Pickup coil wires p & n

[S.O.B.B.]

Thank you.that helps a lot.I don't know if my timing is iratic at higher rpm as about 4300rpm is as high as I've had it.from the first time I got this to fire it's felt like I'm not getting the power it should have.I started thinking the same things.valve spring or lifter.cause this engine sat in a bagged crate for near 20 years.I thought about it but all my spark plugs look about even.the distributor is in factory form running factory direction.but the ecm I'm using gets the pickup coil signal the opposite of what its now getting.I found running the advance much higher it seemed more responsive.but to much ping. I think I'm gonna try swapping the wires and play with it to see if it resolves this.I've been playing almost daily with this tune for 8 months. I didn't realize I was having fuel issues again till I couldn't Rev it.put in new tank and new e2000 inline pump.since then I've still played daily with tuning but far less correction and more consistent data.thanks for your input.that gave me something to try.I wanted to have it running properly b4 attempting 7427 pcm swap.thanks again

[lionelhutz]

I would say it is correct if you align the reluctor points at TDC and get close to 0* spark when you start it with the bypass wire disconnected.

The ECM does not receive the signal from the pickup coil. The ignition module receives the pickup coil signal and conditions it for the ECM. So, the ECM knows nothing about the coil connection direction. The pickup coil connection will not have any effect on the electrical signals that pass between the ECM and the ignition module.

[S.O.B.B.]

Thanks for more input.so reversing the distributor rotation would not change the signal from the icm to ecm. That leaves me a little confused.from what I had read about the variable reluctor and how the gm set up works I was understanding that reversed rotation is equivalent to reversing the pickup leads and does make a difference in the signal output.or is it just the time of the output signal.something along the lines of reluctor puts out a zig zag wave of current .rise/fall.icm converts that to square wave form.halfway it inverts the voltage so it continues to rise.so u get the strongest signal from the end of the square wave.if wires backwards or reverse rotation it gets the signal at the beginning of the square wave.something like that.I don't have it here to quote.I hope I said that right. I'd like to understand why it does or doesn't make a difference. Is there a lot off disagreement on this I'm unaware of.thanks for any enlightenment.

[S.O.B.B.]

This is a screen shot so sorry for the small print.I realize this is microsquirt related.just figure the hard parts work the same.same parts numbers.just opposite rotation. Screenshot_2018-06-21-04-33-26.jpg

[lionelhutz]

The signals that go to between the module and ECM are not affected by the coil connection. Reversing the coil will not affect the signal levels or what the signals look like as they switch on and off. However, reversing the coil messes with the signal conditioning inside the ignition module and will change the timing of the signals going back and forth between the module and ECM. In other words, the coil reversed messes with the timing, but it's not something that can be corrected in the ECM or that the ECM could even detect by watching the signals it receives.

The last time I set-up a TBI I set the timing marks to 10* and then aligned the reluctor teeth. It started fine and was fairly close to the 10* base timing I wanted to use. So, I'd still say that lining up the teeth a TDC and then seeing close to 0* base timing once started says the coil is correctly connected.

The distributor is built for that rotation, correct? I'd fully expect that if you ran a distributor backwards, the rotor would be off from the posts. On a clockwise rotating distributor, the posts should be further clockwise from the rotor location when the cylinder is at TDC. The location should allow the rotor to hit the post as the timing advances through the ~10* to 50* range of the timing advance.

[S.O.B.B.]

Ok so my engine and distributor are a factory set up.ccw is the direction it was designed to run.so being that all the hard parts are the same and wired the same (only diff from a corvette dizzy is the lower half uses a shorter configuration so shaft. gear .and lower part of casting is all I see different)but spins ccw instead of cw.so my question to this is it must be the ecm that receives the output signal it requires.so the factory cadillac ecm received a ccw rotation signal. I'm using a 7747 that received a cw rotation signal.so does running it this way make the ecm think the signal it's received is not right. Is this something I'd see some how in logs. As I said.it just has this said light miss feel to it that I have not been able to solve.I hoped this would be clear and easy so as to eliminate mechanical issues that my spark plugs say are not there.but thanks for more info.your help is greatly appreciated.

[lionelhutz]

I'll try to spell it out clearer. The signal the ECM receives from the ignition module have no direction information. It's just a pulse each time the ignition module detects the reluctor teeth pass each other.

[S.O.B.B.]

Thank u for clearing that up.I'm gonna post a current bin and logs etc.maybe someone can have a look and tell me if I have the correct info to aquire correct data and if anything odd stands out.I've never done any other ecm tuning b4 so I'm unsure of if the data I'm getting looks right at all.thanks for your time.