1970charger440
Member
I've been chasing a problem for months. 1970 charger 440 restored fairly stock. 3000 miles since rebuild 440 and restoration. Stock manifolds, electronic ignition, but changed to Holley sniper EFI after problems with vapor lock. Atermarket AC. Car ran great for 2 years, then one day it ran rought all of a sudden, and I haven't been able to drive it since. When I start the car is runs fairly well. There is a slight hesitation when you accelerate quickly and can lead to a backfire. As the car warms up it gets worse. Car will idle till about 120 degrees and then you have to keep feathering the pedal to keep it running. At full temperature (165) it will only run above 2000 rpm. if it gets below that it pops and backfires and dies. Seems to run smooth at high RPM.
I started changing parts on ignition system.
- coil (2 new ones)
- ingition module
- voltage regulator
- balast resistor
- distributor and timed to stock (5 degrees)
- tested spark plug wires. Replace a few questionable ones.
Then to charging system
- new battery
- new alternator
- replaced battery ground
- added firewall and engine grounds
Fuel system
- cleaned lines
- changed pressure regulator 3X
- sent sniper back to Holley. They said it checked out fine.
- sent Holley data recording. They said it is getting air or missing fuel.
- moved sniper wiring away from ignition system and relocated coil to firewall.
- changed out O2 sensor.
- re-gasketed exhast manifold at block and pipe.
pressure gage at EFI reads 58lbs very steady. When you punch the throttle it moves but only drops a pound or two. Seems the pump and lines seem to be keeping up. All the lines worked fine before. No leaking. Return runs about 1.5lbs of back pressure. I don't imagine that air could come in between the pump and the EFI or I'd see a leak. I've tightened and checked lines between tank and pump. Air getting in the line doesn't seem to equate to the drastic difference between cold and hot. Why would fuel be missing if gage reads well?
The motor has developed a "tick". I think it is from the EFI system. I pulled my valve covers and felt all of the rods and rotated them, no slack. Also ran the car with valve covers off and clearly no ticking at the rockers.
I'm at a loss. Would love to drive my car again someday
I started changing parts on ignition system.
- coil (2 new ones)
- ingition module
- voltage regulator
- balast resistor
- distributor and timed to stock (5 degrees)
- tested spark plug wires. Replace a few questionable ones.
Then to charging system
- new battery
- new alternator
- replaced battery ground
- added firewall and engine grounds
Fuel system
- cleaned lines
- changed pressure regulator 3X
- sent sniper back to Holley. They said it checked out fine.
- sent Holley data recording. They said it is getting air or missing fuel.
- moved sniper wiring away from ignition system and relocated coil to firewall.
- changed out O2 sensor.
- re-gasketed exhast manifold at block and pipe.
pressure gage at EFI reads 58lbs very steady. When you punch the throttle it moves but only drops a pound or two. Seems the pump and lines seem to be keeping up. All the lines worked fine before. No leaking. Return runs about 1.5lbs of back pressure. I don't imagine that air could come in between the pump and the EFI or I'd see a leak. I've tightened and checked lines between tank and pump. Air getting in the line doesn't seem to equate to the drastic difference between cold and hot. Why would fuel be missing if gage reads well?
The motor has developed a "tick". I think it is from the EFI system. I pulled my valve covers and felt all of the rods and rotated them, no slack. Also ran the car with valve covers off and clearly no ticking at the rockers.
I'm at a loss. Would love to drive my car again someday
