stuck choke

[lytemup]

i do believe i have a stuck choke. my first indication is the choke light staying on, the second being the 1700rpm idle (it's 80degs out today). my question is, how do i diagnose why it is aparently stuck?
thanks for any help.

 

[Stingray6974]

It's not the choke. You've lost power to the choke coil. First check the alt. output. The alt powers up the relay for the choke.
Second check the oil pressure sending unit. Make sure it's plugged in. The relay will only send power to the choke coil if the engine has oil pressure.

Mike

 

[ZAL81]

stuck chock!

Just had the same problem! Chock stays on high idle and the chock light stays on!! Check for a blown chock heater fuse! Its a 20 amp fuse thats at the top of the fuse block. Fought with mine for over a week! Replaced the fuse and no more problem! ZAL81

 

[lytemup]

thanks for the replies, I need a little more detailed help I think.
the fuse is good, and i've checked all the vacuum hoses and wiring harnesses i could trace to or from the choke area - all seem good. how do i check the oil pressure sending unit? also, short of looking at my voltage gauge (which reads good), how do i check my alternator output? sorry, i'm still a novice w/all this but i want to learn rally bad.
thanks for any help!

 

[DDLS3]

lytemup,

Your voltage gauge should read over 12 volts at idle, and between 12.8 and 13.5 with some increase in rpm if your alternator is working ok. There is a single wire to the choke element connected to the side of the carb. First make sure it is connected, then check the voltage with an indicator light or meter at the connector. If you have power there with the engine running then your choke element has failed. If there is no power with the engine running then you may have a broken wire.

 

[lytemup]

ok, i checked the alt output and the power to the choke coil, both good. which is the 'choke element'? the main coil part i assume, not the little vacuum guy next to it..?
if i hit the throttle, the butterfly valve closes completely, and i can then push the high idle bar(? - marked w/an 'E' and right behind the choke coil) down and it clicks down and stays down, until i hit the throttle again that is (engine running or off).
does this mean that main choke coil part is bad?
thanks again

 

[lytemup]

i'm still trying to figure this out if anyone could give me some guidance...which is supposed to 'pull' the choke off? that little vacuum thing or the coil?

also, anyone know where i can get these parts???

thanks!

 

[DDLS3]

The coil is supposed to open the butterfly. Once the butterfly has completely opened the linkage is now positioned to delatch once the throttle is kicked. There is a small linkage that is mounted on the end of the butterfly shaft, which is connected to a tang in the end of the coil. The only way to see this is to remove the 3 screws from the black choke coil cover and then remove the cover. Pay attention to the orientation of the marks on the cover so that you can get it back in the same position. If you find that your coil has broken, you can buy or order a replacement at about any parts place.

 

[lytemup]

unfortunatly, the coil housing cover is riveted in. so the only way for me to check that is to remove the carb, then drill them out (?).

what does the vacuum break (to the front of the coil) exactly do? does it affect the fast idle (1600rpm)? i just can't seem to understand this system for some reason. i disconnect power to the coil and it seems to me everything should work 'fine' (with the exception that there is no choke). if i do this, there is little effect, and after the fast idle kicks in, she stays on.

this is really gettin at my gut and i really *don't* want to take it to a dealer.

 

[DDLS3]

The 12 volts is applied to a themostatic coil which heats up and opens the choke butterfly. If the wire off makes no difference then it is quite likely the coil has failed. The position of the butterfly rod also determins if the fast idle cam will be engaged or disengaged. The original factory choke coil assemblies were riveted and must be drilled out to replace the coil. New self tapping screws are included in the coil kit. There are 2 good manuals that have a pretty fair description of how to do this along with some pictures. One is Haynes Chevrolet Corvette 1968-1982 manual, the other is put out by Motor Books and is the Corvette 1966-82 Shop Manual. Both should be available through Barnes and Noble either at a store or through their website.

 

[vigman]

I believe

The vac thing is designed to draw air thru the choke coil thing... to keep it cooler.

In the before days it was used to draw hot air into the choke assy.. the little pipe that bolted an in & out into the intake mainfold was a 1 turn tube that was in the exhaust line under the intake ( the crossover ) to heat the bottom of the carb... well it would heat the air in that tube as well... and IF memory serves correctly it BLEW air onto the Bi Metal spring in the choke assy... and I think the plumbing is backwards now....

But it sounds like you must remove the carb
( DRAW A GOOD DIAGRAM OF THE VAC FITTINGS FIRST)

Then pull her out... and do your thing!
BTW it might be a good idea to have the carb overhauled while it's out.


Vig!

 

[lytemup]

well i replaced the choke therm and put a new carb gasket on to boot. start 'er up, everthing's looking good, choke light goes off...
get a mile down the road, choke light back on, then we're back to being stuck at 1600rpm idle! ahhhhhhhhh!!!! what's going on here??

 

[MoeJr]

Sounds to me like the wire to your choke therm is losing juice for some reason. I would start the car up disconnect the wire and run a new wire to the choke from a wire that comes on with the key like the wiper motor and see if it works properly. If it does then you know your feed is bad. Hope this helps.

 

[DDLS3]

Sounds like a broken wire or your loosing the ground. Did your new choke kit come with a ground wire? Many do. Try running a new wire even if only temporary, any 12 volt switched circuit will work fine as long as it powers down when the key is in the off position.

 

[lytemup]

even if the coil only got current for the first mile or two of when I took the car out - the choke had turned off...so why if it lost current (since the coil was aparently warmed enough to relax to the point the choke could come completely off) would it come back on (and bring the high idle with it this time)? :confused

 

[DDLS3]

The coil is a bi-metalic spiral. Meaning.......when energised it heats and moves, opens the choke plate and releases the fast idle cam. When the power is off, it returns to the cold position and sets the fast idle cam up to engage the the fast idle latch. No power, coil cold, choke closed, fast idle.........power on, coil hot, (as in very hot) choke open, normal idle. To answer your question.........oh yes.

Dale

 

[8T8T2]

If you have consistent power to the coil and the coil itself is good than there's a grounding problem. A couple of years ago I had a carb. kit put in and the small gasket for the choke housing cover was installed. Choke stayed engaged because the gasket interupted the ground causing high idle. Long story short check to make sure you have a good ground for the choke. Like DDL-81 said run temp. wire for volatage supply to the coil and or wire from choke housing to ground.

 

[lytemup]

well i do believe you guys are nothing short of amazing. (;worship looks like it was the ground. while i couldn't road test it due to rain, it seemed to be acting like it should.

my final question (hopefully) is how is this *supposed* to be grounded and what would be a somewhat elegant, non-jimmy-rigged, way of permanently ground this housing?

thanks again, i've sure learned a lot about troubleshooting.

 

[DDLS3]

lytemup

My Edelbrock actually came with a small ground wire attached to the electric choke as this is somewhat of a common problem. I would suggest that a small wire off one of the choke cover screws to a ground point on the firewall could be made without looking too bad.

 

[drsantos]

Had same issue

Is your ac on, then the high idle is cause from the idle solniod, which compensates for the AC compressor. I had the same issue, even through i have the belt remove. my heater switch was set in the ac position causes 12 volts to be constantly supplied.