Bad Hesitation Under Load Advice Needed

[Dobalovr]

Ok so finally went to pull Scorch into the shop Friday. Couple of pumps started up after not touched for last 4 months. Great go to move and whoa no power hesitates like crazy bucking popping through exhaust running like its on 7 cylinders. Ok so do the usual idles good revs up ok in park little stumble but holds 2000rpm ok. Under load it falls on its face. Here is what has been done so far:

Replaced cap rotor plugs wires - no change
Replaced coil no change
Checked firing order twice
Checked initial timing 10btdc at idle vacuum hose off n plugged
Checked vacuum hose on 22btdc at idle
Timing at 2000rpm vacuum advance 37 btdc total 47btdc
Has the vacuum solenoid disconnected as it has broken wire
Plugs black greasy look to them so running rich?
Replaced Holley with Eddy 1406 no change although idle smoother
Points condensor not changed
Brake booster has vacuum leak when pedal pressed
No other vacuum leaks can be found

So whats left?
Gonna swap out dizzy for electronic conversion kit and see if its that
Could the booster leak be the issue? Ill clamp off the hose
Burnt valves? Vacuum is steady at 12hg on ported 17hg on manifold
Timing mark not bouncing so chain not stretched?
Compression not checked yet as its a PITA

Need ideas please!!!
1970 Chrysler 300 with 440 727 Eddy 1406 everything else is stock

 

[cantflip]

oops... missed the carb swap... may be fuel separation... Try to get a sample into a container and see what you've got... stuff with ethanol doesn't sit well. Check you oil for fuel, may have a pump issue. But whatever you do stop throwing parts at her.

 

[Dobalovr]

Thanks J! Fuel could be crap looks like a newer fuel pump is on the car. The look of the fuel in the filter looks clear. Maybe ill try a remote tank and see if it improves. Sure feels like ignition though shakes and shudders under load no power.

 

[CanCritter]

what about that fuel pump rod wear that folks spout of on now and again here?

 

[rags]

my general rule with backfires is if it fires out the top it's lack of fuel. if it fires out the pipes it's ign. figure if it's firing in the pipes it's 'cause unburnt fuel is present there. crappy points? condenser? check the dwell? use a grounded test light into the plug wire boots at the cap to isolate dead cyl. mouse eat your wiring? i've seen the pictures. nice car.

 

[Dobalovr]

Thanks Rags the two bad backfires came through the carb when i cracked the throttle just a bit so it may be leaning out. The problem seems to be just off idle until it revs up (parked) in gear it can barely pull itself around. Maybe bad fuel pump like critter mentioned gonna test fuel pressure and change out points condensor stay tuned

 

[CanCritter]

have read so many issues in here re probs and those fuel pump rods honestly if l bought another 440 that's the first thing ld swap out whether it needed it or not...piece of mind deal...would do fuel pump same time so l could rule them both out and if rags advice is right would look to tank,sender and sock ect...check fuel lines ect...this is all basic stuff l would do first anyway just so l know it all works as it should...if there was still issues would look to engine...carb floats ect...think adding electronic ignition ect is wise move and get rid of the points

 

[65Fury440]

I'd try the easiest first, put some dry gas in it and fresh fuel on top of that.

 

[Dobalovr]

Ok so pull Scorch into the shop determined to isolate the hesitation problem. Bypassed the fuel tank ran clean fuel no change. Ok running out of ideas. Feels like ignition miss like something is just not firing. Check firing order for 5 th time pull the new plug wires wait a minute #4 plug wire seems odd...whats this arcing in the boot? WTF!! Brand new wires #4 is pooched. Replace wire turn key car is happy. FML! Go back to fuel from tank car still happy! Owner now happy! Sometimes its just that simple!

 

[cantflip]

Ok so pull Scorch into the shop determined to isolate the hesitation problem. Bypassed the fuel tank ran clean fuel no change. Ok running out of ideas. Feels like ignition miss like something is just not firing. Check firing order for 5 th time pull the new plug wires wait a minute #4 plug wire seems odd...whats this arcing in the boot? WTF!! Brand new wires #4 is pooched. Replace wire turn key car is happy. FML! Go back to fuel from tank car still happy! Owner now happy! Sometimes its just that simple!

Usually in fact... we just seem to have trouble seeing it in the moment.

Glad she's on her feet again...

 

[live4theking]

The simplest of things are often the hardest to find. Years ago my Dad (retired mechanic) and I were replacing the plugs, wires, points (ect.) in my 68 NYer. We took off down the road and it was running horrible. I looked at him and asked if he mixed up a couple of wires, if looks could kill. That was exactly what happened though.

 

[Fury440]

Glad to hear you got her fixed! Years ago my Fury had a dead battery. I jump started it, drove around and all was well until the next morning, dead battery again. So, new battery, worked for a couple of days, then dead battery again. So rebuilt alternator, and a jump start. This worked for nearly a week, then dead battery. I played this game of throw parts until winter when I parked the pig in back yard. She sat for 20 years. As I was taking everything apart I discovered my "bad battery, bad alternators, bad voltage regulators" hiding in thed bulkhead connector.

If only I had used my multimeter instead of my wallet to trouble shoot. What irritated the most, I'm an Electrical Engineer and darn well know better. BTW, pin 16 on a '70 car is the main battery feed and if it gets dirty, it gets hot and burns the connector. If left too long, it burns the whole car.

 

[cantflip]

If only I had used my multimeter instead of my wallet to trouble shoot. What irritated the most, I'm an Electrical Engineer and darn well know better.

Anyone who says they have never done something really silly and embarrassing even though they knew better is A LIAR. Thanks for sharing, I appreciate the insight and consequences...even though I know better too. Cant count the number of crispy connectors I have redone over the years, often due to a little corrosion somewhere... I often have found poor ground connections are damaging to electronics too...

I still have not had the time and energy to check out the Imperials as I would like to...and some of the wiring in this generation of cars has caused me problems in the past. I do not want to let myself get lazy and comfortable about this stuff.

 

[Dobalovr]

pin 16 on a '70 car is the main battery feed and if it gets dirty, it gets hot and burns the connector. If left too long, it burns the whole car.

Eep! That will give me no end of sleepless nights now! Ill check that bulkhead connector out this weekend. Gonna be 20 degrees Friday woohoo!