Pickup coil wires p & n

[delcowizzid]

If you have the positive and negative backwards it will retard timing as rpm rises and will misfire and carry on no matter what you do tuning wise

[S.O.B.B.]

Thanks.I neglected to mention.I did try to reverse the wires this morning but it would hardly run so i put it back the way it was.same as is wired in a pic of a new distibutor.I had the dizzy at 10°advance and my bin b4 i started messing with it as thats the cadillac spec.put the crank at 0°TDC on #1 compression stroke and aligned the reluctor tabs on the pickup coil.changed initial advance to zero in my bin.then started it with bypass disconnected.it was at about 2 or 3 ° atdc.so I advanced distributor till timing tab at zero.reconnect bypass.unplug ecm to clear codes.start it and ran Decent.I then did the testing to try and figure what spark latency should be which is when I saw that at the crank I was getting about 30 and tprt sa hack says same.but that was with a chip with entire timing table at 20°.so I'm kinda stumped.went back to the garage to compare distributor to pics.still unsure if the difference I see makes much difference.I did the zero setting to see if that would change the miss feel.I did end up changing my main spark bias from 0 to 10 and that changed what tprt reports for timing.less that ten. I didn't get the chance to look again with the light to see if it was 10 less at the crank but id bet so because i could feel it and hardly any knock count.as compared to b4 the main sa bias change.

[S.O.B.B.]

From some bins I looked at from f body and y body tpi cars with large cap hei none are initial sa zero.they have 6° advance for most.one f body had 10°.so I'm thinking a reason for this.I don't have 2 distributors on hand to verify if there is any phasing difference. Anyone know for sure? Or why the difference in initial advance from large and small cap?back to reading and searching. No adjustable rotor for hei that I see.only way I can think of getting phasing adjustment is to use a hei vacuum advance style housing with all the parts from cc hei and make an adjuster for the pickup where the vacuum was.I don't know if that could work.

[S.O.B.B.]

Found some cam specs for 4.9 which I believe is identical to 4.5.Screenshot_2018-05-29-02-29-28.jpgScreenshot_2018-05-29-02-29-08.jpg can anyone tell me how different this is compared to a stock 305 tbi

[delcowizzid]

If you swap the wires round it shifts the timing a long way will need to reset base timing for each wiring polarity

[S.O.B.B.]

Delco wizard you sound familiar with this.the top of my cadillac distributor is identical to corvette large cap.same part numbers for pickup coil and icm.its wired the Same.only it spins ccw.I'm using a 7747 which the distributor spun cw from.does it sound like this could be my miss feeling problem.I don't know if it could even be set up and able to run if it wired opposite. Been driving it 8+ months.when I did reverse the wires I did it with it set on #1tdc and could not see the timing mark.hence I didn't even try to advance it to see if it would run better.I thought if the p and n is wired correctly then when u set to Zero and start it that it's supposed to be within a few degrees and if it's far off its backwards.this leaves me confused.should I have it backwards so ecm gets the correct signal for drp. Any advice is appreciated.

[delcowizzid]

The pickup coil could be wound different which would negate having to swap wires around but if its the same part number as a coil to suit the opposite rotation I would try swap it arse about colours wise and reset base timing and see how it runs.ive had Chinese distributors with the coil wound backwards or the coloured wires soldered on wrong that run not right till you flip the wiring .same with msd dizzys they say they can be wired either way but in practise its wrong the signal shape is totally different and things like rev limit dials on some msd boxes do nothing when the pickup is backwards
I just fixed this exact problem in a 351 Clevo wouldn't rev out sputtered up top low power on the dyno everyone the guy took it too did stuff one said lifters one said valvesprings so they just fitted new lifters nope fitted new heads with heavy springs nope tried other dizzies and mad boxes nope .I turned up reversed the wires for backwards spinning dizzy and set timing its an animal gained 2 seconds on the 1/4 and no more eratic timing above 4500rpm and low and behold his rpm limiter now works lol