My 80' Chevrolet Malibu Classic SW

[ZeblodS]

All right, thank you for all these details!

I think I know what I'm gonna do:

- First, change the headlights. I currently have a H6054 to H4 conversion kit (mandatory for Europe I guess) but they are both rusty inside (driver side is very rusty...) which diminish the efficiency. I found these replacements on eBay, I might buy those.

- Both parking light and turn signals uses the same bulb (with two filaments). So in order to have parking light white and turn signal amber, I could use white/amber LED that are direct mount for European parking lights. But they are quite expensive so...

- I checked on my car, the front marker lights are wired, but there is no bulb. So I will put new bulbs on the sockets, and according to the Haynes I will have to change the wiring a little bit. There are two cables: Brown (parking light) and Blue (turn signal), I have to cut the brown and connect it to a ground so the front marker light will behave only as turn signals.

 

[O. D. Showtime]

Welcome from Canada! Good looking wagon and with a nice compliment of options as well! I'm sure you'll get the little "bugs" worked out in no time.

 

[Longroof79]

The H4's will definitely be an improvement...especially if the reflectors are on the rusty side.
To comply with the European laws, the wiring was modified to work with the export lenses. Even when I added my European taillight lenses, I had to modify the harness and add an additional separate wire from the brake light switch directly to the red brake light lens. The amber lens is used specifically for turnsignal and hazard lights.
Thanks to the wiring diagram in the Haynes manual.

Sebastien had mentioned the French laws being very strict when it comes to having the properly installed original lighting. The USA lens configuration would actually be illegal in some countries.

 

[ZeblodS]

Welcome from Canada! Good looking wagon and with a nice compliment of options as well! I'm sure you'll get the little "bugs" worked out in no time.

Thank you.
Yes, little by little.

The H4's will definitely be an improvement...especially if the reflectors are on the rusty side.
To comply with the European laws, the wiring was modified to work with the export lenses. Even when I added my European taillight lenses, I had to modify the harness and add an additional separate wire from the brake light switch directly to the red brake light lens. The amber lens is used specifically for turnsignal and hazard lights.
Thanks to the wiring diagram in the Haynes manual.

Sebastien had mentioned the French laws being very strict when it comes to having the properly installed original lighting. The USA lens configuration would actually be illegal in some countries.

According to the Haynes wiring schematics and how my car behave, the front lights on my car seems wired similar to the US behavior right now. They only removed the marker light bulbs, and put H4 headlights. It can be improved by making the front turn signals amber and using front marker light as side turn signals (see my previous post).
But yes, I have the European taillights with specific wiring for amber turn signals. I won't touch anything on the rear.

Using "French" lights is good for the law, but more important it doesn't confuse other drivers, making everyone safer on the road.

 

[Ribbedroof]

I like it!

 

[ZeblodS]

I received and changed the light switch this afternoon.
Took the car for a ride for about 30 minutes headlights on, works fine.
Plus I have the dimmer function that works again, and this switch is way more smoother to use (the old one was very hard to pull and push).


Has anyone tried to "transform" the speedometer to electric?
It works well except at low speed (under ~40kph / 25mph) where the needle make little jumps. It bothers me a little because I already changed the speedo cables, it's better than before but it still is not perfect at low speed...
I found a compatible electric speed sending unit (16 pulses per rev) which has a passthru to keep the mechanical cable to the cruise control.
And I know there are units to plug at the rear of the dashboard fo "convert" back the speed in mechanical right before the speedometer, like the Cable-X but it's both impractical (uses a quite long mechanical cable) and pretty expensive (about $300).

Are there electrical speedometer that are direct fit for the Malibu?
Or any cheaper and more practical solution instead of the Cable-X?

I was thinking of trying to build some kind of Cable-X with an arduino, a DC motor (the speedometer takes 1000 revolutions par miles, which is about 1000rpm for 100kph), a motor driver, an encoder sensor for the DC motor speed reading, and a stabilized DC/DC converter. Everything can be found at Pololu for less than $100... I'm not afraid of the electric/programming part (I'm an embedded software engineer, I see pretty well how to do it) but I'm way less comfortable with the mechanical aspect of this project...
Anyway, if I make some progress on this project in the few weeks, I will post here.

 

[ZeblodS]

Ok, I've made some calculations:

Usually a GM speedometer takes 1 mile every 1000 revolutions, which makes at 1000rpm 1 mile per minute or 60 miles per hour. I hope it translate in kilometer per hour the same way (60mph -> 96.56kph).

I have a posi with a 2.56:1 ratio which means 2.56 revolutions of the drive shaft for each revolution of the wheel. The wheel is 2040.78mm in girth (245/60R14), so the car move 797.18mm for each revolution of the drive shaft, so the car move 49.82mm for each pulses of the electric sending unit. At 60mph the car move 1 mile per minute, which means 32303.17 pulses per minutes.

I suppose I should choose a DC motor that can make my speedometer go up to 120mph, which means 2000rpm. DC motor are rated with no charge plug on them, so I'd better take a motor rated 3000rpm to be safe.
I think this 3000rpm extended life motor can do the trick, and I can plug this magnetic encoder to monitor the actual speed of the motor.
This sensor provide 6 pulses per revolution with a ratio of 9.96:1 in regards with the output, so 59.76 pulses per revolution of the output.
At 60mph displayed if means the sensor will give 59760 pulses per minutes.

Now I just have to do a cross product between how much pulses I have on the input and how much I will need to have on the output.
I can use this kind of arduino clone with a motor driver to write a simple PID controller in order to make the DC motor go at the exact speed I need.
I can use timers on the arduino to count exactly how many CPU ticks (16MHz CPU) there are between each input and output pulses. It gives me the rotation speed of both the transmission and the speedometer.

On top of that, a basic step down can provide me a stable voltage for all this. Plus, I can make the enable input to work with the +12V key so it doesn't use the battery when the car's off.

 

[drogg1]

Ok, I've made some calculations:

Usually a GM speedometer takes 1 mile every 1000 revolutions, which makes at 1000rpm 1 mile per minute or 60 miles per hour. I hope it translate in kilometer per hour the same way (60mph -> 96.56kph).

I have a posi with a 2.56:1 ratio which means 2.56 revolutions of the drive shaft for each revolution of the wheel. The wheel is 2040.78mm in girth (245/60R14), so the car move 797.18mm for each revolution of the drive shaft, so the car move 49.82mm for each pulses of the electric sending unit. At 60mph the car move 1 mile per minute, which means 32303.17 pulses per minutes.

I suppose I should choose a DC motor that can make my speedometer go up to 120mph, which means 2000rpm. DC motor are rated with no charge plug on them, so I'd better take a motor rated 3000rpm to be safe.
I think this 3000rpm extended life motor can do the trick, and I can plug this magnetic encoder to monitor the actual speed of the motor.
This sensor provide 6 pulses per revolution with a ratio of 9.96:1 in regards with the output, so 59.76 pulses per revolution of the output.
At 60mph displayed if means the sensor will give 59760 pulses per minutes.

Now I just have to do a cross product between how much pulses I have on the input and how much I will need to have on the output.
I can use this kind of arduino clone with a motor driver to write a simple PID controller in order to make the DC motor go at the exact speed I need.
I can use timers on the arduino to count exactly how many CPU ticks (16MHz CPU) there are between each input and output pulses. It gives me the rotation speed of both the transmission and the speedometer.

On top of that, a basic step down can provide me a stable voltage for all this. Plus, I can make the enable input to work with the +12V key so it doesn't use the battery when the car's off.

From an electrical engineering masters student's perspective this seems reasonable. I have not looked up speedometer specs or anything but it seems you have worked through it correctly. The motor, encoder, and micro all seem reasonable. You could probably use a cheaper motor driver (https://www.pololu.com/product/2990) and probably find a cheaper step-down somewhere else but the one you linked is fine. Pololu is such a great resource for motor stuff.

You seem like you have it covered but feel free to shoot me any questions you might have.

What kind of embedded programming work do you do? I admit I prefer hardware over software but embedded/DSP stuff I usually enjoy.

 

[ZeblodS]

Thanks for the support, I'll contact you if needed.

I'll see if this motor driver can do. Usually, PWM output on arduino-like board is limited to 8 bits value (256 values max) which is too few steps. I'll check the doc of the µC to see if I can up this value to 12 or 16 bits by manually editing registers.


I work on embedded software for commercial planes (Airbus 350 and 380 mainly). Usually pretty large applications, with real time operating system, and fully segregated resources (time, CPU and memory) between each application on each board.

 

[ssn696]

Before you tear your dashboard apart, try to lubricate the speedometer cable. Years ago, my needle would jump around as you describe. There is a ring clamp on the back of the speedometer; push it towards the speedo and you should be able to pull the cable out. There isn't much space to work in there, so try to slide it out of the firewall. There is a rubber grommet that you can gently pry out of the firewall. Once freed up int he engine compartment, put about 10-20 drops of clean motor oil down the cable. Let it drip all the way down to the other end. Since you have cruise control, you'll have to work the two cables separately, same method.