Sudden extreme rich condition

[MP81]

So I got the new choke the other day and decided to put it on today.

After installing, it exhibited the exact same symptoms as before - running stupid rich and at high idle. So I decided to replace the connector - the voltage readings I got were hit or miss on the terminal, but were fine at the wire.

Put the new pigtail on, and as soon as I keyed on, the choke closed entirely and now the car won't start at all.

I made sure the fast idle cam (I think it is) was inside the enclosed part of the "tang" of the clock spring, and then rotated back to roughly vertical (so the connector is on the bottom, as my other choke was). Did I need to rotate it more or something? Or is that how it's supposed to be - I do remember the choke plate at cold start being closed prior to all this goofiness (maybe the carb was flooded from it running so rich just a few minutes prior).

[Cliff Ruggles]

Just leave the key on for a minute or two as the engine is warm enough it isn't like the fully closed choke flap.

Also verify that the pull-off is unloading the choke correctly on a cold start.

The basic setting for the new choke is to install it and rotate counter-clockwise unit the choke flap just fully closes.  There is a fine line on the choke that should be at or close to the center mark on the choke housing and well within range from rich to lean.

Make sure when adjusting the choke that the throttle is open some or the fast idle cam/linkage may prevent the choke flap from closing......Cliff

[MP81]

So I went ahead and set it up that way yesterday - turned it just until the choke flap closed. This put the mark (on the top of the choke) within the little set of dashed marks. My original choke had the line at about the 2 o'clock mark, computer to 12 o'clock, however, so the choke did not appear to be rotated by about 45 degrees (where the connector sits, was right at 6 o'clock compared to about 8 o'clock now).

The car did start, so it was probably just flooded, but that choke never opened more than 1/4" of an inch. How would I know if the pull-off is causing this (or could it not)?

I measured voltage at the connector (I believe this is the factory choke wire) and I got right around 10.5-11V.

[Cliff Ruggles]

The choke pull-off unloads the choke at initial start-up, it has nothing to do with how the choke is adjusted. 

Vacuum test it to make sure it is working?

I would also test the electric choke by grounding it on a negative battery post and attaching a positive wire to the connector from the positive post.  It should heat up in about 2-3 minutes and the coil will move so reference the initial position and watch it move as it heats up.

Once you verify both parts are working put them back in place and set the choke so it just closes the choke flap.  Make sure the throttle is open so it can do this or the mechanism will lock out the choke and prevent a correct setting.

Once the choke flap is fully closed apply the pull-off with a vacuum pump or just fully compress it by hand.  The choke flap should open some or it will need correctly adjusted as well.  It only needs to open enough so the engine doesn't flood out on a cold start, and can be fine tuned to perfection with a little effort if you move quickly after the engine initially fires up.....Cliff

[MP81]

I meant more that can the pull-off prevent the choke from opening?

It does seem to have proper vacuum as you can only move the pull-off in/out after the engine has been off for a while and the vacuum bled off. Otherwise it's not really possible to move.

The choke flap does open some, so I don't think the pull-off is causig my issue - but rather a choke only getting 10.5-11V not heating up fully - though I'm not entirely sure how that suddenly is a thing (voltage at the battery is fine).

[Cliff Ruggles]

The pull-off should be easy to fully compress with the engine off and it should hold vacuum.

When released it should fully open in about 2-3 seconds.

If it is difficult to move or doesn't release quickly it needs to be replaced....

[MP81]

I'll check that. Could that not allow the choke flap to open fully, or would it cause other issues and not that?

[Cliff Ruggles]

The pull-off only unloads the choke flap on cold starts and unless something is bent it will NOT contact any parts of the fast idle cam or choke linkage to prevent it from fully opening.

The electric choke does the rest, and the flap should be fully open in about 2-3 minutes, depending on how you have the electric choke adjusted.......Cliff

[MP81]

Finally got around to checking - I can compress the pull-off when the engine is off, so that seems to be fine.

Ran a wire right to the 12V terminal and in a few min, the choke blade was all the way open - so it's definitely due to the low voltage at the connection...it's confusing, though - how can that wire just suddenly have low voltage? It was fine earlier in the year...

[Cliff Ruggles]

The choke needs high current flow to work correctly so there must be an issue someplace with the wiring and it is lacking "potential" to effectively supply the choke with enough current to work like it's supposed to.

That is a very easy problem to correct, you can run a new wire to it from a "keyed on" source.  I like to go to the wiper motor as there is one wire there that works well for that purpose......Cliff

[73ss]

It could be the oil pressure sending unit. There should be one above the oil filter. It allows current to the choke when there is oil pressure. Does the car have the choke/oil light? I had one fail once. Jumped it out.

[MP81]

It does have the oil light on - coincidentally...that came on when the speedo cable detached, and all this started...I have oil on the dipstick (it doesn't leak any) and I'm pretty sure the engine would have seized by now if it actually had zero pressure...

[73ss]

most likely the problem. You might have dis-connected it when messing with the speedo cable..

[MP81]

That would explain a lot - it's pretty nice out, I'll give that a look at today.

[MP81]

So my sending unit is up next to the distributor and the connection seems wayyyy looser than one would expect. It doesn't seem to snap down all the way, not sure how it would have done that on its own, but its 36 years old, so...I won't question it, haha.

I'm currently double checking that it is not intended to be that way, but it sure seems like that could be my culprit...