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Pretty sure my mechanic is dodgy


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#1 Luni260z

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Posted 29 October 2011 - 02:16 AM

Hey people.
My car's electics burnt out recently. Wires fried around the coil and the alternator.
Wires died as I was starting the car.

Took car to local mechanic. he says he wants to look at the alternator.

I say this is bulls*t, because the car isn't even starting (how can he blame the alternator). The alternator hasn't been examined. Car died on starting so I find it impossible to believe that something that puts out such sh*ty power could fry wires (where as the coil is something that pumps out volts and is far more likely to cause troubles).

Am I correct in telling him to f*ck off? I find it suspect that he blames the alternator without even replacing the wires and testing the amps/volts.

The ground wire was snapped off the battery. So personally I believe that caused the wires to fry as it couldn't ground and leaked out wherever.

I bought replacement coil, electric ignition parts (which I doubt are the cause but I think are at least possible).

What do you think ?

Quick responses appreciated .. wish to confront him tmrw.

Thanks in advance.



Sam.

(also, can we get rid of the word filter. People here are old enough to drive a car. They are old enough surely to not take offence at the word "sh*tty')



#2 RB30X

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Posted 29 October 2011 - 02:27 AM

Personally, I think he has every right to look at the alternator as part of the diagnosis as it (or the voltage regulator) controls the system voltage.

And if your battery isn't grounded then you don't have a completed circuit and you won't get any power anywhere?

#3 Luni260z

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Posted 29 October 2011 - 04:29 AM

Thanks RB30X.
Will take your word for it.

I guess you are right.
With a poor grounding it really shouldn't be able to pull too much power (so i assume the ground to the engine is fine).

Wouldn't it be more likely to be a short or corroded wiring rather than the alternator causing problems though.

I mean, If I fix the alternator isn't it going to put out more rather than less amps ?

Can an alternator fail and put out more than standard amperage?

#4 RB30X

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Posted 29 October 2011 - 04:55 AM

I don't know very much about electricity except cars and houses use different types ;D

But if your voltage reg on your alt is dodge or your battery signal to voltage reg is dodge, than it could tell your alternator to ramp up and put out 14+ volts etc.

When you say it happened when you were starting the car, was the engine running, or cranking for a long time, or just the ignition switched on etc?????

#5 peter mc

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Posted 29 October 2011 - 07:55 AM

The alt has power to it all times its main b+wire goes to the bat+ so u can have the alt cause fires in cars very easy
and if it has a short it will fry wiring or a bad connection on the b+ wire it will have a high resistonce and will cause the wire to get so hot they can catch fire .............VT commodor did this all the time Holden did a recall to fix the problem.  and you say shity power from the alt it may be 14v but it 60+ amps and you can weld steal with 25amp

#6 dat2kman

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Posted 29 October 2011 - 08:54 AM

Go figure, there is possibility that within your Alt, when you last drove your car, and you shut the engine off, the brushes could have collapsed due to wear, the rotor could have just ground through the stator windings due to bearing wear, or, a wire dislodged due to vibration.
These things do happen to our 30 plus year old components!

You then hop back in, a few days later, turn the key, energise everything, of poof, wires fried.

Just be thankfull we have the great Samurai Warrior, Hitachi, helping us, the british have evil nasty Doctor Lucas!!!

#7 Six_Shooter

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Posted 29 October 2011 - 10:11 AM

Just as a forward, I have been working with automotive electrical and electronics for over 20 years, so I've seen a lot...

Yes, it is possible that the alternator and/or regulator could cause a problem at start up, while it would be a rare situation, I wouldn't rule it out. I'm also not sure that would be the first thing I would check, but it would be on the list.

A poor or broken ground can also cause problems like you describe, and because of the lack of proper body grounding, the chassis would need to find a ground source through other components, the alternator and regulator being one of those components.

Unfortunately for those of us that work on the other side of the counter and perform the diagnosis and repairs of vehicles, we have to deal with people like you a lot. Who don't know much at all about how a particular system works and because their bartender's best friend's dog walker's little sister's day care provider's uncle said some stuff about electrical components in a car once, they think they can assume that a particular situation just can never happen. If there's one thing I've learned in all the years I've worked with automotive repair and especially electrical, is never rule out a possible cause, until the diagnostic procedure has been performed.

On the next part of your post, I'm glad the filter is there, for people like you, that think the rest of us want to be cursed at when we are relaxing in the evening catching up on the world of the intarweeb. While I don't mind cursing in certain contexts, this would be where where I think you are an under-educated pompas ass , whom unable to express himself in a manner which would want me to help you.

#8 RB30X

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Posted 29 October 2011 - 10:40 AM

Well said Six Shooter  ;D

#9 Lurch ™

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Posted 29 October 2011 - 11:05 AM

I'll let the current comments stand.
Luni & SixShooter: Behave yourselvs or you'll both be taing a short holiday from the forum >:(

#10 nizm0zed

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Posted 29 October 2011 - 12:46 PM

gotta say, as a mechanic, im taking six shooter's side on this one.
However, i suggest that instead of slagging off about it, learn about what it is that needs fixing.
You can still take it to the mechanic to fix it, but at least then you'll have some idea of how and why it works the way it does.

So, looking at what you have said;
1. you have fried wires. (im going to assume by fried wires you mean they are black and burned and the insulation is breaking off?)
2. the battery cable negative was snapped off at the terminal.

Allow me to paint you a possible picture....
Ok, the alternator charges your battery, to keep it full.
It uses the voltage level of the battery to self adjust its output in Amps, eg, if the voltage is high the output is low, if the voltage is low, the output is high.
Think of it like having a rainwater tank, you have a small hose coming out to water your lawn, and a hose going in to fill the tank.
If the tank is empty and you are watering the lawn, you need to put enough water in the tank to fill it up AND water the lawn at the same time. eg, more going in then going out. If the tank was full, you'd only need a small trickle going in to keep the tank topped up while you water the lawn.
Now, if your negative cable was snapped off (and you didnt know) then you wouldnt have a battery in the system, your alternator would have no reference to know when the battery is full, infact it would see it as being completely empty.
Basically that means 100% output from the alternator AT ALL TIMES.
It also means that the system has to find a ground through some other components that weren't designed for it.
Lets say that one of those grounds was the wires upto and through the coil.
How do you think they would cope with 60 amps of power running though them?
As peter said, it only takes 25 amps to weld steel.
Those wires would only be rated to 10, maybe 15 amps anyway.
In technical terms, the resistance through the small wires would be way too high to pass the power being fed, they would heat up and melt off the insulation, causing short circuiting and potentially fires. the wires would also be permanently damaged.
The same over voltage and damage could have also happened to other components, eg, inside the alternator, the coil, fusible links.
If your wires are damaged they need to be replaced. No if's no buts.
if those other components fail the diagnostic tests they also need to be replaced.
You should also replace BOTH the battery cables and terminals with new ones, just to be safe.

the electrical system of the datsun is very simple, a good example for you to learn on.
EDIT:
Here's a link for you to follow and read about, it'll explain the basics for you.
You may need to read some bits over a couple of times to get it round your head, however it is made as simple as possible.
http://www.secondcha...m/public/98.cfm

#11 Luni260z

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Posted 29 October 2011 - 02:36 PM

Thanks everyone.
And I'm not sure why six shooter believes I'm sweating at him. I'm saddened with my failing car parts and wish to express it.
This is a car forum, not English Gentleman's club.

I don't see the point of the word filter because when you read shiver you say the naughy word in your head anyway. So what's the point? I can understand the F word being a little much in my post. But does anyone really take offense at the word sh*t?

I appreciate your response on that matter anyhoo six shooter .. if people feel that way, then fine. I just thought perhaps with this not being a forum for kids that we could avoid unnecessary censorship. If you take offense and others do also, then fine.

My reason for being dubious with the mechanic is that he hasn't yet replaced the wires, started the car, or tested anything. He just upfront wants to charge me for a new alternator or parts to fix it. I've told him that the ground from the battery had snapped off and I'd continued to drive it, so that's why I assume that's more likely the cause than the alternator. Him wanting to charge me for something without inspecting seems concerning.

The car died a few hundred meters from my house. It was kinda running, but just wasn't kicking over. So I gave it a few extra turns of the ignition in hope it would fire up.

Pics attached. (sorry, don't have pics of the snapped off cable on the battery, but its the one that goes right from the battery to the car itself (only a few inches long, kinda fat).

Special thanks nizmozed.

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#12 peter t

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Posted 29 October 2011 - 03:01 PM

Hey mate,
              You really have to grow up. If you have electrical probs than you take the car to an auto electrican  not a mechanic. If your neg cable is not connected wouldn't that ring alarm bells. But I can see by your attitude you really haven't got a clue. Typically of the "Y"generation. as far as the swearing is concerned this is a great site where you don't have to put up with people like you going off at other people about things that you know nothing about. We are all good people that wish to help others but if you swear at us you will be banned. 8)

#13 Luni260z

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Posted 29 October 2011 - 04:12 PM

Hey mate,
              You really have to grow up. If you have electrical probs than you take the car to an auto electrican  not a mechanic. If your neg cable is not connected wouldn't that ring alarm bells. But I can see by your attitude you really haven't got a clue. Typically of the "Y"generation. as far as the swearing is concerned this is a great site where you don't have to put up with people like you going off at other people about things that you know nothing about. We are all good people that wish to help others but if you swear at us you will be banned. 8)


TIL I am the oldest Gen Y'er on the planet. I guess I was Gen Y before it was cool.

I'm trying to point out that there is a difference between swearing, and swearing at a person here on the forum. Sadly it seems one isn't allowed to question censorship. How sad. I'm suggesting that rather than a word filter simply ban those who are abusive towards forum members, or who are excessively foul mouthed.

I came here for advice and knowledge before confronting my mechanic. I didn't just wander in and go off based purely on my suspicions. I sort out answers from a helpful community that doesnt profit from my ignorance. If I go into the mechanic and tell him I know close to nothing I'm sure I'll end up paying for replacement fluids for my headlights that I probably don't actually need.

The cable had snapped a few times and I'd reconnected it. When the car stopped I noticed that the cable had once again snapped off. I don't know much, but a snapped off ground lead certainly tells me that without a proper ground electricity will try to find its own shortest path to ground. That's something that can be spotted as a point of failure without having to even connect up an multimeter.

I took the car to this place because he does blue slips. There are a few other things that need attention outside the wiring and I figured it'd be best to have one person look at all of it (and it might as well be the person who has the final say over whether or not the car gets back on the road or not legally).

It saddens me that questioning a mechanic who wants to replace parts without testing them results in some people blaming me for my ignorance.

people like you going off at other people about things you know nothing about

.

If someone here posted "my wires are burnt" .. who on this forum would say (without having looked at anything) .. "you will need to replace the alternator" ?
People might certainly say "you might need to replace it", but would anyone really say it'd have to go without having tested it.


Sorry, but I also fix things for a living. (computers, computer networks). I would never tell someone to replace something simply based on "sometimes this is the cause, I haven't tested anything, but I reckon you should replace this". My knowledge of troubleshooting problems says you should think about what might be the issue, research it if needed, narrow down the problem, test, action appropriately . I don't go on a  "lets replace all the things it could be just to be safe" policy.


I've had a bad run with mechanics.
I've lost my 2 seater 260z to a mechanic. Car unrepairable. Not his fault apparently. Car was not on his lot when my car was totalled. I lost everything from that car but the engine and carbies. (i wanted the newly reconditioned manual gearbox swapped over for the auto that came with the replacement car I bought. But no, apparently they "threw that away". They didn't remember me wanting it. I've lost a wicked diff my mate gave me (well, he gave me a whole skyline with it, but the diff was worth as much as the car). Mechanic says "oh, we didnt think you wanted that", and then "it was no good, ask the other mechanic here". I say "i've driven the car for a year with that diff, it was rock solid, and you are not allowed to throw out my car parts" ... "oh well", they said, "that'll be $$$ or you aren't getting your car back".

Sorry, but my viewpoint of mechanics is not the best. I had one wonderfully helpful mechanic who sadly moved up the coast. But I've been ripped off on numerous occassions over the years.  :'(




#14 Luni260z

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Posted 29 October 2011 - 04:23 PM

To backup my above posts.

Look at this thread I posted when the issue occurred :

http://www.viczcar.c...0.html#msg79140

Not a single mention that the alternator might even be related, much less need to be replaced.

Thanks again to Peter mc26 and others previously mentioned with helpful advice.

What a shame that I question a mechanic and that makes me an idiot for not taking his word for anything and everything and not simply handing over fistfuls of dollars without question. If questioning things and wishing to know more makes me an idiot, then I don't wish to be smart.



#15 peter mc

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Posted 29 October 2011 - 04:39 PM

You don't just take the $$$$ to him, you ask him to show you the parts and whats the problem with that part then if your happy pay him ,,there are good and bad trad people out there it up to you to find a good person that you think looks after you, like some have said the alt would not be the first thing to change but it needs to be checked and i to have replaced them after a wiring fire

#16 Luni260z

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Posted 29 October 2011 - 04:54 PM

You don't just take the $$$$ to him, you ask him to show you the parts and whats the problem with that part then if your happy pay him ,,there are good and bad trad people out there it up to you to find a good person that you think looks after you, like some have said the alt would not be the first thing to change but it needs to be checked and i to have replaced them after a wiring fire


Thanks Pete. That's pretty much my feelings on the matter.

I took my car into this guy a while ago (before the wires burnt) for a blue slip. He told me straight up that it wouldn't get slipped due to a hole in the exhaust, and sent me away without having to pay for an inspection (which was nice).

So I figured based on that he was likely a trustworthy mechanic. Fingers crossed



#17 peter t

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Posted 29 October 2011 - 06:48 PM

Sorry mate, Didn't check your profile before calling a "Y" You just came over as one in your first words. I too have been burnt by a gearbox shop and now an engine builder. People on this site have helped me a lot as I have tried to help others and I hope you can find a solution to your problems, but I still stand by what I said in regard to the filter. Sorry I can't help with your wiring problem. :-[

#18 Luni260z

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Posted 30 October 2011 - 03:07 AM

Sorry mate, Didn't check your profile before calling a "Y" You just came over as one in your first words. I too have been burnt by a gearbox shop and now an engine builder. People on this site have helped me a lot as I have tried to help others and I hope you can find a solution to your problems, but I still stand by what I said in regard to the filter. Sorry I can't help with your wiring problem. :-[


All good. Better to be called a youngen than an old fart I suppose.



#19 MaygZ

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Posted 30 October 2011 - 03:46 AM

Have I missed something here?  Why is this guy getting flamed?  He's not even South Australian??

OK, it is like obvious that he has limited knowledge of like cars and stuff.  (someone please call me a Gen Y) And he has a natural distrust of those in the auto repair business (who doesn't) and probably other professions also (wanna buy a car, house, used car, invest with a solicitor?).

But really an instant flame session??

Those of us with some understanding of how these systems work - crickey the poor fellow doesn't even understand the basics of a 12v DC system and his sparkie couldn't help himself - will appreciate that most of the wiring and elements between the battery and the ignition system will need to be checked and most likely be replaced, but this poor fellow is really hoping to hear "It's just a $2 fusible link and you'll be fine."

I'm sure that if others posted up "I fired my electrics!" we would get some empathy and some sympathy - we might even get some good advice (which he has received from some - love the water tank analogy) and probably some offers of help.

Come on now, give the bloke some good, positive help and save all the venom for those that deserve it (ie: the South Australians!)

MaygZ

#20 Six_Shooter

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Posted 30 October 2011 - 03:57 AM

For the record I never said to just up and replace the alternator, but that I wouldn't rule it out as a possibility in a diagnostic procedure.

It seems that you have other issues, in "losing" two cars to other people. There's usually more to the story, how long did the cars sit there? Did you make any attempt to inform them that you wanted the cars, or to arrange transport of the vehicles to a location where they would be secure?It might be that you need to find a better mechanic, this one may just be bad news. I've never understood why people will complain about about a certain store, or auto repair shop, barber, etc, then in the next breath say "Well, I gotta go, I have an appointment at the shop I was just complaining about...."  ??? If you don't like something or someone, change what you have or where you go. Nothing says that you have to keep going back to some place that you don't feel like you're treated fairly by.

I can't see the burnt wires in the second picture, the above of the driver side engine bay. I do see the burnt wire in the coil picture.

Any repair like this you start with what is known to be bad, such as the broken ground wire. Even something that may seem unrelated fix it first. You'd be surprised just at how related different systems are in a vehicle. Without actually looking at the vehicle myself, I would have to say the broken ground is related, and you may find more wires that are just as crispy. Unfortunately they would be in the wire harness and possibly in the dash. So if after repairing those wires you still have problems, you'll have to dig deeper.

Use better techniques to repair that broken ground. If it keeps breaking, you're not repairing it correctly. The definition of insanity is doing the same thing over and over expecting a different result. What exactly is breaking? The repair, or the connector, or the wire itself? The only wires or connections I have had break on me, have some sort of physical property affecting their longevity, such as weight of a harness pulling on it, vibration, corrosion, etc. Make sure the wire is supported, not vibrating and not able to have corrosion form and you should never have a problem.

So start with the known problems, repair the burnt wires, using proper techniques (solder/heatshrink/wrap), then using proper tools, such as a DMM, set to current mode, find any circuits that have a higher than normal current draw, either while running or not, or better yet, both.

I take offense to threads like this, because I have stood on the other side of the counter for many, many years, literally and far behind that counter performing the actual work. I've been told I have no idea what I'm doing by the people paying me to do it. What? I've been called a rip off, even though I was giving a deal, among other things all because people paying me to do it, have little to no knowledge about what it is that I'm actually doing, and assume that it's easy, because I didn't spend 4 years in university to learn how to do it. No, I learn everyday about what I'm doing. There's always something more to learn. Threads like these just keep confirming what the problem is with people that have little to no knowledge about a subject or just enough to make them think they know, when there is much more to it. As the saying goes, "The more you know, the more you realize you don't know." I have had people describe problems to me, even over the phone and have figured out the problem, even though it has seemed unrelated to most, before the car ever showed up. It's from experience, and diagnosing many years of problems or systems. In this case, wanting to replace the alternator without going through an actual diagnostic procedure does seem a bit odd. Even if I have figured out the problem just from a description, I will go through a diagnostic procedure to confirm it, before replacing parts, if possible.

I'm not trying to call you names or tell you are wrong here, but just to say that maybe, there's a reason why someone will want to do something that seems unrelated or not likely the problem, because they have likely seen the problem before, or something very similar. Before someone gets into a diagnostic procedure, they may not know there are other issues. Like I said before you may need to find a different mechanic if he just wants to throw parts at a problem instead of doing a proper diagnosis. Unfortunately sometimes a proper diagnosis does involve replacing parts, especially when it comes to electrical. I'm sure as a computer tech you've seen some common problems on certain MoBos, programs power supplies, vid cards, RAM, HDD etc, and when someone says I have XXX components and I have this issue, you will in your own mind, say "Yep, I know exactly what that problem is... (I also dable with computers too and see some common problems pop up. ;))

As far as the filter, I'm not offended by swearing in general, but why is it so necessary to use it? Why put up such a big stink to be able to curse on a forum that has already set filters in place? To go by the idea of "banning those that abuse it," what is considered abuse? 1 curse word in a thread, in a post, in a sentence? Each of us have a different tolerance for people that curse and swear, so it is better, as a whole to just say none of it, and move on. If you really need  to use cursing in your posts I can think of many other forums that allow it, and choose not to be a part of those ones, because I prefer the atmosphere of forums where they limit or don't allow it all. I find the membership is generally more mature, and can convey their thoughts much more positively and with a higher grade of understanding.

In closing, before the next time you want to call someone names because you don't fully understand the system or procedure, you might want to stop, think of the other side of the coin and re-word what you say. ;)




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