I don't currently have the funds to swap the 1 bbl to a 2 on my 225, so i'm just going to try to get it running the best i can. The 225 is completely rebuilt with about 250 miles on it and the carb is only 8 months old. To start, you have to pump the pedal twice and then give it gas while trying to crank it, and then you have to keep giving it gas until it warms up or it will die. when its warm it stays running, but it feels like it idles just high enough to not die. Any ideas on how to fix this? I'm in college and its pretty nerve wrecking to not know if i'm gonna be able to get my car to start in the parking lot.
idle issues
- Thread starter 74darts
- Start date
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BillGrissom
Well-Known Member
Regardless of year or caburetor (please tell us), cold starting is very dependant on the choke plate setting. That is the plate at the top of the carb, connected to a rod w/ thermal sensor (bi-metal spring) in the exhaust. On a winter morning, the choke should be closed fairly tight. There is a screw adjustment on the sensor ("rich" or "lean").
The "choke pull-off" must also work. At the top of the carb, it looks like a "dash pot" (but isn't). It's job is to pop the choke open slightly the instant the engine fires, so it doesn't die rich. The rubber diaphragm is often torn. You can check by pushing in the short rod, covering the vacuum tube w/ your finger and see if vacuum holds it in. Can also test w/ a vacuum pump. Fairly cheap to replace (ebay).
Otherwise, if you have a strong spark, it should start. Read the manual for adjusting the "fast idle" and "normal idle" speed screws. Can find on-line for Carter BBS, Holley 1920 and 1945.
The "choke pull-off" must also work. At the top of the carb, it looks like a "dash pot" (but isn't). It's job is to pop the choke open slightly the instant the engine fires, so it doesn't die rich. The rubber diaphragm is often torn. You can check by pushing in the short rod, covering the vacuum tube w/ your finger and see if vacuum holds it in. Can also test w/ a vacuum pump. Fairly cheap to replace (ebay).
Otherwise, if you have a strong spark, it should start. Read the manual for adjusting the "fast idle" and "normal idle" speed screws. Can find on-line for Carter BBS, Holley 1920 and 1945.
Exactly like mine. I purchased a remanufactured Holley 1945 from Carburetors and More for $145. When I got it in, bolted it on and hooked up the linkage. Pump the gas twice, push the pedal to the floor and let off, hit the key. Started right up, high idled at around 1200-1500 rpm and purred like a kitten. After she warms up, she idles back down on her own and we drive off. They set the carb, choke plate linkage and choke pull down perfectly.
Well.....then I pulled my engine and forgot to unhook the throttle cable and bent the linkage all to heck and back. Bent it back as best I could but haven't been able to get it right since. Now I pump the gas, hit the key, rev it up and hold it for about 10 minutes. Then she's fine. Never fails to start this way.
The car is a 1974 dart sport but i'm not sure what year the engine is, as my dads friend sold it to us after the last one blew. im pretty sure he just ordered another stock carb for it. im definitely not a mechanic, but im trying to learn. if i were to take it to a shop, what should i tell them to do?
bbrroowwnn
never re member
tell them to check the choke....it is not working....they can take it from there.....leave it overnight though so they can start it cold in the morning and see if the top plate is closing when motor is cold.
nm9stheham
Well-Known Member
If it does start everytime, then it is likley the choke.
Let me ask, when it does start, does it run OK for maybe 20 seconds and then get rouhg? Or do you have to immediately start pumping the gas to keep it running?
Let me ask, when it does start, does it run OK for maybe 20 seconds and then get rouhg? Or do you have to immediately start pumping the gas to keep it running?
1970Dart198
Well-Known Member
74DartS, I had the exact feeling as well when I drove my slant in college. It was nerve wracking the whole semester. It sounds like your choke isn't working correctly OR its simply not adjusted for cold starts. I find this interesting because I literally had the EXACT same issues as you. Find the Choke adjust article in the slantsix.org website. This is incredibly easy to fix, all you need is a toolbox (good to have just in case) and a good attitude when working on these old cars. I'm a college student like you, and I find it interesting when other students' cars break down at my college, they pop the hood on their new car and all it is is computers and plastic!
Naturally I try and help them with my tools but there's not much I can do with no space under the hood and a computer!
Trust me, it may seem annoying and an inconvenience to keep adjusting these old darts, but the valuable working experience you'll get is worth more than anything. Enjoy your classic!
Best,
1970Dart198
Naturally I try and help them with my tools but there's not much I can do with no space under the hood and a computer!
Trust me, it may seem annoying and an inconvenience to keep adjusting these old darts, but the valuable working experience you'll get is worth more than anything. Enjoy your classic!
Best,
1970Dart198
1970Dart198
Well-Known Member
You're quite welcome! I have empathy for your situation because I've lived it! Just like a college essay, doing some research and maybe getting some images to really assist in fixing anything that comes up.
What I would also highly recommend is finding an auto repair garage close or reasonably close to your college where you've formed a good relationship with them. Use them for any car - lift required fixes like brakes (in my experience!). Find one that has a good hourly rate (no dealerships!). This is critical for any emergencies or fixes.
I'm living the same scenario as you so I truly hope my experience helps!
Best,
1970Dart198
What I would also highly recommend is finding an auto repair garage close or reasonably close to your college where you've formed a good relationship with them. Use them for any car - lift required fixes like brakes (in my experience!). Find one that has a good hourly rate (no dealerships!). This is critical for any emergencies or fixes.
I'm living the same scenario as you so I truly hope my experience helps!
Best,
1970Dart198
BillGrissom
Well-Known Member
This car will be a great learning experience and invaluable in understanding modern cars. The basic concepts are the same, just the implementation of the controls changed. As mentioned, manuals for all possible carbs you might have are free on-line and detail all these simple "tune-up" techniques. You need to do legwork, pull the air cleaner, look at the carb, write the PN down and compare to photos on Google Images. There must be youtubes showing how a choke plate and pull-off work. The only tool you need is a screwdriver. Anything listed you can't do? Only requires motivation. Somebody here might have a cattle prod.
DodgeLad
Skipped the Light Fandango
That's what mine is doing. What is it?
nm9stheham
Well-Known Member
1) It could be the choke as mentioned. Make sure you look at all the adjustments suggestions. The choke plate should be snapping closed when you pump that gas (before you crank the engine any at all), and then should pull open about 1/8" when the engine starts to run. This opening is due to the 'choke pull-off', which is the approx 2" diamter disc with the rubber vacuum line in one side and the mechanical linkage coming out of the other side. This opens the choke plate more an more when the engine is still cold as the engine pulls in more air to prevent it from bogging down.
2) The choke has to be adjusted and this is a process that requires multiple cold starts to get right. If it is the long rond from the intake manifold, the long rod can be bent to adjust or the small choke spring in the 'choke well' on the intake has an adjustment.
3) The delayed misfire symptom can be caused by a wrong ballast resistor or weak coil. The ballast is on the firewall over on the passenger side and is a long, squarish white ceramic block screwed to the firewall with 4 terminals with push-on wiring connections. There is a common wiring feed on one end (blue wires), and 2 output feeds on the other end. One side is low resistance and should go to the coil (brown); the other side is high resistance and goes to the ECU module (green-red). If the output leads get swapped, then the high resistance sdie will go to the coil and will cause weak spark and cold misfiring.
The ballast's resistance is designed to increase as the car runs, but too high a resistance will starve to coil for current and reduce the spark enenrgy; this shows up often as rough running when cold only after 20-30 seconds (when the ballast has warmed up some). It will go away as the engine warms up and the fuel/air mixture gets better mixed in the warm intake manifold.
I have some good/better/best parts for the older 2 lead ballast but not for the 4 lead ballat. I would install a new one and make sure the wires are arranged correctly. Let us know if you need more help in figuring out the wire lead arrangment on the 4 prong ballast.
Associated with the ballast is the coil. If that gets weak, then a cold warmup misfire is a common symptom. You might consider replacing this with a Pertronix Flamethrower PN 40011; these can be found or ordered at some Advance and Oreilly stores. It gives a bit hotter spark to combat cold warmup misfires.
2) The choke has to be adjusted and this is a process that requires multiple cold starts to get right. If it is the long rond from the intake manifold, the long rod can be bent to adjust or the small choke spring in the 'choke well' on the intake has an adjustment.
3) The delayed misfire symptom can be caused by a wrong ballast resistor or weak coil. The ballast is on the firewall over on the passenger side and is a long, squarish white ceramic block screwed to the firewall with 4 terminals with push-on wiring connections. There is a common wiring feed on one end (blue wires), and 2 output feeds on the other end. One side is low resistance and should go to the coil (brown); the other side is high resistance and goes to the ECU module (green-red). If the output leads get swapped, then the high resistance sdie will go to the coil and will cause weak spark and cold misfiring.
The ballast's resistance is designed to increase as the car runs, but too high a resistance will starve to coil for current and reduce the spark enenrgy; this shows up often as rough running when cold only after 20-30 seconds (when the ballast has warmed up some). It will go away as the engine warms up and the fuel/air mixture gets better mixed in the warm intake manifold.
I have some good/better/best parts for the older 2 lead ballast but not for the 4 lead ballat. I would install a new one and make sure the wires are arranged correctly. Let us know if you need more help in figuring out the wire lead arrangment on the 4 prong ballast.
Associated with the ballast is the coil. If that gets weak, then a cold warmup misfire is a common symptom. You might consider replacing this with a Pertronix Flamethrower PN 40011; these can be found or ordered at some Advance and Oreilly stores. It gives a bit hotter spark to combat cold warmup misfires.
DodgeLad
Skipped the Light Fandango
Thanks! I will keep tweaking. The new electric choke is the 1234 kit for Holley 1 bbl. from Carbs Only. And I just upgraded to TrailBeast's HEI kit, so it's not the ballast resistor.
Well, first off, it sounds like it's pretty normal except maybe it's idling a little low.
It's a carburetor. It's not EFI. It will never be EFI. It will never run like EFI.
Carburetors have to heat up some to operate properly. First thing I would do would be to get the timing right. Then, get a dwell/tach meter on it an see where the idle is. Should be around 750 give or take.
Adjust the air screw so that you have the highest reading on a vacuum gauge at idle with it in gear (if it's an auto). With the parking brake set and wheels blocked of course. We don't want anybody dead.
Once that's ironed out, you can adjust the choke. This is best done with the engine dead stone cold, first thing in the morning when it's cold out. Adjust the choke so that it is barely closed.
It sounds to me like it is simply out of adjustment a little and nothing is really wrong. Adjust and check as I outlined and get back.
It's a carburetor. It's not EFI. It will never be EFI. It will never run like EFI.
Carburetors have to heat up some to operate properly. First thing I would do would be to get the timing right. Then, get a dwell/tach meter on it an see where the idle is. Should be around 750 give or take.
Adjust the air screw so that you have the highest reading on a vacuum gauge at idle with it in gear (if it's an auto). With the parking brake set and wheels blocked of course. We don't want anybody dead.
Once that's ironed out, you can adjust the choke. This is best done with the engine dead stone cold, first thing in the morning when it's cold out. Adjust the choke so that it is barely closed.
It sounds to me like it is simply out of adjustment a little and nothing is really wrong. Adjust and check as I outlined and get back.
DodgeLad
Skipped the Light Fandango
750 rpm in gear?
BillGrissom
Well-Known Member
I agree w/ everything except that the choke pull-off opens the choke gradually (implied). All it does is the initial "pop open 1/8". The thermal spring in the exhaust does the gradual opening as the engine heats up. That "pop open slightly" action is critical to keep from dying rich. Even worse, dying rich can carbon-foul the spark plugs so you won't be able to start no matter what. A thin layer of carbon lets the spark run across the ceramic insulator instead of sparking at the gap.
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