MSD Atomic EFI: Tuning Tuning Tuning

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FSJ Guy
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by FSJ Guy »

babywag wrote:
Dr. Marneaus wrote:Well, bumping fuel pressure in either direction is like a 3 minute operation, so, I guess it couldnt hurt to try, and see if drivability changes, and go from there.

just trying to think about the times I have tuned it and it did not exhibit the major stumble on cold start issues. I also feel like im getting really poor fuel economy right now though, but thats just speculation. I will have the opportunity to gauge that this weekend with a few hundred miles on the highway.
Maybe start a list, write down setting changed and old/new values each time.
Tuning software takes care of this for you automagically, so it's easy to recall when/what was changed in a tune.
Don't change to many things @ once, or you'll never know which specific setting made the most difference(good/bad).

Compare results, frequency of issue, when it happens, etc. etc.
Might help you nail it down, or lessen/hopefully eliminate it?
X2.

When tuning, I try to ONLY change one thing and I ALWAYS log what I've changed. I even printed out a log sheet to keep my notes on. Because I'm nerdy like that.
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Tatsadasayago
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Tatsadasayago »

X3
If you don't record or write down your changes...they never happened.
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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Dr. Marneaus »

I've been keeping a little notebook these past few weeks on this exact topic.

However, last night I bumped fuel pressure to 45. Initial impressions are good. Started up well, no hesitation on initial driving. However 2 minutes into the drive it did have a hiccup, but that was all. I'll be driving to Graeagle with it this afternoon, and will pay attention.
Well it ain't just the smoke and the traffic jam that makes me the bitter fool I am But this four-wheel buggy is A-dollaring me to death.
For gas and oils and fluids and grease, And wires and tires and anti freeze....And them accessories, Well honey, that's something else.

FSJ Guy
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by FSJ Guy »

Another thing I do is log what changes (if any) I experienced as a result of the modification. That can be just as helpful.

Happy tuning!
Ethan Brady

http://www.bigscaryjeep.com

Jeepless, but I still have a lots of old parts in my garage!
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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Dr. Marneaus »

FSJ Guy wrote:Another thing I do is log what changes (if any) I experienced as a result of the modification. That can be just as helpful.

Happy tuning!
Yup yup. What I've been doing is writing down how it performs each time I start it up and if anything else happens while driving it. Noting things that are the same AND things that Are different
Well it ain't just the smoke and the traffic jam that makes me the bitter fool I am But this four-wheel buggy is A-dollaring me to death.
For gas and oils and fluids and grease, And wires and tires and anti freeze....And them accessories, Well honey, that's something else.
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Tatsadasayago
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Tatsadasayago »

Does your Atomic system have an OBDII compliant data port, or serial data port? I ask because I think it would be prudent to log all data from cold start until the hiccup thing happens. The cause is there, ya just have to spot it in the data stream...
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babywag
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by babywag »

Tatsadasayago wrote:Does your Atomic system have an OBDII compliant data port, or serial data port? I ask because I think it would be prudent to log all data from cold start until the hiccup thing happens. The cause is there, ya just have to spot it in the data stream...
I'm not aware of any ODBII compliant aftermarket EFI TBI system.
Some have data logging support if they are laptop tunable. Some have CAN bus support for aftermarket data loggers.
I've asked a few times earlier in the thread, it seems this system does not have the ability out of the box to log data.

That is a major drawback IMHO to these aftermarket systems.
Say what you want about old school ODBI GM TBI systems, but they are far superior in both cost/tuning abilities vs. aftermarket.
As many folks find out there is no such thing as "self tuning" systems, it is just a marketing ploy.
They all require "tuning" to run properly.
-Tony
'88 GW (aka Babywag)

FSJ Guy
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by FSJ Guy »

Yes. And I think Dr. Marneaus has said previously that the Atomic EFI doesn't have capability for datalogging. :- (

That is a big hindrance, IMHO. Without data, we're all just making WAGs. (Wild *ss Guesses)
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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Dr. Marneaus »

Okay so I drove about 200 miles this weekend and it did all the exact same stuff. Including the initial drivng hiccups which seemed worse. It doesn't matter if the engine warmed up or not. Hop in start driving and within like 100 yrds it bucks and tries to die unless you let off the gas. If I stay on the gas and either try to accelerate MORE or just keep trudging through it, it'll get worse and stall. If I let off the gas, give it a sec, and try again, its a little better or equal. It seems like it's struggling until it hits like 2000 rpm for the first time, then all is well.

Also I'm getting awful mileage. I thought I noticed it on those last two trips where I towed the camper (davis lake and ft. churchill) but chalked the 8pmg up to the fact that I was pulling a trailer even though win my carb I would get 10-11mpg towing. This trip without towing and doing mostly 55-60mph I got about 9.5mpg which ain't right. Again, carbed I would get 1-12 on the highway and have pulled in as much as 14 under ideal conditions of sustained highway driving.

When I took the trip to Susanville a few months back loaded down with camping gear fire wood water etc I got like 13 mpg which included miles of slow uphill dirt roads, lots of grades, and lots of smooth highway.

On a positive note, the idle RPM's are right on target.

I think my next step now that I've fiddled around here is to try to go back to that tune, which was the 400 CID one, and see how it performs.

Right now, I'm running 360 CID, 45PSI, Idle AFR 13.6 or 13.7, Cruise AFR 14.5 (seems to have no negative effect), and WOT AFR is 12.5. Power valve i think is set to 30%, and pump squirt is set to 15%.

Planning to go to 400CID, 25PSI, and then keep the rest where it all is and see how things pan out.

Another related but unrelated item is that maybe 1/3rd of the times i shut the engine down now, the starter and flex plate are not aligned and I get the awful grind. I have to put the truck in gear, rock it or let it roll a tiny bit, and then try again. I only ever used to get this if i killed then engine while it was at like 1100 RPM. Seems like it wouldnt stop in a natural spot. Now, when I'm idling, my RPM is about 850, and it;s doing the same thing. I try my best to shut it down with the RPM's in the 900 range which seems to keep it from grinding, but I found it odd that it's stopping in a weird spot now that I have it all adjusted as such.
Last edited by Dr. Marneaus on Mon Dec 05, 2016 10:39 am, edited 3 times in total.
Well it ain't just the smoke and the traffic jam that makes me the bitter fool I am But this four-wheel buggy is A-dollaring me to death.
For gas and oils and fluids and grease, And wires and tires and anti freeze....And them accessories, Well honey, that's something else.
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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Dr. Marneaus »

Please excuse the typos above this was all written on my phone
Well it ain't just the smoke and the traffic jam that makes me the bitter fool I am But this four-wheel buggy is A-dollaring me to death.
For gas and oils and fluids and grease, And wires and tires and anti freeze....And them accessories, Well honey, that's something else.
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az chip
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by az chip »

Question from ignorance. Are these units supposed to be paired with a certain kind of cam?
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Tatsadasayago
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Tatsadasayago »

Andrew, it sounds like your flex-plate ring gear is out of round and your starter drive gear is getting hung up.
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Tatsadasayago
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Tatsadasayago »

Oh, and since I came into some unexpected gas money, I was thinking about running up the hill and seeing if I could help you sort out the Atomic issues. What's your schedule next weekend? I need to see me some Reno in the snow :)
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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Dr. Marneaus »

Tatsadasayago wrote:Oh, and since I came into some unexpected gas money, I was thinking about running up the hill and seeing if I could help you sort out the Atomic issues. What's your schedule next weekend? I need to see me some Reno in the snow :)
Now thats an idea! lol.

This weekend (the 10th) i have company in town and am kinda busy with a christmas party as well.

Next weekend, however, I'm free.

I'm sure we could round a few of the fellas up and hit a trial, too.
Well it ain't just the smoke and the traffic jam that makes me the bitter fool I am But this four-wheel buggy is A-dollaring me to death.
For gas and oils and fluids and grease, And wires and tires and anti freeze....And them accessories, Well honey, that's something else.
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Tatsadasayago
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Tatsadasayago »

That may work out! I'd have to bring the baby jeep or the Altima since the Blair is immobilized. :(
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babywag
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by babywag »

az chip wrote:Question from ignorance. Are these units supposed to be paired with a certain kind of cam?
Not really, however the stock '80's AMC 360 were pretty anemic. Low compression, small lift cam, etc.
Tuned to pass emissions w/ bunch of smog 'bits mandated by EPA that made them even worse.

An RV grind cam or better really wakes them up, as well as the normal things like dual exhaust/4bbl intake & carb or EFI, etc. etc.

A stock 360 engine vs. one with an rv grind cam, is night/day.
-Tony
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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Dr. Marneaus »

Tatsadasayago wrote:That may work out! I'd have to bring the baby jeep or the Altima since the Blair is immobilized. :(
Well in that case, you might as well stay home!

Just kidding, lol.
Well it ain't just the smoke and the traffic jam that makes me the bitter fool I am But this four-wheel buggy is A-dollaring me to death.
For gas and oils and fluids and grease, And wires and tires and anti freeze....And them accessories, Well honey, that's something else.
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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Dr. Marneaus »

So, i adjusted things.

Went back to 30psi, which is the lowest I can go with the regulator (well, it hit 28, but the adjustment screw was loose in the threads at that point), and set it to 400CID.

I havent driven it yet, but I fired it up twice on below freezing temps, and mannnnnn oh man did it idle well. I'm probably jumping the gun with that statement though, I'm sure once it drives a bit it'll start acting-up just like normal.

Hopeful to drive it to work tomorrow or Friday.
Well it ain't just the smoke and the traffic jam that makes me the bitter fool I am But this four-wheel buggy is A-dollaring me to death.
For gas and oils and fluids and grease, And wires and tires and anti freeze....And them accessories, Well honey, that's something else.

FSJ Guy
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by FSJ Guy »

It's a "start"!

(Sorry, I couldn't help it....)
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Renodemona
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Post by Renodemona »

I think I'm available during the day on the 17th. I really need to have the bung for my 02 sensor welded in. It's been like 2-1/2 years though. I'm also thinking of going to an in-tank pump (probably the tanks one Dr Marn did). I'm also thinking of the MSD atomic. But you know, money...
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