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Sat Jan 26, 2019 8:21 am

My van is an 85, auto, with GW 2.2, running Digijet. Other than intermittent hesitation at tip off when engine is hot, and ambient temperature is warm, (which I determined must be a slight dead spot on AFM track), engine has ran great since install last spring. My MPGs had dropped very slightly and I decided a tune up would do me good. When spark plugs were out and engine warm, I checked compression. 162-165 all cylinders so moved on happy. Installed spark plugs, STI ignition wire set, and new air filter. Was working outside and cold front moved in early with rain so was in a bit of a hurry to wrap up. Turned over engine for about 5 seconds and it sputtered and wouldn't start. Checked engine bay and found that in my hurry I had switched #1 & #2 ignition wires. I corrected #1 & #2 wire placement, but it was cold and wet so decided to call it a day. Next day, engine fired up on first try, idle smooth, no hesitations.
I like to check ignition timing when I do a tune up so hooked up the light and.........no timing marks to be seen on pulley. Turned off engine, scratched my head, restarted, still no timing marks to be found. Pointed light to sides of pulley and determined after 3 restarts that the timing marks must be on bottom of pulley with engine running. I sat down, scratched my head some more, and after a few minutes, restarted engine, pointed the light, and timing marks were now exactly where they should be at idle. I started, restarted a couple of more times with timing marks remaining on top and ranging right at the seam at idle. Checked timing at all in which is about 3700 rpms for this engine, and timing was slightly above 40 degrees, which is where it was set at last check in June. Last spring, when I was chasing the hesitation issue at tip off just after engine install, I adjusted timing for a couple of days to see if that was the issue but those ranges always stayed between 35 and 47 advanced until I settled on around 40. Timing has been set since that point at slightly above 40 degrees advanced, and was rechecked in June before a long road trip.
Since timing appeared correct, and engine sounded good, I went for a test drive. Drove great, good power, no hesitation, steady idle. I parked the van happy that everything seem to be in order, but still confused on how the timing marks were at 180 degrees off and then somehow self-corrected with no change in engine performance at idle. Seemed impossible to me.
Next morning (yesterday), went to start engine, turned over but no start. Didn't backfire or stumble, just turned over and appeared no spark.
So today I am going out to do the usual FI diagnostics realizing that I may have jostled the distributor when changing the wires. I have a new distributor that I will probably drop in, in case I damaged the hall sensor plug. But keep in mind, I did a long test drive with no issues at all the evening before.
BUT, my main question continues to be, how could the timing marks, with engine idling smoothly and starting without hesitation, be 180 degrees off, and then self correct?

Sat Jan 26, 2019 12:42 pm

Was your timing light connected to the correct plug wire? Could it have been getting interference from an adjacent wire?

Sat Jan 26, 2019 1:01 pm

MayorMcCheese wrote: Was your timing light connected to the correct plug wire? Could it have been getting interference from an adjacent wire?

This ^ It didn't self-correct (it is impossible), you were just getting interference from an adjacent plug wire. You could be on the right track re: damaged hall sensor (if you indeed verified no spark). Would be worth checking for voltage at the coil, and that there are no cracks present in the dizzy cap.

Sat Jan 26, 2019 8:25 pm

Yes, timing light was connected to #1, but didn't even think about adjacent wire interference. I knew it was impossible with my brain, but my eyes were trying to convince me it was, and then when the engine didn't start again, crazy thoughts bounced around in my head.... As for the update, I worked my way through distributor/hall sensor, to AFM testing, double checked new wire set connections, then went back to ignition coil. Spark test showed spark from coil wire but it seemed weak to me. Was going to check voltage but remembered I had the OEM coil so I replaced the less than year old Bosch with my original 1985 ignition coil, and she fired right up. Idle steady, ignition timing right on, crazy thoughts put to rest, new coil ordered. Faulty coil may explain my loss in MPGs.
Thanks for the responses.