HAILERS

Opps. again. I had another thread on this site in mind when I wrote on posts 22 and on. Ignore me. I'd get another trail coil assy if I were you and pay no more than twenty bucks for it. Or if you know someone with a RX, borrow his.

HAILERS

I had this thread in mind when posting the last few times. Right now its just above your thread. Clicking on the wrong theads. https://www.rx7club.com/2nd-generation-specific-1986-1992-17/does-my-timing-seem-too-far-advanced-video-included-861764/

that one guy300

alrighty then.... i personally think its the computer.... not sending out the correct rpm, but ill try a coil just to check it out

edit: i checked out the price on oreillys auto web site, for only the ignitor... its $620!!!!!!!!!!!!!!!! the junk yards here look at the price at all parts houses in town and go 50 under.... wow!!!!!!!!!!! $620, thats more than i paid for the car... almost double..... and then each coil is $160!!! wow thats... $940 for the entire set brand new.... also i use nothing except BWD, i have never had a single problem with one, and i've put hundreds on cars all around town, never had one come back...... but every single time i used another brand, it failed... wow 940, i will try the wanted section for oem

that one guy300

Soo sorry, didn't realize i couldn't promote a product like that... i was just reading the must read section in classifieds, and found out that this type of stuff is illegal on this website... i was just saying what i use, not trying to promote them

HAILERS

I shoulda said this earlier. Pin 1M is a Input to the ECU.

I just cut/deleted the other words I wrote on this post. Just FYI.

HAILERS

I really dont' understand 1M the feedback signal. Here's why.

I extracted the 1M from the ECU plug and then reattached the plug to the ECU.

Put a meter on the extracted blue/red wire and had the meter itself in the engine bay.

Installed a spare CAS on the harness in the engine bay. Key to ON.

With key ON, the meter read 24 mv (yes, milivolts). As I turned the spare CAS and heard the sparking of the Trail coil, the reading on 1M went to 60mv. I've a meter that captures the high and low outputs of a signal. If I didn't have that I'd not have been able to see the high of 60mv as the coil(s) fired. I doubt you'll see this on a regular digital meter. Might though if your fast.

I kept rotating the spare CAS bottom gear and the trail coils spard each time.

So lack of a feedback signal does not prevent trail spark. At least under the conditons I just mentioned.

If you KNOW how to extract a wire out of the ECU plug, then extract 1M and see if your trails now work or.......not. Some risk in this. Each wire is there for a purpose. And although I've been seeing spark under the above conditions, I have not driven the car with 1M extracted. No guts, no glory. Might do that later, might not.

ONe thing of note is that I'm seeing an output in milivolts not the 12vdc your seeing. Quite a difference there, right? Yes.

HAILERS

Aw shucks. I started the car with 1M feedback disconnected and theres no trail spark and no tach. Turned car off and installed the spare CAS and did the rotation of the spare cas as described in the post above, and there was spark again plus bumping of the tach needle.

So the ECU must kill the signal to the trail ignitor if it does not see the feedback signal for??? a period of time? so many rpm? got me. Probably anything over 500 rpm.

Enough playing around today.

FYI: Also take note of the CONTROL UNIT pages where all the CAS signals are INPUT signals TO the ECU, not outputs from the ECU to the CAS.

that one guy300

okay, i checked out 1M with key on and ecu plug unplugged, 0 volts, but while plugged in i get 12 v, so i decided to check the wiring... i ohmed out M U and X all three have 0 continuity, thats right 0, they are not connected to each other at all, the wiring diagram says there is nothing inbetween these 2 points like a connector, but there has to be, or a wire is broken.... really the only time i see broken wires in any other car its in a moving environment like the window electrical on the hinge of a door, or wires comming from the body to the engine.... it might not be either component and just wiring.... but i am lost as to where this break in all 3 wires could be at... btw i checked with both components disconnected, and watching my voltmeter closely..... even checked the voltmeter... btw its a fluke 73 III voltmeter, very good in my eyes...... but missing some features

HAILERS

OOPS. No voltage on 1M with the plug off the ECU, but you have 12vdc when it's connected to the ECU. Makes it sound like a ECU problem put like that.

Somewhere above in another post above (post #18), I had .99v on 1M with key ON, engine off, connector on the ECU. My car works fine so you should have the same figures give or take. You having 12v does sound like the ECU is kaput instead of the ignitor.

About those wires you ohm'd out. I never have tried to see if they have continuity b/t each other. I'm not sure that's a valid method. So I don't know if they should or not. Probably not. But each wire should ohm out from the ECU to the ignitor plug from one end to the other. Takes long meter leads or something cobbled up as a meter lead.......like a piece of long electrical wire.

On a series four there is a plug b/t the ECU and the ignitor. But if the plug is on the ECU and you see 12v on 1M, it soundsl like the ECU. I'll go out and look at my car again later, but I'm fairly sure of what I wrote in that other post mentioned above.

I'm not being fickle, saying at one time it's the ignitor and now saying it's the ECU. I figured you were showing 12v on 1M with the connector off the ECU, which would mean it's the ignitor.

that one guy300

yeah, its all good i didn't notice you wrote that before, if you could check out the ohms between those wires, and where do you say that connector b/t the ecu and ignitor....? i think for sure it needs an ecu, but if the power isn't getting to the ignitor from the ecu and likewise for the ecu to the ignitor, then it definatly wont work, i am excited to hear what those results are, btw i check voltages for cas and they were all sitting around .7 volts, which sounds right, so it is either the computer, the wiring or both, and then i can even check to see if the coil works, i will start with the wiring, (because its cheapest) and work my way from there to the computer, which should fix the problem if the coil works

HAILERS

Ah shucks, I was thinking of the CAS wiring and not the trail coil wiring. No, no connector inbetween. I'll go mess with the car in a few minutes. Takes about a hour to get back.

The reluctors make a/c voltage and send that to the ECU. GOOGLE RELUCTORS and you'll see what I mean. The CAS turns and the pointer(s) pass the black reluctors and the reluctors put out a a/c voltage to the ECU.

Google Reluctor Sensors and not just Reluctors.

that one guy300

yeah i understand all that, learned it way back, i was just going by voltage spec, strait from the manual under 1 volt, which it is.... darn i was hopeing that some connector just wasn't hooked up.... is there a way to trace the 3 wires through the harness? like a diagram or something of the route

HAILERS

Let's get M out of the way first thing.

I measure M with all plugs connected. Get 0.95 vdc. Measured by backprobing the blue/red at the ECU with plug on the ECU.

I pull the four wire plug off the coil assy and measure M. Get 12vdc. Huh???

I put the plug back on the coil assy and return to the ECU and now get 10.5vdc. Huh?

OH, easy resolution. When I took the plug off the coil assy, I had to unbolt the assy and lift it up and to the side. When I did the measuring on M, the body of the coil assy was not grounded.

INstalled one nut on the assy and measured at M again. Back to 0.95 vdc like I started with in one of my OTHER posts.

The internals of the ignitor get their ground circuit from the body of the coil/ingnitor assy. At least one of the two inboard nuts has to be installed for the ignitor to work or for any meaningful voltage measurments.

So anyway, now I see how you might see 12vdc on the M wire.

If you have everything connected ujp and bolted down, M should read 0.95vdc.........X read zero.............U reads 4.3vdc. Thats backprobing the wires at the ECU plug with everything connected up.

Put the plug back on the ECU and pull the plug off the coil assy and you get: X is 5.17vdc........U is 4.98 vdc.........M is 11.64vdc.

If you have everything connected up and coil assy bolted down with at least one inboard nut and KEY TO OFF.....and read resistance b/t X and U you get 1.9 K ohms............read resistance b/t X and M and you get 1.6K ohms......read b/t U and M and the resistance is 1.6K. Can't prove much one way or the other doing that 'cause you/I don't know what we're reading thru inside the ignitor.

So now I understand why you read 12vdc on M. M should be read with all plugs on and the coil assy bolted down by backprobing the wire at the ECU. Should read 0.95v that way. IF the coil assy is unbolted and all connectors connected, the voltgage rises to approx 12vdc because the internal circuit of the ignitor is not functioning (no gnd to the internal elect guts).

I'm tired/lazy so if I wrote something that didn't make sense ....ask.

The coil assy's and the alternator are the only two items I know of on this car that get their gnd thru the body of those units bolted to the chassis/engine.

HAILERS

CAS reluctors work like the attached jpg. I've seen up to six volts ac with a meter and spinning the CAS by its bottom drive gear. So don't look for any meaningful voltage from the CAS wires with the engine not running.

that one guy300

i am starting to see now.... but i was checking ohms of just the wires....not the coil also...but i will try that to see if i get anything, if not, there is a break in these 3 wires.??? hopefully all near the same place

HAILERS

Well I was too lazy to check each of the three wires from one end to the other with the connectors off the ECU and the coil assy. Mostly I did not do that, since I'd already left the plug on the ECU and removed the plug off the coil assy and seen power on each wire with key ON (reading from the four wire plug at the coil assy.

If I ohm out each wire end to end, I'd suspect I'd see 0.3 to 0.4 ohms on each wire.

Ohm yours out and I'd bet you'll get similar figures of approx .3 ohms (meter leads have some resistance). I might do that tomorrow, but it's a waste of time since I"ve seen volage at the four wire coil/ignitor plug with key ON, proving the path to the ECU is good. I'd be wasting my time and yours.

HAILERS

Well I ohm out all three wires from end to end this morning and they all ran in the range of .7 to 1.2 ohms. Most of that was/is in the meter leads and the short pieces of stripped wire I shoved in the plug receptacles.

Remember the part about bolting the ignitor/coil assy down when measuring the voltage on those wire with key ON.

that one guy300

yeah, well hopefully the only problem i have is this wiring, ill just have to track it all down one day, and check ohms in different places until it goes out of limits, i bet i can pinpoint it, it'll take some time, im kinda weery of pin 1X, it says it has .002 v, which is basically nothing, but it was there and flucuating up to .010, but im sure if the trailing side still doesn't work after i fix these wires, im going for the computer first, which btw i found a website, of basically junk yards selling stuff, i found a ecu there, and they wanted 20 for it, but im not sure its legit, know any reputable places that deliver, or ship? i was thinking ebay also...

that one guy300

just an update.... i tried following the wire.... wow, hard stuff under that dash.... got up behind the instrument panel, and found the blue and red wire, 3rd one is the charm... got continuity through to the ecu, after that, checked continuity to the coil, nothing... so the open is getting closer, but, when i started moving wires around looking for the other 2, i rechecked blue and red, it works, all the way to the coil, its the wiring , know any good ways to get into all those wire comming directly in from the firewall? as far as i can feel i can touch where they come in at, but i cant see the wire im looking for, it took me 4 hours just to find it the first time, i think i am going to just leave it and test drive it.... what a pain this had better fix it....