RetroMat
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Posts: 3,442
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Jul 19, 2012 19:57:56 GMT
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So my '79 Toyota hiace is back on the road, I 'rebuilt' (gaskets and a good clean out!) the original carb a while back but it was all pretty knackered at 240k! so the old van still wasn't running as good as I'd like it. So I managed to get hold of a 1983ish 18r engine Hilux pick up carb, in much better condition. Its a later version of the carb on my van. Problem being its an autochoke not a manual so I wired it up as per the wiring diagram: Which all seems to work but the mecanism that works the choke flap etc is a metal coil fed by the 12v from the relay. But the coil seems to get bloody hot! Which made me think i've made a glaring error in my wiring or the coil its self is buggered! Any one got and ideas, should the electronic coil thing get hot!?
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Last Edit: Jul 19, 2012 20:12:43 GMT by RetroMat
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Jul 19, 2012 22:47:47 GMT
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A coily spring thing? If so, yes it should get hot - it's a bimetallic thing that opens the flap as the engine and electricity warms it.
I suspect that the way it works is that the flap is held fully shut when everything's cold to allow maximum richness for easy starting. When the engine starts (as signalled by the charge light turning off), the relay is energised, supplying power to the coil. That will open the choke flap a bit, to allow a cold running mixture. As the engine warms up the coil will open the flap all the way to weaken the mox for hot running.
Quick Qs:
Do you have the thermistor connected?
And is the charge light circuit and alternator the same on your vehicle as on the one that the carb came from? Differences in the way that works will change the way the relay switches.
And does the carb have a coolant circuit running through it? - many European ones do. If not, all the choke control heat is provided by the electric coil.
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Yes, they should get hot, that's how they work. Most auto chokes on older cars generally just run on ignition live and receive 12 volts all the time. You adjust it when cold, so that the choke flap is held fully closed. Then, after a couple of minutes of being heated up by the current, the metallic spring expands and the choke flap should open. Current keeps flowing while the car is running to keep the choke open.
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RetroMat
Posted a lot
Column Shifting!
Posts: 3,442
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Jul 20, 2012 17:51:01 GMT
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cheers guys thats cleared things up alot! More investigating still to do, jrevillug: I'd presumed the thermistor was built in to the coil itself, I think I will remove the thing to have a look in side. Maybe the thermistors not there at all or gone out of range. The carb has no coolant feed its all electric, i;d just presumed once it had done its job of opening flaps etc the voltage would be cut!
It might be working perfectly but i've only ever owned cars with a manual choke so far ;D so was a bit paranoid.
I've ordered the manual that should cover this carb so more fun when it arrives.
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