MSefi.com read only forum (Jan.15,2018)

So I've had this fairly rare issue where I'll be driving along and the car will die for a few seconds.... then wake back up. I finally had it happen while logging and I noticed the RPM drops to 0 and the RUN field shown in MegaLog Viewer shows N. What determines when RUN will show N - or is that coming straight from the MSII serialization?

The MSII has power since the log acts normal other than 0 RPM. Could I be losing power to my Distributor (Mallory Unilite) or Ignition box (Mallory HyFire IVc) briefly or would something else cause RUN = N?

TY!

Looks like the Engine serial protocol entry is likely what Run: is based on. Still not sure what would determine the value of Engine or what the different values represent.

I have the original ballast resistor wire installed on my 1966 Ford Mustang which supplies power to the distributor and ignition box. It's not necessary so I'll try removing it and supplying a full 12v and see if that legacy item is the issue. Maybe it was dropping the power lower than is acceptable.

Removed the ballast resistor wire and ran a dedicated power line to the dizzy and so far so good. Min value on Engine was 1 on my first 20+ minute trip. Will comment here if the problem comes back.

Is MS working in a fuel only mode? Ie, not controlling the ignition timing? Whatever, if MS loses the tach signal it stops injecting as it thinks the engine has stopped.
Sadly, this could be a problem with your ignition system or MS

I used a Unilite with resistor for several years on fuel only MS. Mallory said to use the resistor, so I did.

trakkies wrote:Is MS working in a fuel only mode? Ie, not controlling the ignition timing? Whatever, if MS loses the tach signal it stops injecting as it thinks the engine has stopped.
Sadly, this could be a problem with your ignition system or MS

I used a Unilite with resistor for several years on fuel only MS. Mallory said to use the resistor, so I did.

MS runs it all. The ignition box controls the coil, so no need for the ballast resistor (since IIRC it originally connected to the coil). The ignition signal that was going in to the ms2 (I think pin 24) was coming from the unilite, then the timing adjusted output went to the ignition box.

I believe that signal from the unilite was dead due to the resistor wire getting too hot and dropping voltage too low. A few seconds later maybe it cooled enough since there was no load and the unilite woke back up? Maybe? That's my guess anyhow.

If the resistor was designed to handle the power the coil took when driven direct from the Unilite - single coil setup - it would carry virtually no current when feeding just the dizzy alone, with no coil. So would likely be doing nothing, so wouldn't get hot. Your ignition box would be taking the power now.

How are you deriving the tach signal from the Mallory setup, and what input are you using with MS?

trakkies wrote:If the resistor was designed to handle the power the coil took when driven direct from the Unilite - single coil setup - it would carry virtually no current when feeding just the dizzy alone, with no coil. So would likely be doing nothing, so wouldn't get hot. Your ignition box would be taking the power now.

How are you deriving the tach signal from the Mallory setup, and what input are you using with MS?

The Mallory IVc ignition box does share a power line with the Unilite, so in some part the resistor wire was supplying power to both the distributor and ignition box.

The Unilite only has 3 wires. Power, Ground, and Signal. That Signal goes to pin 24 (IIRC) on the MS2. It's had this setup since 2005 - just with intermittent power drop issues appearing more frequent over the last few years. Only recently did I manage to trap it in the log and found that the Engine field was dropping to 0. Who knows how old that resistor wire was too.

60 minutes driven since the change and zero Run:N entries in the logs. I'll call it fixed if I can make it a week of commute without an error.

The resistor is there to help limit the maximum current your ignition setup can take. With the Unilite only setup I had, Mallory said it should be used - but oddly didn't supply it with the dizzy kit. You might be OK without, but I wouldn't be sure of that. It was very expensive for what it was, though.

trakkies wrote:The resistor is there to help limit the maximum current your ignition setup can take. With the Unilite only setup I had, Mallory said it should be used - but oddly didn't supply it with the dizzy kit. You might be OK without, but I wouldn't be sure of that. It was very expensive for what it was, though.

Yes, it could eventually wipe it out. If this is the fix, I'll purchase the Mallory ballast resistor they sell separately. If it's not the fix, the old wire goes back in haha

https://m.summitracing.com/parts/msd-8214

That was the msd part no. Mallory part no was unavailable.

https://m.summitracing.com/parts/maa-700

Ah. Misread the part that it was the original resistance wire. That could well have had a different value from the resistor Mallory recommend, so unless knowing for sure it was the same, I'd have bypassed it anyway.

No issues so far so it must have been that old resistance wire. Next I'll be installing the recommended ballast resistor and will see how that goes. If it fails again, I'll come back and post as such.