quote:

Originally posted by "The Bender":
Mark, I don't have a problem, but figured I'd ask for future reference. I run an 8+ with the grid controller, is this considered analog or digital, or both?

Ignitions with plug in chip (resistor) rpm / degree ports will be analog.

If 7730 Grid control, which is Digital, is used with an analog ignition in the Legacy mode, I believe that this is still considered Digital because of the control.

When I remove the 7720 and plugged in the 6al to the 7730, the ignition timing remained the same in my engine as I recall. I did not put my patch cable in to see which way the timing would move with 6al. The car did run the same et with either 7720 or 6al installed. And this was with the HVC 2 ignition coil attached to 6al which is not recommended by MSD.

I'll have to put my patch cable in when I have 6al back in the car just to see what the timing does.

Verify the MSD box is wired straight to the battery. Probably not the problem, but it can't hurt.
My car was originally wired to the alternator and grounded to the frame. Rewiring it straight to the battery cleaned up some electrical problems I was having.

Well after putting in motor in a friends car. I can say that it is something in my electrical causing my problems. Went out last night and ran perfect with my fuel system on it also. So now to find my cause looks like it will rewired in the near future.

Glad to hear you found it.

quote:

Originally posted by jimmyc:
Well after putting in motor in a friends car. I can say that it is something in my electrical causing my problems. Went out last night and ran perfect with my fuel system on it also. So now to find my cause looks like it will rewired in the near future.

When re-wiring and if presently using a relay board, consider replacing the board along with the switch panel.

quote:

Originally posted by Curly1:
"Maybe it"s the Engine"

Congratulations! You are getting closer!

For a motor to fire it requires AIR, FUEL and IGNITION source. Not seeing Converter on that list. Just saying.

That makes a lot more sense when the ENGINE is missing, banging and popping to look at the engine than say Converter or tires. Stating the obvious for those oblivious to Facts and clueless to how things work.

Fact is the motor is missing because it has and electrical issue (Bad Ground, box, switch or other component or wire), Fuel issue (Carb, float, bad fuel etc) or Mechanical engine issue such as broken valve spring.

Now you have narrowed it down to a wiring issue. Are you planning on checking everything or just rip it all out and replace everything?

As it sits there is no type of relay board in it. There is 5 relays and a 4 fuse panel on the firewall in front on my feet. I would love to find the wire causing the issue just for the satisfaction factor of it, but I may just rip it all out.

quote:

Originally posted by jimmyc:
As it sits there is no type of relay board in it. There is 5 relays and a 4 fuse panel on the firewall in front on my feet.

Because you have few relays something like this could be an inexpensive update.
Digital Delay Panel

Well let me ask you this Mark, would you redo the whole wiring or just the switch panel like that, and leave the gauges and delay box alone. I’m not sure what way to go with it. I’d like to redo the switch panel for the updated look and the msd stuff but not crazy about the gauges and delay box being done.

If it were me I’d go least expensive way possible. Leave your gauges, delay box and Shift coil. Just replace the wiring to / from these and everything else. If using a separate relay for the shift, replace the relay with a new one.

When I last did mine , the only wiring I keep was to the analog gauge lights. I R+R everything else.

That’s what I’m leaning towards doing. Thanks

quote:

Originally posted by Bucky:

quote:

Originally posted by markemark:

quote:

Originally posted by Lenny5160:

quote:

Originally posted by rusty:
if this thing is not fixed ,just for grins reverse the trigger wires.i had a friends car do the same as yours and it fixed his

Good call. Don't just swap the wires and make a pass. Check timing, swap pickup wires, check timing again.

You want to run the wires in whichever configuration gives you the lowest timing advance.

With a digital MSD box, you want the configuration that gives you the highest timing advance.

This is where I believe this polarity problem could occur the most. On analog ignitions like 7al2 , 7al3 or MSD8, these ignitions require you to land the trigger wires on the correct M- / M+ terminals. Sometimes mistakes are made.

On the rare occasion, it's possible the sensor could be wired incorrectly. With ignitions that have the mating plug pigtail this could possibly (rare) be wired incorrect. Same goes for the cable connecting the ignition to the trigger.

Here's a PATCH CABLE I made to switch polarity of the trigger sensor quickly .

Don't VR sensors' leading and falling edges look considerably different? EFI systems need to know leading or falling edges.

VR sensors produce a sine wave with varying amplitude (voltage) and frequency (rpm). At low speeds the voltage output is very low, and the sine waves are spread far apart (like AM radio). At high speeds the voltage output is very high, and the sine waves are much closer together (like FM radio).

The problems with VR sensors are: Low speeds = low output and the device "reading" that signal has to filter-out the noise included with that small waveform. That is why you would try to get the sensor close to the magnet to help generate more voltage. But.... if too close, it can generate too much voltage for the device "reading" the sensor and can cause clipping (in the audio world this is the sound of distortion). This is what can cause a high rpm miss when the sensor is too close to the trigger wheel. And too far, long crank times and sometimes a no-start situation.

A hall effect sensor does not suffer these issues. Will always send back a nice 5 or 12 volt signal no matter what the rpm is. And yes, there is a falling and rising edge and the ignition system or EFI system much know which one to use. Typically a falling edge is used.

I think someone said a hall effect sensor can be fed into the "points input" on a typical ignition box. I have never tried it. If true, that would be good for people to know.

I use a hall effect sensor from Holley that directly replaces the MSD VR sensor that most people use. It is feeding my EFI system which can be setup for either type of sensor.

Bored from reading all this yet.....

quote:

Originally posted by jimmyc:
Well after putting in motor in a friends car. I can say that it is something in my electrical causing my problems. Went out last night and ran perfect with my fuel system on it also. So now to find my cause looks like it will rewired in the near future.

Did you use his converter or yours?

Mike,

So you’re saying that the Hall effect sensor can be used with an MSD ignition but must be hooked to the points input?

It’s his converter

Well then according to eds wisdom it could still be the converter.

quote:

Originally posted by Cashflow:
Mike,

So you’re saying that the Hall effect sensor can be used with an MSD ignition but must be hooked to the points input?

sure would be nice to use a hall effect with a non EFI ignition system.

quote:

Originally posted by Cashflow:
Mike,

So you’re saying that the Hall effect sensor can be used with an MSD ignition but must be hooked to the points input?

I am pretty sure someone said you can do that. Not sure if the sensor I use from Holley sends 5 or 12 volts out, and not sure what the typical MSD points input needs. Obviously it was designed for 12 volts coming into it, but I am curious if it would work properly with a 5 volt Hall Effect sensor.

Now, most Hall Effect sensors simply switch the output from ground to the rail voltage, which in our case is either a 12 or 16 volt source. Some do have a built-in 5v regulator so they can be hooked to a wide variety of power sources, from 6 to 24 volts, and still output a nice clean 5 volt signal.

Update?