Carb problem with choke

[2dooreighty5]

So my car has been running at high rpm's and wont kick down to idle speed...I took my car to a local carb rebuild store and the guy says that its could be the choke solinoid not functioning which moves the high rpm click down thingy...or also because my oil light is on and my oil sender unit is not functioning...it might be that...I tested voltage to the wiring harness that plugs onto the carb/solinoid and its getting 12.5 volts but when i put it on the solinoid its getting .5 basically half a volt...IM SO CONFUSED!!! any ideas fellas[IMG][/IMG]

[j cAT]

with the engine running you need full 12 volts at the electric choke stove connection when connected.. if not the choke plate will never fully open and the engine will never kick down and run rich..


make sure alternator output is 13.5-14.75 volt range..check wiring from choke stove to 12volt supply.. could be fuseable link corroded feeding this. since you have 12 volts at connector when not connected I suspect that when connected the feed wire has a bad connection or corodded fuseable link. etc..causing the loss of voltage to heat up this choke stove..

using a fused jumper wire from battery , connect to the choke stove ..place a 25 amp fuse in this feed jumper see if it now works !

[2dooreighty5]

yea thats whats wierd is there is 12 volts going to the female piece but when i connect it to the male piece which is the "choke stove" i guess...it looses all power...and the male piece is not dirty...

[j cAT]

Originally Posted by 2dooreighty5

yea thats whats wierd is there is 12 volts going to the female piece but when i connect it to the male piece which is the "choke stove" i guess...it looses all power...and the male piece is not dirty...

you may think this is weird I do not.....when a load is placed on a feed wire with a bad connection etc the voltage will drop.....NO LOAD NO DROP ! Chase back the wire with a meter and find where the voltage is now good..also bypass this feed wire like I stated in the other post to see if the choke stove is working and good...if it works with the bypass feed wire , then find the issue with the OEM wire !

[2dooreighty5]

Do you know if there are fuses for the oil sender and or the choke stove?

[2dooreighty5]

thanks for help also bro

[j cAT]

Originally Posted by 2dooreighty5

Do you know if there are fuses for the oil sender and or the choke stove?

check the back up light , and or the transmission fuses...

I did just look this up..I am not sure on your vehicle it is this way but the description does seem to apply...

the feed wire to the electric choke stove is switched when the oil pressure is seeing pressure. this has 3 wires on it.. the ignition switch applies power to this oil pressure switch from the fuses I mentioned, then when the engine is running the switch closes applying power to this choke..

this type of feed is used so that only when the engine is running would you get power to the choke ...........

I know that other systems that use this type of choke get power from the alternator...when alternator is running engine running the choke has power...

when your vehicle has this oil pressure switch failure / fuses ,,,this will cause those red dash light to come on !

with a voltmeter check for proper voltage at switch..remove choke feed wire the check again ...then you will know if the switch is bad..

since you do have 12 volts when not connected I suspect no fuses..but a switch that old I bet its the switch !

[j cAT]

Originally Posted by 2dooreighty5

Do you know if there are fuses for the oil sender and or the choke stove?

I had to get the diagram for this so the fuse would be the CH fuse..

but like I said I doubt it is a fuse....must be the oil switch...

post back whats up ..

[2dooreighty5]

oil switch? the unit that screws into the block? Im gonna clean it off and check for power coming to it...

[2dooreighty5]

Cuz my oil light is on...and came on right after i took off the harness and put it back on the oil sender unit...same time choke started acting up...i just thought they couldnt be related..

[Blue Bowtie]

Whether this is a domestic 1985 or a Canadian '85 there will be differences. A domestic '85 has only the oil pressure switch fed by the C/ fuse or the 20A fuse below it. There is also a choke relay on some years and models, but not a domestic '85 B-Car.

If there is only half a volt with the choke heater element connected I'd suspect a poor (resistive) connection. This is most likely the connector at the oil pressure switch or a failing pressure switch itself, with resistive contacts as the Cat described.

If the voltage is low when measured at the red wire on the oil pressure switch with the choke heater connected, look farther upstream toward the fuse panel, including the bulkhead connector.

[2dooreighty5]

MAN...Thanks for help guys...i kinda feel stupid...its was the oil pressure switch/sender unit...got a new one and the car running right...thanks for help...always apreciate it guys!!!!

[j cAT]

Originally Posted by 2dooreighty5

MAN...Thanks for help guys...i kinda feel stupid...its was the oil pressure switch/sender unit...got a new one and the car running right...thanks for help...always apreciate it guys!!!!

It has been many years since I troubleshooted this problem. But I have my diagrams and other diagnostic info in my windows 98 computer that I use only for off line work ...

with this setup that GM used as blue bowtie mentioned some vehicles have a relay .. this would have been the more reliable way to go...the switch contacts would go to the relay coil , and the choke feed would come off the fuse block to the relay contacts which would be designed to handle the high current required for the choke heater...

good luck ..

[GirchyGirchy]

Sounds like how my electric choke was acting. It was replaced when I had the carb rebuilt.