when code sets.” GM used to be really good about providing that, but they don't seem to be any more, or else Mitchell has gotten really cheap and doesn't buy all the data. Either is possible, really.
That's handy to know, because you could find yourself attempting to diagnose a problem which is normal operation. For example, when the PCM thought that the coolant temperature sensor had failed on certain GM vehicles, it would turn the fans to full speed—it didn't know how hot the engine was, so the safest option was to assume it was hot from the moment the key turned on. Like as not, the customer would complain about the fans running, but not that the Check Engine light was on, since the engine ran fine.
The good news with the Mustang is that it did have good code documentation.
The Mustang was a late model, throttle-by-wire vehicle, and the complaint was that it didn't have any power, and there were lights on on the dash. We pulled the code, and I can't remember what it was (we worked on this car six years ago), but it was a code for “Incorrect Air Flow.”
You might be wondering how airflow can be incorrect. Surely the engine sucks in however much it wants, right? And if you've been reading car magazines, you know that you can stuff a cold air intake and cone filter on it, and it can get even more air, which will make it faster because reasons.
This is where we get back to the rationality checks.
For starters, an engine is an air pump. Assuming it's naturally aspirated, it can't get more than it's displacement in air thorough it every two crankshaft revolutions. So if it's a 2.0L running at 2,000 RPM, it can't pump more than 2,000L of air through itself (and it will actually be less, because of various inefficiencies [like not having a cold air intake]).
The computer knows this.
It also knows how much air ought to be going through based on throttle position and air density. It's not super fiddly; it knows that there's going to be some variation, but it also knows it can't go too far afield. That 2.0L engine is never going to be pulling 4,000L of air at 2,000 RPM, no matter how efficient the intake is. It just can't do it.
Back in the good old days, that would have caused the computer to set a code for the Mass Airflow sensor, and that would have been that. The car would have defaulted to backup strategy (either speed-density if it was GM, or straight lookup tables if it was anyone else), and it would have never lost power and the customer could have gone on ignoring that check engine light for as long as they liked.
But not with throttle-by-wire. Those of y'all who remember a few years back when Toyotas were allegedly running away for unknown reasons will understand why having a car that suddenly is pretty sure you've got your foot flat to the floor when the reality is that you don't is a bad thing. If you're not sure, listen to this Ray Stevens song:
See, it's probably the MAF sensor, but maybe it isn't. Maybe the throttle position sensor is screwed up somehow, and the throttle is open wider than the PCM meant for it to be, and that's how that extra air is getting in. There's no way the PCM can be sure that this isn't the case.
Like I said before, Ford actually had pretty comprehensive documentation about various throttle codes and related codes, and what the computer would do. Ultimately, it came down to the severity of the failure.
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This is a severe failure, or in GM terms, a thermal event.
To avoid unintended acceleration, there are two separate throttle position sensors, and two separate accelerator pedal position sensors, and they both run different voltages at different rates so there is no single voltage that would ever be valid for both (except 0V when the car is turned off, I guess). There are physical checks; the computer usually sweeps the throttle blade through its entire range every time the key is turned on, for example. Many of them also have an 'icebreaker' function, in case a little bit of moisture in the throttle body froze the blade shut or partially open. And then when the car is running, it constantly monitors various things—like the incoming airflow—to make certain that they're logical and reasonable, and if they aren't, it shuts things down.
How much it shuts down depends on the severity of the problem. It can limit the throttle blade to a certain percentage of its range—it might not let you go over 50%, let's say, or over a certain RPM regardless of throttle position. If the problem is more severe, it won't even open the throttle blade. The car can idle, and that's it.
What was even more interesting was that the documentation went on to say that if things went really far south, it would try to shut off the engine, first by killing the injectors and if that didn't work, it would shut off the spark plugs. It didn't say what scenario Ford had envisioned where this would be the solution, but it was good to know that it was something that the car could do if it felt like it had to.
One possibility was to address unwanted acceleration. I think this car was built before Toyota's big fiasco, but that doesn't mean Ford wasn't thinking ahead. One of their Econolines had been involved in a very high profile runaway collision, and while it was in no way Ford's fault, they might have considered the outside possibility of a reoccurance . . . anyway, the basic idea is that on a throttle-by-wire car if you push both the accelerator pedal and the brake pedal at the same time, you probably meant to push the brake pedal, and it will therefore idle down the engine. And now that I'm thinking more about it, that would probably also be a handy bit of coding if the cruise control went rogue.
One really nice diagnostic tool for Ford mass airflow sensors was that they had the barometric pressure sensor built in, and if it was wrong, it was a safe bet that the MAF was bad. Obviously, the appropriate value varies depending on what altitude you live at, but for us the expected value is 155Hz, and I don't like to see it more than a couple of Hz in either direction of that.
Obviously, that car didn't know where it was, so it didn't know that the altitude it was reporting was wrong, but I can't help but wonder how soon it's going to be that the PCM gets GPS data and can use that to help in its diagnostics.
Anyway, we slapped a new MAF in it, and the problem was fixed.
The Intrepid didn't turn out so well.
So my manager has me look at this Intrepid. A 99, IIRC, with the mighty 2.7L V6. The customer's complaint is a lack of power.
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It wasn't actually that nice
The first thing I noticed when I started it was that it had a dead cylinder. Number 2 didn't fire at all, ever.
I took it for a test drive, and it actually performed pretty well. I mean, as well as you'd expect a small V6 that was now a V5. Right up until you hit 3,000RPM, and it wouldn't go any faster than that. If you backed off the throttle and let it shift, though, you could keep on accelerating and in fact you could get it up to highway speed.
Sometimes, especially with a misfire, the honeycomb in the catalytic convertor will melt, and partially restrict the exhaust flow, and that tends to limit how much load the engine can take. The computer does its best to protect the convertor, but if you keep driving too long with a misfire, there's nothing it can do—the smartest PCM in the world can't outwit chemistry and physics. But this didn't feel like that to me. A plugged convertor there's usually an inverse relationship between throttle and resistance. It's kind of like pushing into ooblick—the more you push, the more pushback there is. This thing went right up to 3,000 and then cut off.
Nearly every car with a PCM has a built-in rev limiter, and it's designed to not let the engine go over a certain RPM, which is usually the red line for then engine. In fact, if you've watched YouTube car videos, you've almost certainly heard one.
3,000RPM isn't where a rev limiter would normally cut in, but that could certainly be a strategy for a dead miss. So I said that the guy needed to fix the misfire.
Well, there was a problem with that. It had had this very same misfire for two years—20,000 miles—and it used to have more power, so it clearly wasn't the dead cylinder causing it.
My manager said that last year we'd 'fixed' it by replacing the cam and crank sensors, and I was dubious (I think it had a different problem at that time, but since he was managing then, there was virtually no documentation on the old work order). He said that the customer had put in a new cam sensor, and since that hadn't fixed it, we could warranty out the crank sensor on it.
So I put one on, and of course it was the same as before. Cleared the codes and tried running it, but since it was a dead miss all the time, it didn't take the PCM too long to figure out that something was terribly wrong. Not even long enough to get up to 3,000RPM.
I was utterly convinced that it was something the computer was doing on purpose, that this was a failure management strategy, and unless we fixed the misfire, we'd never fix the rev limit. Being utterly convinced isn't the same thing as being right, though, and so I needed to do one of two things—either figure out a way to fool the car into thinking that #2 worked like it was supposed to, or find documentation that proved that the car was doing this on purpose.
If we'd had another identical Intrepid, the first option might have been doable. I could have unplugged the coil for #2 and taken the car for a drive, just to see what happened. We didn't have one, though, so that was out.
The second option involved wading through lots of not terribly helpful documentation.
Episode Screencap
Now, some of you might be wondering how the car knows that it's misfiring. Well, it knows where the crankshaft is (angularly), and it also knows how fast it's turning. It should speed up just a little bit after each cylinder fires. If it doesn't speed up, or if it slows down, then the computer knows that the cylinder didn't fire.
To be super specific, it actually uses the camshaft sensor for this purpose, since the camshaft sensor is more accurate. This is important.
I could bore you by discussing in depth all the different not terribly helpful things that I learned about how the misfire monitor worked on this particular car (and most of them weren't too helpful), but I did learn two important things.
- The car could flash the check engine light for a cylinder misfire, even if it couldn't identify the cylinder that was misfiring.
- If the car hadn't learned the crankshaft variation, it couldn't set a cylinder specific misfire code, only a generic P0300.
The reason that the car needs to know crankshaft variation is because the crank and cam are connected by either a chain or a belt (on most vehicles; some are gear drive). That chain or belt can stretch, and as a result the two go slightly out of sync, and the vehicle needs to know how much. If it doesn't, it can't be confident that its numbers are accurate when it's trying to identify a misfire.
As luck would have it, the Snap On scan tool actually had a function to clear cam/crank variation. So I did, and then I took the car for another drive.
Just as the documentation had said, the check engine light started flashing immediately. It knew there was a problem, but not the extent of the problem.
And then I punched the throttle, and that little 2.7L cranked all the way up to 6,000RPM. I did it again, and got the same result. And I did it a third time . . . and I was limited to 3,000RPM.
So I cleared the codes and reset the cam/crank variation, and once again, the car managed two wide open passes before the PCM shut things down. It had no idea which cylinder was misfiring (the fact that it was also setting a circuit code for injector #2 should have been a clue to it, but it wasn't programmed to make that leap), but it did know that something was terribly, terribly wrong, and went to failure management strategy.
When I got back to the shop, I came in and my manager said, “Well?”
“I know what it's gonna take to fix this.”
“What's that?”
I held up our Snap-On Veris. “One of these. Every two accelerations, he'll have to reset the cam/crank variation. Or he can fix the misfire.”
Any thoughts on why the engine might surge when pressing the clutch down after it had been parked outside overnight in -20 degree weather?
I expected the brakes and stick to be stiff, but not sure why the tach briefly shot up to 4000 when I took my foot off the gas and pushed in the clutch. Maybe my feet were just a bit numb and I hadn't let off the gas all the way when pushing in the other one. Maybe some crystallization or separation of components in the fuel. A temp sensor somewhere detecting the cold and trying to warm it up faster?
Also, from the handling, I'm pretty sure my tires are uneven. I topped them off with the free air hose a little less than a month ago. Maybe I should use my own air compressor to fill them with warm room-temp air from inside. Definitely going to get them rotated this spring.
4760068
Could be a stuck throttle body or IAC; those seem most likely. I can't think of any modern car or truck that would run the RPM up that high at idle no matter what, but that's not to say that there isn't anything that does. It's also possible that you messed up with your feet, or that the throttle cable was stuck due to ice, or even the floormat caught the gas pedal for a moment.
I would expect that fuel separation of any kind would lead to the engine not running.
Sometimes, the documentation is very important.
We had a Reliant (worst misnaming of a car ever)
It had oil usage and pressure issues.
Needed the crankshaft rebuilt.
We coughed up the money. They did it. The oil pressure was still far lower than they liked.
They rebuilt it again. Same issue.
They rebuilt it again. Same issue.
This time, one of the service guys happened to be at a convention afterwards, and asked the dealer rep what was going on.
"Oh, that vehicle is supposed to have very low oil pressure."
Not sure if it was a lie or what, but it lasted a few thousand more miles at an end cost of about a dollar a mile until it died and we sold it to a friend to use as a storage barn outside his apartment.
No more US cars for us.
You must have been cringing sooooo hard when I told you about my old Millenia's grand ol' time with a leaky head gasket fouling the spark plugs and causing misfires all over the place. Nothing like having the entire car shake like Pinkie on a doozy every time the vehicle tried passing 2500 rpm. (Which was, incidentally, almost exactly highway cruising speed over level ground...)
P.S. I was going to read a chapter of something before bed, but your blogs work equally as well.
He opted for a used Snap-On Veris from craigslist didn't he.
You know, I love it when a customer comes in and says 'my transmission doesn't work' and then I take the car for a test drive, put it in gear, feel a good firm engagement, step on the gas and nothing happens at all. Yep, you have a throttle problem.
I can't recall what car with a misfire I was working on recently. It was something fairly common, and not even that new. The miss was so slight it was barely noticeable, but if you drove the car real hard, it would trigger a misfire code and then start missing real badly. Actually quite a nice example of good car coding - it shut off the injector to that cylinder. While it made my diagnosis a little more difficult, unlike most older cars, it won't foul the converter with unburnt gas, and it'll run bad enough to make the customer want to fix it. I like that.
lel. GEE I wonder why it was missing.
I'm assuming you get paid for doing shit that your manager tells you to do that you know is unnecessary.
4760089 It probably needed an oil pump, oil pressure regulator, valve guide seals, and piston rings... basically a whole rebuild rather than just a crankshaft. See, they were probably thinking along the very-old-school lines of thought that worn main bearings cause oil pressure loss - which they do. But modern engines aren't as bullet-proof as they were in, you know, the 50s. Other things wear out, too. And they obviously made a stupid assumption that their first diagnosis was correct, even AFTER it was proven wrong.
I gotta tell you though, as an experienced mechanic who's worked on all manner of different cars, American, Japanese, German, they're all pretty much the same. Sure each brand has its own idiosyncrasies and faults, but in the big picture... they're really all the same. Until you start talking about cars like Yugos, Saabs, anything British, that is.
4760147 I've got a (I think) 2005 Toyota Camry that has the funkiest starting issue that we've been working around.
If you start it *without* tapping on the gas, it starts, but will not rev, shift gears, or do anything other than just sit there like a lump. Turn it off, start it with tapping on the gas, and it works perfectly. (We think it thinks it has a remote starter.)
What kinda weirdo doesn't fix the misfire for two years, and yet complains about it not having enough power...
(Obviously other stuff, but still)
4760158 *cracks fingers* I honestly doubt any aftermarket remote starter would have anything to do with the gas pedal, as there is never any reason for such a device to be wired to anything remotely relating to it. I tell you though, me personally, I really hate electronic throttles on any car. They're made so complex, in order to be failsafe, and programming has a great deal of complexity and a lot of failsafes as well. And they're very sensitive to dirt and sensors being even slightly out of whack. In other words, it would've been way easier and more reliable to stick with a cable operated throttle. But I digress.
Your particular issue - though I'm merely speculating - sounds like either one of two things. A - carbon deposits on and around the throttle plate. Or B - one or more of the internal throttle position sensors don't register correctly at 0% open. In either case, the computer is able to tell immediately that something is wrong when you start the car, and it just says 'fuck it, I'm out'. As the throttle is a super-important control and safety concern, it's something that gets checked out the microsecond that the engine is started - in fact, probably at ignition on even if it's not started. And it seems that it likes it better if the throttle is more than 0% open during those initial checks.
Like I said, they are sensitive little devils. I find that all cars with electronic throttles are very sensitive to even a tiny amount of carbon deposits on the plate, resulting in performance issues, and sometimes tripping codes. Basically, at 0% open, it is actually, say, 10 thousandths of an inch open. With carbon buildup there, even a thin film, it's now 8 thousandths, and the computer doesn't know it's dirty, it just thinks something's wrong. I recommend cleaning the thing. Besides, you really should clean it annually anyway. Best way is to completely remove the throttle body, take it somewhere you can sit down, get a rag and a can of brake cleaner and just go to town. Don't actually spray down the thing in brake cleaner, as it might get into the electronics. Just put it on the rag and use elbow grease to get it sparkling clean.
If you make it sparkle and there's no improvement, get the codes read from the car - if any - and we'll take it from there, but you'd probably just need a new one. Looking at ~$200.
4760175 A customer...
If I know something is wrong wih the engine in my Mustang, I can pull the codes on my own, and possibly reset them. If the problem reoccurs, I want it fixed.
If that fix means to sort out another problem elsewhere first, then that’ll be adressed first.
Running a car with a known problem for 2 years and then complaining about another problem which most probably is related to the issue already 2 years underway, in my book Would mean the guy/girl doesn’t really care that much about the car. Your comment on the picture reflects that.
That kind of attitude almost makes me feel sorry for the car...
I love how this became a "ask the internet experts what's wrong with my car" Q&A.
I've got a leaky tire. What do?
yeah it does. FMEA is a pain to do.
I'll have to keep that in mind for the future. Although i think it just gets lost somewhere as it works its way down from the engineers, because it obviously is in the documentation some where.
yes, that's definitely a thermal event.
maybe i'm just not quite getting what your saying, but doesn't the brake pedal already override the cruise control (at least on the cars i've driven).
or a stupid driver.
yay documentation. There's a microcontroller I have my eye on for some stuff in the future (computer vision stuff), it had a 3000 page manual. Fun.
This one was particularly interesting to me. I'm a mechatronics engineer so this kind of stuff is what i'm getting ready to do for a career.
4760089
I had a similar issue on my Plymouth Duster. Valve noise; I took off the valve cover to adjust them, and discovered that they couldn't be adjusted. Called the Chrysler dealership and talked to a mechanic; he said that they weren't adjustable, and if they were making noise to ignore it.
So I did.
4760104
The expression one of the techs I used to work with was "shaking like a dog sh
ing razor blades."
Head gaskets are one of the jobs I hate, because it's one where you don't know what you're going to find until you get in there, and customers never understand when you can't tell them how much it's going to cost before you've seen the actual extent of the damage.
4760114
Well, he didn't fix it. I don't know what his solution was. I can say that he could buy a better car than that Intrepid for what a Veris costs, even used.
4760147
That Lincoln I blogged about a while back that had an exploded ignition coil and dead PCM came in because the customer thought it had a transmission problem. Customers are idiots.
A lot of them do that these days, if for no other reason than to save the cat.
Going forward, according to our trainer, there are going to be codes that will just make the car go into idle only mode if they're ignored for too long. Kinda like diesels do with the exhaust fluid.
Actually (and this is true) the injector was deliberately disabled, to keep it from melting the cat. The manager says that the car has a valve problem, which is certainly possible.
Yeah, I'm hourly now so if the manager wants me to do something pointless that won't fix the car, I'll do it. It's easier than arguing with him, most times.
4760175
Let me put it to you this way. One of our customers once asked us if we could hang his exhaust back up, and he said that he had the part it needed.
It was a metal coat hanger.
He handed us a metal coat hanger.
Personally, in the case of the Intrepid, I'm willing to believe that it did have more power before--I think that something else has gone wrong with it, but I never got told any other symptoms than it cutting out at 3k RPM, so I didn't have anything else to go on. I suspect that he ignored the misfire for long enough that something else went wrong with it. likely caused by the dead miss. But I have no idea what, and wasn't willing to go too far into the thing if he wasn't even going to fix a dead miss.
4760283
Sadly, that's something we see a lot. And we rarely get to tell customers "I told you so."
Sometimes, though, we do. Like in really cold weather, when that battery we told them was bad last winter just won't cut it any more.
Actually, compared to a couple of cars we worked on today, that Intrepid was pretty nice. A Nissan with rusted-out floors that reeked of weed, and a Dodge Avenger that we recommended taking to the junkyard three years ago (and I stand by that recommendation, even though it's still somewhat driveable).
What really depresses me sometimes is when someone has a far nicer car than I do and won't fix anything on it. My cars are all piles, but then most of them only cost a few hundred dollars.
4760646
Jack the car up until the tire is just touching the pavement, cut a slit in the top of the tire (the tread part) [For safety, you should probably let the air out of the tire before you cut the slit in it]. Jam a funnel in there, and pour in Quickcrete until you can't get any more in. Wait for it to cure (this might take a couple of days), and bam! That tire will never go low again.
4760709
Yeah, I'm sure there's documentation somewhere, but if I can't get to it, it doesn't do me any good.
Ford used to be the worst offender; they would just have you perform certain tests off a flowchart, and then tell you to replace a certain part. They assumed that Ford mechanics were idiots, and couldn't figure out anything unless they led them by the hand. Now, though, Ford's actually pretty good about giving us theory and operation, and they've changed some of their repair procedures based on what their reps have seen people doing in the field.
It's supposed to, but there's the possibility it won't. On an older cable system, if something stuck open, there wasn't anything that the car could do to help you--if you didn't know to shut off the engine or ride the brake hard, you were in trouble. With coding, though, the computer can kill the engine for you.
Like I said, I don't know if Ford intended for that to be a possibility, but the documentation suggests that it might be. Thinking on it more, it was more likely designed as a strategy if something got physically jammed in the throttle body. I really ought to look up that article again; I'm going off memory from 6 years ago. . . .
Well . . . to an extent, they can. Some of them even have an 'abuse management' strategy.
What's nice for us is when we have a neatly laid out description for the code. Like (and I'm just pulling this out of my butt):
I'd have to get a real code description, but the good ones tell you everything you need to know about when the code sets, what identifies the failure, what it does when there's a failure, etc. It makes diagnosis so much quicker!
Expect a lot of mechanics to throw curses at you.
Of course, you'll also be able to say "what did you do to my beautiful machine?" Possibly more often than you'd want to.
4760280
Most
customerspersons are, as far as I can tell in my experience, either outright incapable of analysis of cause and effect, or know so little about the problem at hand as to correlate one end of the problem not with even its opposite end, but something orthogonal, translated, squared, logged, inverted, and in a completely different postal code.4760832
Those fucking 2.7's always have some kind of timing chain/valve train problem. If that dude hasn't bothered to fix a miss in 2 years, it's unlikely he changed his oil. And those engines always accumulate sludge.
4760888 The best part is when you get an unlikely customer who actually can use their brain. One of mine is a shriveled 80 year old lady who walks with a cane, and yet SHE can check her own oil and take a fairly decent crack at diagnosing a problem. And then you look at the other customers and you're just like 'what's your excuse?'
4760969
I happen to work in an electronics department at a Walmart store, and customers say to me, very frequently, when asking about an esoteric topic, "This may be a dumb question, but..."
To which I almost always reply, before all present, "The only dumb question is the one you don't ask."
I stand by that. No matter how ignorant or foolish you think you may be about your conundrum of the day, if you are willing to admit it and ask and seek an answer and learn, you are far from stupid.
If you choose not to ask, if you choose not to observe, if you choose not to gain and retain and use knowledge to your benefit, then you choose to be stupid.
4760842
I find that cars in the US for a lot of people are just user objects, and there is little care taken in regards to them. Sure, there's the enthousiasts that take good care of their car, and the middle ground where people just make sure to keep up with the car, but when I compare the US attitude towards cars to the one I see around here in Europe... The upkeep is a lot more regulated here.
In the case of the intrepid, a misfire is gonna have an impact on the emissions. Over here if your car is 3 years or older you're required by law to have it checked on it's major points every year (unless it's an oldtimer vehicle, in which case I recall it's once every 2 years). Brakes, safety restraints, rust, tires... and ofcourse emissions. I suppose that exceeding the values for the car that a misfire might cause, would result in the car not getting a new certification for the next year. Which would mean it'd get flagged in the police database, and as soon as you were found to drive the car by traffic violations, speedcameras or the almighty catchken setup (which basically does nothing but read licenseplates, and compare those to a database, to flag those it recognizes), you can expect a hefty fine on your doormat. If you keep on using the car it'll get impounded.
So besides the fines that kind of make you want to keep up with maintenance here, the fact that a lot of taxes are tagged onto a vehicles purchase prices also makes sure the vehicle is more coveted. Not to mention our gas prices which will make you want to make sure the car isn't using more fuel than it should (as a comparison, we're currently nearly at $7 per gallon).
It still amazes me when I'm in the USA for vacation what kind of vehicles I sometimes see driving around that wouldn't even be allowed on public roads over here.
Anyways... I do enjoy your stories on vehicles. Allows me to pick some info up, and you do write them entertainingly :) Keep it up :)
4760844
Man... That sounds like a tough job. I hope my local repair shop has enough Quickcrete on hand, 'cause I think I'll let them handle it.
PS Your shop counts as 'local,' right?
PPS I'll need directions.
Why wasn't a misfire a full-stop fix it first problem? Like, if you won't let us address this major fundamental problem with your car, then asking us to do anything else in relation to getting your car running right is a waste of our time and your money? The whole reason the CEL flashes when there's a misfire is to get the attention of everyone who normally ignores the light. "Help me out, there is something REALLY wrong with me (that is probably ruining the expensive mandated emissions equipment)" Like I already know the answer, because your boss told you what to do, but how could they be that wrong about EFI and run a garage? They had an angel investor that thought they were just a really good guy?
Also, who spends money on fixing an Intrepid? :P
4761044
In a global sense, yes.
Drive WNW for about 500 miles, then look around for the sign.
4761930
Well, that would have been my call, if I were in charge.
He's generally good at selling stuff; certainly better than I was. Although he also seems to let a lot of stuff slide that I wouldn't have. So I don't know. This year, we made the most in gross sales than we have in a decade, and we did it with only two employees instead of three. . . .
Yeah, these days it's probably not a car worth fixing anymore.
4760850
I can think of two places of the top of my head. I typically add an action taken column when i'm doing mechatronics based FMEA, it's also in finite state machines for the code.
ahh, ok. Forgot about older analog stuff.
your lucky. I'll have something not work correctly because on page 2635 the manual said to use a 100 pF capacitor for frequencies below 8Mhz that I didn't see. I also register lists which contain all the settings for the microcontroller.
The problem with having a device that can do 1 million things is that you have to tell it which of those 1 million things to do, and they all have to be written down.
well, i'm not looking at auto industry in particular, although I haven't ruled it out. I was talking about mechatronics in general. Plus I already know how to pass the buck along. I know I documented it, it's not my fault you guys didn't get it.
Funny story about that. A buddy of mine was designing a tool for working on turbines for his senior project. He got to see a turbine being taken apart and the engineer with them was just cringing the whole time because the techs were risking damaging some parts.
4763085
Well, the automakers make their diagnostic manuals so that the mechanic can understand them and fix the car.
It's funny, though, one thing that we learn in class is stuff that isn't documented, because a couple of our trainers like renting brand new cars with nothing wrong with them, and then spend a weekend scoping waveforms and causing problems to see how the car deals with it. That has backfired; one of our trainers is no longer allowed to rent cars from Avis after he took apart the high voltage battery on a Prius and didn't get it put back together again properly.
Yeah, it's probably a bit harder from the engineering side of things. When we get the cars in our hands, they've already been designed and tested and documented, and we have the sure knowledge that the car worked before it got towed into the garage--we don't have to start from scratch.
You'll still get plenty of curses
Since I live in Michigan, many of our customers work in the auto industry, and it's always interesting talking to them about design things.
Actually, here's a funny story: my brother is a rocket scientist (literally), and they were having problems with their rocket, so their team called some other rocket scientists and asked them how to deal with that problem.
"Well," the other guys said, "usually when that happens, the rocket explodes."
"We're carrying people on ours."
"Oh."
Somebody sent me this video once:
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There's just so much information that sorting through it all is a nightmare. There's just so many settings and they all need to be explained.
Nice.
well, to be fair we're not quite doing it from scratch. We're building on what's been done before. But yeah, it's a mountain of work, it's enough to keep large teams occupied full time for years on end.
yeah, I bet.
that's great.
That's a really bad sound to hear. My buddy was working with the big industrial ones like these.
tynaghenergy.ie/wp-content/uploads/2013/03/4.jpg
and the techs were removing the blades from the disk with a hammer and chisel. One wrong hit and you have to scrap the entire disk. Which, as you can imagine is not cheap.
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Well, yeah, but when you're building something up, it's something that didn't exist before, whereas when a dead Monte Carlo gets towed in, I can be confident that it did work up until somewhat recently. (In that particular case, I first had to fix what the customer broke trying to fix it, and then fix what was actually wrong with the car in the first place.)
I saw a video where they were installing one of those at a nuclear power plant. IIRC, it cost about 100 million (not sure if that's just the part or the part and labor). Not something where you want to screw up, that's for sure.
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that's true. But you might start with an existing frame and then just tweak it a bit instead of starting from scratch. But your right. It is a lot of work.
i'm not sure, my guess is both. The manufacturing is really difficult.