The Dart has never had better drivability. Aftre much trouble shooting and tracking down fundamental flaws, most systems are now excellent. It is still a little iffy for the first 30 seconds on a cold day, but still better than a carb for sure. It is smooth ast cruise, and will idle smoothly all day at 800 rpm. The tip in of throttle off-idle is smooth, and controllable. It always starts no matter the temperature. This means I am no longer nervous in traffic that the darn thing might die at a light and fail to re-start (this had happened a few times in the past).

However the ignition still breaks down over 3200 RPM above 5 lbs of boost. I have concluded this combination of HEI and VR pickup gets seriously unstable under boost, and no amount of tweaking the system as it is configured is likely to fix it. The fueling and timing are not that far off. So after living with this for 18 months, I am on the horns of a dilemma. Do I take a car I am no longer afraid to drive and take a giant step backwards by starting over with a different ignition set up or just drive it, or seriously reduce the boost on the turbo?

I have had at least one credible person speak against every ignition option for what they thought was a good reason. The ignition I wish to move to is the Ford EDIS. I have the pick up wheel and pick up installed, but not dialed in. Here are the hesitations:
1. I must pull the radiator again to get at it enough to get it trued up, and I am infull swing into cruise season, which I do participate in every weekend weather is good.
2. I do not know if the EDIS is strong enough to work under the turbo load.
3. Peter says he is not a fan of the Ford EDIS for reasons I did not understand.
4. I am not savvy enough to make the internal changes needed to make the MS II work with the EDIS. I will have to send it off to someone who can reconfigure it internally. Which again takes the car off the road for a couple of weeks.

So there you are. Stuck with a nicely running car that still will not pull all the way to red line at WOT. I am going to cut back on the turbo boost, but really think it is time to get the fundamental ignition configuration better. I am needing some encouragement to make this change from some confident souls who are also willing to listen to me whine when something new doesn't instantly work out, and are willing to support me during the inevitable ensuing trouble shooting phase that will follow. Any ideas for a better ignition out there? I think the HEI has to go. It cannot be included any new system.

Sam

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Man Sam this isn't encouraging news. As your aware I'm in the process of installing and tuning a megasquirt 2 3.0 for my blow thru setup with a hei ignition.
Sam can you tell me if your MS has the VR conditioning circuitry
Similar to these mods
http://www.msextra.com/doc/general/tachin-v30.html#vr

I've read some post from other mopar and gm hei user who have had similar issues but we're able to clean there tach signal up thru out there rpm range.

Sam can you post a up to date tune I'd like to see how you have your megasquirt configured
Aaron

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http://youtu.be/2Y4i4UOLiSA

http://www.forabodiesonly.com/mopar/sho ... p?t=126611

Sam,

If I had a car as nice as yours, with as much time and money invested as you have put into yours, I would not be happy with it until that turbo slammed me back in the seat up to your red line. There is no reason it should not be able to work.

Can you explain what is wrong with the HEI ? Or any other good quality ignition for that matter? If the ignition system is good, what part of it causes the break up at higher boost/RPM.

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Agreed!

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Yeah....Im the one who destroyed this rare, vintage automobile.....

Thanks for the kind comments.
Rick, That is, and has been the $64,000 question for everyone. There were other issues, and each one as it was solved was hoped would be "the" answer. While it ran better each time, the break down at around 3200 continued to happen only under boost above 5 pounds. Lou was convinced it was fuel, until we drove it when he fussed with the fueling, and a few other things. He walked away shaking his head. It seems to me we did manage to kill it completely once when we fooled with the filtering style, thinking that might be the problem. The fact that it will go over 4K rpm if you keep it out of boost seems like a real clue here.

Here is the list of fixes so far. These were all needed.
1. Stabilized fuel pressure. (new in tank pump, accurate pressure gauge).
2. Grounded HEI to ECU, which took away extraneous tach reads at start up, idle, cruise, etc. It did work for all miss-reads except the ones at boost over 5 lbs, and rpm over 3K.
3. Replaced defective pick-up.
4. Shielded VR pickup wires.
5. Put chokes on all potentially noisy components as well as 12+ supply to MS.
6. Wired fan to come on in stages.
7. Replaced battery.

One thing I have not done is shield the sensor wires, which is factory on my BMW. The other thing I have not done is re-gap the plugs down to .020, which had been done before in attempt to cure the problem, but undone when I put new plugs and shielded spark plug wires in.

I also have not done a recent datalog through the miss. I will do that soon. I am inclined to think there is too much sensativity in the HEI module to operate under these conditions.

Sam

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Have you tried using an adjustable spark tester to see how much kV your present ignition system can put out? HEI should be able to fire across a 3/4" gap in open air at the end of the spark plug wire- easy. If your spark is "blowing out" under boost/load- that'd explain your symptoms. I often see weak coils breaking down under load & sending high voltage spikes from the ignition secondary back thru the primary circuit & scrambling the ecm.

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63 Valiant Wagon
225 - 4 bbl

Sam, just out of curiosity are you using a standard style coil, or have you switched to a CD coil? I would think that going to a modern style of ignition you would also go to CD as well, I couldn't find a 'final word' post on everything done to your build.

-D.Idiot

Sounds like progress, and I think you can get this to work w/o EDIS. I second trying a more powerful coil. Also, I assume you have tried another known good HEI unit in place of what's in there?

Look forward to catching up in 3 wks!

Lou

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Home of Slant6-powered fun machines since 1988

I have the MSD blaster coil. And, I have tried several different HEI modules. Here is an important clue: When I first enabled ignition control on the MS II, and tried to drive it, upon high vacuum, coast down conditions, coasting in gear it would go into reset mode, and then back fire and start again once I pushed the clutch in and let the ecu find itself. It was clearly flooding under those conditions. Once I employed the over fueling cut off feature, this quit happening entirely. Here is what I took away from this, the misfire from two much fuel sent shock waves of interference back into the HEI module and caused the ECU to need to reset. It scared the heck out of me, as I was driving in Labor Day traffic up route 95 from Richmond and around the Capital Beltway. I soon learned to depress the clutch any time I took my foot off the gas. But the important thing here is that with MS I this never happened. There is no over fuel cut-off feature. Something about this combination of MS II and HEI is extremely sensative to interference of any kind. And apparently misfires create a ton of EMI interference. Is that the right acronym?

Sam

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Sam here's a good post I've found with similar issues and speedy6963 talks about the VR conditioning circuitry on page 2

http://www.msextra.com/forums/viewtopic ... i&start=20

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http://youtu.be/2Y4i4UOLiSA

http://www.forabodiesonly.com/mopar/sho ... p?t=126611

Thanks. Apparently fiddling with pots 52 and 56 cleared up their problems. I have not had this open in forever. Are the pots clearly labeled? I read in the mega manual about the other tach signal conditioning tactics, and honestly, most of it was way over my head. I did not build this MS box, and that leaves me in a seriously dumb state.

Here is the broad history.
1. Version 1, fuel control and MS I installed by Lou. It ran pretty well, but always had pre-ignition problems because of timing issues.
2. Version2. Accell Gen VII at great expense (and annoyance on the part of Lou) controlling both fuel and spark. It never ran well. Wouldn't start at all for weeks. I cannot remember what got it to start.
3. Version 3. Back to original MS I. Ran fine but with same early issues.
4. Version 4. MS II with fuel only. Ran essentially the same as with MS I, but better fuel control.
5. Switched over to MS II fuel and spark. Tach read has been a problem from day one. All above fixes applied. Accell problably would have worked better if these later fixes had been worked through then.

I know you guys have been down this road now for years with me, and I appreciate your concern, and your frustration with my seemingly dumb, and or illogical actions regarding the problems. There are so many options when you get into this kind of thing that the permutations and combinations of choices gets kind of overwhelming. One thing that holds me back is I am almost always hesitant to take a car off the road to "fix" something if it is running. I prefer to drive it running half-assed to "fixing" it so it will not run at all. That has happened too many times with the fuel injection.

Here is a simple question: What do I have to change in the MSII ECU to fire it directly from the crank trigger? This is a tough question because Peter wired the HEI feed directly to the ECU, bypassing the relay box, and I am not sure what he did internally. If this can be done, then this would be a clear path to better tach signal.

Sam

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I vote for closing up your plug gap, .020 seems a bit close though. Go for .030 and work from that.
Just a thought,

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Mattelderca
78 NYB (gone now), two S series, three old Snow Cruisers and a Doo.

I read the entire thread posted above, and then posted my own question at the end of the thread. It seems there is a complex relationship between the rising and falling lines of the sine wave on the VR signal, and the dwell time of the coil. There are also concerns about the voltage supplies to or from the adjustable pots in the ECU. I have never fussed with them at all.

It was somewhat over my head, but I did get the basics of what he was doing. And, he was firing an HEI module with a VR distributor on a turbo charged SMC (apparently), and experiencing the same kind of interference break down. At least I do not feel quite as crazy now. It does seem as if the EDIS system would eliminate most if not all of that concern. And, there has been mention that the HEI ignition is not totally crazy about the signal that comes from a Mopar distributor.

Next step is to take off the splash pan, and check the run out of the trigger wheel with a dial gauge. I will do that this afternoon. Apparently the sensor I purchased from DYI is a hall sensor, and not a VR. So once I get this dialed in, I have to figure out how to interface it with the MS II.

Sam

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You could also bolt a MSD 6AL-II programmable on there and call it a day.

Not quite as flexible as the MSII or MSIII ign maps, but has been dead reliable for me up to 10 psi and about 330 HP (100 MPH 1/4 mile trap speed in 3500 lb 68 Dart).

I doubt I will ever mess with HEI after your experiences.

Lou

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Home of Slant6-powered fun machines since 1988

Smart people learn from others' mistakes. And honest people admit their mistakes so smart people can learn from them. But they blush a lot.

Hoestly, when not it boost, I think HEI works "OK". If I modulate the throttle to keep it out of boost altogether, it will climb to 4K pretty smoothly, and just hang there for lack of air and fuel, but does not break down ignition wise.

Yes the programmable MSD seems like the simple, smart way to go. Actually, if it had been available back 5 years go, and maybe it was, I would never have spent the first money on the Accel. So would this work with the locked distributor, or go back to the mechanical curve dist. and adjust it with the programmable MSD box?
Sam

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