1974 valiant stalls in gear 225 automatic

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moparjon

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1974 valiant 225 stock carb . automatic . when i got back from going to carlisle from new jersey a good 3 hrs both ways no trouble at all until when dropping off a friend almost all the way back . i filled the tank at a gas station i never used , probably at least 3 quarters of a tank . ( maybe its the gas ? ) then , when starting right there , and put in gear , the car stalled , cut right out . so now and since then , if you put it in drive or reverse , it either dies or barely runs with a very low idle . fast idle is high curb idle is around 800 rpm ( though i tried upping the curb idle to 1200 ) , still falls flat on its face when put into gear . unless i also hit the gas at the same time . then it will go and stay running until i get to a light . occasionally it stays running , again at very low idle , almost cutting out , but usually dies . any opinions or suggestions . is it bad gas ? should i mess with the idle mixture screw ? or am i missing something entirely ?
 
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Many possibilities, some simple
1...Any chance something came loose
2....How was the idle speed before, IE was it on the low side, high side, ??
3....Reach down and wiggle the distributor see if it's come loose, maybe the timing changed. It's possible something came loose/ worn in the distributor
4....How is it's history, using oil, etc, any possibility a plug is fowling
5....I would get some pressurized carb cleaner, remove the idle screw and with the "snorkel" (make SURE one is on the can when you buy it, they have a habit of "walking") spray into the idle screw. If you can devise a makeshift seal around the snorkel, even say, would up tissue paper, will help pressure the cleaner through the idle passages.

LOL.........how long since it's been tuned up.......cap/ rotor/ wires/ plugs/ carb cleaned, air filter ?? Hey jus' askin'
 
67Dart273 said:
Many possibilities, some simple
1...Any chance something came loose
2....How was the idle speed before, IE was it on the low side, high side, ??
3....Reach down and wiggle the distributor see if it's come loose, maybe the timing changed. It's possible something came loose/ worn in the distributor
4....How is it's history, using oil, etc, any possibility a plug is fowling
5....I would get some pressurized carb cleaner, remove the idle screw and with the "snorkel" (make SURE one is on the can when you buy it, they have a habit of "walking") spray into the idle screw. If you can devise a makeshift seal around the snorkel, even say, would up tissue paper, will help pressure the cleaner through the idle passages.

LOL.........how long since it's been tuned up.......cap/ rotor/ wires/ plugs/ carb cleaned, air filter ?? Hey jus' askin'
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1. still checking but nothing obvious yet
2. idle speed normal around 800
3 distributor not moving , but i pulled the cap and checked the surfaces looked fine and rotor looked ok , but i pulled the coil wire and i looked slightly carboned , i went to scuff it up a little with sandpaper , but part of the metal tip came right off , something funky going on in the caps coil tower i think . thanks for putting me in that direction . i will definitely get a new cap and rotor .
4. possible , it used up about half a quart on the 3 day trip , but alot of miles . i'll check the plugs later.
5. thanks will do that if the other stuff does'nt take care of it .

would anything cause the caps coil tower to burn up besides age or corrosion ?

it is probably time for a tune up , thanks for asking . got three mopars and i slack on some things , sometimes .
 
Sounds like it is flooding. Giving it throttle gives it air, so it runs.
 
Sounds like you may have sucked some crap up in the fuel system when it got low. Remove the fuel filter and tap the inlet on some white paper and see if any crap comes out. If it does, it might be time to remove the tank and clean it out good. Just a guess on the internet.
 
thanks everybody all good ideas . i forgot to mention , but right before leaving to come back from carlilse . i replaced the muffler with a cheap one i found at carlilse , it was the right size , but no other info . it is new though . is it possible that the new muffler could somehow be causing this ? like wrong backpressure or something , i think i installed it in the right direction for flow . just a thought . only thing changed before the problem started .
 
Murray said:
Vacuum leak? Check timing, has it moved?
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6pak said:
Vacumm Leak.
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when i spray carb cleaner at the bottom of the carb the engine by the hoses and idle screw rpms go up . with air cleaner on and with it off . but also , when i spray carb cleaner into the top of the carb itself , same thing , the engine rpms go up . should i start with changing the carb to manifold gasket ? it has one of those thick cork ? style gaskets . i tried pinching each hose with needle nose pliers , no change in rpms .
 
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further update : changed cap and rotor and coil wire . seemed to be better for just a few minutes . then back to same conditions . also, there was some crud in the fuel filter , and restricted . which i replaced . again same result . though i am not ruling out crap from the tank .
 
oops left out the part where the vacuum hoses looked ok at carb base , but i trimmed the end of the small one anyway , and the bigger on that goes to the pcv valve , i pulled the valve off and put my finger over the hole and had great suction , but car stalled when i removed my finger .
 
update . replaced plugs and all old ones looked ok visually . brown residue , gaps were good . after that i drove the car for 10 miles . heavy on the pedal . when back , the idle rpms were up a bit from before , and the car stayed running even idling in gear , though it seemed low on rpm . after i got back i set idle rpm to about 750-800 and even though when put into gear it seamed really low rpm and really quiet . stayed running . short drive . seems ok , just maybe still to low when in gear . not sure . tried two different timing lights but couldn't get a reading . just flashes no line . ran great on the 10 mile though . really great . just the low rpm at stops . tried the carb cleaner again at base of carb . rpms went up a tiny little bit . then sprayed down the carb and it didn't raise rpms this time . it wanted to cut out from the spray .
 
Almost sounds like the timing is far retarded, Have you CHANGED the timing? Maybe the advance is stuck have you checked that?
 
Don't use carburetor cleaner to check for vacuum leaks. It can degrade vacuum hoses really quickly, but the biggest danger is finding a spark and causing an engine bay fire. I've seen it happen first hand. It burned right through a rubber fuel hoes with the engine running. Before we got it put out, it had burned just about everything in the engine bay that could burn. It was a huge repair. Use water in a squirt bottle.
 
I have the same problem on my 1964 AP5 Slant 6. Ihave changed points,plugs,Put a kit through the Carby, checked all of the vacuum lines and have just changed the manifold gasket. I am out of ideas. Did any one come up with a reason for this problem. Appreciate any help
 
MYAP5 said:
I have the same problem on my 1964 AP5 Slant 6. Ihave changed points,plugs,Put a kit through the Carby, checked all of the vacuum lines and have just changed the manifold gasket. I am out of ideas. Did any one come up with a reason for this problem. Appreciate any help
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For various reasons , i have not done anything since . it has been driving ok , when i do drive it . I really think it is the timing . i just haven't got around to trying anything yet . My gut feeling is that advancing the timing would , likely fix the issue . when you changed the points , did you set the Dwell ? and , did you reset the timing ? changing points and dwell changes the timing .
 
I have done all of the above. The car is fine when you first start off. But after 10 miles or so when you stop and turn it off and go to restart it thats when it refuses to idle.
 
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