MSD Atomic EFI: Tuning Tuning Tuning

[babywag]

I would definitely get your Duraspark module wired up correctly. As mentioned, it is not designed to run on less than 12V. That definitely could be the reason for your misfires. The EFI could be trying to compensate for this and that is why you're seeing erratic idle RPMs.

The engine must be in good running order so the EFI can do it job. :- )

The Duraspark system is indeed designed to run @ less than 12v. It should only get 12v while cranking. Running one continuously @ 12v will result in module failure.

[Flip]

On the power issue, is it just during hard acceleration, or is the overall power down compared to when it was at 50psi fuel pressure.

I think it needs more fuel pump squirt and power valve, but if overall power is down, we probably need to do a global change, by changing displacement first. Then run it like that for a bit.
If you are going to be out for a while Probably best to start this when you get back.

It was absolutely most evident under WOT or high load conditions (climbing an on ramp and trying to gain speed, etc). I felt like it was even better under highway cruise though, like with the 50 psi I felt I could just barely get into the gas and it would pull from 65 up to 75 with ease, but when it was lower fuel pressure I feel like I had to get into the pedal allt more to gain speed on the highway.

That all could have just been an illusion tho

Probably not. The global strategy controls injector timing. Even though it monitors fuel pressure, it doesn't have the capability to make global changes based on just reducing fuel pressure.
Go ahead and bump up your Power Valve setting to 30% and retest for both hunting, and WOT power. If better but not great, go to 35% test again. Don't go above 35%.
Let us know.

During the "tuning" phase, it is very important to only make one change at a time, and test for both of the issues. So please, only do this test.
Depending on this outcome will base the next change, as needed.

[Stuka]

I would definitely get your Duraspark module wired up correctly. As mentioned, it is not designed to run on less than 12V. That definitely could be the reason for your misfires. The EFI could be trying to compensate for this and that is why you're seeing erratic idle RPMs.

The engine must be in good running order so the EFI can do it job. :- )

The Duraspark system is indeed designed to run @ less than 12v. It should only get 12v while cranking. Running one continuously @ 12v will result in module failure.

Every single diagram I could find for Ford and AMC (including my own truck when I converted it to HEI) has a straight 12V going to the ignition module. With the resistor being after where it grabs power. The coil gets less than 12V yes, but not the module.

If you guys have a diagram that says otherwise, please post it up.

EDIT: Should note this goes for Duraspark I and II style boxes.

[babywag]

The Duraspark system is indeed designed to run @ less than 12v. It should only get 12v while cranking. Running one continuously @ 12v will result in module failure.

Every single diagram I could find for Ford and AMC (including my own truck when I converted it to HEI) has a straight 12V going to the ignition module. With the resistor being after where it grabs power. The coil gets less than 12V yes, but not the module.

If you guys have a diagram that says otherwise, please post it up.

EDIT: Should note this goes for Duraspark I and II style boxes.

My bad I was thinking the coil voltage...been so long since I actually ran one of them. Running the coil voltage @ 12v is what fries the duraspark modules.

[Dr. Marneaus]

so are we suggesting I dick around with my duraspark, or that I install the HEI. OR that I do neither and then check the power valve adjustments.

[REDONE]

Well, I'd say to go full MSD and get the dizzy and box recommended for the Atomic. My Duraspark was fine until the box died and then two replacement boxes died also. My streetfire was fine to replace that until I wanted TBI with spark control. My HEI is ok, but it barely fits against the power steering pump. I think you have the ability to have computer controlled ignition, any steps you take that don't lead to using it are steps off the shortest path to where you ultimately will want to be. Regardless, I'm enjoying following along with your journey!

[Dr. Marneaus]

Well, I'd say to go full MSD and get the dizzy and box recommended for the Atomic. My Duraspark was fine until the box died and then two replacement boxes died also. My streetfire was fine to replace that until I wanted TBI with spark control. My HEI is ok, but it barely fits against the power steering pump. I think you have the ability to have computer controlled ignition, any steps you take that don't lead to using it are steps off the shortest path to where you ultimately will want to be. Regardless, I'm enjoying following along with your journey!

all MSD would be cool for sure but thats definitely a $500 investment.

[Flip]

so are we suggesting I dick around with my duraspark, or that I install the HEI. OR that I do neither and then check the power valve adjustments.

Just try the Power Valve adjustment. 30% first, then 35%.
Note what happens with both settings, in regards to the two biggest issues.

1). Hunting when cold
2). Lack of overall power, and acceleration

30 may be better, 35 may be over the top. Or it may be better than 30 overall. Or it may be totally the wrong direction. Let's see what happens.
That will tell us a lot about the next step.

[az chip]

I was speed reading. I should not. Have plug wires been checked? What kind how old are they? My spark plug wire was shot and I had all kinds of weird issues. Before you spend a ton of money I have a brand new Jeep ignition module and/or a MSD-6 that you can try out if you want. Any way, my offer stands if you want this stuff just say the word. I am not using it right now.

[Dr. Marneaus]

so are we suggesting I dick around with my duraspark, or that I install the HEI. OR that I do neither and then check the power valve adjustments.

Just try the Power Valve adjustment. 30% first, then 35%.
Note what happens with both settings, in regards to the two biggest issues.

1). Hunting when cold
2). Lack of overall power, and acceleration

30 may be better, 35 may be over the top. Or it may be better than 30 overall. Or it may be totally the wrong direction. Let's see what happens.
That will tell us a lot about the next step.

Hi. I got home from Chicago at like 1am yesterday, so after work I had a few minutes to fiddle around.

Adjusting to either 30 or 35 did nothing noticeable in regard to cold start hunting.

I didn't have the opportunity to let it warm up and drive it yet.

[babywag]

for cold engine idle issues aren't there any choke settings to change?

a power valve setting suggests it's for transition from cruising to heavier load(like a carb), unlikely it would have any effect on idle quality?
it's function should be to dump more fuel when needed when vacuum drops.

[Flip]

so are we suggesting I dick around with my duraspark, or that I install the HEI. OR that I do neither and then check the power valve adjustments.

Just try the Power Valve adjustment. 30% first, then 35%.
Note what happens with both settings, in regards to the two biggest issues.

1). Hunting when cold
2). Lack of overall power, and acceleration

30 may be better, 35 may be over the top. Or it may be better than 30 overall. Or it may be totally the wrong direction. Let's see what happens.
That will tell us a lot about the next step.

Hi. I got home from Chicago at like 1am yesterday, so after work I had a few minutes to fiddle around.

Adjusting to either 30 or 35 did nothing noticeable in regard to cold start hunting.

I didn't have the opportunity to let it warm up and drive it yet.

Glad the trip went well.

OK perfect, that is exactly what I was hoping. It means there aren't any major issues we need to worry about.
When you welded up the shaft on the exhaust valve, did you remove the blade?

When you get a chance, run a grade and see what happens with power. You can just do this once at 35% if you don't have the time to mess around.
It's either going to be a noticeable difference or not. We aren't looking for maximum power yet. We just want to know does it make a difference that you can tell. So don't think this one step is going to fix everything. But we need good input to know where to go from here.

Also, if you want to mess around with the adjustments to see what does what, by all means, go ahead. If you get really off whack, just hit the reset.
Take a note pad with you, and write down what difference each change makes.
There is nothing "magic" about this, and you'll learn a lot from the experience.
I usually tune on the road, and then make a tweak here or there over the next few weeks if needed.

[Dr. Marneaus]

for cold engine idle issues aren't there any choke settings to change?

a power valve setting suggests it's for transition from cruising to heavier load(like a carb), unlikely it would have any effect on idle quality?
it's function should be to dump more fuel when needed when vacuum drops.

That was kind of my understanding too, but i've never owned a carb with a power valve so the equivalent function is unknown to me.

[Dr. Marneaus]

Just try the Power Valve adjustment. 30% first, then 35%.
Note what happens with both settings, in regards to the two biggest issues.

1). Hunting when cold
2). Lack of overall power, and acceleration

30 may be better, 35 may be over the top. Or it may be better than 30 overall. Or it may be totally the wrong direction. Let's see what happens.
That will tell us a lot about the next step.

Hi. I got home from Chicago at like 1am yesterday, so after work I had a few minutes to fiddle around.

Adjusting to either 30 or 35 did nothing noticeable in regard to cold start hunting.

I didn't have the opportunity to let it warm up and drive it yet.

Glad the trip went well.

OK perfect, that is exactly what I was hoping. It means there aren't any major issues we need to worry about.
When you welded up the shaft on the exhaust valve, did you remove the blade?

When you get a chance, run a grade and see what happens with power. You can just do this once at 35% if you don't have the time to mess around.
It's either going to be a noticeable difference or not. We aren't looking for maximum power yet. We just want to know does it make a difference that you can tell. So don't think this one step is going to fix everything. But we need good input to know where to go from here.

Also, if you want to mess around with the adjustments to see what does what, by all means, go ahead. If you get really off whack, just hit the reset.
Take a note pad with you, and write down what difference each change makes.
There is nothing "magic" about this, and you'll learn a lot from the experience.
I usually tune on the road, and then make a tweak here or there over the next few weeks if needed.

Got it. I'll try warm it up and go for a ride in the next few days.

When we welded the flapper I did indeed remove all parts. It was just a metal donut with 2 shaft holes on the sides, and we welded those shut as well.

[FSJ Guy]

A power valve does what its name suggests. During the "olden" days of carbs, the valve would open during high engine loads, allowing the mixture to richen (more gas) and thus, give you more power. The apparent setting on this system mimics that feature.

Hopefully minus the "blown" power valves if your engine backfires! LOL!

[Dr. Marneaus]

Okay so the results of my highly scientific butt dyno tests are as follows;

First off still no change in hunting or miss.

So I fired it up let it idle a few minutes and hit the road. I drove down and then back up the hill to my house.

Then adjusted the power valve to 30% and repeated.

I noticed no real 'off the line' improvement.

Otherwise it felt pretty similar. But I did a little test where I was moving up hill at 50mph then kicked it in the guys and counted how long it took to get to 60, from the same location for both settings.

With the power valve at 20% it took 13 seconds to gain those 10mph.

With it set to 30 it only took 9-10ish

So there was a minor improvement but I really didn't feel it, I only counted it that one time.

I was tired (12 hour work day) so I parked it and retired for a cocktail and a cigar.

[Tatsadasayago]

Sure sounds to me like a leanout under load Bro.

[nightglide]

I know I had to add a bunch to my accel setting on the fitech. I've heard amc's like a bunch there....even the diy tbi guys need to add lots there.

[Dr. Marneaus]

I know I had to add a bunch to my accel setting on the fitech. I've heard amc's like a bunch there....even the diy tbi guys need to add lots there.

I haven't had any issues on take off.

What was yours doing that made you adjust the pump squirt?

[nightglide]

Would fall flat on its face if you stabbed it from idle