Do you have access to another distributor you could just swap in, which would rapidly confirm or eliminate this area as the problem?

An unstable or noisy power supply will cause a myriad of issues which can turn you on your head trying to chase them down.

Do you know of anyone with a good oscilloscope that could look at the DC that feeds your electronics? That would substantially augment the information that you can gather from a DVM. Noisy power sources would show up immediately on an oscilloscope.

That tool would also make short work of determining how well your reluctor and pickup are working, for that matter.

- Mac

Thanks all. I will set about checking voltages tonight. I picked up a new battery for another meter I own. Maybe it will work. The old one was fine for years, and I used it much. I have a friend with an oscilloscope, and he will be happy to help me out I am sure. He is on business travel right now, but I will begin to ding him for help when he gets back. He is the EE I referenced before.

Sam

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The new battery revived the VOM I have been using for years. The other one was pretty much dead. I checked the voltage at the battery and at the alternator with the power turned off on everything. It was the same at 12.2 volts. I then turned on the key and checked the same voltages and it now read 12.2 volts at the battery and alternator, but 11.95 volts on the other side of the relay that powers the ECU. That was as far as I got tonight. It seems the connections between the battery and Alternator are fine. I do not know why the voltage on the other side of the relay would be less. This must be the resistance in the contacts inside the relay.

Tomorrow evening is not available for car work, and I might have to work late Thursday. So I may not get back to this for awhile. Thanks again for all the ideas. I will go through the check list you suggested Pierre. That is, if I can get it to start. If history means anything, it should start and run for maybe 15 or 20 minutes. That should be enough to tell us something.

Sam

Sam

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12.2v battery voltage with nothing on indicates a partially discharged battery. This doesn't surprise me as we suspect your alternator isn't doing a good enough job.

That voltage drop across the relay is nominal and expected. Nothing to worry about. If you want it any less you will have to go to a solid state relay but that's unnecessary complexity.

If the alternator isn't running, then you will measure the same voltage at either spot. The same holds true whether any accessories are on or off. Current would flow from battery to devices. The wire to the alternator essentially acts as an extension of your meter leads. If the alternator is running and your measuring different voltages at these points then the wire between alt and bat is inadequate to carry the load.

If you have an automatic battery charger throw it on there while you go about doing your other business. How old is this battery?

The battery is actually pretty old. It is maybe 5 years. It is an optima, which has been pretty reliable until now. But then things have never been great with this set up I suppose. What should the battery read with the engine not running? The last two days have been pretty hard on it with lots of restarts and attempted restarts.
I do have a battery charger and will put it on. Thanks.

Sam

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12.6+

Directly off the charger it may read higher - put a light-moderate load on it, like headlights, for a minute or two to remove the surface charge then evaluate its open circuit (nothing hooked up, no loads) voltage.

If its a red top optima - they are very sensitive to being deeply discharged. 5 years old is not that old actually for one of these but consider it compromised.

I got back into this again this morning. I removed the air intake which was blocking access to the distributor, and removed the cap and plug wires and am looking at the distributor and am thinking, man it would be nice to just eliminate the distributor. So Pierre, I would like to take your lead and consider putting the EDIS ignition on it. I will proceed with trying to get this set up running, but it seems the fixes we have talked abut so far involve removing the alternator, and the radiator (again) to put on the mechanical fan. While the radiator is out, I can work on getting the crank trigger pick up dialed in, even if that means taking the harmonic balancer off and taking it to a machine shop for truing up. Once the crank trigger is correct, the ECU will get a direct read from the crank. However, I must reconfigure the Mega Squirt module, and I am outside my comfort zone. This is where I need help, and need to expand my comfort zone.

Now I am thinking if I am going to reconfigure it for a crank trigger wheel, why not go ahead and reconfigure it for EDIS and just get rid of the distributor. Maybe down the road use it as a cam sensor if I get that far.

So that is where I am now. Pierre, I put the charger on the battery this morning. I will report back tomorrow morning on where that took things. Tonight I have band practice, so will not be able to spend time on it.

Every time I have mentioned EDIS to Peter he simply says, "You could do that", but offers no support. He has said I few times he doesn't like the fact that there is no "true" crank position sensor. But there is none on this set up either. So why is that a problem. I do not know what kind of ignition has a true crank position sensor. The BMW has a trigger wheel similar to the one on the Dart, and a cam sensor. Is the cam sensor a "true" crank position sensor?

Thanks for your thoughts. This is going to take awhile, so be patient with me.
Sam

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I think what Peter means is that while EDIS has a crankshaft position sensor, the ECU can't actually see its signal. It is also possible to set up the EDIS-type trigger wheel so it is wired straight to the MegaSquirt and the MegaSquirt controls the coils; that would not be very different from using the BMW sensor setup. We have an article on the different ways to make MegaSquirt work with an EDIS-style trigger wheel here:

http://www.diyautotune.com/tech_article ... erview.htm

And yes, we can rework MegaSquirts we built for any of them. (That would take a lot less time than we spent on the distributor - that was pretty hard for us to set up a suitable way to test it.)

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Sam,

I certainly love EDIS but I still say we at least diagnose this low voltage situation before you make any further major changes. Even without the fan your voltages were too low.

Agreed. This is kind of a long term plan I am trying to formulate now.
All this will have to be a slow pace. I do not have money or time right now to do much. But getting the mind back into it is a first and important step. If you are happy with your EDIS set up then I will begin to read the megamanual info on it. I have it printed out and in my notebook. I also have your posts book marked.
Sam

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