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Sherlock Ohms

I Fixed My Broken Corvette for $0.00

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naperlou
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throwing parts at it
naperlou   10/26/2012 10:33:47 AM
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Bob, it is very common for auto mechanics to "throw parts" at a problem.  Actually, I found when I was working on my own cars (typically old British sports cars), I did it myself, since they were not easy to diagnose.  That is why we often collected old cars and parts, so it generally did not cost a lot.  We also did not have the on-line forums. 

JimT@Future-Product-Innovations
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needs replacing SOON, anyway -so-
JimT@Future-Product-Innovations   10/26/2012 1:01:44 PM
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I have to agree with comments so far – Mechanics often play it safe, and replace parts – not to intentionally run up the bill (as my Wife speculates) – but, because they can't find the real root cause issue; and then they justify it with statements like, "well, that element had a lot of corrosion, and would have need replacing SOON, anyway -so- better safe than sorry".  The much more frugal side of me has often frequented On-line blogs and boards to find better clues.

richnass
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Blogger
Re: needs replacing SOON, anyway -so-
richnass   10/26/2012 3:24:31 PM
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Love your story Bob. I too do a lot of my own car repairs (I own a 33-year-old car). Usually, whatever repair I need to do has been done by someone else who has posted step-by-step instructions, often with a video. This Internet thing is great. I hope it sticks around.

 

Rich

Charles Murray
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Blogger
Re: needs replacing SOON, anyway -so-
Charles Murray   10/26/2012 4:25:53 PM
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The potential $1,000 figure quoted in the article is probably not very far off. Having the ability to do the repairs yourself is huge, given the cost of parts on many of today's vehicles. Even more so on the 'Vette, which, according to Consumer Reports, has only an average reliability rating for models between 2006 and 2011.   

Bob Salter
User Rank
Iron
Re: needs replacing SOON, anyway -so-
Bob Salter   10/26/2012 4:31:44 PM
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One thing that I learned with this episode is that the modern computer controlled automobiles are sometimes very difficult to troubleshoot. Sure, one can push some buttons on the Corvette's dash to troubleshoot, which is more than one can do with most newer automobiles, but other maladies can prevent the system from working. Bad ground connections, usually from corrosion, and low battery voltage can often disable the computers. These were checked first. In my case, the two computers, Power Control Module (PCM) and Body Control Module (BCM) seemed to have enough voltage to operate a relay (clicking sound) and flash the dash lights, in sync. However the BCM didn't have the ability to read the resistance of the pellet in the key to satisfy the security system. But, a couple times it did as the engine would crank but not fire. Each GM dealership should have a diagnostic computer called a Tech II for trouble shooting, but this is still no guarrantee of identifying the root cause of the problem. The gentlman that helped myself and others is a GM certified technician, and the way he identified the problem was experience. He recommended that a previous Corvette owner with the same problem replace the ignition switch on a hunch, which solved this owner's problem. He was good enough to send the faulty switch to the technician, who disassembled it, observed the contacts, and figured out how to fix them. My good fortune is that he shared this insight on the forum. This epsisode reinforces my long time theory that experience in auto repair is the best diagnostic tool.

 

Kevin Shaw
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Iron
Re: needs replacing SOON, anyway -so-
Kevin Shaw   10/29/2012 10:11:48 AM
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Great story Bob. I too had a problem with the ignition switch of my 2001 C5 coupe. While you were doing your research, you may have read my posts in the Corvette forum documenting my troubleshooting and repair . I had posted schematics in the forum to explain the process I went through to find the problem. To confirm the ignition switch was at fault, I jumpered between two fuses on one of the fuse blocks. The problem disappeared and the car functioned perfectly so I took the dash apart and headed off to the Chevy dealer to buy a new switch.

Bob Salter
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Iron
Re: needs replacing SOON, anyway -so-
Bob Salter   10/29/2012 12:51:33 PM
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Hi Kevin,  I realized a long time ago that I was electrically challenged, which is why I became a Mechanical Engineer who was proud to obtain Bs in EE 101 and 102. So, I'm not conforable reading or understanding wiring diagrams. I do know that the computers in modern cars are controlling more and more auxilliary functions, usually through micro relays. So, after checking the fuse for non-operating function, I think the next thing would be to check the relay. Next would be the ground connection followed by possibly hot wiring the device itself. The root cause of the problem with my Corvette was found in the ignition switch that has to be "on" to supply voltage to many auxilliary circuits. Fortuneately, from a technicians experience and advice, I was able to go directly to the ignition.

When you bought a new ignition switch, did you get the whole assembly with the key/lock mechanism? If so, did you get a key with the same "pellet" resistance?

 

Kevin Shaw
User Rank
Iron
Re: needs replacing SOON, anyway -so-
Kevin Shaw   10/29/2012 1:27:20 PM
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Hi Bob,

My situation is the opposite. I'm comfortable with the electrical schematics and less so with the mechanical side of things. I warned those "electrically challenged" readers of my posts in the Corvette forum about the dangers of jumpering between fuses in the fuse block.

The ignition switch assembly was in two sections: the actual switch and the keylock cylinder which had the contact to read the resistor in the key. I kept the original cylinder and just replaced the multi-section electrical switch. I found instructions on how to do it on a website that sells service manuals online (not sure if I'm allowed to mention the name of the website in this forum). The instructions on how to take the lower half of the dash apart was worth every penny.

Kevin

Jack Rupert, PE
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Platinum
Re: needs replacing SOON, anyway -so-
Jack Rupert, PE   10/29/2012 10:38:11 AM
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Any idea what the blacik substance was that you were dealing with?  Sounds almost as if you had some bad contactors there.  Glad the switch continued to survive until you got rid of the car.

Bob Salter
User Rank
Iron
Re: needs replacing SOON, anyway -so-
Bob Salter   10/29/2012 1:00:26 PM
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Hi Jack,  I have no idea what the black substance was or any way to remove it for analysis, as it all went into the 2000 grit paper. What is interesting is the black coating exacly matched both contacts. The shape of the black on the third contact was a long thin triangle, both contacts. It took very little polishing as the "black" appeared to be very thin, with absolutely no visible pitting. I do know that most "springy" electrical contacts are brass with Berilium alloyed in. Could the "black" be an oxide of Copper, Zinc or Berilium?

Tim
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Platinum
Group knowledge
Tim   10/26/2012 8:54:47 PM
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The internet is a true wonder of communication.  Lately, I have seen use of the internet as one of the best tools in my tool box.  The work of fixing the problem is not hard part.  Knowing how to fix the problem is the big problem.

Nancy Golden
User Rank
Platinum
Re: Group knowledge
Nancy Golden   10/27/2012 11:08:34 PM
I agree, Tim - the internet is a HUGE resource. I have used online forums to get information from programming a PIC microcontroller to fixing a plumbing problem to figuring out the best approach when one of my horses decided to misbehave. The first thing I do when I have a question (after I have completed preliminary research) is to search for a forum online to get help. We have to keep in mind that anyone can write anything in cyberspace, but it is usually pretty easy to establish credibility just by using common sense. That was an awesome fix on the corvette thanks to forum help and some initiative on the part of the owner.

Ann R. Thryft
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Blogger
Re: Group knowledge
Ann R. Thryft   10/29/2012 6:00:23 PM
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This story reminds me of our current problem with my husband's aged Honda coupe. The check engine light has started to go on occasionally, usually solid but sometimes blinking. Then it goes off, for days or even weeks at a time, before going on again. After reading what seems like a zillion forum postings on this issue, we've decided that the alternatives are many: sensor malfunction indicating nothing at all is amiss, sensor malfunction indicating the sensor didn't like the way my husband replaced the gas cap last time, and sensor malfunction indicating it didn't like several other things that have nothing to do with possible engine malfunctions. It's also a very remote possibility that something catastrophic is about to happen to the engine, but the more we read, the lower that probability appears. As the owner of my second Nissan Sentra--both of which I kept for well over 10 years, and which never tell me anything they don't mean--I am boggled by this non-working device that says everything *except* what it means. For now, we, too, have decided to spend $0.00 to fix it, in our case by doing nothing.

rickgtoc
User Rank
Gold
Re: Group knowledge
rickgtoc   11/1/2012 3:56:22 PM
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If the Honda is not too old, it has an OBD II connector under the dash near the steering wheel (some '94 &'95 cars,all '96 and later).  Big chain parts stores in my area will read those codes for free using their code reader, which may or may not help you, given the intermittent nature of the trouble light.  If it doesn't show up on the parts store's reader, you could buy a bluetooth enabled dongle to read those codes and transmit them to a smart phone using a free or low cost app.  Then you could leave the dongle attached and run the monitoring app while operating the car and see what codes, if any, the car's computer posts when the Check Engine light comes on.  It's not a cure-all, since the  diagnostic codes are sometimes misleading or point to something that's a long way from root cause, but it's an inexpensive thing to try.  And you can use the app to reset the diagnostic codes once you have effected a repair.  I bought a dongle for about $20 online, and I'm using the free version of an Android app to translate the signals.  In addition to diagnostic codes, the app generates all kinds of related stats, incluing RPM, fuel economy, speed, acceleration (using the phone's accelerometer, I believe).  But safety first -- let someone else drive while you look at all the goodies the phone spits out.

I originally took my Tacoma to a parts store and had them use their code reader when my check engine light came on -- O2 sensor.  I bought the dongle to reset the codes after I replaced the O2 sensor, and to let me read the diagnostic codes should the light come on when I'm on the road in South Nowhere out of range of an open mechanic or parts store.  I just put the dongle in a bag behind the seat to have it available when needed.

Ann R. Thryft
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Blogger
Re: Group knowledge
Ann R. Thryft   11/6/2012 11:54:22 AM
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rickgtoc, thanks for your detailed feedback. We've thought of going into the local chain store to get the code(s) read, but once you turn the engine off a time or two, the codes disappear. Your suggestions of how to DIY capturing them look intriguing. Otherwise, we have to be already at the store to catch it when it serendipitously happens. Since we're about 30 minutes away from the closest of one of those stores (we *live* in South Nowhere), this presents some logistical problems.

Tool_maker
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Platinum
Re: Group knowledge
Tool_maker   11/1/2012 4:53:52 PM
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Ann: your story almost duplicates our experience with my wife's 96 Blazer. A "Service Engine" light comes and goes, sometimes for weeks at a time. I have had it in numerous garages with no change, so have adopted this rule. If the oil pressure is where it belongs and the temperature gauge is okay, forget it. So far that has worked and it is free.

Braditude
User Rank
Iron
Re: Group knowledge
Braditude   11/5/2012 12:51:31 PM
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I had a similar problem with a 87 Nissan Maxima.

It was only 3 years old when I purchased it.

It started to run rough, and not having time to look for the problem, I had my wife take it into the Nissan dealer to have it fixed.

The technician told her it had a bad injector, and needed to replace it, and to do it right, he wanted to replace all of the injectors at a price of $600 plus labor!

I told her no, and to bring the car back.

I played with the car for about a 1/2 hour and found that the only problem was a bad connection on the injector, sprayed contact cleaner on all injector plugs, wiggled and replaceed them and the car ran fine from then on!

It pays to know and analyze instead of letting an amateur do it, as I called the Nissan dealer back and talked to the service manager and told him what I found.

I have not taken any of my cars back to a dealer since.


BH

Ann R. Thryft
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Blogger
Re: Group knowledge
Ann R. Thryft   11/6/2012 2:40:51 PM
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Tool_maker, we're inclined to use your rule. But since the car has 190,000 miles on it, there's a reasonable possibility that something actually is wrong with the engine. That's why we're contemplating spending more than $0.00.

Scott Orlosky
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Platinum
Re: Group knowledge
Scott Orlosky   10/30/2012 11:09:32 AM
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Tim.  I couldn't agree more.  The real power of the Internet is the shared collective knowledge base of the civilized world is at your disposal.  It's my first stop for just about any problem these days.  Of course I can still tackle things the "old fashoined" way by just disassembling stuff until I find the problem - if I have to.

Tim
User Rank
Platinum
Re: Group knowledge
Tim   10/30/2012 7:29:31 PM
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In 2004, we had a need for a minivan.  Looking at the local used car lots, we found a 99 Toyota Sienna at a fantastic price.  The vehicle was old, but it was low in mileage.  To be safe, we checked the Carfax on the vehicle, and it showed no issues.  We also ran a google search for the 99 Sienna and found that a significant amount of that model year had problems with oil sludge buildup and catastrophic engine failure associated with no oil flow.  With that knowledge, we knew why the deal was too good to be true.  The dealer was most likely sitting on the vehicle for a while and needed to move it.  We passed and bought a Ford instead.  125k miles later, we bought a brand new Sienna that had no sludge related issues reported.

tekochip
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Platinum
Part Swapping
tekochip   10/26/2012 10:36:26 PM
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I ran the Factory Service Department for an Agricultural Electronics business for a number of years.  Part of the troubleshooting process for many technicians was to replace parts and see if the symptom went away.  I always cautioned against that type of repair and demonstrated scenarios that would result in many parts being replaced without the root cause being found.  Rarely would semiconductors fail, but an unskilled technician would always replace the largest, most complicated component first.  The technician that used an oscilloscope to find the actual failure not only benefited the customer but also the company by finding problems that may have been in the design.


jayprab
User Rank
Bronze
similar
jayprab   10/29/2012 9:37:37 AM
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I had a Mercury Sable wagon once, probably a mid 90s model, I forget. One day the driver side window switch just stopped working. I called the dealer and he wanted about $600, installed. I went to the local junk yard and they wanted something less, but not by much, indicating that this was a high-failure part and much in demand. So, i decided to at least SEE what might be wrong. I took the switch assembly out and noticed it had CB-point style dry contacts and that these were hefty enough to run the main motor current through. They were heavily pitted and oxidized over, hence the lack of operation. I dismatled the switch so I could clean the points and in doing so noticed that the PCB to which the switch assembly was wired, had pads for spark suppression capacitors on it. They were unpopulated... The engineers HAD foreseen this problem, made provisions to correct for it and the bean-counters (I am guessing) did away with them... I put in caps and NEVER heard from that part of the car again. SEVERAL other things went bad electrically with that car, prompting me to sell it. I always wonder what more was removed as unessential in the interests of cost-management...?

tekochip
User Rank
Platinum
Mystery Light
tekochip   10/30/2012 9:04:39 AM
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I had a `98 Explorer a few years ago, when it seems that everyone did.  Anyway,
the vehicle began to run poorly and then a light appeared on the dash.  It was
one of those icon lights that looked like a fuel pump, but the cute little
pump had small drops of rain falling on it.  I had never seen the icon before,
not even when starting the car, so I was really confused.  Just the same, the
icon suggested water in the fuel, and the car was acting like it had water in
the fuel.  I stopped at a gas station where the vehicle struggled to idle and
threw in a can deicer.  Almost instantly the combustion smoothed out and I made
it back home.  I went through the manual and couldn't find the rainy fuel pump
icon anywhere.  I drove to the dealer and asked them about it, but they said
there was no such thing.  I took a flashlight and lit up the dash where you
could see the little rainy fuel pump icon, the service people were astonished to
see the icon, but said there was nothing at all in the service literature.  I
did a little digging on my own and found that there was a fuel contamination
sensor and light on the diesel version, so for whatever reason my vehicle had
been equipped with the mystery sensor.

jmiller
User Rank
Platinum
Good idea
jmiller   10/30/2012 10:06:32 PM
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I love it when a little enginuity and hard work save a lot of money.  I just wish I was a little better at that sort of thing and had the patience to do it.  Quite often I fall into that trap of thinking it's just easier to pay and have someone else do it.

Rob Spiegel
User Rank
Blogger
Re: Good idea
Rob Spiegel   11/1/2012 12:30:38 PM
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Jmiller, I agree it is easier to just let someone else fix it. But it's more satisfying to figure it out and fix it yourself. Plus, the price was right.

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