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Automotive/Toyota Celica '91 electrical issue
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Question
Why would a vehicle not start in temps below 40 degrees? Over the years I
have changed batteries (multiple times); removed auxiliary systems,
(dealership claimed after market auto alarm system was draining power - no
- vehicle failed despite costly removal of system) auto mechanics have
checked electrical system thoroughly, no alternator problem, no wiring issue.
One mechanic thought it may the the CD changer! A lot of $ wasted on red
herrings. What are the components in a vehicles electrical system that are
temperature sensitive. It does not make sense that an aging vehicle will start
routinely in warm temperatures and struggle to start as the temperatures
drop and then fail in cold temps. Is it so difficult to diagnose that dealership
mechanics, supposedly, the dealership's factory rep and competent
mechanics cannot determine point of failure? Despite "expert" advice and lots
of $'s the problem continues year after year. Thanks for any constructive
comment you can offer. I've kept the vehicle because it is an "old friend" and
have been resigned to jump starting it a couple of times a week just to keep
it functioning in the winter months. It always jumps immediately upon cable
connection - charging vehicle doesn't need to be on. Have tried trickle
chargers but have not had success.
The facts that (i) a trickle charge does NOT help, and (ii) you can start it immediately upon clamping on jumper cables, cold weather or not apparently, "might" suggest a questionable battery cable clamp itself, if contraction is playing a role in opening an oxidised connection between a bolted clamp and stranded cable, or any clamp and the battery itself. If you haven't already done so, you might consider unbolting the battery clamps and inspecting them. I would replace them if there is any sign of burning or scorching. Whether you replace them or not, be sure to clean and grease the connection (using electrical contact lubricant) before putting them back together, and torque them to spec.
Failing that, why not get a Hall-effect clamp-on ammeter with sufficient sensitivity to read into the 100 mA range and find out what the parasitic draw is when the engine is shut down. Using such a meter, you could isolate out candidate components by removing them one at a time until the current drops off. DO note that all cars have some parasitic draw, the clock function in the radio or instrument cluster, if nothing else.
Generally, a few tens of milliamps of draw should not pose a problem in any vehicle with a good battery, especially if it is started once a month or so.
A draw in the range of hundreds of milliamps or more WOULD be a problem, and any component that draws in that range has either been incorrectly wired so as to be powered at all times rather than only when the engine is running, or is defective.
Whichever you do, you are going to have to hunt for the problem in a systematic manner. Only once you find the component(s) that really are drawing the current can you make an assessment as to how to solve the problem.
Good luck ... EGK
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| Rating(1-10) | Knowledgeability = 10 | Clarity of Response = 10 | Politeness = 10 |
| Comment | Thank you for your advice and I'll give it a try. I had thought the "parasite" checks had been done but I'm not a mechanic and relied on the mechanic to do the checks. I'll get a "second opinion" in that regard. Thanks again. | ||
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Answers by Expert:
Ernest (Ernie) Kenward
Expertise
The challenges I most enjoy are thoughtful technical questions of a trouble-shooting nature in both electrical, power electronic and mechanical systems, mainly automotive but also machine control and small-machine PLC applications. Please note, however, that I am NOT a walking shop manual! I DO, however, make it a point to have those manuals and other service literature for those vehicles I DO own, and highly recommend that anyone serious about maintenance or modification of their vehicles do the same; MOST of your answers WILL be found there. For that matter, I do NOT go out of my way to acquire shop manuals for any vehicle I do NOT own! That being the case, any general query to me along the lines of "What is the meaning of this code read from the ECU of my 2015 XYZ?" or "Where is the fuse for the windshield washer pump found?" (try your car's electrical distribution panel for a start!) will not go far. What I do offer is a pretty good collection of literature, insights and hands-on experience with 1950s to 1980's Ford products (plus a developing database of information and practice with the Mercedes diesel cars), along with an engineering perspective and the ability to design and implement custom control, electrical and mechanical subsystems for vehicles. For that reason, I am happy to make my thoughts and efforts available to those who are of like mind and/or are seriously making a point of learning about their vehicles. Use the Opportunity to Learn!
Experience
A key skill in my work and hobby pursuits both is STRATEGIC TROUBLESHOOTING. I am a senior instructor in Electrical Engineering Technology at a leading Canadian polytechnic, my areas being Electrical Power and Industrial Control, electrical and electronics design and manufacturing, and AutoCAD and related CAD/CAE software - plus equipment problem-solving and new equipment design and prototyping.
Hobby-wise, I have 30-plus years of experience in auto restoration, mostly in electrical and mechanical systems. Ongoing projects include a 1959 Edsel Corsair, my 1978 Ford E250 class-B motorhome conversion, and the care and upkeep of my Mercedes 300CD.
My vehicles become engineering test beds for electrical and mechanical upgrades as ideas present themselves. This includes the design and production of circuit boards to restore or enhance features for which no OEM replacement parts are obtainable, or where better specifications or reliability can be had via newer concepts. Regarding the E250 RV conversion, I designed and continue to revise a custom power distribution system, managed by a Programmable Controller (PLC); this has made most revisions as easy as uploading new firmware as I develop it.
The "mini" PLC is a powerful device for custom automotive control systems. One good example (there are many) would be the Moeller "Easy Relay"; these offer a wealth of control, monitoring and variable-and-status display options for such projects. A good example project which has worked well is that one for my RV noted above, which has been on the job - revised in firmware only - for a decade now. It is a load management and charging control system to avoid the sulfation-induced early failure that often befalls deep-cycle batteries used in RV power applications. The battery installed in 2003 lasted long enough to more tnan pay for the PLC that contributed to its longer life ... and the PLC will be there for the next battery as well!
Organizations
IEEE - senior member ... past WCC Student Activities;
SME - senior member ... past chair, greater Vancouver chapter chair 318;
Edsel Owners' Club - have served in various capacities on chapter executive during seventies;
have been Power and Driveline resource on the Edsel Owners' Club "E-team" for more than a decade.
Education/Credentials
Graduate of UBC
Awards and Honors
Certificates of appreciation from IEEE and SME for work in student and chapter activities
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