ECU not coming to life

[Jadewombat]

Running a 3.57 unit, 009 distributor with petronix for now. I got it to start and run for about 20 minutes the other before I shut it off. I was programming the next day and testing a little too long with the key on but not running and it damaged the petronix. It would still spark, but the voltage would drop like crazy across the ignition coil. The only thing I changed below is ignition components.

This morning I replaced the ignition coil with a brand new black Bosch 12V coil showing 3.5ohms resistance. About 12.1-12.3V on the (+) side of the coil and only 3V cranking on the negative side. OK, decided the petronix is bad so went down and got a new petronix. Now it still shows 12.1 on the (+) side and 12.1 static on the negative side, but the voltage drops to only 6-9V on the (-) side when cranking.

Thoughts? Why is the negative side voltage dropping so low? I tested the MS unit by putting 12V to the same wire #25 and the fuel pump kicks on briefly.

I could put the original (used) Bosch blue coil back on as it still shows 3.5 ohms.

Thanks in advance.

[Piledriver]

The "points" side is being pulled to ground intermittently, so its going to read lower on a meter when cranking.
The only thing that matters is that you get sparkage at the right times.

The opto circuit has to be built for coil input, and the jumpers need set etc so it gets the signal.
The VR circuits cannot deal with the high voltage kickback a coil generates.
Its those spikes that trigger it.
(It can also be set up as a hall input but the circuit setup is different)

You'll be a lot better off when you have direct control of the coils/dwell etc, test mode makes troubleshooting much easier.

You can even put the 009 to good use:
This supports fully sequential operation with only one sensor/wheel.
Its an RC truck spur gear with a tooth filled in with TIG.
(I currently have a 36-1 in the car)

72-tooth-1.JPG

[Jadewombat]

I agree 100% crank-trigger would be easier, but I'm not familiar with MS fuel (only spark) and wanted to get the fuel settings first.

A few years ago, long story, different state, before the bus went into storage, before we moved overseas...I mounted an EDIS unit at the same time as the MS 3.57 setup. After 2 weeks of evenings messing with the EDIS and quazuple checking every freakin' wire, it would still only fire like once or twice a revolution--I gave up and put the 009 back on just to get the bus started.

Four years later. I buy a new battery earlier this week from Advance (they bought Carquest). I get it fired up and run it for a long time. Now this though with the screwy (-) side coil voltage. It's still jumping from 6-9V but not enough to kick the ECU on.

Anyhoo, I still have the 36-1 trigger wheel and VR sensor mounted. My question is, if I wanted to try to run the trigger wheel to control spark through the 009, what do I have to do? Do I have to do that internal soldering of a wire to the board or is that only to drive the Ford coilpack?

[Jadewombat]

To put it another way, if I'm not interested in spark control but want the ECU to see the rpms and kick the fuel pump on, fire the injectors, etc.--could I just hook up the VR sensor to pins 1 and 24?

[Piledriver]

To put it another way, if I'm not interested in spark control but want the ECU to see the rpms and kick the fuel pump on, fire the injectors, etc.--could I just hook up the VR sensor to pins 1 and 24?

You can, but then you get into indexing the distributor, which is a cluster.... of its own and does you no good.
The fastest thing to do at this point is fix what you have.

If you hit it with starting fluid, does it go? (does ignition work, basically)
If so, we try to find the signal...
Do you have a stim?

Its easy to kill the $2 opto-isolators... shouldn't be but is. I put them in an (good machined-pin type) IC socket.
(I eventually gave up using them)

I'd pick up a VW New Beetle 4 tower coil and get it over with, the ignition side is trivial, and you can start off with a ~stock like ignition "map" which gets you ~95% there.

The EDIS coil will work but you'd need 2 ignition drivers, the NB coil is logic controlled.

If you still have the EDIS stuff we could probably get you going, it doesn't even require the MS at all to run in limp mode.
Note: it is ~absolutely intolerant of wheel runout. (most setups are)

I still have a heavy preference for direct control as troubleshooting gets ~trivial when you can just tell a single coil or injector to fire 100x, and fire every 200 ms or such.

I similarly prefer hall sensors as you can troubleshoot with a DVM, moving the crank by hand it sees the teeth etc.

EDIS is (literally) a black box that works or you throw parts at it.

[luftvagon]

What "ECU" are you using? I'm guessing you are using OPTIN +/-? I burned a resistor on both of my microsquirt boards. Both required solder bridges, and an inline 1k resistor if i recall correctly.

[Jadewombat]

I'm going the route of getting the VR sensor wired up as an rpm signal. It's a 3.57 unit which I bought preassembled. IIRC 3.0 is DIY and 3.57 is preassembled.

Well, I've had a not so fun afternoon in the Texas heat. After spending nearly 1 hour going back through the harness to find which wire corresponded to pin 1, I couldn't find it. I opened the plug to look at the backside of the pins.

No wire for pin 1!!! (It should be just to the right of the shielded wire in the picture)

I think I had some correct connectors from when I was messing with MJ a few years ago. Correct?

What's odd is there's a wire connected to pin 8 and the diagram doesn't show any function for it. Just ground it like the others?

[luftvagon]

Which input are you using for RPM pickup?

[Jadewombat]

I was using pin 24 to the negative side of the ignition coil with 009 and a pertronix. It started and ran earlier in the week.

Now I plan to use pins 1 and 24 for the VR sensor and rpms. It's a 36-1 trigger wheel and Ford VR sensor.

[Piledriver]

You need to pull the ECU, open it up, and see where those wires go inside, and how all the jumpers are configured.
DIYautotune may have a build record, but it shouldn't be too hard to sort out, as everything is documented to death.

Save yourself pain and make yourself a configuration document, and record all the hardware ins/outs etc.
The std wires in DIY harnesses are labeled every 12".(printed on the insulation) as to function.
This can save you agony the next time you want to change things or if something breaks a year from now..

You need to switch some physical jumpers to use the VR circuits, one to get in, and one to get the result into the CPU.
Right now its set to use the opto, so VR is not connected internally.
(Its there, just needs jumpered and adjusted properly)

Be certain ONLY to refer to the msextra documentation. Forget about the megamanual. Forget anything from B&G---forget it exists.
Load the LATEST release firmware, Use the loader that comes with it.

If it was set up for EDIS, its likely set up wrong internally for what you are doing now..
It may also not have an ignition driver ---didn't need one for EDIS as ordered.
(not a bug, actually, you WANT logic driven coils or external drivers to keep the powerful ignition noise at bay)
The "LED" drivers are trivial to drop a 1K resistor across and use for ignition logic outs, works to drive an external driver or LS2 coils, and most common logic drive coils (Some of the VW/AUDI COPs will not work with a pullup, they need a high current "logic" signal, so PNP transistor circuit, or there is a tiny solder-in driver module to do the deed)

A megasquirt V3 is rediculously configurable internally and if you do not have a good diagram of where all the goesintas and goesoutas go you really are wasting your time as well as potentially generating smoke...

Don't let the magic smoke out.

[Jadewombat]

Got it swapped over to the VR sensor settings today on fuel only and it popped to life seeing the rpm signal. More in a bit. Thanks.

[Piledriver]

Cool.

[Jadewombat]

OK, several days of trying to adjust settings to get it to start and run. I spend about 10 minutes a day, adjust this, get it to run a few seconds, run the battery down, then go back and read this and that. On and on.

Just noticed today (I thought it was working correctly but now I'm not so sure after I changed it to the VR sensor and trigger wheel) that the RPMs during cranking TS shows somewhere in the neighborhood of 3000 and up (not 200-300). What the hell? I have it set to fuel only, rising edge.

It wouldn't "see" the RPMs at all if it was a VR distance to the trigger wheel adjustment, correct? What do I need to change or adjust? Tried swapping the wires on the VR sensor, no change. Thanks.

[Piledriver]

Triggering on noise.
Turn on the noise filter.. don't jack with any other settings, just turn it on.

May need to fiddle with the VR ppots or perhaps put a series resistor if you have too MUCH signal.
It is just as bad.(but usually shows up at higher RPM, cranking produces a very low signal)
Poor connections/weak battery and dying starter don't help at all, either.

Yank the plugs and pull the injector fuse until you can get a clean correct wheel signal cranking, and verify timing again when done.
The battery will last 100X longer with no plugs//load..

[miniman82]

Sounds like false triggering, are you running resistor plugs?