MSD Atomic EFI: Tuning Tuning Tuning

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letank
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby letank » Fri Apr 13, 2018 8:50 am

babywag wrote:FYI you can use an IH distributor cap to keep your male hei wires.
Just need to file a slot like the stock DS has for the little locator clip in base.
Part# AL-482


Cool, thank you.

As for datalogger, back to simple current monitoring, voltage drop is probably the culprit, a simple voltmeter wih cables securely clipped at the critical location and unit tapped to the windshield. Our voltmeter solutions are usually on the master circuit, not the auxiliary wiring to the distributor.

HEI requires a clean source of current, it has been recommended a relay feed from the battery with 12 gauge wires...
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby Stuka » Fri Apr 13, 2018 9:37 am

letank wrote:
babywag wrote:FYI you can use an IH distributor cap to keep your male hei wires.
Just need to file a slot like the stock DS has for the little locator clip in base.
Part# AL-482


Cool, thank you.

As for datalogger, back to simple current monitoring, voltage drop is probably the culprit, a simple voltmeter wih cables securely clipped at the critical location and unit tapped to the windshield. Our voltmeter solutions are usually on the master circuit, not the auxiliary wiring to the distributor.

HEI requires a clean source of current, it has been recommended a relay feed from the battery with 12 gauge wires...


I normal volt meter won’t detect small transient changes. You would need a scope with a pretty fast scan rate.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
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babywag
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby babywag » Fri Apr 13, 2018 10:27 am

letank wrote:

HEI requires a clean source of current, it has been recommended a relay feed from the battery with 12 gauge wires...


HEI doesn't play well with some ecu(s), the signal is sometimes poor, or randomly fluctuates.
Seen it several times with different efi systems.
-Tony
'88 GW (aka Babywag) '90 GW (aka JunkBucket) both fuel injected.

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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby Dr. Marneaus » Fri Apr 13, 2018 11:03 am

babywag wrote:
letank wrote:

HEI requires a clean source of current, it has been recommended a relay feed from the battery with 12 gauge wires...


HEI doesn't play well with some ecu(s), the signal is sometimes poor, or randomly fluctuates.
Seen it several times with different efi systems.


My HEI is fed through a relay from the battery, being a 1973, there isnt a single suitable wire that is switched 12v hot during both start and run positions of the ignition. Because of this, I had to tap into 2 sources, one for start and one for run, using a diode to prevent feed back to the starter solenoid.

That wire provides the "on" trigger to my ECU, and that wire also provided the 12v trigger for the relay.

Now, that wire provides the "on" signal to the Street Fire unit I just installed.
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

Postby Dr. Marneaus » Fri Apr 13, 2018 11:25 pm

Well, did about a 15 minute test drive and the initial impression is favorable.

It didn’t hunt on start up, though occasionally that wasn’t a problem.

It didn’t cut out and try to stall on me which was almost always a problem.

It didn’t seem to have any miss at idle.

It pulled pretty hard when I got in the pedal.


I did have to dick around with the total timing specs. I originally told it to kick in total timing at 2500 rpm which is way too low for 34*.

It started stuttering at 2500, so I upped it to 3500, when I was hard on the gas it would stutter st 3500 and refuse to shift, so i upped it to 4500.

If I’m not mistaken 34* should be good for total timing. I’m not sure of exactly what rpm it would be at though.

I have it set for 12* at idle (650rpm) and it seems to like it there. No misses with the AFR set to 14.0

So, as mentioned, initial impressions are good.

My questions are approximately what should my tota tiking be (32-35* seems right) and at what rpm should I be hitting the total timing.

What should I set the idle timing to (currently 12* at 650rpm)

What should I set the vacuum advance to? Presently it’s at 10*

I’m hopeful....but I don’t wanna get tooooo hopeful.

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babywag
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby babywag » Sat Apr 14, 2018 10:34 am

Timing is always one of the things you have to experiment with, every motor is a little different.

Just my .02 and there will be opinions galore when it comes to timing!

@ sea level I run ~15* initial all in ~3600 ~32-38* total(depending on MAP sensor reading/rpm heavy throttle)

I'm guessing your vacuum advance setting is simulating old school setup, and just there to make it easier for tuning.
10* would be a good start, but you can likely bump it a little more more, just keep an ear out for pinging
Cruising total timing on my table is ~40-43*, again depending on MAP/rpm light throttle

4500 seems a tad high for all in, maybe try 4000?
What are your AFR settings?
-Tony
'88 GW (aka Babywag) '90 GW (aka JunkBucket) both fuel injected.

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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby Dr. Marneaus » Sat Apr 14, 2018 2:44 pm

Okay, I have some info.

I live at 5100’ just FYI.

My AFR settings are 14.0 at idle, 14.5 at cruise, 12.8 at WOT.

Yesterday with total timing set to 3500, it was misfiring at 3500 really badly popping and wouldn’t shift. That’s why I went up to 4500, to make sure it was all in at the upper rev limits. I assume there’s a curve that it bases this on in addition to the map sensors and vacuum and stuff.

Today It was running like a raped ape on surface streets.

I got on the highway and at 65mph if I even let slightly off the gas to part throttle it sounded like loud popcorn then a pretty MAJOR single backfire. The popcorn wouldn’t stop until I got back on the gas. Pulled over, googled, dropped my total timing to 30*, and bumped up to 5000 for total timing to be achieved.

As soon as I did that, the issue almost completely disappeared. No popping and no explosions if I coasted.

However it is still doing what it has done since the EFI was installed. If I let off to 0 throttle then even slightly touch the gas after coasting for a second or two I get a pretty decent pop out the tailpipe. Pretty loud. It has always done that to some extent, but at this juncture it seems to be worse than before.


So I need to play with this. It sounds like those settings you mentioned above absolutely won’t work for me, considering that when total timing was acheieved at 3500 my truck wasn’t running correctly. It was missing.

So aside from the decel pop the current settings are allowing me to drive it without any of the issues I used to have :-)

It didn’t cut out. This is the major one that was killing the drivability.

It doesn’t really actively hunt, it seems to try to settle down to idle speed a little early, on a cold start then come back up for a second then smoothly settle in at around 700rpm. So that seems less of an issue now.

If I can get that pop on deceleration figured out or at least reduced a bit, I’ll be happy
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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babywag
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby babywag » Sat Apr 14, 2018 5:16 pm

@ 5000' you should be able to run more initial 12* is not enough IMHO
Increase initial, and lower all in threshold.
-Tony
'88 GW (aka Babywag) '90 GW (aka JunkBucket) both fuel injected.

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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby Dr. Marneaus » Sat Apr 14, 2018 8:01 pm

babywag wrote:@ 5000' you should be able to run more initial 12* is not enough IMHO
Increase initial, and lower all in threshold.


Okay so 15* or so intial.

Then do what? Drop total and lower the RPM for 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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babywag
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby babywag » Sat Apr 14, 2018 8:21 pm

total timing stays same, all in lower rpm than 5k
30* seems little low to me

higher elevation needs higher initial.
should wake it up w/ more initial and give snappier throttle response.
-Tony
'88 GW (aka Babywag) '90 GW (aka JunkBucket) both fuel injected.

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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby Dr. Marneaus » Sun Apr 15, 2018 4:00 pm

Okay I drove it today and put it back up to 34 which didn’t work it was backfiring like nuts any time I letmoff the fat on the highway. but even at 30* total timing I still got some pop corn from the exhaust on an uphill situation. It was super minor. I dropped vac advance to 8* and checked of that fixed it, it seems to have gone away.

I will try dropping the total timing rpm down to 3500 again and leave it at 30* to see what happens. Last time at 34* at 3500 rpm it sounded like my engine was going to explode and the truck refused to shift up. It was stuck at 3500rpm popping and crackling under the hood.
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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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby babywag » Mon Apr 16, 2018 10:46 am

Hmmm, might want to verify that TDC on harmonic balancer is actually TDC, and that the MSD timing displayed is the same as the engine timing.
Should verify @ higher rpm as well w/ dial back light.

Obviously shouldn't be backfiring like that.
On low throttle/cruising I can get away w/ ~42* of timing.
Something is going on here.
-Tony
'88 GW (aka Babywag) '90 GW (aka JunkBucket) both fuel injected.

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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby Dr. Marneaus » Mon Apr 16, 2018 1:19 pm

babywag wrote:Hmmm, might want to verify that TDC on harmonic balancer is actually TDC, and that the MSD timing displayed is the same as the engine timing.
Should verify @ higher rpm as well w/ dial back light.

Obviously shouldn't be backfiring like that.
On low throttle/cruising I can get away w/ ~42* of timing.
Something is going on here.


On the deceleration pop/backfire, it seems that this is "just a thing that happnes" with MSD because due to emissions regulations I guess they REFUSE to offer an update that allows you to program fuel being injected during closed throttle, and its that super lean mixture igniting in the muffler that causes the pop. lots of people have this. We'll leave that alone for a bit.


I've never had issues with the timing before any of this, and we did check that its TDC.

Only thing I can think of is that the phasing on my reluctor is off a little but realistically that could only be off by a few degrees. It clearly isnt phased 45* or even 30*, i made a mark at 45 then divided that into 3, and used the first mark for a "roughly" 15* phase. I cant imagine it would be more than a few degrees off.

I locked out the timing control to 15*, then timed the dist to 15*, and then unlocked the timing control, as per instructions.

I can check the actual timing vs. the timing displayed. I can also go back to the original settings and see what happens, if it still pops and backfires when the total advance kicks in. I dont really know what else to try to check or do after that though. I'm in territory here where I have almost no knowledge or experience (telling a computer when and where to do the things my mechanical distributor used to do)..

I'm still not that great on the theory of timing. I recall revving my engine up to like 4k and checking timing, and seeing that it was all in around 34*. So, i'm not sure why I'd want to be much higher than that (42 like you mentioned). I don't know at what RPM that advance hit, though.

I wonder if my plug wire routing could cause any problems.
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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babywag
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby babywag » Mon Apr 16, 2018 2:20 pm

Ah, so it's a firmware dealio decel fuel cutoff? and going uber lean?
I guess if lotsa folks have it, not much you can do about it, unless they offer a firmware update.

My reference to 42* = simulation of how a normal distributor would act, it's a table based on MAP/RPM.
Like a normal distributor centrifugal timing(rpm) + full vacuum can advance(map).

Sounds like you covered the setup bases, weird that it's acting that way tho.
A stock curve/values should be a decent start point, but seems that isn't the case for you.

I'd maybe recheck phasing...pretty sure BIll USN-1 has a good write-up on binderplanet & ifsja for phasing the duraspark.
If phasing is off, it could potentially be trying to fire on the fringe to another cylinder = VERY BAD.
-Tony
'88 GW (aka Babywag) '90 GW (aka JunkBucket) both fuel injected.

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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby Dr. Marneaus » Mon Apr 16, 2018 3:28 pm

babywag wrote:Ah, so it's a firmware dealio decel fuel cutoff? and going uber lean?
I guess if lotsa folks have it, not much you can do about it, unless they offer a firmware update.

My reference to 42* = simulation of how a normal distributor would act, it's a table based on MAP/RPM.
Like a normal distributor centrifugal timing(rpm) + full vacuum can advance(map).

Sounds like you covered the setup bases, weird that it's acting that way tho.
A stock curve/values should be a decent start point, but seems that isn't the case for you.

I'd maybe recheck phasing...pretty sure BIll USN-1 has a good write-up on binderplanet & ifsja for phasing the duraspark.
If phasing is off, it could potentially be trying to fire on the fringe to another cylinder = VERY BAD.


We phased it exactly as per his writeup the original time around, with a hole drilled in an old cap, etc. Also, I went to large cap to help reduce any potential issues with arcing back or firing too close to another contact in the dizzy. I did have to remove the reluctor for a second but i put it back exactly where we had it phased originally probably to within a fraction of a milimeter.

For the record, it's phased so that the trailing edge of the keyway in the reluctor is basically in line with the leading edge of the keyway in the distributor shaft, in other words, its only phased forward the distance of the pin/keyway
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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babywag
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby babywag » Tue Apr 17, 2018 10:28 am

Well if it likes 30* then it is what it is.
IIRC stock spec is 10*, but jeep issued a service adjustment for over 4000’ saying to add 7* to initial.
So 15-17* should be in ballpark?
Stock timing curve all in ~4000?

So do what engine likes, they’re all a little different. What works well for one doesn’t for another.

I recall this is an ‘87 engine? May have mechanical issues or wear that’s a contributing factor.
Don’t jump around to much, meaning one setting @ time.
Remember don’t change all of them @ once, it’ll just make it harder to dial in. When it cones to EFI small adjustments to single setting @ time, w/ exception being if it runs like total crap or obvious bad settings.

So maybe 15* initial, 30* total, all in 4000, vacuum 8*?
Then experiment with individual settings to find happy spot
-Tony
'88 GW (aka Babywag) '90 GW (aka JunkBucket) both fuel injected.

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Dr. Marneaus
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby Dr. Marneaus » Tue Apr 17, 2018 3:43 pm

babywag wrote:Well if it likes 30* then it is what it is.
IIRC stock spec is 10*, but jeep issued a service adjustment for over 4000’ saying to add 7* to initial.
So 15-17* should be in ballpark?
Stock timing curve all in ~4000?

So do what engine likes, they’re all a little different. What works well for one doesn’t for another.

I recall this is an ‘87 engine? May have mechanical issues or wear that’s a contributing factor.
Don’t jump around to much, meaning one setting @ time.
Remember don’t change all of them @ once, it’ll just make it harder to dial in. When it cones to EFI small adjustments to single setting @ time, w/ exception being if it runs like total crap or obvious bad settings.

So maybe 15* initial, 30* total, all in 4000, vacuum 8*?
Then experiment with individual settings to find happy spot



Thats more or less my plan, make single adjustments. I'm pretty used to tuning then driving then tuning then driving then tuning then driving due to all the crap I have been through with this system. Hopefully I can get it mostly dialed in before too long. I am hopeful this make make some big improvements and regain some of my faith and love for the thing, but I am expecting to be let down due to its history.
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

Postby Dr. Marneaus » Tue Apr 17, 2018 9:48 pm

And thank you again for taking the time to talk me through this.
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

Postby az chip » Wed Apr 18, 2018 12:31 am

I have nightmares about this Jeep and its timing. But seriously, this has been going on for so long I cannot remember every attempt at a fix. Has the MSD controller ever been checked by MSD?
'81 Cherokee Chief 81 WT Chief/MSD 6/ Rusty 4" Spring lift/ Bulltear oil adapter/K&P Engineering Oil Filter/ NP 208/ Serehill Light Harness/ H4 Headlights/ Evil Twin Fab Roof Rack and sliders/ Ross mirror mounts.

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babywag
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Re: MSD Atomic EFI: Tuning Tuning Tuning

Postby babywag » Wed Apr 18, 2018 8:01 am

Dr. Marneaus wrote:And thank you again for taking the time to talk me through this.


Welcome, just attempting to help ya get the stoopid thing running right.


Yours seems to be one stubborn as hell Jeep :P
-Tony
'88 GW (aka Babywag) '90 GW (aka JunkBucket) both fuel injected.


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