Difficult cold start

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MorganKane

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I have stock slant 6 (valiant -64) and I Am having hard cold starts.
I have tried different methods, first "don't touch throttle pedal" as manual states, and then pumping pedal few times and then crank. It always needs very long crank. I think it starts best if I keep throttle pressed fully open. Still needs many and long cranks.

Choke works (plate closes and opens when engine warms up). Ignition timing is correct and new spark plugs. Engine runs great and idles well when warm.

Any suggestions? My guess is that old holley 1920, but would it benefit if I put repair kit on it?
It is not really cold now here in Finland, just about +10 degrees (celsius).
 
Make sure choke is adjusted closed enough. Also, make sure that your accelerator pump is working property and actually dumping gas when you pump the pedal before starting. (Make sure the float bowl has fuel in it anyhow)
 
If when cold you get the shot of gas in the carb, Make sure you have 12 volts in the crank position on the coil. it'll be less in the run position. You could run a 12volt jumper from battery to positive side of coil to see if that is the problem. If starts right up trouble shoot wiring problem. Don't run too long with jumper because coil will burn up.
 
Look down the carburetor throat and confirm you get a STRONG squirt of fuel as soon as you move the throttle all the way to wide open and report back please.
 
Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.Tune-up parts and technique suggestions are in this post.
 
I have a 73 Duster with the slant six & looks to be un-modified at all. Sometimes it will sit outside for months without starting it. (it's not road worthy) I just tap the throttle pedal to set the choke, crank it for a split second, crank it again & it always fires right up. Too much fuel on starting (one full pump) & it is hard starting. Try just tapping the gas pedal first to set the choke (confirm that it's working) & see if that works.
 
I am returning to this problem as it still persists. Reason is not cold climate as we have summer here in finland and temperatures have been high (25 degrees celsius).
Problem is still there. If car stays few days without start, it is very difficult get it running. Starter runs fine.

What I have tested so far:
- added one way valve to fuel line to prevent gas flow away from carburetor bowl (i don't know if that is even possible)
- checked ignition coil resistor bybass and tested with resistor shorted.
- locked choke to open position as it is not needed in warm climate.

I am wondering if it is possible that gas evaporates from carburetor bowl causing long delay to get it full again with starter? fuel pressure seems to be very low in this pump.
Bowl vent stays open what makes me wonder if it helps gas to evaporate? How it is designed like that and why is this valve needed?
 
I would NOT disable the choke. Even on warm days the choke is helpful in starting a cold (un-started for a few hours) engine. Like I mentioned in my last post, sometimes it just needs enough pedal pressure to set the choke, at least mine did. Try just pressing the gas pedal, maybe an 1/8th to 1/4 of the way down, let off, remove the air cleaner lid & check to make sure choke closed all the way, then try to start it without touching the gas. It may be like my Duster was, too much fuel & it was hard to start. If I just hit the gas pedal enough to set the choke, it would start right up, even after sitting for a few weeks! Hot out (summer) cold out (mid-winter) it didn't matter, it always fired right up. Maybe I just had a freaky engine, I don't know, but I would try that first, it may be all it is, too much fuel.
 
Install the newer generation "Dakota" Mini Starter.

Cranks the engine over much faster. Newer electronics in the mini starter is more efficient and robs less power from the ignition system to give a hotter longer spark at the spark plugs.

Starts like it has fuel injection.


☆☆☆☆☆
 
Letting car sit for several days, fuel evaporates and now no fuel in the carb bowl. Best way to solve the problem is to an electric fuel pump, if the problem is no fuel after the shut down for any length of time. As was mentioned above check for a good squirt of gas down carb throat after the lay off. That'll tell if it's a fuel problem. Could also be a weak fuel pump. We can only suggest things, but you have to do the work to find the answer.
 
I would NOT disable the choke. Even on warm days the choke is helpful in starting a cold (un-started for a few hours) engine. Like I mentioned in my last post, sometimes it just needs enough pedal pressure to set the choke, at least mine did. Try just pressing the gas pedal, maybe an 1/8th to 1/4 of the way down, let off, remove the air cleaner lid & check to make sure choke closed all the way, then try to start it without touching the gas. It may be like my Duster was, too much fuel & it was hard to start. If I just hit the gas pedal enough to set the choke, it would start right up, even after sitting for a few weeks! Hot out (summer) cold out (mid-winter) it didn't matter, it always fired right up. Maybe I just had a freaky engine, I don't know, but I would try that first, it may be all it is, too much fuel.
I have tried this method you suggested. It didnot help, so I disabled choke temporarily to eliminate too rich fuel issue.
Letting car sit for several days, fuel evaporates and now no fuel in the carb bowl. Best way to solve the problem is to an electric fuel pump, if the problem is no fuel after the shut down for any length of time. As was mentioned above check for a good squirt of gas down carb throat after the lay off. That'll tell if it's a fuel problem. Could also be a weak fuel pump. We can only suggest things, but you have to do the work to find the answer.
Yes, I will test this next time. It is hard to solve issues cause I had to wait several days without driving the car until I can do next test. And in summer I like to drive :)
 
If problem is evaporing fuel, what would cause it? Should not be like that by design. I cannot imagine any reason but bowl valve?
 
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Still fighting with this issue.
Car stood a week and I tested fuel "squirt". It is strong. So no fuel evaporation issue.
Manual says that cold start should be done without pressing gas pedal. But this thing would never start that way.
Best effort to get it running after standing few days is pump gas pedal many times and then keep it pressed down when starting. This way it soon tries to run, but shuts down after I stop starting. Pumping and giving it very many long starts keeping pedal pressed it starts at last, if there is enough power in battery.

Somehow it sounds like it does not get enough gas to start, but why?

I am confused what causes this? With warm engine I also need to press gas when starting or it would not start. But it starts instantly.

Could it be so simple as bad starter motor? It sounds fine, but maybe it would benefit about new "mini starter"?

Or maybe there is something wrong with ignition causing bad spark? How can I diagnose that?
 
I don’t you the condition or situation of your motor, but my kinda worn out 198 responded brilliantly to a mini starter. Just a little faster spin at startup made all the difference.
 
Hook volt meter to + side of coil and neg side of battery. How many volts when your cranking engine? My car was cranking no start due to low volts at coil when cranking. I cleaned bulkhead connectors and new ignition switch car fires immediately after sitting for days.

And like several others said get a mini starter they require less volts to crank engine which frees up volts to go to coil. They also turn engine over faster too.
 
Here in the states almost all fuel has some amount (15%) or so of alcohol. That is what is causing the fuel evap problems, along with fuel pushover and flooding on hot days. I improved my V8 with a rear mount electric pump, and home built vapor return system. (3 port fuel filter)
 
I think I will convert to pointless electric ignition. I have seen guides here how to use hei parts.
But I found this in ebay:
for MOPAR Slant Six Hi-Po Electronic Ignition Kit OEM Dart Duster 225 170 198 | eBay

Have anybody used this? Is it crap or useful? It should fit without modifications.

Can anybody suggest mini starter that would fit to -64 valiant with 170 slant from rockauto?
It looks that there is many options available.
 
When the intake is cold, the fuel falls out of suspension, condensing on the walls of the intake. It takes more for an adequate mix ratio to reach the combustion chamber.

Improvements aside, pump the gas pedal two or three times before engaging the starter and try choke on and choke off. You will need to determine the best combination under those conditions.
 
I start with few pumps and usually it needs a lot of pumps. Problem is that it does not stay running after starting. It just promises and stops when releasing starter.
Choke or no choke it is difficult.
 
The intake being cold doesn't stop being cold instantly. You need to keep it going with pumping until it smooths out enough to where you can hold the throttle open and it will idle, then idle without holding it open or on the choke. It takes a few seconds. There are many things you can do to improve the situation that were covered in previous posts, including triple webbers or dual SUs with an aussie valiant intake, or custom port efi that eliminate a long cold, wet-flow intake, but you seem to be having enough trouble with one carb right now.
 
It is hard to believe that cold intake causes this massive startup problem. First, it is summer here in Finland and temperatures have been near 30 degrees celsius. Second, that king of problem would been there from the factory and I don't believe that car is designed the way that it would not start easy if it is cold.

I think that there is some kind of problem with carburetor, but I am not good with carbs so I have no idea what kind of problem it would be.
Or maybe spark is so weak that cold fuel/air mixture does not ignite. This is difficult to test also.
 
I can't help you with not believing me, but the story seems to be changing. We can't see or hear anything you claim. All we have are your words. What was a "difficult" start at 10 Celsius is now "massive" at 30 Celsius. What was running and idling "great" warm is now suspected of having ignition and carb problems, but again, those areas can be improved by a mechanic.
 
I found this in ebay:

Not a good pick; read this (about the same kit/same seller).

Then read about the HEI upgrade for a guide on how to do it better.

Can anybody suggest mini starter that would fit to -64 valiant with 170 slant from rockauto?

This one. As with all others you can buy now, it's going to be a Chinese copycat part.

Didn't sound like your starter was having problems, though; what makes you think it is?
 
It is hard to believe that cold intake causes this massive startup problem. First, it is summer here in Finland and temperatures have been near 30 degrees celsius. Second, that king of problem would been there from the factory and I don't believe that car is designed the way that it would not start easy if it is cold.

I think that there is some kind of problem with carburetor, but I am not good with carbs so I have no idea what kind of problem it would be.
Or maybe spark is so weak that cold fuel/air mixture does not ignite. This is difficult to test also.
Did You run a compression test recently?
 
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