Choke staying closed too long

[realgone58]

Quick question, since my service manual isn't here yet. '86 Fifth Ave. First start of the day, any temperature outside. One pump on the pedal, starts right up. High idle, choke stays closed, loads up bad. Takes about 3 minutes before it will kick down and clear up. Checked voltage from choke thermostat switch. 12 volts in, 10.75 volts out. Replaced choke thermostat. No difference. Is there any other adjustment? I'm about ready to just wire the choke open.

 

[jasperjacko]

Is the choke pull off working? If it is, you may need to gently bend the link or rod on the choke so it opens a little more on start up.

 

[Shorty Thompson]

X 2 .

 

[slant6billy]

X3. Make certain that choke moves- period. Don't disconnect it. Florida might be warm enough, but you need some choke to get started. Get the engine warm and then pull the choke off. If it is truly the choke staying too long, your loading won't occur.

 

[kkritsilas]

I'm having a choke issue with my 1981 Mirada CMX as well, but this is more to do with the missing choke rod in my case. This is a very relevant thread to me though, so I am going to ask a few questions. The choke thermostat is sitting on the intake manifold isn't it> Its bolted on, and the rod connects to the Themoquad to my understanding. The thermostat is basically a bimetallic strip that bends when the heat from the exhaust cross over reaches a certain temperature. So what is the electrical connector for? Also, can a stiff wire be bent into the proper shape to replace the choke rod? My 1980 Cordoba has the same 318-4BBL as the Mirada does, so can I use it as a pattern to bend up the rod for the 1981 Mirada, or are there year to year variations? I have had no luck finding either a complete 318-4BBL choke thermostat (3 local stores have said parts are no longer available), and the internet searches haven't turned anything up yet.

Kostas

 

[My imp]

I'm having a choke issue with my 1981 Mirada CMX as well, but this is more to do with the missing choke rod in my case. This is a very relevant thread to me though, so I am going to ask a few questions. The choke thermostat is sitting on the intake manifold isn't it> Its bolted on, and the rod connects to the Themoquad to my understanding. The thermostat is basically a bimetallic strip that bends when the heat from the exhaust cross over reaches a certain temperature. So what is the electrical connector for? Also, can a stiff wire be bent into the proper shape to replace the choke rod? My 1980 Cordoba has the same 318-4BBL as the Mirada does, so can I use it as a pattern to bend up the rod for the 1981 Mirada, or are there year to year variations? I have had no luck finding either a complete 318-4BBL choke thermostat (3 local stores have said parts are no longer available), and the internet searches haven't turned anything up yet.

Kostas

eBay has a rew, but I don't know if you want to pay their prices. Look under "Mopar choke thermostat electric assist". I saw at least three, but real expensive! Hope it helps, Larry

 

[slant6billy]

I have a few as you can see. The difference is the arm length. Anyone know the length for the Mirada? There is a little clasp on the end. My question, which direction does it move from cold to hot position? I assume it pushes up when heated?

 

[kkritsilas]

Slant6Billy,

If one of those is for a 318-4BBL, I would buy one. If by clasp, you mean the little self locking washer, that would be right, it keeps the choke rod from falling off the carburetor. All the Carter Carbs that I have seen use one or more of them. They are pretty hard to find alone, but there are tons in the junkyard Mopars. They do vary some in diameter, and there are kits of new ones out there.

Kostas

 

[Yellowdart69]

I have a similar question. My car seemed to be using too much gas. When I checked , I noticed that the choke wasn't fully open. I feel stupid asking, but what do you do, to make the choke plate fully open on a hot motor? Thanks.

 

[alf44]

I have a similar question. My car seemed to be using too much gas. When I checked , I noticed that the choke wasn't fully open. I feel stupid asking, but what do you do, to make the choke plate fully open on a hot motor? Thanks.

as stated above, try slighty bending the rod to open choke a bit more,, there is a s type curve in the rod you can try pliers to gently close the curve which will shorten the rod length, opening the choke a bit more

 

[My imp]

When purchasing your choke, make sure to get one with the rod & clip. The blister pack assortment from parts stores doesn't have the proper size clip. Also make sure you get the clip that attaches from the proper side of the rod. eBay had exactly what I needed when I switched from an electric Holley to a Thermoquad, get the "Carter" brand choke, if the same vendor is still selling, it comes with everything. Good luck, Larry

 

[slant6billy]

That's going to be the question- which one of these is the 318 4BBL? If someone can help me identify it, then it is the one for you. I think one might be off a late 70s bigblock for sure, but the 2 that are identical are most likely the 318 ones. Perhaps someone on here can help us id the correct one. with either some markings or arm length or something. We get that and I'll send you a PM. Right now these are just taking up space, so I would just be looking for shipping cost.

 

[realgone58]

Everything is working on mine, and once fully warm the choke is all the way open. Tomorrow morning, I'm going to remove the air cleaner, and cold start the car, and see what is holding that butterfly closed all the way. Because as soon as mine starts, it's all the way closed and fully loading up. Bending the "S" rod is referring the the one from the vacuum kick, correct?

 

[slant6billy]

Can you take a snap shot before you bend the arm? Post it to get the go ahead. I call it a choke arm, some a rod, pull... etc. I'd hate to tell you to bend it and we are talking different pieces. Plus I am thinking a good spot to bend is in the straight.

 

[realgone58]

Ok, I think I figured out my problem. Here are some pics. Side pic is how the adjustments sit right after I set the choke with one pump of the pedal, second pic, you can see the butterfly is all the way closed. First pic is right after startup. Butterfly open a bit, but not enough. You can also see that the vac kick diaphram hasn't moved.Pulled off the vacuum line from the vac kick. Nothing changed, but it does have a bit of vacuum to it. Plugged back in, nothing changed. When I manually pull the vacuum kick back, it stays, clears up, and nicely kicks down off high idle with a tap to the throttle. With this being noticed, I believe I need to get a new vac kick diaphram.

 

[MiradaMegacab]

Realgone58, remove the vac line from rhe manifold tree,spray the ports of the tree with carb cleaner. Sometimes carbon builds up inside the tree, reducing the vac signal.

 

[83Imp]

I think you're right - the choke pull-off diaphragm is gone. Pull the vacuum line off of it and plug one long enough to pull a vacuum on (yea, suck on it) and see if it holds. The Carter 2bbl choke pull-offs are cheap and easy to get.

 

[NoCar340]

When I put the ThermoQuad on my old Fifth Avenue, I just bought a choke stat for an '83 W150 with a 360-4V and the choke pull-off for the carb number, which I think came from a '78 360. It all fit together perfectly. A lot of the choke stats have a hole in the side of the housing, and can be adjusted with a flat-blade #2 screwdriver well enough that no linkage bending is required.

I always adjusted my chokes "backwards", which is to say I started with a hot engine and made sure the choke plate was fully open by a small marge, then let it cool off and see where the plate ended up with one pump. I don't know if someone mentioned it previously, but making sure all the linkages are clean and move freely is of paramount importance.

 

[realgone58]

It was the choke vacuum pulloff. I scored a new one for twelve bucks free shipping. It came the other day. Took the old one off, put it to my mouth and sucked on it. (I know that doesn't sound good) and nothing happened. New one, pulled the vac right in no problem. Even came with the correct S hook on it! Installed on cold engine, works like brand new. No need to bend the rods.

 

[NoCar340]

Excellent! Always nice when it's that simple.