Stall and no start

Hello and thank you.

I have actually ran down all the wires off the ignition. Both when it starts and then again when it doesn't want to start. During those periods, the only thing that changes is the fuel injectors loose power. But nothing on the ignition switch / circuit changes. I replace the distributor because I know the camshaft sensor can keep the injectors off and I don't know how to test the kind I have, I was getting spark with the old one as well, so i'm pretty sure that wasn't it now. If it helps ring a bell, I can also add, after it shuts off and makes me wait, I touch nothing. I don't wiggle wires that could be barely loose, I don't continue to try and crank it, I just let it sit (with battery connected, it makes no difference). I will go back to it every hour or so, and tada ! It starts and lets me drive it back home.

Just a thought, could that be negative pressure bleeding off from the fuel pump? Could the fuel pump cause a condition to cause the injectors to panic and the time I am waiting is the pressure dropping? I am just spit balling here, although I have tested and confirmed the pump is pushing. The "wait until I say it is okay" thing has got me really stumped.

It idles in the drive for hours just fine (i literally let it idle for an hour), then less than five minutes under load and it does this.

Yes it will and I can tell you, I have no injector pulse during that period as well. Out side of the box, could a fuel pump cause the ECM to panic? What I mean is, it idles fine for a very long time and I know it doesn't take a lot of PSI for that, but under load, is when it does its thing. What if the fuel pump isn't pushing enough PSI under load and it causes the ECM to shut the injectors off. I don't know why it would take so long to "release" them, but eventually it does and it will start back up.

I understand you aren't here, and it is hard, but I will follow everything you ask and report back, and thank you for your help.

It is for sure fuel issue.

Okay, after testing I can 100% tell you, when it does this. I have no power to any of the injectors they are all dead. I do have spark, and will fire with starter fluid. But the injectors are completely offline. However, like I said, if I let it sit and do nothing at all, they will come back on. I have swapped out two different ECM's (three total including my original one) and the behavior is the exact same.

I replaced the fuel pump and ECCS relay just because, and it didn't change anything. I have good pressure at the rail.

I really feel like smtg is turning them off and then cooling down or doing smtg, and then they turn back on.

It cant be a loose ground, because I am not poking around in the engine bay or messing with anything, I just let it sit.

Could another relay be failing and then that little piece in there makes connection again? Maybe a sensor?

Okay, lets go another way. Do you have a pin out for the ECCS? I can check if it is sending the signal to the injectors and then check if the injectors are getting it. Then I can back track and see where it the breakdown is.

Okay, I was able to find some information, and I will post my results here, if you can fill in the missing pieces, I think I will get it. I am starting to think I have a faulty injector harness. There is a plug labeled 101E / 70M (page 180 section EF & EC factory manual) that is the plug that connects the injector harness to the ECM. 101E side goes to the injectors and 70M side goes to the ECM. It is located under the hood. I disconnected it, and the ECM and tested for continuity from the 70M plug to the ECM connector and all the wires are fine. Next I plugged the ECM back in and had my helper turn the key. This is part I need guidance on. They all seem to get power, and I will list it below. Can you translate these numbers and see if that is in tolerance. If so, that narrows down quite a bit, but if not, then it has to be smtg else. These are the ranges of volts each injector wire produced at the 70M connector unplugged from the rest of the harness and testing on the 70M side.

Injector
1 =.1 - 1.1
2 =.1 -.9
3 =.1 -.8
4 =.2 - 1.2
5 =.2 -.8
6 =.2 - 1.1

Okay update again. I found that the injectors should have 12 volts. I swapped around all three of my ECM's and they are all giving the same power readings. Now I have to ask, what would/could cause that to happen? The ECM is not pushing enough power, so the injectors are not firing. Then for no reason, it starts working again.

Okay, I will check the ground to the ECM. Those numbers I logged are off the 70M plug (not plugged in) in one of your diagrams you posted. So it is the straight feed to/off the ECM. Basically taking the injectors out of the equation. But I have not checked the ground to the ECM I will try that now. Also, I can tell you I did check the engine ground on the 70M plug. It goes directly from the pin to the ground spot on the distributor. Pretty easy to test.

Thank you for keeping the ideas coming.

Okay, quick question I tested all the grounds and and the battery voltage on the ECM when the car is in the on position and when it is cranking. They are all good. When I probe the 6 injector pins directly on the ECM with the 70m plug disconnected, I get the same readings I posted. So im 100% that is the issue.

My question is, from what I am reading, those reading should be battery volts and not.1 and 1.2 and such. Is that correct?

If so, what could cause the volts from the ECM to not be the right volt? I am skeptical it is the ECM only because I have 3 and they all do it. Could be 3 bad ones, but seems unlikely now.

Where does the ECM get the power to pass to the injectors? I am eliminating a relay because it does it right off the ECM, however, if there is a relay that gives the ECM power and then it passes it, that could be my weak link.

I will check the diagram also.

Okay, fresh thought. Can you confirm if my system is a negative trigger system? If so, what would prevent the ECM from sending the ground signal?

I can confirm, with the key off, on or cranking, I have battery volts to all the injectors. So that would lead me to believe I am not getting the ground signal from the ECM and that is the break down.

Okay, positive movement. I 100% can confirm the injectors have battery volts when the car is working. When it does its thing, that volts drops to 3. After a period of time it goes back to battery volts and it starts.

That sounds like a wonky relay. But I cannot find any mention of a injector relay.

What relay provides the battery volts directly to the injectors? Or where does that power come from if it isn't a relay?

Its not the fuel pump or ECCS relays for sure, those are brand new.

So I don't want to leave anyone hanging. And I know its hard to diagnose issues over text. But I was repeatedly saying my injectors are losing either negative feed or power when the car would no start. I also said, it feels like something is overheating or clipping off and then after a period of time, it would come back online. The issue was always, it would work fine until it was under load and then it would stall and no start until the condition "fixed" itself.

I was able to 100% confirm my injectors have full battery volts when the condition does not exist and 3 volts when it does, I also can confirm 100% the power is not coming from the ignition, the ECCS or any relay. With all that unplugged I still have battery volts.

So, what was causing my injectors to lose power when it gets under load and yet run forever just idling? And why would it eventually correct itself?

I had a fusible link that has a crack in it. The injectors are directly attached to the battery via a FL. When the car is under load, it would cause the link to swell and resist current to the point it will stall the engine. Then after a period of time, it would cool down, make the connection again, and fire right up.

Replaced the fusible link and all is right in the world.

Ken, thank you for your help. I know not being here is difficult to troubleshoot, if you care to look on page 280 of the FSM (section EC) you can see exactly where they get power from.

Cheers