13 votes

How stable is voltage in a 12V car outlet?

Don't go with that model for automotive use. It passes through the "12v" input directly to the motherboard and drives, meaning you'll be delivering ~14v with the engine running, and all sorts of ugly ...
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13 votes
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Fixing a water-damaged remote key

If you can access the electronics soon after they get wet, the chances are pretty good to keep it working. Unfortunately, after all this time, it's kind of a long shot. There are three major things ...
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12 votes

Are mechanical relays still used for turn signal circuits? If not, where does the clicking noise come from?

In my car the indicators are controlled with solid state electronics and so could switch silently as there is no relay or bi-metallic strip contactor to make a noise as they are activated. There is ...
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9 votes
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Reliable 12V supply in car

When properly installing an amplifier a large gauge wire is run from the battery to trunk area. A fuse is installed as close to the battery as possible. The amplifier then connects to that wire. If ...
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8 votes

Why do cars still use mechanical blinker relays?

I can think of several reasons straight away: Cheap Easy to replace Have a very distinctive click that makes it obvious when they are on, and when a bulb has failed Are very well understood Anyone ...
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7 votes
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Are all drive-by-wire cars completely (brakes, clutch, gas, steer) by wire?

If the car is drive by wire it doesn't mean everything There are some cars that are drive by wire where it's the accelerator only. Brake by Wire If it's an electronic brake system the term EBS or ...
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7 votes

How stable is voltage in a 12V car outlet?

ANSWER: Pretty unstable. Connect a voltmeter to your ciggy lighter socket, and watch it while starting and running the car. It will be ~12.5V when the motor is off, up to 14.5V while just started, ...
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7 votes
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Simplest installation of car-powered car-pc

Most everything external of the ECU is going to be 12vdc (+/-2v). (NOTE: As @juhist points out, more and more cars are supporting 5vdc output to charge handheld devices through USB ports. 5vdc may ...
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7 votes

cigarette lighter is always on

This behavior is by design and it was the same on pretty much any Ford of that era (at least it was on the Mondeo, Fiesta, Fusion and Focus IME) You can modify it to come on with the ignition but not ...
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7 votes

Control Systems of Modern Engines

Another way to go would be to check out Speeduino. It's an open source DIY ECU. The software is freely available here: https://github.com/noisymime/speeduino/ and it can run on an Arduino. If there's ...
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6 votes

Since when is CAN bus mandatory for new vehicles?

There is a distinction that needs to be made between: OBD: this is an interface, that specifies the physical and electrical parameters required to connect a diagnostic computer and the car's ...
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6 votes

Fixing a water-damaged remote key

I accidentally ran the smart key for my '09 Jaguar XF supercharged sedan through the washing machine once. It was submerged in water for about 10 minutes until I found it. I was able to fix it by ...
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6 votes

what sensors and formula are used to control VGT/VNT turbos?

Dodge installed VNT Turbochargers on cars in 89 and 90. The most well known of which is the 1989 Shelby CSX-VNT. The vanes were controlled by a dual port vacuum actuator. There was nothing ...
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6 votes
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Tapping into the on-board computer

You cannot easily "tap" into any ECU/PCM. Depending on what year your vehicle is, it could be a simple set of analog gauges which you could tap into the signal line, but you'll need to do some ...
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5 votes

How to control a car (accelerating, braking, steering) programmatically?

No car has every attribute to be fully autonomous out of the box. Brakes: If a vehicle is equipped with dynamic stability control then software control of the brakes is possible. Dynamic stability ...
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5 votes
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Which electrical parts in motorcycles are obligatory for basic driving capacity?

Generally manufacturers aren't going to waste money on unnecessary components. You've got electrical components to: provide spark to the engine. an on/ off / kill switch to control engine on or ...
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  • 6,479
5 votes

Tapping into the on-board computer

If your car has a OBD2/ODBII port then it is achievable. I'd imaging the simplest way would be to use a ELM327 type cable or even a bluetooth adapter to provide the interface between the pi and the ...
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5 votes
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What happens if I disconnect the battery while the car is running?

Removing the battery with the car running is a bad idea. Rather than re-writing something which exists on the interwebz, I pulled this from Troubleshooters.com under the section called Automotive ...
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5 votes

What happens if I disconnect the battery while the car is running?

When a Battery is disconnected from a running engine, there is a milliseconds high voltage spike that occurs the instant the terminal leaves the battery connector. Some researchers say it can be as ...
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5 votes

What's wrong with using domestic flex cable for automotive purposes?

Automotive cables are normed (ISO 6722 ?). The insulation of automotive cables offer a superior resistance to heat, cold, chemicals and vibration. A common FLYR-cable should guarantee its insulation ...
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5 votes
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Why did the old-school thermal flashers remain in use for so long?

Three major reasons why they were used so long: 1. Cost - Even today a thermal flasher units cost about $2-2.50. The cheapest equivalent electronic flasher unit, which happens to be a direct ...
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5 votes

Are mechanical relays still used for turn signal circuits? If not, where does the clicking noise come from?

In the old days, the flasher used to be controlled by a little device that contained a bimetallic strip. When current was supplied to the flasher lamps, the strip would heat up, bend and turn off the ...
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5 votes
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Should ground wires be fused?

I have fitted many accessories to cars, trucks and agricultural vehicles, some taking less than 1 amp and others several hundred or more. I have never put fuses on the earth or ground side. If the ...
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5 votes

Control Systems of Modern Engines

Yes, do some research about early fuel injection systems and electronic ignition. You will find Bosch had some superb info about how they worked etc with really good diagrams and detailed explanations....
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4 votes

How stable is voltage in a 12V car outlet?

I would go with the more expensive one in this case. Typical output of a "good" system is in the neighborhood of 13.1vdc. Depending on the alternator and how much it needs to put out to recharge the ...
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4 votes

How stable is voltage in a 12V car outlet?

The voltage available on the "Accessory" circuits on some modern (last 10 years, at least) can be pretty stable at 12-12.5V. Ignition circuits, not so much (9-14V). To be safe, however, you should ...
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4 votes
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How to diagnose undervolt in electrical system

There are several things you can look for: Complete paths Electricity requires a complete path from positive to negative. In a car with that kind of age, I would be checking that you don't have bad ...
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  • 9,286
4 votes

What voltage does the ECU need?

If you're talking about a regular 12V battery vehicle, then the ECU is likely to work from 7V until 14V with no problem. That's the usual requirement for this kind of component.
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  • 217
4 votes

What happens if I disconnect the battery while the car is running?

If the car has electronic components, like ECUs, central commanding modules, etc, doing that "may" fry them...or not. Sometimes the ECU turns off the engine if the battery is non present. Same reason ...
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4 votes

What happens if I disconnect the battery while the car is running?

The answer is a bit complex here: As Paulster2 has mentioned, the battery does help protect from transients, but as the alternator has its own regulator and the computer and audio system have their ...
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