73 SE 400/4BBL Won't Idle After Warm Up

[dodgeboyd]

I need some help. My 73 SE has a 400 with an Edlebrock Torker intake and a Holley (650 I think) carb. I have replaced the dist. cap, wires, rotor, and plugs. Even swapped out the coil. The problem I am having is that when I start it up cold, it runs like brand new. Once the engine warms up to normal, it dies like it is not getting fuel. I can pump it and restart it. It will stay running until it goes back to idle. Even after warm up, it still runs like new until it goes down to idle. It was originally a 2BBL car, but was changed out. Oh, and it has a new fuel tank and new fuel filter. It just seems like the engine heat is doing this. I has always done it, but I knew it needed the plugs, wires, etc. and tank. Please help.

[Chryco Psycho]

Probably all to do with tuning .
the first thing that comes to mind is the fuel pump pushrod , if it is worn it will not cycle the pump fully & can starve the carb of fuel but you say it runs fine everywhere but Idle .
Do you know what vacuum the engine is making at idle in gear , you may need to replace the powervalve or it could be bad ? is the float level ok ? I assume you have set the idle mix screws turning them in until the rpm drops & turning them back out to get a smooth idle ? Where is the timing set , often the engine run far better with 12-16* at idle , you need to adjust the vacuum advance though so it doesn't overadvance at high rpm , this can be done with an allen wrench inside the vacuum pot assuming you have electronic ign ?

[Musicman]

Curb Idle Adjustment Screw... what rpm are you idling/stalling at?

Idle Circuit Tuning

[dodgeboyd]

I don't have a vacuum gauge. The only adjustment screws I can find besides the idle adjuster are on each side of the carb. There is an air screw on the drivers side and a lean screw on the pass side. They both have about 2 turns of adjust, which doesn't make any difference turned all the way either way. They are both plastic headed.

[Cooter]

Was that Holley rebuilt when installed? What about ignition system? Stock Chrysler electronic?

[dodgeboyd]

Previous owner installed intake and carb. It's not a rebuilt one. Still has stock ignition system. When I bought it about 3 years ago, he told me that it needed the aforementioned things. Once everything was replaced (tune up & fresh gas), this thing runs like a jet except at warm idle. I have checked for vacuum leaks to no avail. The electric choke is disconnected. When I crank it, the choke is almost completely closed. Once it warms up, I have tried to open it slightly (the width of a knife blade). This killed the engine as well. Trying to close it any at all does the same thing.

[Cooter]

Sounds like that Holley is in need of a rebuild. Runs great till warm and won't idle. Sounds as if the idle circuits are clogged. Will need to soak most likely. Try shooting some carb cleaner in the top of carb when you are trying to get to idle and see if it's a fuel related issue. BE CAREFUL!! Try not to "load" the engine down with it. Shouldn't take but a fine mist, not full spray. If the engine continues to idle, your idle circuits are plugged. i assume you know where the idle adjustment screw (NOT the mixture screws on the sides in front metering block) is on a Holley right? And it is adjusted correctly to where it should idle right?

[dodgeboyd]

I think you are right. I have done everything under the sun, and nothing really makes a difference. It's got to be time for a rebuild. Once I do that, there is nothing left. I will get it done as sonn as I can get to it and let you know. Thanks everyone. I really appreciate it.

[Chryco Psycho]

Sounds like the choke is the problem , it should be lightly closed when you start & should be completely off once it warms up , it sounds like the thermostat is not working . Is it an electric choke , if so it has to have 12v power when running & the thermo needs to get hot .Or you can adjust the choke so it is wide open all the time .
  So you need to open the choke & tune the engine with the choke off , simply tuning float levels & mixture screws should be a start . You may have an emissions carb if it says lean on the side by the mixture screws , you need to turn the screws out to lean so turn them out until it starts to run poorly then turn in until it smooths out .

[dodgeboyd]

Chryco, when I start the engine, and it's cold, it runs great. The electric choke is completely disconnected. With that being said, the choke is almost completely closed on it's own. The car is running like new. Then as the engine warms up, it begins to run down and I have to accelerate to keep it going. Then as soon as I let off, it's as if it runs out of gas. I pump it a couple times and it starts right back up, but won't idle. (running out of gas again). If I prop the accelerator a little to keep it going and try to move the choke either way, even the width of a pocket knife blade, it kills the engine. If I open the choke fully and try to start it, (tried this last night) it will not start and it backfires. May have to do a teardown and rebuild of the Holley. It's a 4160 List #8006.

[Chryco Psycho]

With the choke closed it is running way rich which is why it is ok cold but when it is warm it is flooding so you need to get the choke wide open & tune it so it will stay running . Warm the engine first with the choke on then open the choke & start adjusting mixture screws& idle speed to keep it running , once it is tuned correctly you should not need the choke to start it in warm weather , just pump the throttle 2-3 times & nurse it for 45 seconds & it should run on its own 

[Cooter]

Dodgeboyd, lemme know if I can help in any way with your Holley rebuild once you have it back on the car and are ready to tune it.

[dodgeboyd]

Thanks men. I will try it like you said Chryco. Cooter, if that doesn't work, I will rebuild and update. I really appreciate all the help and suggestions. Dick.

[4aThrill]

have you tried the power valve its part of the idle adjustment screw, located on the bottom of the carb,there are different sizes in different colors. 

[dodgeboyd]

I got the Holley rebuilt and Cooter was right. It was full of trash. Now it runs really good, except when i drop it into gear (727). It pulls the idle down to dying unless I set it up high at the curb idle set screw. Do I have a Vacuum line wrong? The only two connected are the PCV valve and the vacuum advance. Everything else is blocked off.

[Chryco Psycho]

you need to know what the vacuum in gear at idle is , the power valve may be open if you do not have enough vacuum so you would need to swap the a lower rated power valve, most have 6.5" PV in them , you may need a 4.5 or lower 

[dodgeboyd]

OK, here's the stats: The Holley 4160 has been rebuilt. When I start it and the engine is cold, The idle set screw has to be turned app. 2.5 turns up and the choke has to be 95% closed. This makes the car run fine except for the fast idle. The manifold vacuum in park is at 19.5" Hg. I drop it to drive and the vacuum drops to 16.5" Hg. It still seems like it is drawing to much air through the carb. Once warmed up, the manifold vacuum is at 20.0" Hg in park and 16.5" in gear. If I try to idle down, the manifold vacuum drops to 14.0" to 17.0", and immediately dies. I turn the idle set screw back up and it runs good again, only idled up. If I drive it like this, it runs strong, but when I let off the gas, it tries to die. I also tried to hold the choke wide open and crank it. It will start, but won't even think about idling. Plus, with the choke opened up, it crackles and backfires. (Maybe a timing thing?) But in any of the above, the idle mixture screws don't make any difference whether completely cosed, opened or anywhere in between. Is this carb junk? It's a Holley 4160 List #8006.

[Cooter]

You stated you had it "Rebuilt"..If it was "Full of Crap", then I'd be leary of someone who rebuilt it NOT soaking it in "The soup" and blowing out all those SUPER tiny little passages in the metering block, base plate, etc. I've even had to use a Torch cleaner set  to run through all the passages to be SURE they are clean.

Sounds like you have a clog in the idle circuit. Common problem when crap is found in the Holley's.

[dodgeboyd]

Thanks Cooter. I'll take it back apart. Also, The carb to manifold gasket they sent is about 3/8" thick. The one on the car is about 1/16". Do I need to get taller studs and use the thicker gasket?

[dodgeboyd]

Alright. Took it back apart. Cleaned every crevice known to man. Everything is right. Still doing the same thing. Maybe it's time to put the T-Quad on it and see what it does. I am ready to give up on this one.

[dodgeboyd]

I ordered a kit for the T-Quad. It will be here tomorrow. What can I expect when using the Edlebrock Torker single plane intake? Will it work with the T-Quad or do I have to find a Mopar cast iron intake?

[Chryco Psycho]

the TQ will be fine on a single plane intkae
You never really answered if the choke was coming off as the engine warmed up with the hollley carb , if I was there I am sure we could get it sorted out but I am not so ...

[dodgeboyd]

The T-Quad has been rebuilt and everything is back to normal. I found a Holley man, (race engine builder) and he said I am pulling a vacuum through the secondaries. He told me that almost everyone makes this mistake the first time they rebuild a Holley. I am taking it to him and he said he would show me how to fix it. It's good to have this Dodge back on the road. Thanks to everyone of you for all the help. Please have a safe and wonderful 4th. And please take a moment to give thanks to God for allowing us to live in the greatest country in the world.