'67 300 440 engine issues

kenfyoozed

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Car seems to be running fine until you stop it. Some times it diesels for 1-2 seconds other times it doesn't. This is not consistent. Also at times it is hard to start after its warm. Sy i go to the store, and come back out to head home it may take 2-3 mins of 10-15 second cranks to get started. Once started it will run fine as long as its running. Any suggestions as where to start? Sadly diagnostic or engine work is not my strong point but I can follow the manuals and instructions. Just need to get my head wrapped around what could be going on. My first thought was fuel issues..... Maybe a weak pump... not getting the fuel to the carb to start and allowing the engine to create a vacuum to draw fuel after its turned off to allow the dieseling....?
 
Check the routing of the fuel lines under the hood and make sure that they are not running really close to the exhaust manifolds. I have had experiences with 440's that when they are hot, the fuel in the carb percolates making the car hard to start.
 
Sounds like it may be too advanced. Check your ignition timing first, and/or back it off a few degrees and see if that helps.
 
The winter mix gas boils easily and floods the engine. It doesn’t need more gas, it needs more air.

Next time when you go to the store try this, push the gas pedal down 1/3 of the way and hold it do not let it up or pump it. Crank the engine until it starts. Should start easier.

Another time when warm at the store when you park it open the hood and leave it open when inside. You can open all the way or just part way like 6” with a block of wood. Then see how it starts.

Report back with results please.

Also dieseling could be idle speed too high, so check that and lower it some if you can. Or the easy thing is to turn off the key while in gear, then put it park.
 
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If you want to do a simulation, including driving it to the store and such, for a complete re-creation, that's fine. Of you could drive it to the store parking lot, park, sit 15 minutes (or as appropriate), then get out, raise the hood, remove the air cleaner, move the throttle to check for accel pump shot or "percolation" of fuel into the venturi area, then put it back together and try to start it.

OR you can do the same amount of driving, then pull back into your driveway and look around for the same things.

The "1/3 down accel pedal depression" technique is straight out of the Chrysler owners manual.

Unless the float level has become way too high, after the hot soak there should be enough fuel in the float bowl to run the accel pump (which usually feeds from the bottom of the float bowl). Enough fuel to get the engine started and run long enough for the fuel pump to re-fill the front fuel line with new fuel, hopefully.

Here's what I'd start with. Check for vacuum leaks in the vacuum hoses and connections. ALL of then, under the hood. Check the carb mounting nuts for correct torque, too. (a vac leak there will be below the throttle blades, so unregulated amounts of air getting into the intake manifold!)

How do the power brakes work? Any extra hisses and such when the engine is running?

Verify point dwell with a meter. After that, verify the engine's base ignition timing, then the idle speed and mixture. In THAT order! And check to see that the vac advance can will hold vacuum.

Possibly not an issue, but shoot some carb cleaner into the pcv valve, shake it, then rinse it out. Repeat until the fluid comes out clean. I've not had a slightly clogged pcv vale cause any issues, but keeping it cleaner and working is always good.

Worst case scenario is that the factory Holley (350 horsepower engine) might need to be kitted. Attention to if the secondaries are fully closed at base idle, or as closed as they need to be, after the primaries are correctly adjusted.

What kind of shape are the spark plugs in? Just curious. Plug wires too?

I'm suspecting it's a vac hose that has a small crack and leaks at certain underhood ambient temps. It could also be that the carb is having issues and has partially fouled some of the spark plugs, but I haven't had any issues like that (although carb issues are always a consideration). You might also check the innards of the distributor for the condition of the breaker plate ground wire, for good measure.

Key thing is to be methodical in the examination of possible contributors to the starting problem.

Keep us posted,
CBODY67
 
High toque mini starter also works wonders. The days ive had my car just crank the high torque just spins her over so much easier and faster. I know how the old stock starter just punishes you as soon as you hit the key at times.
 
I always like the old "Highland Park Hummingbird" sound, myself. I did hear some that obviously had some "build tolerance stack" issues that just sounded "not good". The new mini-starters sound neat . . . same sound just at a higher pitch as its turning faster. And more consistently "good", too.

CBODY67
 
Most of those old original starters have been monkeyed with so much I would break them down and scrap the parts. Buy a new style starter for a Dodge truck circa 1999.
That's not your problem. You have tune or heat problems. If it has electronic ignition it could be traced back towards the pick up coil. I have no way to test this except by process of elimination of everything else, then bite the throw parts at it method and try a replacement. Of that fixes it great if not you have a good spare pick up coil for your glove box.
 
As already noted, my money is on timing. Its still too cold for it to be a hot fuel/percolation problem.

Dieseling or Run-on is generally caused by 2 things. Timing is incorrect ( advanced too much) or the idle is set too high allowing the carb throttle blades to stay open more than they should which can allow the engine to continue to suck gas from the idle circuits of the carb and it'll keep running on due in part to any heat/hot spots in the engine that ignites the air/fuel mixture.

If timing is too advanced and you drop back the timing, you will most likely notice the engine RPM drop at idle. If this is the case, you may need to idle the engine up a bit to compensate UNLESS the idle is already set too high and is contributing to the problem.

It is also possible that the timing chain has gotten sloppy and can also effect timing at the distributor. This can be checked as well IF the above are not the problem.

So this would be the easiest & first thing I would check - timing & idle setting.

Next could be a leaking carb that is dripping into the intake. When you shut the engine down, pressure in the fuel line can still push gas and if it is dripping internally and dumping into the intake or you have a bad gasket, it is the same as flooding the engine and you have to put the gas pedal to the floor when starting to clear it. But, you would most likely have a smell of gas or possibly see gas dripping on the outside of the carb from the throttle blade shaft if severe enough.

As suggested, do not allow the engine to continue to run after the key is shut off. You can severely damage the engine. Put the car in gear just prior to shutting the car off to pull down the engine and then put the trans in Park.
 
"Dieselling" became an issue in the later '60s as many base idle setting began to use idle speeds above 700rpm or so. This was in the "points ignition era", so the yearly (15K miles/year) tune-up was done to fix the problem. New points, condenser, and spark plugs. Spray some carb cleaner into the carb to clean the venturis and throttle bores. Set the timing to specs, along with the base hot idle speed/mixture. Seemed that the GM and Ford vehicles had more issues in this area, rather than Chryslers, from what I remember.

Until you get it figured out, plan on turning off the ignition with the car in gear, then put it in Park. No dramatic "after-run" that way. Also make sure the plastic fast idle cam is still intact and moves freely, for good measure.
 
WINTER FUEL percolates much easier than summer fuel. They do this so cars will start and run in the cold weather. When you park it hot it heat soaks and percolates the fuel and floods the engine. It needs air to start, so don’t pump the pedal.

I read all the replies and they all have some value, but let’s try the simple things first.

I own 15 BB mopars and drive a dozen of them and this happens to me also.
 
Not a bad idea to check the length of your rod at this time.:lol:
Your fuel pump pushrod that is...
 
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I've been waiting for this fix. I'm with Matt on this one. Kinda ah PITA to swap out but you probably won't live long enough to ware out another one. slather up the new push rod with packing grease before you insert it and bottom it into the hole when you do. (The grease will hold it in position long enough to insert the fuel pump lever underneath it) The pic JCT iz showing US iz enough ware on ah push rod to leave you on the side of the road scratching your head, Happy Trails, Jer
 
IMHO, you have two problems that may or may not be connected. You need to do some diagnostics before you start just throwing parts at it.

"Dieseling" or run on is usually caused by some sort of hot spot in the combustion chamber. While it's possible that incorrect timing is causing some sort of overheating, it's more likely something else. Still worth checking it, as it's a simple check with a timing light. Next, I would pull a couple plugs and take a good look at them. Are they the correct heat range?? Is the gap right? Electrode rounded off? Is the color right? Plug color will tell you if you have a lean condition. Google it if you don't know how they should look. One thing that nobody asked is if the engine is running hot.

Next, the starting issue. You haven't mentioned if you have an electronic ignition or points. There's different issues to check. Again, timing check and a look at the plugs since you have the other issue. Look at the distributor cap, rotor, plug wires etc. Everything look OK? Any carbon tracking under the cap? If it's points, is the gap correct? Next test I would do is a very simple fuel volume check. Takes a coffee can and some rubber hose. Disconnect the fuel line after the filter and place a rubber hose into a coffee can. Disconnect the coil wire so the engine doesn't start and have someone crank the engine over. There should be a good shot of gas every time the engine turns over. If it's just a trickle, it's probably the pump or the pump rod (as mentioned).

These are the first things to check. It may be something else, but these are some places to start.
 
I have an electronic ignition.

I have just checked the timing. It seems to be spot on 12.5*B.T.C.- I am going by the FSM without C.A.P

The idle speed was set high. Higher than what I though it sounded---1200. I reset it to 700. It seems to crank easier but haven't taken it for a drive yet. Will do that in a moment as I head to work.
 
1200 RPM idle is certainly high enough to cause dieseling.

All the concerns for not enough fuel would be causing other problems besides hot start. But it’s good to check everything.
 
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