stuck at gas station part II (no spark)
 

Well, I'm not flooded like I originally thought in my previous post. As a quick recap:

my car wouldn't start at home the other day. I thought it was flooded so i gave it time and it started up. I went to the gas sation, filled up, and then it wouldn't start again. Its been 48 hours and no luck. It turns over fine but it just doesn't start. The plugs are dry.

Heres what I know. I checked the plug of the coil closest to the front of the car (leading i think) and one side has power when the key is on. I heard from an ex mazda tech that the other should make the test light flash when the car is turning over. It doesn't flash....the problem is before the coil packs.

I checked for error codes from the ECU. There are NONE. That is weird because I've ALWAYS had O2 Sensor and Pressure sensor. That makes me think that it has something to do with my ECU. Maybe a bad wire? How often to ECUs fry? SOmebody also told me to check my crank angle sensor because that tells the coil packs to ignite. What do you think about that?

Thanks for the input, the more the better.

if you really wanna see if you have spark, take the spark plug wires off from the coil and turn the engine over the coils with arc and hit the frame if that happens your getting spark..

Frank

oops, i forgot to put that i did that...there isn't a spark. Thanks though

Can you hear the main relay clicking when the key is turned? Out there near the trailing coil pack, bolted to the side of the engine compartment...

when i get a ride back to my car tomorrow i will check. I thought that the main relay was near the fuse box. I thought i heard a soft click down there when I checked but maybe my eyes were just playing tricks on me.

The main relay is making the click when the key is turned.

I bought a multimeter and started checking the wiring going to the computer. The "ignition switch" wire (1C on the S5) was only reading 9V when cranking instead of 12 but i think thats because ive been cranking the car so much that the battery is starting to fade some. Correct me if im wrong. On the traiing ignition coil (1J on the S5)...the repair manual says "IGs-t Select Signal" i didn't get a reading.....but i measured it off the wiring harness when it was unplugged. I think thats an output so Im assuming i should have taken the measurement from the pin on the ECU. Is that right?

I also checked the impedance on the crank angle sensor to make sure it was good. Once I learned how to use my meter i found out that it was good.

It looks like im back to the drawing board.

Anything 8v & over should be good for the crank signal input...

The select signal comes FROM the ecu, so the plug needs to be on. In fact, the plugs should stay on for every voltage check given in the FSM...

Check for the 12v from the main relay at the black/yellow wires at both coils. You can disconnect the plugs to read these wires, if you wish, you should be getting it if the relay's clicking...

All of your ECU timing signals for both igniters are going to have to be read while cranking...You can also check your CAS input signals this way, for each coil...

when i check the black yellow wires, should i check at the coil side or at the relay side?

thanks so much Wayne. I know you've answered a good amount of similar wiring questions in other posts and I appreciate your time.

The relay side of the plug, every black/yellow wire (3 of them total between the two coils) should have 12v on it with key on...This is your coils' charging circuit...

BTW, both coil packs are bolted down good to the chassis, right? No rusty hardware or anything goofy like that, right?

Wow you're fast!

yes, they are bolted down good and i checked the grounds. They tested good.

I will get a ride back to my car in al ittle bit and check those black and yellow wires.

Before I had my meter i took a test light to the 2 wires that plug into the leading coil and one was lighting up while the other did not, even when i was cranking. A friend of mine that used to work on mazdas said that it should have lit up while I was cranking.

thats what happened to me. tutned out it was a bad afm. unplug it and see if your car canks up. it should atleast try to fire up and fire up, but die automatically.

try that. could be the problem. dont unscrew the cable from the afm. that fucks it.

its not the afm, i just tried that. Thanks though

hm... could be a connection just joggled loose.

Depending upon which plug you're talking about, the one that's showing no "lamp illumination" could be your timing signal, which is a tiny tiny tiny voltage, certainly not enough to light a 12v bulb. Need a meter for that one. There are no "grounds" coming off of the coils or igniters via wires, unless you count the plug wires, which are de facto grounds...Or the capacitor circuit, which shouldn't read a ground with a normal meter, I would think (gonna have to try that one of these days)...I'm rambling again-what was the question?

The plug i was talknig about was the one with a black wire and a yellow wire that plug into the leading coil. One is 12v when the key is on and i heard that the other should flash when the car is turning over.

btw...don't worry about rambling....i can use ALL the advice...and I've been rambling way more anyway. I think Im going to try to find a computer at a local yard and main relay. It could pay off... or it could be a waste of money

BTW- you HAVE checked the 40A "EGI inj" and 30A "EGI comp" fuses in the engine bay fuse box, right? If in doubt, pull 'em and put a meter on 'em, should read about, ahhhhhh, ZERO ohms :)

Your timing signal is this "flashing" one you're talking about.... It's about .8 volts at idle, if read with a meter...

Now, if you're talking about the black and white wires that are on the coil assy itself (terminals), then yes, they both will read about 12v at idle...But you need to get an idle first...

Both of those fuses are good unfortunately. I say it like that because I wish (and still hope) that it is that simple.

mmmm...idle...*drool*.....I can really go for one of those right about now.