Mrmerlin

weak spark takes about 20 seconds to figure out,
get a spare plug,
pull one of the wires off the plugs,
insert your spare plug ,
attach a ground wire to the electrode tip and then crank it look for the spark

mnotz

Had a bit more time today, so I checked a few more things. A grounded plug produces a spark. Hard to quantify in bright daylight how strong that spark is just by looking at it, but there is definitely a visible spark in daylight.

Went through the entire ignition troubleshooting guide in WSM - everything checks out perfect to spec - coil, resistors, distributor sensor/green wire, voltage during crank and so on. Checked cap and rotor, which also seemed fine. Tried some carb clean and some ether again - nothing. Not a cough.

I am slowly thinking something crazy must have happened the moment I pulled into the driveway - it's just SO weird for anything like a bad cam/sprocket mojo to happen just then. I guess my next course of action is grabbing the compression gauge at the shop next week and check...I am still just as stumped as before...

docmirror

Properly timed spark, you spritzed carb cleaner and no fire? Take the air cleaner off, and spritz right down into the TB intake while cranking. Hold throttle open a bit too.

This is weird.

mnotz

That is exactly what I did...yet nothing. Not even a burp. I am just as baffled, believe me!

Mrmerlin

did you pull the connector off the computer and check for corrosion its under the 14 pin connector in the engine compartment

mnotz

Hahaha, great minds think alike ;-) I did, since I checked the whole run from the connector pins to the distributor sensor, and de-ox'ed the pins for good measure.

Thanks for keeping the suggestions coming - I really appreciate it, because I am wrecking my brain over this...

GlenL

So this is an '80 with L-jet ignition?

It's not sensible that the spark is good but your didn't get any response with the starting fluid.

I'd check the timing while cranking to see if it's firing repeatably and near TDC. If that works, I'd try the starting fluid again and fog it a bit more. Remove the air cleaner, prop open the door and blast it into the plenum.

mnotz

Yes, it is an '80 L-Jet, and I agree, it does absolutely not make sense that it doesn't even cough with ether (with air cleaner removed and propped open door and spraying into the plenum)...that's why I am so frazzled. Even with spark timing way off, once there is a bit of ether in the cylinder and a spark, it would burp at least I'd think.

I have a feeling there is something I overlooked, and feel like a total idiot once figured out. Especially since so to say, "this isn't my first rodeo" when it comes to cars, been around and working on cars for the last 30 years, but this one really has me scratching my head...

GlenL

It is weird. It won't spark unless the distributor is going around so the cams are moving (at least one) and the T-belt is moving. I could be problems with ignition timing and, possibly, green wire weirdness.

At least it died at the house.

mnotz

Hahaha, YES! It did! Was in the driveway and in the right spot too :P And, see, those are the few things you don't think about when you start to "overthink" - you're absolutely right - if the left cam wouldn't turn, the distributor wouldn't either...and the belt is there, tension and tracking seem just fine.

Green wire *tested* good according to WSM specs for resistance including entire wire run. But, maybe I'll hook the scope to it and see how good the waveform looks, just in case. Everything I could test on the module I did test according to WSM, and it checks out fine.

So back to the thinking cap...I'll do a manual TDC / distributor position check when I check the compression...just in case something weird went wrong...


Thanks,
Marcus

docmirror

Uh, you said you followed the ign troubleshooting completely, and I asked specifically about a properly TIMED spark. You mean you don't know if your spark is properly timed or not yet?

mnotz

No, I do not know that yet - the guide in the WSM that I followed was the flowchart that covers coil, resistors, sensor, green wire, module. The TDC/timing step was what I am planning on doing next as I had mentioned above. I figured I do that when I have the compression tester here to check that as well. Probably won't happen until Thursday night though.

Thanks for following up on this!

--Marcus

mnotz

Holy thread resurrection, baby!

BUT, since I already feel bad enough that I totally abandoned this thread and pretty much the whole forum because of a few unforeseen circumstances, and over the last two years spending almost every free minute after work and on weekends to build a shop bigger than the house attached to it with the help of my awesome wife. Feels good to finally be back in the game of working on cars, and having a nice heated and air conditioned shop that is almost complete now to work in! Makes all the difference!
Anywho, I was moving cars around the other day and figured I push that '80 into one of the bays to get back to figuring out what's going on with it. Didn't get around to do much for a couple days, last night finally had some time and went through fluids, etc, etc. All looked good, dropped in a battery, evaluated the electrical system and figured I give it a crank. Yes, obviously...just as you expected, the damn thing started right up after a few revolutions of the starter. After sitting for 3 years. After it not starting no matter what I tried. Started, runs, most of everything working just fine, valve train noise went completely away after idling a few minutes and she sounds awesome. Little bit of a rough idle, but I am sure some fresh gas will fix that.
So here I am with the worst thing that could happen to a mechanic - the problem went away without fixing it. Now the real detective work starts, because obviously I don't want to have the trailer sitting ready every time I take her out...stay tuned!

Good to be back!
--Marcus

Mrmerlin

well what was the last thing you touched?
I would say you have a bad connection at the battery

Zshark

Could there have been some moisture causing a short somewhere that has dried up in the past years, now leaving an intact circuit?