Help diagnose my 323 that won't run

Hey all,

The other day on the way to work, my '90 Mazda 323 just shut down on me. 55 miles per hour and it just shut off.

After about 5 minutes on the shoulder and several unsuccessful attempts at starting it...it just randomly started up and ran fine. I drove it 25 miles to work (dumb...I know).

After work, it didn't want to start. It did the same thing it did earlier after it quit. It would kind of fire and stumble...idle rough for just a second or two, and die. Then again...it randomly just decided to run fine. For about a mile. then it was done.

My first thought was fuel pump...I "rented" the parts store fuel pressure test gauge today and the car has ~32 psi. I don't know what this car is supposed to operate at...but I figure if the pump was bad, it would be lower than that.

I was really kind of banking on a bad fuel pump...so now (if it's not a bad fuel pump) I'm sort of at a loss. Anyone have any other ideas?

It does this rough, stumbling half-idle thing...but it won't run. Throttle input doesn't seem to make much difference. I'd think I had jumped a tooth on the timing belt or had bad gas or something...but on two occasions it has run fine AFTER it just shut off on me. I know one time (and possibly both times)...it fired up when I floored the throttle pedal. Not sure if that was coincidence...or indicative of something important.

Has anyone experienced anything like this before? Help appreciated.

Thanks,
Clem

My friend tells me he looked up on Autozone and it shows 64-85 psi [edit: fuel pressure] listed for this car. Can anyone confirm that that's what it should be?

For fuel pressure? Almost definitely not.

This is probably ignition related. Check the connection at the ignitor.

I had the 'old' 323 once. I would randomly shut off and then only start when it felt like it. Turned out to be the pickup or ignitor or something in the distributor. Had a whole spare engine sitting around so simply swapped out the distributor.

Yeah, I was going to say distributor as well. They're pretty much the only finicky thing on the whole car. At least they're cheap and easy to swap over.

15 years ago i remember the distributor being a hot item on those cars, to resolve symptoms just like what you're describing.

Before you thow a disty at it, check groundwires. When those all turn out to be OK, unplug the throttle position sensor and see if the resistance changes nice and smoothly on an ohmeter. When my old GTX did what you describe, it turned out to be a piece of the variable resistor inside the TPS had gotten loose and was randomly shorting out in there. The easiest check is to wait till it dies and unplug the dern thing and see if that lets it run. It'll run without the TPS, it just runs kinda rich mostly.

I did unplug the TPS with no change (it still didn't run). I learned on an OBDII escort that it ran better without the TPS than with the wonky one it had on it. I'm not saying I think the 323 is necessarily the same...but I figure it was worth a shot.

I'll take out the ignition module tomorrow and see if O'reilly can test it.

Thanks folks...I appreciate the help!

Clem

ClemSparks wrote: My friend tells me he looked up on Autozone and it shows 64-85 psi listed for this car. Can anyone confirm that that's what it should be? That is the max pressure that the pump is capable of.. 30-45 psi is usually the normal operating pressure with the engine idling, a little higher , engine off. I agree on the ignition module.

Though...I gotta say: I do think I'm getting spark. because it'll do this lumpy idle (sounds like a huge vacuum leak) for 10-30 seconds most of the time. Can't run that long without spark...right?

Thanks again!
Clem

Most likely the Distributor Pickup inside the Distributor. That's the biggest issue on the Mazda B series dizzy motors.

That seems to be where most of the bad Mazda jujus reside. If there's anything wonky with my MX3, chances are pretty good it's the disty. Those things are freaking possessed. The only time my 323 has ever failed to start, has been due to moisture in the distributor. Indestructible car.

Yeah...this one's been leaking oil around and inside the distributor. I can now say this because I removed the distributor today.

I took the distributor off because I couldn't figure out how to extricate the ignition module (and it's integral hall effect sensor) alone. The auto parts store looked at me like I was from 1990 when I asked them if they could test the module.

What's the deal here? Just replace the module and hope for the best...or can anyone test them?

Thanks,
Clem

well...I'm inferring from my armchair-internet-mechanicin' that the cure here is to replace the distributor. The module inside is not available by itself.

I'll probably bite the bullet and get one (used or reman) and hope for the best. I'll report back.

Thanks for the discussion/help folks!

Clem

Jay_W wrote: ...unplug the throttle position sensor and see if the resistance changes nice and smoothly on an ohmeter...

I wasn't able to figure out how to test this. What pins should I be checking with an ohm meter? One pin to another? One pin to ground? I'd like to check it even if I am going down the distributor/ignition module path.

Thanks!
Clem

ClemSparks wrote:

Jay_W wrote: ...unplug the throttle position sensor and see if the resistance changes nice and smoothly on an ohmeter...

I wasn't able to figure out how to test this. What pins should I be checking with an ohm meter? One pin to another? One pin to ground? I'd like to check it even if I am going down the distributor/ignition module path. Thanks! Clem

One pin to the other. Then rotate the TPS and see if the changes resistance smoothly. Any sudden jumps in resistance or "dead spots" means it needs replaced.

The used, ebay brand distributor fixed it. I fired it up and drove it home yesterday. So...the faulty ignition module diagnosis was the correct one.

Thanks for the help folks!

In the meantime...I've located a wrecked parts car that I'll probably buy to keep on hand for just these kinds of parts swapping endeavors.