87 cranks weak spark has fuel no start

[boogieman]

well im stumped..87 4x4 manual has been running great with 257k now, bought with 232k..had it stop running close to home headed out on a trip, was pretty cool at this point i.e. not heat soaked, towed it home, diagnosed weak yellow spark, smelled gassy underhood, checked fuel pump and pressure anyway was good, got it to start, tapped on igniter and afm(likely coincidental)...decided to replace coil, went on trip 600+ miles into the mountains, didnt miss a beat. got my usual 19 to 24 mpg, fast foward 2 weeks, gas up for trip, drive home to pack, get ready to go and no start..same scenario, definitely gas getting to cylinders, spark seems yellow and weak..so.8hrs in today:

try 4 different ignitors, i know i at least tested 2 or 3 of these previously
change coil from oreillys china to rockauto bwd taiwan
have 12v to coil +
air gap good, over .008"
pickup coil ohms out but swap distributors anyway
cap/coil/wires
swap ecu (never tested, junkyard, but for same van)
all fuses checked swapped ign relay and circuit opening relay
cleaned at tightened ground at intake manifold and 2 main negative connections to block and body (where do the rest of grounds live?)
fusible links all good
battery in good conditon cranks strong
checked ignition switch continuity
no codes..although i did wire my kill switch to the efi fuse if i recall correctly, wouldnt advise that one)


concerned maybe the plugs were too wet during some of the operations but never saw a nice fat blue spark, letting everything air out now, ive got fuel leaking out of exhaust couplings..

what an i missing here? thinking grounds somewhere else? what about this capacitor? mounted to the side of the distributor?

also is there a simple way to disable the injectors while diagnosing for spark?

[boogieman]

interesting development today, day 3, although my spark doesnt look super fat and blue after many coil, ignitors, etc. i let it dry out over night and pull the circuit opening relay and put the fuel pressure gauge back on...the van starts and idles with no fuel pressure?!? wont take throttle and has a noisy lifter or two..i check oil and theres quite a bit of gas in it now..as soon as i plug the COR back in it dies, fuel pressure reads just shy of 40lbs and bleeds down right away, when power is cut, i can almost hear the fuel pissing out an injector!!! i just checked the resistor solenoid and ohms out a tad high but im not condemning it...buried back in the fsm now but what would cause a stuck injector or cause the ecu to hold it open..maybe just old age and/or debris?

edit: hit #1 and ,#2 injectors with 12v and clicking like it should, also used a noid light and it shows pulsing at connector. when i use the fuel pump check connector without cranking it holds fuel pressure (38lbs for over 2 hours) but if cranking it bleeds down immediately..tried with cold start injector unplugged and the same..

i can pressurize with the jump connector and turn key off..as soon as jumper is out and i turn the key to on, pressure bleeds down immediately...into the engine im assuming...wtf?!?!

tried my spare ecu, same result...
afm checks out on all the resistance tests..

[boogieman]

well, its running perfectly once again..what was it? dont have a clue.. as usual ill jump to conclusions and chase my tail for a while, but it did seem like weak spark not being able to ignite in the combustion chamber leading to wet plugs and no start, until i noticed how much fuel was getting introduced and put the guage back on...last things i was doing was checking for grounds and powers at ecu, i had done some inconclusive tests at the injectors and connectors to injectors, wiggled the efi main relay...decided to give it a crank and it fired immediately and is running as it should..w t f
i did notice the efi relay feels a bit warm to the touch, ill be replacing that one to check, i dont believe it should be getting warm..

so im still trying to figure out what would cause the inejectors to open and dump all pressure when key is to 'on', since its running proper now it doesnt do this...i dont have alot of confidence in ol blue right now, shes always broke down close to home or in the driveway though, so shes a keeper...

[boogieman]

well, i know your all on the edge of your seats and im pretty sure i found the culprit, shoddy wiring to injectors 3 and 4, i didnt want to split the manifold but glad i did...looks like PO spliced some connectors in and wiring was draped over fuel rail with no insulation...(tried to post pic), the only breach in the wires insulation looked like number 3, and not from the fuel rail but i think it was grounding on the air valve...been meaning to replace the brittle connectors and make a new harness, and have some peace of mind...if it still acts up, ill start another novel for yous all...

and please, insulate and protect wiring, especially in hard to get to places damnit

[skibum]

Glad it went well! I was scratching my head, and probably would have replaced condenser ( found out the importance of them, by chance one dark night in Missouri. on my old '49 panhead with points. Pulled points cover and sparks were flying all over the place, so I've never discounted the importance since :-) ).

[boogieman]

hey thanks, im not even sure its a condenser on the side of the distributor, its part of the pickup coil/test port...earlier in the week a friend asked if it was carburetor or injected..my response was it would be fixed already if it was carb and points...

[skibum]

Yep, the good old days!