'94 drivability problem

[boisking]

My car has an intermittent issue with losing spark (I'm sure of that much). Sometimes it stumbles for a short portion of warm-up, running on 2 cyl. Other times, it won't start at all (thank mother nature and timing for spring motorcycle weather). It acts like the coil is breathing its last breath. Does anyone know a test to decipher between an intermittently bad coil and an intermittently bad ignitor? I'd rather not start throwing expensive parts at a problem and hope I'm a good guess. For that matter, does anybody have a working, used coil that I can borrow/have/buy for testing? Ignitor? I would be gratly appreciative to any help with cheap parts or good tests to isolate the problem.

[Adam Payrot]

My car has an intermittent issue with losing spark (I'm sure of that much). Sometimes it stumbles for a short portion of warm-up, running on 2 cyl. Other times, it won't start at all (thank mother nature and timing for spring motorcycle weather). It acts like the coil is breathing its last breath. Does anyone know a test to decipher between an intermittently bad coil and an intermittently bad ignitor? I'd rather not start throwing expensive parts at a problem and hope I'm a good guess. For that matter, does anybody have a working, used coil that I can borrow/have/buy for testing? Ignitor? I would be gratly appreciative to any help with cheap parts or good tests to isolate the problem.

Coil/igniter are one in the same on 94-97's I might have a spare lying around, I can look for it tomorrow and if I find it, I'll bring it out Wed if you're going to be there.

[boisking]

Coil/igniter are one in the same on 94-97's I might have a spare lying around, I can look for it tomorrow and if I find it, I'll bring it out Wed if you're going to be there.

According to Todd (looking up the parts with his mazdaspeed account) and the guy at O'reiley's, they are not the same. Nor are they the same price. If you can prove me wrong, though, it might save me some guesswork. I'll be there on Wednesday. Thanks, dude.

[MadMonkey]

and the guy at O'reiley's

Hah, I had a guy at Autozone insisting that I didn't need anything but 1157 bulbs for my Miata tails... don't trust them with anything.

As for Todd... well, use your own judgement

[trickyrix]

My car has an intermittent issue with losing spark (I'm sure of that much). Sometimes it stumbles for a short portion of warm-up, running on 2 cyl. Other times, it won't start at all (thank mother nature and timing for spring motorcycle weather). It acts like the coil is breathing its last breath. Does anyone know a test to decipher between an intermittently bad coil and an intermittently bad ignitor? I'd rather not start throwing expensive parts at a problem and hope I'm a good guess. For that matter, does anybody have a working, used coil that I can borrow/have/buy for testing? Ignitor? I would be gratly appreciative to any help with cheap parts or good tests to isolate the problem.

I had a similar problem and it turned out that I had water down in the spark plug holes. Don't know if you've washed your engine lately, but the first time it happened to me the problem didn't pop up until a day or two after I had been to the car wash - very odd, but that's all it was.

Just a thought...

[Adam Payrot]

According to Todd (looking up the parts with his mazdaspeed account) and the guy at O'reiley's, they are not the same. Nor are they the same price. If you can prove me wrong, though, it might save me some guesswork. I'll be there on Wednesday. Thanks, dude.

Check this...

I can find a lot more examples that say the same. 90-93 had them separate, 94-97 had them combined.

[boisking]

Check this...

I can find a lot more examples that say the same. 90-93 had them separate, 94-97 had them combined.

Good enough for me. Thanks, man. I know that the coils are getting steady power, but is there a test to see if they are getting good signal from the ECM? No water in the plug wires.

[Adam Payrot]

I'm sure there is a range for the resistance that should be seen at the connectors, but I don't know of any other way to test the signal. I never had luck with the resistance values when I had one of my coils blew; they were "good" according to the readings. I pulled a plug, plugged it into the wire and sat it on the valve cover while turning the engine over; no spark meant bad coil. I learned not to trust those readings after that.

[Titus]

This is what we were looking at from Mazdaspeed... It is supposed to be just for a '94, and it lists the Ignition Coil & Igniter together as BPE8–18–10XA, but then also lists just the Igniter Set alone as B61P–18–251. I should have noticed that the part number starts with B6. Looking at the 1992 sheet, the number is the same. Perhaps Mazda screwed up the when they made the PDF.

[channelmaniac]

Don't forget... a bad CAS can make the spark do crazy things.

RJ

[boisking]

Don't forget... a bad CAS can make the spark do crazy things.

RJ

What kinds of symptoms are we talking about here?

[cam76034]

Don't forget... a bad CAS can make the spark do crazy things.

RJ

Good call.
Recently I helped a buddy with a Corolla that had all the same symptoms. Everything pointed to a bad coil. Replaced coil only to find out that wasn't the problem. It was the CAS crank angle sensor (known as crankshaft position sensor on Toyota) but its the same sensor, just a different name.

Definitely worth checking out.

[CraiginTX]

Hah, I had a guy at Autozone insisting that I didn't need anything but 1157 bulbs for my Miata tails... don't trust them with anything.

As for Todd... well, use your own judgement

So I walked into Autozone and asked the nice young man in the red shirt if they had a vacuum gauge. He looked at me with a puzzled look on his face and said: "Vacuum gauge? What does that do?"

I almost left immediately, but instead said (slowly) "Measures vacuum"

He said, I'll have to ask...

The *other* guy said "if we have them, they'll be right over there." So the first guy walks over and starts looking at the endcap stocked with spark plugs.

I walked over to the *next* aisle, where the vacuum gauge was hanging next to the fuel pressure gauge and some other diagnostic stuff and said - "I'll take this one..."

Sheesh!

[Titus]

Hehe... When ever the parts dope asks my father-in-law for year, make, and model when he has asked for something by part number, he always tells them the part number is for rear rotors for 1941 ford pick-up. I was with him when he did it once at NAPA... Very entertaining! We watched the guy try to find it in the computer, then ask the guy next to him to look, then they got the manager. It took them 10 minutes to get somebody smart enough to tell us that a 1941 Ford couldn't possible have disc brakes. We had to take them outside to show them the hot-rodded truck before they were willing to look for the part by the part number provided when we walked in.

[boisking]

Good call.
Recently I helped a buddy with a Corolla that had all the same symptoms. Everything pointed to a bad coil. Replaced coil only to find out that wasn't the problem. It was the CAS crank angle sensor (known as crankshaft position sensor on Toyota) but its the same sensor, just a different name.

Definitely worth checking out.

Any test(s) that you know of to determine whether the CAS is still good?

[Titus]

Any test(s) that you know of to determine whether the CAS is still good?

Sure... it starts with getting someone to distract Wags while you "borrow" his for testing.

[cam76034]

Any test(s) that you know of to determine whether the CAS is still good?

Sure don't, short of replacing it with a known working unit. I would look at the connection there, clean the contacts and reconnect. Maybe channelmaniac knows a better way.

[boisking]

Sure... it starts with getting someone to distract Wags while you "borrow" his for testing.

I like the way you think, good sir!

[johnwag]

Sure... it starts with getting someone to distract Wags while you "borrow" his for testing.

I like the way you think, good sir!

Ahhh..... nice try you 's . Unfortunately, Bo is forgetting that we swapped coils from my car last summer when we were trying to diagnose the rough idle problem, to find out that there was a hole in the intake pipe. His car wouldn't start with my coils connected. My coil pack and his coil pack have different part #'s.

[Adam Payrot]

Ahhh..... nice try you 's . Unfortunately, Bo is forgetting that we swapped coils from my car last summer when we were trying to diagnose the rough idle problem, to find out that there was a hole in the intake pipe. His car wouldn't start with my coils connected. My coil pack and his coil pack have different part #'s.

Yeah, I believe there is a 4th wire on the 94-95's that runs to the tach (and something else I would imagine). The 96-97 coils are 3-wire and don't need that 4th wire. You can put the 94-95's in a 96-97, but not vice-versa.

I'm about to head over to my "storage" and see if I can find that extra coil. It came off my 94, so no worries on compatibility for Bo.