| T O P I C R E V I E W |
| tcd |
Posted - Apr 19 2004 : 02:22:46 AM
Why ?...Because when the bimeatal heats up it causes the choke to fully open on the carburetor.., which this is fine as long as the engine is running ,but if some one leaves the switch on accidentally with the motor off ,then the bi -metal spring can burn out due to no air flow and thermal runaway....so if there were some intermediate device to disconnect it imediately when the engine is off then the electric choke would be spared .....the first thing that comes to mind is a zener in series but I wonder if a 13v 5watt zener work for this idea? The the bi metal in this electric choke is about 4 ohms and voltage is about 13.5 so my amps are a little less than 3.5 giving just a little less than 46 watts........tell me what ya think....
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| 8 L A T E S T R E P L I E S (Newest First) |
| tcd |
Posted - May 10 2004 : 04:21:09 AM
quote:
oil pressure switch no oil pressure no 12v when engine starts oil pres goes up and choke gets 12v. GM uses that on there older models 88 and older.and a thermal cut out would be a good idea but the choke would cool off and cause a rich situation and gaz economy would go down till the choke get warm up again.
to do or not to do
thanks ! THE OIL PRESSURE SWITCH! Now why didn't I think of that ?  That will surely solve that problem ........ Again thanks!!
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| ecm |
Posted - May 05 2004 : 8:34:41 PM
oil pressure switch no oil pressure no 12v when engine starts oil pres goes up and choke gets 12v. GM uses that on there older models 88 and older.and a thermal cut out would be a good idea but the choke would cool off and cause a rich situation and gaz economy would go down till the choke get warm up again.
to do or not to do |
| tcd |
Posted - Apr 27 2004 : 04:06:01 AM
quote:
You could very easily use a thermal switch. They come in all different heat ranges. You would screw it to the block/rad and then use it to trip your relay...
I like that....I believe that'll work. I think instead though that I'll just shunt the electric choke with a ballast resistor through a temp switch that I would screw into the little thin metal shield piece that partially covers the exhaust manifold.
THANKS for the feed back.
quote:
Or avoid the problem and convert to EFI. 
Well let's see ...... I 've never entertained that thought ,...but let's say I did convert to feul injection.....what kind of money
are we talking about here (new compatiable intake,injectors,onboard Cpu ,etc.)? 
Now...., what could possibly be done to protect the elec. choke from an accidental occurence of the ign. switch being left on, without the engine running.
THANKS
TCD
Edited by - tcd on Apr 27 2004 04:24:27 AM |
| Aaron Cake |
Posted - Apr 26 2004 : 08:59:02 AM
You could very easily use a thermal switch. They come in all different heat ranges. You would screw it to the block/rad and then use it to trip your relay...
Or avoid the problem and convert to EFI.
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| tcd |
Posted - Apr 26 2004 : 01:05:52 AM
On the original wiring schematic for this truck (86 FORD F350 351 engine with a 4 Barrrel Holly on top),......that's the way they have it wired up....... ,but here's the catch..... when the engine is running there's a constant pulse dc 13.5+ from the alternator ,but with the engine offand ignition switch not all the way off, then the relay is still open,......thus allowing pure dc 12.+ through the electric choke . The chime that buzzes to warn you of the ignition switch not bieng completely off does not work in this truck. And even if it did work ,it's just the thought that if someone didn't turn the ignition all the way off...then the end result is that I'll end up with a burned up electric choke , that cost anywhere from$ 30 and up with about a three day wait for shipment. Another potential problem is that the elec. choke in normal operation, stays on all the time,while the engine is running ,which could lead to a premature burnout.I have observed that when the engine is hot the choke opens on its own eventhough the elec choke is not plugged up. I 'm convinced that the heat from the engine is acting on the bi-metal spring,through either convection or conduction. SO ....part two of this question is ......How could I electronically use this engine heat to disconnect or diable the current to the bi-metal in the elec. choke? By doing so ( if there's a way) I would prolong the life of this device by allowing the engine's heat to take over and control the device rather than continuosly allowing current through it to make it work. give me some input please THANKS TCD
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| Aaron Cake |
Posted - Apr 20 2004 : 09:12:04 AM
Get a standard automotive 12V relay. Connect one side of it's coil to ground, the other side to a 12V source that is active when the ignition is on. Now cut the wire that leads to the choke, and connect one end to one normally open contact, the other to the common contact.
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| tcd |
Posted - Apr 20 2004 : 01:32:12 AM
Sounds good ..... elaborate a little more please......thanks, TCD
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| Aaron Cake |
Posted - Apr 19 2004 : 08:57:47 AM
Why not just a relay connected to the IGN line?
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