Still No Spark

[tooldude]

No, I didn't figure out the quote thing. I just used "reply with quote" under post #115. It was already on that post. I've made so many mistakes trying to use this forum it's unreal, but I've learned a couple of things.

[tooldude]

or use the "Reply with Quote" tab located under each post.

That's just it, reply with quote picks up the entire long post when you may want to reply to one sentence or paragraph.

[Chobobulous]

That's just it

Jus delete the parts you don't want to quote

[burnt_toast]

So to not chase ghosts, I'm thinking, deal with the injector grounding problem because, solved, that will probably be the end of it.

OK, where are we at there? Using the logic probe should be the same as using a noid light, right? I know I can't probe both ends at the same time though. Testing the connectors with the logic probe I get a solid red light from the one wire, and NO light from the other wire. I dunno where I'd go from there (other than the aforementioned ground checks). The Haynes manual ain't much help in that realm. I'm also not willing to ignore the missing CEL though; I think the grounds you called out in your previous post should be the focus of my attention first.
-toast

[burnt_toast]

If that is true you're left with the problem that your injectors are not being grounded by the ECA during cranking. That brings up the premise again that the ECA grounding could be bad. The EVTM shows ECA terminal 2B grounding at G102 and terminals 2A,2C,2D,&2J route through 4 splices in the wiring harness, then ground at G103. G103 is listed at "LR side of engine compartment, at frame". G102 is listed at "engine compartment, near coolant temp. sensor". Also, when you changed the alternator did you remove a ground strap?-those grounds need checking too. What is called rear of the engine compartment looks like it's more like off-center than in the back. (There is also a ground on each fender well, more forward to check, G100 & G101).

EDIT:
MAJOR CONFUZZLE... I just went out there with the logic probe and checked all the black wires bundled near each other and got a RED light on all of them. That would be like, the opposite of green... Like, how is there voltage in the ground wires? I did not have the probe hooked up wrong to the battery. Lemmie go out there with the multimeter and have a jab at those wires.
-toast

[burnt_toast]

With the car's negative lead disconnected from the battery, a multimeter set to VDC going from the battery negative post to ground (the radiator mount, strut tower bolt, valve cover, etc) shows 11.2VDC. How in the hell does that happen? I thought the logic probe was on the fritz, now I think my brain is on the fritz....
-toast

[tooldude]

With the car's negative lead disconnected from the battery, a multimeter set to VDC going from the battery negative post to ground (the radiator mount, strut tower bolt, valve cover, etc) shows 11.2VDC. How in the hell does that happen? I thought the logic probe was on the fritz, now I think my brain is on the fritz....
-toast

Oh you are a tricky rascal. If you have the positive battery terminal on and you connect your voltmeter from the negative battery post to ground, you have completed the circuit back to ground with your voltmeter. If anything is running, connected,shorted you're going to measure voltage. You're hooked up like an ammeter but you're getting voltage because there is resistance in the circuit, therefore voltage drop. You got 11.2V because that's the voltage drop and maybe you're running down the battery gradually because it's not being charged.

[getnpsi]

There are a lot of components that would keep it from firing...does a good distributor need to be in there to key on engine off and lite up that cel? This is the round and round im still thinking about. How to get spark and fuel signals. the ultimate pursuit but again, no cel when you insert key and turn to run is not happening...John...I found a craigslist fellow who's going to trade me civic interior for black leather miata seats straight across in apple valley...i may be able to stop by up there wednesday or thursday if you are free. I can bring a disty too.

[tooldude]

EDIT:
MAJOR CONFUZZLE... I just went out there with the logic probe and checked all the black wires bundled near each other and got a RED light on all of them. That would be like, the opposite of green... Like, how is there voltage in the ground wires? I did not have the probe hooked up wrong to the battery. Lemmie go out there with the multimeter and have a jab at those wires.
-toast >I'm not sure which black wires where, of which thou speaketh. However, if you remove a screw and remove a ground wire from physically connecting, and if that ground wire connects back to voltage somewhere, then you have a static (standing,waiting) voltage, a potential of force, that would like to drive current somewhere (to ground), but guess who will not let it, there is no circuit. Now if you connect a voltmeter/test light to the end of that ungrounded wire, you will measure the voltage on that wire. Now, amazingly, you fasten that wire back to ground, have your voltmeter negative probe on battery negative, positive probe on the WIRE itself going into the ground terminal held by a screw, what do you get: nada,nothing-EXCEPT, if there is a slight resistance to current flow from the wire, through the end terminal, through the contact area of the terminal against the metal surface it is screwed down to, and you probe that metal surface, you will get a voltage reading: the voltage drop across that slight resistance, which could be something like,say, 0.01V like you got when you were checking those fusible links. Now what if you connect your test light to that grounded wire? It can't show you a voltage measurement in numbers, but it can react to one. So we have to know it's sensitivity, does it have a threshhold, by design, or not, above which it will show red for voltage? Will it go red at 0.0001V, 0.001V, 0.010V? I would want it to be red by at least 0.1V myself because that is beginning to be significant. A circuit is only that, when it is a complete circle. Voltage is only a force, pushing, and can only be measured across a resistance. Amperage, the movement of some volume of electrons, does the work, and resistance is it's friend when it gives a desired result, but it's enemy when it shows up where it's not wanted, such as in a terminal connection. Positve and negative voltage is relative, for where in a circuit does positive become negative? If you have several series resistances in a circuit and you measure a voltage drop across each one, you place the positve voltmeter probe on the side that is relatively closer to the B+ and the negative probe on the side that is closer to B-. Yet when you measure the following resistance, you have placed positive probe in the position you previously had the negative probe. If you reverse the probes your voltmeter will show negative voltage. You are measuring where it is relatively more positive or relatively more negative. So for our automotive purposes, I believe we can say that a circuit becomes negative after the last significant resistance, yet it is relatively positive and negative all up and down it. Isn't this fun?

[burnt_toast]

I freakin' hate electrical troubleshooting.
Well okay, back to the original thing we were doing: checking grounds...

So with the battery connected and the logic probe connected, poking the 5 black wires coming out of the ECA I get a green light. Doesn't that in itself tell me they are good grounds? Or do I need a specific resistance to know the ground is "good enough" ???? You had said you don't know the wires I speak of, but they are all the wires you called out in post #113: the grounds running out of the ECA and terminating all over the car. Instead of finding each one individually and cleaning and reinstalling, I'm wondering if a green light with the probe means it's good?

I'm assuming a circuit being complete from the negative connection on battery to the ground wire I'm probing, which should indicate it is good and doesn't need pulled apart and attacked with a wire brush? I'm just assuming a ground is either "good" or "not good" but I so know that grounds aren't just a yes/no thing. I'm trying to save myself from going after 5 different grounds and cleaning them if it's not going to improve anything.

-toast

[tooldude]

This is the kind of problem I have dreaded having one day, a possible bad computer. I have been intensely interested in your problem here, so much so that I have spent many hours with it and working too much without sleep, leary I might make mistakes. The biggest time drain is in editing and re-editing to get clarity and keep continuity and fix typos, but I missed a few. Glancing back through the posts, I see some typos that need fixing, and some where I flat out left off some process. Also, I see some things that got passed over too quickly, some that should have been dealt with. I'm going to read back through all this and focus on what may have been missed. For myself, this has been good to go through these processes in the fuel injection system in case I convert mine over. I keep thinking how it was that your car was running though, what simple little thing changed?

[tooldude]

Looking closely at the Festiva ignition system, I can see there is no possibility of the computer controlling spark outside of the SPOUT signal. That IS the one and only control, there are no extra connections as may be on some other type modules. All the Festivas are the early MECS ("MECS1") up to 1992 for sure, and the later "MECS2" was on different models. I was hoping we could ignore that Spout signal because I had not seen a conclusive test. I have since found that it can be tested with the ICM connector disconnected. Also, I believe you can easily test for grounding with the injectors disconnected using the LED. I have schematics on your car but not the PCED manual, which should have test steps plainly laid out. There are way too many loose ends here that goes back to when you had no schematics and you didn't have that LED test light, especially in post 36. There's too much bouncing around, this should have gone quicker and easier for you. My comment about the ECA grounds was because I couldn't tell the exact procedure you used or if they were disconnected. I would just clean them as they are just as important as B+.

[tooldude]

It wouldn't hurt to check on that G102 on the left front of the engine (on the head I believe), a lot is grounded there: CKP, ICM, TPS, VAF, EGO, & maybe that's where the injectors ground (seems most likely), there are 5 ECA terminals grounding there. That is an important ground, suddenly I'm suspicious of it.

[tooldude]

OK, here's what I've got. Now that the ECA is swapped, some of the previous probing doesn't apply. Start with the quick and easy. I would first check that G102 to be sure it wasn't left unfastened or loose. Check that the ECT sensor is plugged in and no wires are chewed back there. Ground the engine with a jumper cable or wire to B- in case your engine-ground cable has a terminal connection problem. Then check for spark with a plug against the engine. No spark, I would clean the grounds in the engine compartment, (they're really subject to corrosion in there) 3 on the fender wells and 1 on the frame, I believe. No spark still, check for B+ at the ECA terminals. Have spark, but no start, disconnect the 4 injectors and check for grounding through GN/Y and GN/BK wires on this new ECA. No injector grounds, we need to know if any sensor signal loss would prevent that, especially the VAF, but I thought that would allow start in fail-safe mode. I don't have definitive information on the cold start strategy, we need to get that from some of these knowledgeable guys on the forum. Otherwise, I thinking we're looking at wiring connections (broken, oxidized, loose terminal). If your car sat up for 2 years there's a good possibility of oxidized connections, especially if it sat outside over grass/dirt and exposed to humidity and maybe it's in one or more splices. Maybe a varmint chewed a wire/wires that are hidden. That's all I'm thinking of at the moment. I've been on the primrose path of responding to these posts, and trying to be clear with what was done, and find a missing signal, still missing, all while trying to think of how you could work with what you have. If you're going to work on these tougher problems you need to gather some information as you've seen. The problem is knowing how to test and where. You can test the PIP signal right off the distributor but the SPOUT wire needs to be disconnected from the ICM to properly test (sorry I didn't have that clear in that post-I was falling asleep and almost fell out of my chair a couple of times). If you had the PCED manual I bet it simply lays out these tests, cutting out the analysis.

[tooldude]

Send me an email address and I'll see if I can send you some pictures