Unusual Problem

billr · Post by **billr** » Fri Apr 24, 2015 3:23 pm

I did some experimenting today (VR with 60-2), I can get sync by 100 rpm and tooth log much lower than that; estimating about 60rpm for lower-limit with my test setup, I think it is a limit for my wheel/sensor combo, not MS. I gotta ask... are you sure about that 40 rpm for cranking? That's slower than any hand-cranking I've ever seen or done.

KhanTyranitar · Post by **KhanTyranitar** » Fri Apr 24, 2015 3:33 pm

When it first cranks it spins a little faster, then slows down.

I don't have my logs on a computer I can post with, but I checked the tooth logs. There is nothing. It does not register anything. The coil is firing, that does work. We are considering running a 36-1 wheel instead of negative coil trigger.

I'm gonna grab another Microsquirt to test with in case this one might have a fault. I have one that is going into my Merkur when I get it ready.

billr · Post by **billr** » Fri Apr 24, 2015 4:48 pm

I changed my test-set to a Hall sensor (same 60-2) and can maintain sync down to 10 rpm. I can't drive the wheel at a steady speed any slower than that.

Edit: "can't" was "can"...

turbo conversion · Post by **turbo conversion** » Fri Apr 24, 2015 4:50 pm

If you remove the spark plugs and relieve the compression the engine should spin much faster.

It should increase the cranking RPM significantly.

Maybe enough to see cranking signal if to slow RPM is the issue.

Just a thought.

David

KhanTyranitar · Post by **KhanTyranitar** » Fri Apr 24, 2015 4:55 pm

On this motor, it has primer caps that let you add gas directly to the cylinders. With those caps open the compression is released and it does crank faster, but I still get no trigger. Good suggestion though.

I'm not sure why this setup isn't working, but I'm going to try switching to another Micro, and if that doesn't work, then I'll switch to a 36-1 wheel.

billr · Post by **billr** » Fri Apr 24, 2015 5:27 pm

I don't know how hard it would be for me to try a "basic trigger" test, do you want me to look into that?

KhanTyranitar · Post by **KhanTyranitar** » Sat Apr 25, 2015 7:07 am

I'm not sure if that will help or not. I know the ignition system on this motor works, it is sparking, and sparking at the right time. The coil is just run by the ignitor, and the plugs are definitely firing. The motor tries to start, but since the Microsquirt doesn't see the triggers it doesn't add any more fuel. I don't think low crank speed is the issue anymore. When it tries to fire, for a moment it is cranking faster. I'm not sure what the problem is, the wiring has been checked and traced. All other sensors are working. The wiring is done according to the instructions we have found for a negative trigger, but still nothing.

I know the connections are good, I have traced the pins.

I will probably head back to the shop today. I found my spare Microsquirt and a Jimstim module, so I can try to do more tests.

billr · Post by **billr** » Sat Apr 25, 2015 9:35 am

In that last few posts you referred to "Microsquirt", but previously (at beginning of thread) it had been "Megasquirt", I think. Just what hardware (MS) are you working with here? My experience/testing has all been with a V3.0 MS3, so may not pertain to Microsquirt. I was just offering to (maybe) find out how low the V3.0 MS3 could handle cranking rpm with "basic trigger", but if you are past that wonderment then I am relieved.

KhanTyranitar · Post by **KhanTyranitar** » Sat Apr 25, 2015 4:09 pm

Sorry, it is a Microsquirt module.

I'm pretty sure that either a basic trigger isn't going to work, or there is something wrong with this particular Microsquirt module (not unheard of).

billr · Post by **billr** » Sat Apr 25, 2015 5:12 pm

Okay, I should leave you to get help from somebody familiar with Microsquirt; I'm not.

R100RT · Post by **R100RT** » Sun Apr 26, 2015 6:53 am

I've had similar cranking speed test results as "billr" with my microsquirts. I did my testing on a drill press when graduating to sequential ignition, as a single toothed VR on a cam drive would not sync below 100rpm initially. Being V2 MS, I added one of Jean's VR conditioners and then logged speeds around 19rpm - hard to create as you are turning a disc by hand as calmly possible - but this is not applicable so I digress.
I don't believe the Micro Squirt will be your problem, and as mentioned the useful thing would be to put the carbs back on, start it have your set up piggybacked into place to log things. Let the engine stall with ignition on in order to come back and restart - see what rpm's will capture. If at all - could be that coil triggering won't work, or worst will use up vast amounts of time getting to work at which point you'll decide to utilize a 36/1 wheel anyways which will most definately work at those lower cranking speeds plus give best results.

KhanTyranitar · Post by **KhanTyranitar** » Wed Apr 29, 2015 5:50 am

I ran a test with my spare module. It gave the same results. No cranking was indicated. I have considered leaving the Microsquirt hooked up and running off the carb, to see if that produces a result, but we are definitely getting enough cranking speed to register if low speed was the problem. So I don't think doing so would reveal anything. Its not simple to do either, since the wiring on the Microsquirt system is set up such that it is as hidden as possible.

Setting up the trigger was supposed to be one of the easiest parts, yet it is the only part that isn't working. I'm about ready to give up on the basic trigger idea.

I'm thinking a 4" 36-1 trigger wheel off the crank might give a good reading. Just to be sure, to try this method I need the following?

http://www.diyautotune.com/catalog/361- ... p-182.html
and
http://www.diyautotune.com/catalog/hall ... p-479.html

Are there any other circuits that would be needed?

I'm thinking if I go this route, I will probably set the computer up to control ignition.

billr · Post by **billr** » Wed Apr 29, 2015 6:39 am

Has this old beast been converted to 12V, or how are you handling that issue? I would use a larger wheel diameter, if you can.

KhanTyranitar · Post by **KhanTyranitar** » Wed Apr 29, 2015 6:42 am

It is already 12v. It has been converted to negative ground.

DaveEFI · Post by **DaveEFI** » Wed Apr 29, 2015 7:04 am

Assuming a four cylinder triggered from the points or whatever, it will produce 2 pulses per revolution. With a 36-1 crank wheel obviously something like 36. Since I've been playing with a gear hall sensor to make a cam position one, I'm pretty certain the actual VR input circuit will read at any speed down to zero - ie from DC upwards. Many cam position sensors as used with MS produce only one pulse per revolution. It also shows a pulse of sorts on the tooth logger - so must be getting read by the processor too. If any of that helps.

KhanTyranitar · Post by **KhanTyranitar** » Sun May 03, 2015 12:31 pm

Ok, did more tests this weekend. So far my conclusion is that the Pertronix unit is completely incompatible with the Microsquirt. No matter what circuitry and attempts I have tried, I cannot get the Pertronix ignitor to trigger the Microsquirt.

I was however able to get trigger events using a VR sensor. Im thinking I might be able to rig a VR sensor element inside the distributor and use that.

billr · Post by **billr** » Sun May 03, 2015 2:01 pm

Yes, adding a missing-tooth type wheel in the dizzy would be a viable option. Adding the Pertronix just increased the confusion. The dizzy wheel should have two missing teeth, 180 degrees apart, so that it is effectively a crank wheel. I don't generally like using a "crank wheel" in the dizzy, but I expect this old engine has timing gears, so slop will be minimal; and the performance level of a Hupmobile is probably low enough that spark timing isn't all that critical.

racingmini_mtl · Post by **racingmini_mtl** » Sun May 03, 2015 2:44 pm

billr wrote:The dizzy wheel should have two missing teeth, 180 degrees apart, so that it is effectively a crank wheel.

That is not necessary (and maybe not even desirable). Actually if you have a single missing tooth, you can have sequential injection or ignition (depending on the engine and hardware) with a single tach sensor.

Jean

KhanTyranitar · Post by **KhanTyranitar** » Sun May 03, 2015 3:36 pm

billr wrote:Yes, adding a missing-tooth type wheel in the dizzy would be a viable option. Adding the Pertronix just increased the confusion. The dizzy wheel should have two missing teeth, 180 degrees apart, so that it is effectively a crank wheel. I don't generally like using a "crank wheel" in the dizzy, but I expect this old engine has timing gears, so slop will be minimal; and the performance level of a Hupmobile is probably low enough that spark timing isn't all that critical.

The Pertronix unit was already there, thats how this engine was run at some time in the past, since old fashioned points were so unreliable.

We might be able to read off the magnets from the Pertronix unit, or to read the stock lobes if they are pointed enough.

Yeah, timing is not that critical.

The tricky part is keeping it all hidden.

billr · Post by **billr** » Sun May 03, 2015 4:23 pm

racingmini_mtl wrote:
billr wrote:The dizzy wheel should have two missing teeth, 180 degrees apart, so that it is effectively a crank wheel.
That is not necessary (and maybe not even desirable). Actually if you have a single missing tooth, you can have sequential injection or ignition (depending on the engine and hardware) with a single tach sensor.

Jean

Yep, my mistake. A single missing tooth on the dizzy wheel will tell all the ECU needs to know.

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