Trailing firing before Leading
 

Coils and ignitors appear to be wired correctly, the green-stripe wire comes off the front-most coil and goes to the ignitor facing the center of the engine bay, the blue stripe wire comes from the rear-most coil and goes to the front-facing ignitor.

The most odd thing is that the car seems to run and idle fairly smoothly.

I tried swapping the leading and trailing high-tension cables and resetting the timing, and the car ran like POOP.

Leading:
https://www.rx7club.com/attachment.p...1&d=1383813480

Trailing:
https://www.rx7club.com/attachment.p...1&d=1383813480

The cables are not crossing in any way:
https://www.rx7club.com/attachments/...ene-runs-1-jpg

one thing that occurred to me is that maybe the anodized aluminum cable spacers are somehow crossing the signal?

When i'm hooking up the timing light, I do notice a slight staticky feeling when i bump the wires.

Another thought is maybe I need to ground something extra betterrer? Currently the engine is grounded from battery to driver strut tower, driver strut tower to starter motor.


This may be un-related, but is ignition based so i figure i'll throw it in - I have 2 RPM switches wired from the tach signal, and they are accurate 99% of the time but will glitch out and read way off-the-charts from time to time, like pop 11k rpm and back while the engine is only at 2500. Happens more frequently during rising rpm.

Any help appreciated, its like i'm taking crazy pills over here.

Well it looks as though I've got the trailing back to a 15 degree retard split, the pot was advanced all the way, however now the car can BARELY start and definitely doesnt run, backfires like crazy. Current timing is 0deg L 15deg T (after TDC), with the dizzy advanced as far as she can go.

I'm re-stabbing the dizzy, trying to get some more useable advance, but now she wont start at all, or rumbles and backfires for a bit (O2 sensor reading way lean), then dies.

Time for some more crazy pills, i think the old ones are wearing off.

When your engine was built, did the distributor drive gear go on correctly? It's directional. Old ones had and F mark. Newer ones have a bevel allowing easier install on the shaft (one side only).

try a non inductive " smudge " timing light in the dark
( ie.. one of those very nasty cheap timing lights that use the spark through the globe )

this will eliminate the possibilty you have crossed up signals

Yup this was my build, Bevel installed towards the rear Jeff, Geoff, did you verify endplay after switching pulleys? Remember that if something dropped out it also changes the position of the gear! As far as the ignitors go, I verify them by removing the distributor cap and verifying which plate the wires are attached to, verify it goes to the L or T magnetic sensor respectively, Canister should end up about centered. there truly is no way for it to be that far ahead unless something in there is switched. Should have called! I'll see you at FEST hopefully!!!

Jesus

Ah, you built the engine. Cool! Then I'm sure all that stuff is perfect. It's gotta be electrical... Maybe his timing light is one of those nearly useless expensive adjustable ones for boingers, or it's too sensitive picking up a slightly leaky adjacent plug wire.

I'm with Max Headroom up there. Get (borrow) an old school unpowered timing light or just hook a xenon strobe tube inline if you have the means (be careful as the voltages are high).

I once used an LED as a timing light. It flashed way too slowly while bench testing ignition on a MegaSquirt. Switched to a xenon tube. :)

Did u by any chance switch the coil wires in the cap maybe

I got the trailing back in the realm where it should be, the trailing advance pot was advanced all the way. Thats odd tho - I didnt think it was possible to advance the trailing past the leading??

As for the popping - apparently I had stabbed the dizzy 180 degrees off in an attempt at figuring out wtf, only to forget to put it back? Something, i donno. anyhow, thanks for the help Jesus, if it werent for the battery being dead from all that cranking I bet we could have got it tonight.

Got a charger - will give it another go tomorrow.