Ok,
As recommended by the very helpful SubFord. ! month ago my 93 f250 5.8 on an uphill pull ,popped ,stuttered and shut off. I crested hill and coasted into a mini market . No restart, no spark. Pulled cap, found broken rotor . Aha! not so fast ... , I had new rotor and cap for intended tune. Still no spark.
Friends house , power to coil hot(12v+-),no signal flash. new tfi (remote,Grey)module . Still no spark, no pip signal at #6 wire shaved at module.
Read Codes , had 4 xxx,334 egr ,cm 212 pip no output,xxx ,the x's are the 2 codes that are on the missing sheet of paper .
Frozen distributor, swapped in Junkyard dist and ecu , from 93 f250 5.8 hd (but Auto) . Still no go, disconnected ecu again ,no spark.

Today ,Installing pick up assy and new cast iron gear broken because of poor shop practice(me) .

Question 1 Does ecu get ground thru harness or case ?
Question 2 . When I have verified pip output on bench , I should have spark with ecu disconnected unless I have harness problem.Correct?
Question 3 Pinout testing and values for ecu and tfi module simple enough for me to follow.

I need help.

 

Yes and no. There are two ground circuits inside the ECU. But the main grounds are at pin 40 & 60 and not connected to the case. They go through a black wire with a green stripe and hook to the NEG post of the battery.

Yes if you have power from the Ignition switch to the Ignition system (coil, ICM/PIP).

I do not know what transmission you have so I will post the ones for the AUTO.



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To review, you've already replaced all the items that typical result in no spark - TFI, PIP, PCM. One thing you missed is the coil, so it might be worth swapping that at this point.

However, before you do that, have you verified that the rotor is actually spinning? You could have a mechanical failure.

 

What about the 175amp fuse? Very rare for it to pop but has happened before.

 

There are no 175 amp fuses in an 1993 ford truck.

 

I guess it's only on the 97 and up trucks then because this same thing happened to a friend with a 98 f-150. Had to replace two 175A fuses.

 

Right. And even if it did, that's related to power distribution. This is an ignition issue.

 

When my friends went out he still had acc power.

 

Ok ,
I will recheck rotor movement

I had power to red (12V) wkire on harness side of distributor connector , just test light, will recheck for voltage

I had power to + side of coil ,will check for battery voltage,

I had power at both sides of all fuses in box and swapped horn relay with ecm or fuel relay,not sure which now

I had no power to signal side of coil ,with 6/12 volt testlight will recheck with meter .

I will install known good coil for giggles , i will disconnect radio cap for fun

I am using new BW pickup in original distr,and new Standard ign TFI,
module

Installed and removed jy parts were distributor,ecm no help .


Question , is it possible for broken ignition switch and or connector to power starter solenoid, and not ecm ?

Above question illustrates lack of schematic ,and help at site .

I will probably have towed to someones shop and start pitching food and heat money at it or scrap ?

 

They are generally very reliable but I recently had a no start condition and since I had backup parts I swapped out everything BUT the coil with no luck. Finally, I swapped in a new coil and of course, it started right up.

I don't have the schematic in front of me, but I would say only if something in the PCM circuit (EEC relay or the computer itself) has failed.

 

You do not need the ecm hooked up to get spark.
But the ecm is powered by the PCM Power relay and the PCM Power relay is powered from the same wire as the Ignition coil, circuit #16 R/LG.
A test light is enough for the test, you do not need a meter.





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Ok ,
little progress dead battery lost access to electric ,welcome at spot apparently worn out .

Tested coil .8 ohms + to - terminal ,8200 ohms either term to output .I have lost track ,these are normal range ?

When I swapped in new pickup ,tried to get spark from coil by spinning distrib by grounding distrib against a/c comp bracket . No spark seen ,but seemed to be plenty between dist body and bracket .

Should there be that much current there ?

I will try to install temp ground to dist and hot wire to coil when I return to truck with new battery.

No matter outcome, I appreciate all the help I have been given.

Regards,Ed Flanagan

 

After I had spark it still wouldn't idle or rev up . After exhaustive other testing,I dropped the exhaust and voila ! It now revs up ,the cat was melted.
Replacement cat installed. All good except my bank account . Many spare parts .

Oh yeah,also pumped tank empty and installed new filter ,long overdue.
and new plugs and cap and rotor. These few lines can not describe the screwing around and carrying on and towing and freezing hands and everything else.
Regards,Ed Flanagan

 

So was it indeed a failed coil that was responsible for the no-start condition?

Assuming you installed a new cat (or even if you didn't), you should want to know what caused the cat melt-down.

FWIW, I blew out a tire the other rainy night on the parkway. These things never happen on a sunny day in June in a parking lot.

 

Probably primary was either coil and / or pip ,coil had .8 ohms primary and 8200 ohms ,both normal . I could not confirm pip signal ,nor spark, until icm ,pip and coil were replaced .