Hello everyone,
So I decided to and bought the MSD Atomic EFI system for my mopar 440. This motor, as of last year, is a fresh rebuilt, bored .30 over, Isky cam (within spec, but at the higher limit of the atomic), Edlebrock aluminum heads and intake.


Last year I was having heat issues...... long story short, I had the car checked out and my timing was off. With the timing fixed, the car would sit perfectly at 180 whether on the expressway or idling at a stop light.


This spring, I installed the MSD Atomic EFI system. Pump is mounted in the tank, returnless, and I am NOT controlling timing with it. Nothing else has changed, have not touched timing or anything.


I'm noticing now, driving down expressway engine will be around the 190-195 range....... if I idle in my garage for a while, it creeps up to 210ish+.


Thoughts on this? Could it be running leaner, causing it to run hotter?


Thanks!
Phil

 

Well you should KNOW if it is lean. Doesn't the atomic have some way of monitoring AF ratio

 

Just looked it up, really neat system.

What does the hand held controller tell you, if anything?

With out getting into all the usual stuff, shroud, pulley size, pump vanes etc. I don't think it's too bad.

That highway temp is great for a clean burn and to make power, the higher temp, don't forget, with a pressurized system can go far above boiling and some of the new cars normally run hotter than what you posted.

For me I would be more interested in knowing what pressure the system is running at, low and high, to see if I'm below my relief pressure on my cap.

 

Phil, Check the plugs... Sounds to me like you might have it a little lean. I agree on the A/F ratio at this point....
Or just take about 4* of timing out of the motor and see if that helps...