1987 AMC Renault GTA 2.0 - Gone to a new home.

[PhilA]

Here's the missing pictures:

Bought the header pins and a little opto-isolator (that blobby bit on the right)


Located the pins in the new LCD board.


Soldered them in.


Board supporting itself. Sad it didn't work properly. I'll think up something else to do with it.


Given that, I decided to build the opto-isolator circuit today.


More components than before. Not too much of an issue though. I don't want to pop the little chip (bottom right), so the regulator (top left) keeps the voltage coming from the car at 12 Volts if it goes above. If it goes below it's not too much of a problem but that car tends to run at 14-15 Volts as it charges hard. That would make the voltage across the opto-isolator about 1.5 Volts, which would burn it out.

This is the best revision so far of the circuit I built before from the light bulbs. This little piece is actually designed for data communications

Going to pack up and head down and try decode the switch bytes (air-con, starter motor, fan etc) amongst other things.

Oh, and I never really explained why I want this little thing in the circuit.

There's two reasons. First, the bit long flying leads to and from the car act as wonderful antennas for all sorts of random noise, mostly generated by the alternator and the car's ignition system.
If that is connected directly to the computer board, it can have the effect of providing some nasty high voltage spikes (take the TV antenna out the back of your digi-box and tap it to a radiator pipe or something grounded, you'll draw a spark, simply from the energy in the airwaves). That doesn't do the circuitry any good at all, which can handle 5V maximum.

Second is if I'm working with really small voltages over that distance (think tenths of a Volt) that can easily get trampled on by the noise and corrupt the data.
Doing this, I can drive the line at 1.2 Volts which is adequate, however it is now powering a small LED chip inside- at that voltage it requires 20 milli-Amps to light up. I'm not going to see noise creating 20mA at 1.2V so the signal is "cleaned up" by using it.

It also has a third use I guess- I can disconnect the circuit easily. Eventually the board will be connected to the car, but it will be through a voltage regulating circuit (probably the same as the one seen on the breadboard there) to actually power it. Right now it powers itself off the USB port from the computer.

More to come. Probably more of it electronics but meh. It's keeping me busy since I can't drive it.

--Phil

[PhilA]

...or not. The sky just opened and I'm not going work with SWMBO's computer in the rain. Weather forecast for tomorrow is unfortunately worse, although we have a cold front coming through which should make the air less humid and cooler.

[PhilA]

Went down this afternoon. Ended up getting caught up in doing something else. Tried the car witht he new circuit and I've done something wrong.

I've redesigned the circuit now so hopefully that screwup is fixed.

More hopefully tomorrow after work as I have to head down there to strim/weedeat the yard for the mother-in-law.

No pictures because I was covered in mud (!)

--Phil

[Deleted]

Can't help thinking life would be easier if you and the car were in the same place more often, which is something I can empathise with from when the Polo was in Lincolnshire and I was in Yorkshire.

[PhilA]

Feb 6, 2012 18:15:47 GMT @volksangyl said:

Can't help thinking life would be easier if you and the car were in the same place more often, which is something I can empathise with from when the Polo was in Lincolnshire and I was in Yorkshire.

Angyl,

Yes. That is quite high on my wish-list. It is a case of swings and roundabouts though. In one instance the car is under a roof and by my tools, on a flat level piece of concrete. In the other location there is sloping gravel, no roof and nowhere to easily store tools (not at least without SWMBO complaining about it).

Things may be changing in the upcoming months. A fairly decent insurance quote and the possibility of the spare cash to be able to pay for the last few bits I need to get it to the point I'd be happy driving about in it may be in the not-too-distant future.

Discussion on another board has already led to me deciding this is one of the better-running GTA's on its original fuel injection system...

Mercy me.

Hence why I'm cracking on with the diagnostics unit because I still think it runs like a bag of spanners lol

--Phil

[PhilA]

Saw some spare time over the past couple of days (read, about 60 minutes in total) and the weather has been nice, so I got the car started- eventually, once it's been sat up for a short while it cranks for about 20 seconds before it finally decides to start- and moved it out into the sunshine.



The interior needed aired out- the door card is off because I haven't yet taken the regulator out to repair it



Stuck the breadboard onto the floor and spun a wire out to the connection point in the engine bay.



Hooked it all up to the computer aaaaaaand... nothing. Well, after a bit of debugging, nothing much of use.



Lesson learned today? Either twisted pair (I'm going to try actually using the twists in the cat5) or shielded single-core for the data, as that 5' length of wire is acting as a wonderful antenna and making a mess of the signal.

Now to find some appropriate shielded wire. I have a thought on that one.

--Phil

[PhilA]

Went down to the post office today so stopped in at the car on the way on up.

Can't get the optoisolator to work. However, correctly using the twisted pair on the Cat.5 Ethernet cable I'm using to transport the serial data works quite satisfactorily biased to +5v

Went back to the original setup. Liberated some data, got a bit of information that I didn't have before. I now know what about half of byte 3 does, by trial and error.

128 64 32 16 8 4 2 1

That's the byte, in decimal.

64 and 32 go high when I select the air conditioner switch.
16 goes high when the accelerator pedal is resting on the stop (foot off the pedal)
8 goes high when I twist the key to START
4 stays high with the engine off.

The other bits... dunno, yet.

That was all good and well... went to start the car, no joy. Cracked the top off the throttle body and cranked it over.. no fuel.



Aha. (Arrowed). That is evidently the point where I run out of fuel.
Also, I'm going to investigate why the little petrol pump icon isn't lit up. It should come on yellow when the fuel level is getting low.

This, however was stopped by the lovely weather that we were forecast:



Tomorrow is supposed to be nice. SWMBO is at work tomorrow too so I have a bit of car playtime. Mojo on the increase again.



--Phil

[PhilA]

Just taken a look... apparently since getting it running putzing up and down the driveway the odometer has rolled over the 4.8 miles on the trip.

How?!

haha

I put a gallon in it, so 4.8 MPG. That isn't very good!

--Phil

[sonofsilas]

Feb 18, 2012 21:38:18 GMT PhilA said:

Just taken a look... apparently since getting it running putzing up and down the driveway the odometer has rolled over the 4.8 miles on the trip.

How?!

haha

I put a gallon in it, so 4.8 MPG. That isn't very good!

--Phil

Yeah, but that's U.S Gallons, so that's about average for a car of that age on your side of the pond...

[PhilA]

Feb 18, 2012 21:43:14 GMT sonofsilas said:

Yeah, but that's U.S Gallons, so that's about average for a car of that age on your side of the pond...

5.76 MPUKG?



I'm hoping with the freshened engine and correctly functioning fuel injection to see the EPA fuel economy, which was 27 City / 34 Highway. they didn't do a "combined" at that age, but it should be somewhere around 30, so about 36 miles per UK gallon.

Ain't too shabby, really. Especially not for a SPI engine.

--Phil

[PhilA]

Didn't have a whole lot of time today with my niece turning 3 and all the Mardi Gras parades blocking the roads up.


Did however manage to put in 5 minutes of diagnostics.

Pulled the fuel pump relay out:


Took the connector apart at the back by the tank. Used a bit of logic that the big black wire was ground and the big red wire was positive feed for the pump (I'd checked these a couple years back but my memory wasn't good). Bridged the brown wire first and pegged the gauge to full- connected it up to the blue instead:



Went back up half hoping it was just the bulb not working... but no.



The light works just great bridged to ground.

Bad connection's in the tank then. Poo.

I guess the tank comes down again to remedy this. Funfun. I like a low-fuel warning light and I'm ADHD enough for it to bug the living daylights out of me that it doesn't work.

--Phil

[tonybmw]

Phil, if it was me, I just make sure it always had fuel in and then you can forget about that light all together

[PhilA]

Feb 20, 2012 19:14:08 GMT tonybmw said:

Phil, if it was me, I just make sure it always had fuel in and then you can forget about that light all together

Yes, there is that. But I know it's there, I know it's not working, that is like nails down a blackboard to me; plus it'll really be by means of punishment to myself for not thinking about it when I had the tank out to replace the rubber hose a few months back.

I'm not going to let French electrics stop me. I'm not.

(BTW the little yellow light on my Cinquecento was one of the best features of the dash IMO, I need an attention-grabber for things I like to put off, ie giving money to a petrol pump)

--Phil

[Sven]

Feb 20, 2012 19:30:33 GMT PhilA said:

I'm not going to let French electrics stop me. I'm not.

My hero! Show them Frenchy 'lectrics that the Wellington spirit is still alive and living in the USA ...

-Steve

[PhilA]

Feb 21, 2012 0:28:11 GMT Sven said:

Feb 20, 2012 19:30:33 GMT PhilA said:

I'm not going to let French electrics stop me. I'm not.

My hero! Show them Frenchy 'lectrics that the Wellington spirit is still alive and living in the USA ...

-Steve

French electrics may not stop me, but a fairly nasty bout of food poisoning from Mickey-D's did. Work on the car resumes probably a couple days from now.
For now I've repurposed the Arduino board with a little loudspeaker to play Happy Birthday for SWMBO tomorrow. Wonderfully versatile thing it is, too.

[Sven]

I've been reading about the Arduino. Very interesting device and I love that it's open source and a whole cottage industry and community has built up around it. Takes me back to my early days of geekness with the Sinclair ZX80/ZX81 and various other arcane devices.

I'm going to get me a Arduino just so I can get back into tinkering with this sort of thing.

-Steve

[PhilA]

Feb 21, 2012 13:41:14 GMT Sven said:

I've been reading about the Arduino. Very interesting device and I love that it's open source and a whole cottage industry and community has built up around it. Takes me back to my early days of geekness with the Sinclair ZX80/ZX81 and various other arcane devices.

I'm going to get me a Arduino just so I can get back into tinkering with this sort of thing.

-Steve

It's a lot more powerful on the math front than early computers- it's actually pretty quick at floating point calculation. Radio shack have the slow version of mine (8MHz) for about thirty bucks off the shelf.
Oh, and I have a working Sinclair ZX81, complete with dK'tronics keyboard and 16kb RAM expansion pack

/offtopic

[Sven]

The latest Arduino Uno R3 can be had for about $27 online. I'll shell out for one of those.

It's sort of on topic because it'll be used for something automotive, I'm sure, eventually ...

-Steve

[PhilA]

Yep. I paid a few dollars more but the R3 is good. Few code hiccups but nothing that stops play.

I'm liking the double clock speed and more memory.

[PhilA]

Having upset SWMBO a little bit yesterday by going play with the car for a bit, I have decided to focus on the (Still fairly unlikely) goal of putting the car on the road shortly.

The old dear was kind and said she'd put a bit of cash up for my birthday which can go towards a few of the bits I've been avoiding buying due to house bills.

Sadly as it stands it would pass inspection.

So, here's the to-do list: (* denotes stuff that needs doing before I'mhappy putting it on the road)

*Passenger side CV joint re-pack with grease and fit new boot
*Passenger and driver side lower balljoints
*Steering arms, particularly passenger side, incl balljoints
*Aux belt idler pulley bearing
*Hose clamp, lower heater hose
*Speedo cable clip
*Rear gearbox to engine nut
Re-route vacuum line for heater controls
*Pipe clips, fuel lines, front
*New rubber seals for fuel unions at throttle body
Fuel filter replacement
New radiator fan thermo-switch
*Exhaust bungies
Exhaust tailpipe, incl muffler ideally
*Adjust handbrake and lubricate linkages
Do /something/ with the gearshift to make it less like stirring porridge
*New wiper blades
Fix interior and refit seatbelts and rear seat
Interior lights (mk2 Clio)

...Paint the outsides

That's about it. Need to pull my finger out, really.

--Phil