No resets before MSD install, now crazy resets

[dtl1982]

I have had my MS-II V3.0 installed for several years now. It has worked more or less okay this entire time. I have never had any problems with resets before.

I installed an MSD 6A this past weekend because the stock HEI just wasn't cutting it. The MS now resets like crazy. It's difficult to get the car even started. Once it does start, it runs fine except for the resets occurring every 10 seconds or so.

Where would you guys start to try to quiet this thing down?

One thing I'll add: While the MSD and MS are not electrically connected very close to each other, they are physically about 6 inches from each other if that may cause problems.

Thanks for your help. This is the first time in many years I've really had a problem with the MegaSquirt system.

[Bernard Fife]

dtl,

If I understand correctly, the MegaSquirt works properly, but the MSD is causing problems. So I think you should look at the MSD, or possibly any wiring changes you made in putting the MSD in (since the MegaSquirt controller worked fine by itself).

There is info on resets here: http://www.megamanual.com/ms2/tune.htm#resets

You should also tell us what code you are using, what PCB version, and post an MSQ and a datalog - these all help to figure things out.

Lance.

[Matt Cramer]

Where is the MegaSquirt grounded, and where is the MSD box grounded? If there was anything marginal about your grounding and you grounded the MSD box to a similar point, you may have pushed the grounding over the edge.

[dtl1982]

Oops, got my hand slapped.

I've got a V3.0 PCB with MS-II, B&G code version 2.89
Hardware kit was purchased late 2005.

I looked at the vBatt on the log, but it doesn't seem to show what I am assuming is going on. When starting, I hear a relay clicking on and off very rapidly. Almost a buzz, but definitely a relay.

I'll admit my grounds are not in pristine condition. It's never been a problem before so I didn't bother, but now I will clean the snot out of them and report after that.

If anything below seems funny, please let me know:

-->The positive to the MegaSquirt is directly connected to the cable coming off of the battery.
-->The positive to the MSD currently comes from a dedicated line from the starter solenoid where the battery connects.
-->All the grounds from the MegaSquirt seem to end up on a single bolt on the engine block, but not the bolt that is connected to the battery. (I say seem since it's been a looong time since I've done this, but that's what I could trace through the harness.)
-->I've tried grounding the MSD to the chassis where the ground strap from the chassis to the battery is, no luck.
-->I've tried grounding the MSD to the engine on the alternator bracket where the engine strap to battery is, no luck.

Thanks again for any help guys.

[trakkies]

I'd say grounding both MS and ignition system to the engine block is the best way to go. It shouldn't matter if it's not the same point as the main engine ground.

[dtl1982]

Been re-doing all of the MS grounds, but I'm confused.

The V3 assembly guide says to take all the ground pins from the DB37 and route them individually to a single point on the engine and not to combine them into 1 larger wire.

However, doesn't the relay board combine all the grounds into one lead to be taken to the engine ground with 1 larger wire?

I'm a little confused on the best way to go about this. If I need to route 45 feet of copper to take the pins individually to the ground that is fine, but why doesn't the relay board emulate this?

Please advise. Thanks!

[kjones6039]

It seems like there are almost as many grounding theories as there are members of the forum.

I agree with your assessment of the MS relay board. I personally do not use one, although have in the past.

I have all (excluding sensor returns) of my MS grounds gathered together near the DB37 and routed, via one 12 awg wire, to a very good grounding stud on the intake manifold. I also use 6 awg wire directly from the battery negative post to that same stud on the manifold.

On the hot side, I also use 6 awg wire from the positive post of the battery directly to my own version of the relay board, where I power everything that is MS, fuel or ignition related.

I keep all connections scrupulously clean and have not experienced any power related problems that I know of.

Just one old guys way of doing things of course...... Might not work for everyone..........

Ken

[trakkies]

It could be the MS designers are just keeping cable joints to a minimum. Not everyone will make a decent job of connecting three smaller cables to one larger one. My original EFI was by Lucas and they ran separate ground wires from the multiple grounds to the block - exactly the same as MS, and probably for the same reason - the plug couldn't handle the current on one pin. I suppose it also makes the loom more flexible, and may be cheaper.

Like you Ken, I don't much like the relay board. It introduces extra connections - never a good thing IMHO.

[dtl1982]

I have re-created all of the grounding for the Megasquirt, due to the fact it was originally installed several years ago and I couldn't track down all the grounds with 100% confidence. (3) ground wires have been individually routed to the same bolt on the engine and are sandwiched together under that bolt:

1. The 5 ground pins on the DB37 have been combined into a 12 ga wire (contrary to the V3 assembly manual, but consistent with what the relay board emulates)
2. The sensor ground from the Relay Board and the MS have been combined into a 'sensor ground' and routed to the ground location
3. The ground for the relay board (for the relays on that board and such)

The grounding location is hospital clean, but there is still no improvement on the reset situation. I went as far as running a jumper directly from the battery positive to the MS, and still no change.

At this point, does the MSD 'filter capacitor' make much sense? If that's what it takes then so be it, but if there are other avenues to approach, I am all ears.

Thanks!

[dtl1982]

Okay, feeling pretty dumb.

I've just now noticed that the instructions for the MSD 6A say to connect the "Coil -" wire from the 6A to the "Coil -" of the distributor cap. I have had it connected to the distributor's ground instead.

When I first installed it(wired wrong), it started up, albeit roughly, but drove around for 5 minutes or so. It has yet to start since. After I fixed the wiring, there was a noticeable improvement in the attempt to start, but it still wouldn't hold up running. I'm assuming I have toasted something.

To sum it up:
1. Power and ground connections are fresh and clean
2. MSD is now wired up correctly
3. Still getting the resets, which is preventing from running.

Any thoughts on where to go from here?

Side note to mods: Why did this post get moved to the Relay Board section? Just curious.