408 Troubleshooting: Won't Idle

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MuuMuu101

MuuMuu101

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A couple of weeks ago, I drove my car from work to home and when I got to the hill my house is on, the car randomly shut off. After that, the car would crank a bit, but wouldn't turn over. I put 2 gallons of gas in the tank and it would fire up but die immediately. After that, it would just sound like the starter is turning, but nothing was happening.

I finally got around to work on it today. Good news and bad news. Good news, took the old starter to Autozone and it tested out good. Bad news, I don't know what's wrong. I reinstalled everything and tried starting the car up again. With a couple of pumps of the gas pedal, it will start and shut down when the ignition is turned. Without any pumps of the gas pedal, it sounds like the starter and flywheel just free wheel. When I keep my foot on the gas and turn the key, it will start up, but I have to keep my foot 1/2-3/4 throttle in order to keep it running and it does not sound happy. Idk what's wrong, but now it's starting to sound like a fuel problem. I have new spark plugs, since all of the old ones were black, but I'm not sure if I want to install them just yet to check to ensure it is fuel. Video attached of me trying to start the car a couple of times. I honestly have no idea where to start with this?

Now here's the thing, I have a brand new Holley Sniper, Tanks Inc EFI tank, Stealth Aermotive Fuel Pump, new lines, new fuel filter, etc. all waiting for the swap. Should I bother trying to make this thing run or should I just start the swap?

 
I just checked the choke and it was closed. I realized that there wasn't a rod in place to keep it from shutting. I tried starting it up (without an air cleaner) and I still had the exact same problem. The only time I got it to fire up, a fire ball came out of the carburetor.
 
Check your timing, sounds like you need to advance it. Should be 10-15 deg initial, 35 total. 65'
 
I think you should find the problem with this setup before you change. Too many variables. When it stalls does it smell like flooding? Check timing to see if dist slipped. Check rotor and cap also. I assume electronic ignition.
 
You probably fouled the plugs up running with the choke closed. Replace the plugs and you should be fine.
 
I had troubles with the carb I had, I got mad and swapped the carb out for the Fast unit, have not looked back since.

Good luck
 
vacuum leak. if it runs with throttle and 1200 RPM but dies if take foot off gas, I would suspect a big ol vacuum leak. first thing Id look for. You should be able to hear that one at a fast idle.
 
Inquiring minds what to know. What's going on? Block open the choke so it's not an issue. Replace the plugs. Check and smell the oil dipstick to make sure it isn't flooded with oil and go from there.
 
Plymouth 65 said:
Check your timing, sounds like you need to advance it. Should be 10-15 deg initial, 35 total. 65'
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How do I check timing if the car won't stay running? I need to borrow/buy a timing light/gun.

3406pk said:
I think you should find the problem with this setup before you change. Too many variables. When it stalls does it smell like flooding? Check timing to see if dist slipped. Check rotor and cap also. I assume electronic ignition.
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The car has always smelled like fuel, but yes, yesterday after starting it up, it did smell like fuel. I'm running an MSD Ready-to-Run Distributor. I'll check to see if the distributor is loose.

fklskv said:
You probably fouled the plugs up running with the choke closed. Replace the plugs and you should be fine.
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I have a brand new pair of plugs. Prior to yesterday, all 8 of them were very black, but I had assumed that was because I had problems with my manual choke cable (which I removed recently) getting stuck and not keeping the choke open.

pishta said:
vacuum leak. if it runs with throttle and 1200 RPM but dies if take foot off gas, I would suspect a big ol vacuum leak. first thing Id look for. You should be able to hear that one at a fast idle.
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Where are good places to check for vacuum leaks aside from gaskets. I'm running manual brakes and I'm not running vacuum advance so I don't have any lines going to those two.

mopowers said:
What do the plugs looks like? Where's the timing at? Vacuum leak?
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Only question I can answer was all spark plugs were black. I didn't want to swap them out because I wanted to retest the engine as-is knowing that the starter is good per Autozone test.

toolmanmike said:
Inquiring minds what to know. What's going on? Block open the choke so it's not an issue. Replace the plugs. Check and smell the oil dipstick to make sure it isn't flooded with oil and go from there.
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Will do. I'll see if I can get this done tonight. I've been extremely busy and have barely had a couple hours a night to do what I need to do let alone what I want to do.
 
To me your dealing with more than one issue. If everything was good before, you say plugs are black so they’re loaded up. Put new ones in. The second issue is the starter. It’s not engaging. I know you say it checked good, but they only basically check the windings. The bendix isn’t engaging or if it is it’s not driving the ringgear until it hits a spot that it grabs. You need to inspect to make sure the ring gear doesn’t have a bad spot. And verify the bendix gear is engaging the ring gear properly. The starter bendix operates like an over running clutch, it will only drive one way and is supposed to be able to be over driven with out trying to drive the starter motor like a sprag in a transmission. If it’s bad it will not lock up to drive the ring gear and can be hit or miss on engaging. If you were cranking and the engine spit back against the starter it could very well have damage the bendix. Yes driving with the choke closed will foul the plugs in short order.
 
To be clear, does the engine spin when you turn the key?
That's the starter's only job. If it starts, then stalls, it's not your starter.
Crank the engine, hopefully it starts.and look in the carb. Do you see fuel dripping in the carb? If so, there's your problem. Watch out for back fires. If you look in the carb while it's off, and you work the throttle, you should see fuel squirting into the carb. If not, there's your problem. Of course, make sure the choke is open at all times for now.
 
I replaced the spark plugs. When I cranked it the first time, it still made the starter free-wheeling noise. On second crank, it started right up and didn't have any problems idling.

20180627_192400.jpg
 
If it is a Mopar ignition system...Ballast resistor? Car starts then shuts down when you let the key return to run? I didnt see mention of it so I figured I'd put it out there. If it is aftermarket or MSD, disregard. Looks like you figured it out as fouled plugs.:)
 
Dartswinger70 said:
If it is a Mopar ignition system...Ballast resistor? Car starts then shuts down when you let the key return to run? I didnt see mention of it so I figured I'd put it out there. If it is aftermarket or MSD, disregard. Looks like you figured it out as fouled plugs.:)
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It's an MSD Ready-to-Run ignition that doesn't have a ballast resistor. I'm glad it's idling again, I just want to make sure the starter or flywheel aren't screwed. I probably won't be able to work on it until Tuesday night.
 
Make sure the floats are shutting off the fuel flow into the bowl. Could be the needle and seat are bad and is allowsming the fuel pump to pressurize the bowl and push fuel right through the boosters. You'll see fuel dribbling down onto the butterflies ...when running and just after shut off.
 
I really wasn't able to do much with it, but on Tuesday I was able to start it after multiple starter attempts. Once I started it, I just let the car sit and warm up to operating temperature. It didn't have any problems warming up. I also used part of an old wire hanger to make something to keep the choke open. Although the car had been sitting for a while, I didn't get black soot coming out of the exhaust when I started the car up. So, it seems like I'm heading in the right direction.

I have a video of it running. I'm still unsure of the water pump pulley. It may be my eyes are fooling me or the play is normal. But I hear something clanking around. I walked around the car and it seemed most dominant under the car by the driver's side door. Again, I took a video, but the video doesn't capture all the sounds. I can post it later tonight. I hope something isn't left over in the bellhousing and it's just me being paranoid. Anyway, the starter and spark plugs are going to have to come out and I'm going to have to inspect, the starter and flywheel and see if any teeth are missing or if something is chilling in the bellhousing.
 
I would say starter could be clunking noise under driver's door.
That wp pulley has a slight wobble. Loosen belt and check bolts.
Check ring gear teeth too.
 
Is is an automatiic? Check the torque converter bolts. If the are loose the converter could be moving in and out playing havoc with the starter gear. Blue loctite on the converter bolts.
 
Oh and don’t trust the rubber cap on the water pump. I had one fail and made a big mess. You can tap the inside of the nipple for the correct pipe plug screw in a plug and cover it with a rubber plug to hide it.
 
furrystump said:
Is is an automatiic? Check the torque converter bolts. If the are loose the converter could be moving in and out playing havoc with the starter gear. Blue loctite on the converter bolts.
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Yup. Blue at least. Had a friend lose a very good running 440 in a very cool car because he didn't listen and loctite those bolts.
 
furrystump said:
Is is an automatiic? Check the torque converter bolts. If the are loose the converter could be moving in and out playing havoc with the starter gear. Blue loctite on the converter bolts.
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yellow rose said:
Yup. Blue at least. Had a friend lose a very good running 440 in a very cool car because he didn't listen and loctite those bolts.
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It's a T56 Manual.
 
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