I confirmed the green wire potential and yes the green did have source 12 with the key kept in the on pos.
this is normal so,, i have to conclude as well that since its the job of the TFI and PIP to switch on and off the ground potential to the coil (green wire) then the dizzy pieces parts must be the issue.
I will try to find a complete dizzy with "STANDARD" branded tfi and pip.. meaning i want the highest quality / rated as such dizzy money can buy.
TFI is Gray the PIP might be bad as well or going out. we will see.
so....after several days of this problem not showing up ,, it did today.
so with key still i the RUN pos i tested the following.............. -TPS org to blk= 5v =unplug spout and recrank but no spark. -poked at the shrader valve and fuel went everywhere. -confirmed no spark at coil -the red wire at coil had 12v -****i am 80% sure the green wire had zero volt but this confused me because after my tests,,, i went to key off then key back on to retake coil voltage readings. the red had 12v,, the green had 12v. when it breaks again,, i will double down on the green coil trigger wire to see if it actually did hold a zero volt condition
sorry for late updates but i decided to wait till the car failed again... evidently it took a few days.
i do have a question though..... the TFI ign system is independant from the computer,, meaning,,, even without a computer installed,,,, i can crank and still have spark. the green wire the leaves the coil is controlled by the tfi.
the green wire sources from the TFI and goes to the coil,, ,, then from teh coil to the cluster tach and another run to teh eec through a 20 or 10k ohm resistor.
so ,,,,, i am not understanding how the 5v power sup in the eec can have any jurisdiction over spark?
thank you ,,, that clears things up. as i mentioned my son has almost the identical issue ,,, too bad i had him test bassakwards. i had him test with spout out before starting..... but i am going to follow what you said,, that actually makes better sense and i can see where your going with it now.
i did replace all three caps a couple years ago because one of the electrolytics was leaky.
sorry in advance of posting such an odd issue,, / problem but i am skeptical of moving forward till i get some more advanced opinions on or if this issue has ever been seen before.
short and sweet,,, i loose spark during drive and the car will not regain spark until i fully rotate the key to the off position and restart.
symptom. - while driving engine will shut down. -no loss of power to the IP, clock, warning indicators or speedo or elsewhere during the event of engine stop. There is no warning of hesitation,, not bucking prior to the event,, no odd "feels" to speak of. Its like someone just unplugged the car from the outllet,, it simply goes quiet in the cabin except for any accessory i may have on. My tach does got to zero though (the 87 20th is the full digi cluster for those who dont know. -I can not while coasting simply go to N and restart. -I must coast over to the side, put car in P,,, turn Ign sw off then restart which it does each time. -I do need to confirm if my fuel pump relay is loosing its trigger sig from the EEC or its high current contact power delivery,,, but i dont think so. The fuel rail does not seem to "sound" like its repriming when i turn the key from off to forward again,, trust me i know what that sounds like.
troubleshooting.... -yesterday i confirmed something. I coasted to the side of the road, put car in P, kept the ign sw in the run pos, popped the hood and removed the coil spark plug wire. I reached into the car and rotated the Key Sw from run to start and as the motor is turning over , the coil is not sparking to the car or anywhere. If i rotate the ign sw to the off pos then crank, sparks fly everywhere. So.... i put the coil plug wire back on and start up and go about my day. This is hapening without regard to engine temp, moisture outside, outside temp or anything,,, its just random and seems as though it only happens once or twice during a driving period of time. **Simply put,,,, engine spark will remain absent until i rotate the key sw back to the OFF pos!!!!!!!!!!!!!!!!!!! -while driving i have beat the hell out of the steering col , inst cluster as well as wiggle tested harnesses within reach and no results.
Comments............. A few months back i noticed that when i first start the car up, i can not tune into any AM stations for my regular Glenn Beck,, Rush L or Hanity shows. The signal is totally washed out by engine noise ,, not static or anything ,, just a constant whine high pitch. Eventually over the course of 15 or so min, the signal is clear enough to listen to but ,,,, its like only 70% there with 30% engine noise. Normally when i have an intermittent what appears to be electrical issues, i tune into an AM station with KeyON Eng OFF or KeyON Eng Running and perform wiggle tests on various connections while listening for voltage / current static induced by my interrupting any possible bad connections. This helps me quickly narrow down particular circuits that otherwise an EVTM may not as quickly reveal.
So.. the reason i bring this up.............. Yesterday when i started my short trip,, my radio was acting up as it normally does but soon the AM band cleared up for the most part. When i had my loss of spark,,,,, and did my prior mentioned test...... when i got restarted instantly,, the radio AM station was back to 100% washed out by engine whine or noise. It soon cleared up again.
Final thought........................... My son's 88 5.0L bird is doing the exact same thing.
Conclusion..... Although i have not pulled codes yet,,, what i am starting to think is that perhaps my computer has reached the end of its life or is getting there. ,, or Maybe that diode that appears near the coil is faulty and is over clocking an EEC chip or over charging one of the 3 electrolytic caps on the EEC PCB,, or ...... nevermind.
SO,,, thoughts on this very odd problem which simply fixes itself ??????????????
so,, we are now at a point of reverse... installing all the new things to complete the improvements and resto of lots of areas.
what i am currently stuck on is the rear window install... i mean stuck... its like the new rubber seal is just too beefy to allow the window to fully seat. we may have to go to the germany source for the seal instead of the one from airheads.
we are on attempt 4 ,, even with vasaline on the car frame and on the glass. the rubber is flaring "out" around the window.
we are up to 33 vids so far and i will post a vid of the problem we are currently having.
here is the youtube link with the testing done live
this was done in a controlled manner, there's no reason to use anything else after you see this.....
my lessons learned are............ use 25% phos acid most times as its more effective than using 50/50. I guess it has something to do with chemistry class. also,, the white ish looking residue apparently is 100% paintable from what i have seen by others.,, as well is the black residue. its almost like a primer layer self built upon the metal.
