Engine Keeps Dying

[BZG Wagon]

My GF's 98 Mazda Familia (1.5 litre, auto, efi, mazda version of variable valve timing) kept dying on the way home (so a long ride home from work today).

Symptoms:
* It would just stop on occasion while waiting at the lights (today). No warning.
* It would lose all power while driving at 80kph - 100kph, sometimes it felt like a small miss before hand, othertimes it would just die. Rev counter was still going (ditto ps & brakes) until slapping it into neutral.
* Foot flat on the floor there was a big miss around 5,000 rpm, and the second time I tried it it just flat out stopped.
* Letting it sit for 5 or so mins seemed allow us to go for a few kays before dying.

I found putting a tiny bit of load seemed to keep the car going. No load it would die. Too much load it would miss & die.

What do you guys reckon? Coil Pack?

[iOnic]

Had a friend with an SP20 that had almost exactly the same symptoms and it turned out to be a bung AFM. Apparently a common fault on them.

but this

Letting it sit for 5 or so mins seemed allow us to go for a few kays before dying.

sounds to me like overheating coil[s]. next time it does it put your hand on the coils and check how hot they are. Should be warm to the touch but not hot.

[BZG Wagon]

Had a friend with an SP20 that had almost exactly the same symptoms and it turned out to be a bung AFM. Apparently a common fault on them.

but this

Letting it sit for 5 or so mins seemed allow us to go for a few kays before dying.

sounds to me like overheating coil[s]. next time it does it put your hand on the coils and check how hot they are. Should be warm to the touch but not hot.

Hmm... didn't think about the afm.

Re: coils - I can't conculsively say waiting helped (I only tried stopping the car and restarting twice before deciding to let everything cool down).

I would have thought with a failing coil though:
1) at high rpm / WOT 3 cyclinders would keep the car running while the 4th presumably fails, rather than it dying at high rpm?
2) The car would have had more of a miss, than simply cutting out.

I've only ever had HT Leads fail - so this is new territory for me.

Is there a way to check coils or test the afm - other than replacement?

[BZG Wagon]

One last thing: when it would die while driving, I couldn't restart it (in neutral). I'd have to pull over to the side of the road, stop, and wait a few seconds (or minutes) for it to start.

Hmm I guess I've just contradicted myself:

Re: coils - I can't conculsively say waiting helped (I only tried stopping the car and restarting twice before deciding to let everything cool down).

[sergei]

I had very similar thing happen to friends arstina. Turned out (after mucking around for very long) it was faulty water temp sensor.

[matt dunn]

Normally once the coil stops the car, it wont go again.

Not knowing the exact type of ign system but guessing,

it probably has a combined crank sensor, cam sensor, and ignter all built into one unit inside the distrbitor.

They give heaps of problems and those symptoms.

AFM's also give problems, but usually driveability problems,
and usually wont stop the car while driving.

[BZG Wagon]

Thanks for the advice guys.

All the plugs looks sweet (I was hoping one might indicate a problem cyclinder).

Below are the readings I'm getting from both coil packs (roughly the same results):

[85AW20v]

Blocked breather to the fuel tank? When you stop it allows air in again. Try running with the fuel cap off. Or maybe blocked fuel filter.

[MrOizo]

Blocked breather to the fuel tank? When you stop it allows air in again. Try running with the fuel cap off. Or maybe blocked fuel filter.

I found putting a tiny bit of load seemed to keep the car going. No load it would die. Too much load it would miss & die.

Thats what got me thinking that it might be fuel related.

I had a similar problem in a AW11 - no others that you have said though :/

[Nuty|Mike]

step mums same model 323 was having similar problems after changing temp sensor and other expensive things it turned out to be a small split in the intake hose,

Could be a good thing to check first ?

[BZG Wagon]

step mums same model 323 was having similar problems after changing temp sensor and other expensive things it turned out to be a small split in the intake hose,

Could be a good thing to check first ?

Fixed that 6 months ago (another common fault). It was running like a p.o.s before that -> ironically it's running better now (at least before it dies), than when the hole in the intake hose split.

[touge_ae101]

my sister in laws exact same car had exactly the same problem!i told her to look at the afm but turned out the battery was just dead. like properly dead. seemed weird but went sweet after a new one.

[BZG Wagon]

my sister in laws exact same car had exactly the same problem!i told her to look at the afm but turned out the battery was just dead. like properly dead. seemed weird but went sweet after a new one.

New battery, 9 months ago. Given the amount of times the car stopped on the way home & I had to restart I'd be surprised if it would be a batt fault. But I'll swap batteries with my car if I can't figure it out just to be sure.

In my old mazda at least all the warning lights would come on under full load and when the alternator couldn't keep enough current going to the batt.

[touge_ae101]

yeah thats what i figured when i explained it to my sister in law.

my guess would be the afm or its not getting fuel through a blocked filter/screwed pump. don't bother wasting money on expensive things such as sensors etc as the ecu should throw a code or a engine warning light if the problem is that severe.

[RS13]

You should be able to pull codes off the OBD plug in the engine bay, however if you don't have an engine light on the dash, you need a multimeter, as from memory those Mazdas use a series of voltage pulses rather than a blinking light.

[BZG Wagon]

Just checked all the plugs - they look a little worn, but nothing too out the ordinary.

However the plug on cylinder #3 had a strong & foul oily smell when I pulled it out & it was immediately noticable.

Pics of the plug:


Radiator fulid looks sweet. Doesn't appear to have used any oil since the last change. No blue or white smoke out the exhaust. Wonder if I should compression test it just in case?!?

Left it idling for 5 minutes after putting everything back - no hesitation or miss & it just died. Restarted it straight away, another 5mins and the same again(this time I was standing over the engine & it sounded like it backfired through the air intake)?

touge_ae101, RS13 thanks for the tips. It doesn't have a check engine light so I'll look into how I can check for faults off the ecu. Then like you said start with the basics & work my way up to the expensive things.

[matt dunn]

Multi coil so forget everything in my previous post it must run the later stuff.

One faulty coil would make it miss not stop, even two is would probably run.

Need to check codes with a decent scanner,
it probably wont do falsh codes with a light and if it does they wont be detailed enough.

[allencr]

The plugs threads don't indicate anything except not being tightened enough & not sealing and, that the engine has a ring problem, or has not been up to operating temp in a loong time. Also gap looks pretty wide. Please show pic/s of the porcelain.

It stops suddenly, like being switched on & off with the key, but does hesitate & stumble & miss & cough, like running out of fuel, before shutting down sometimes or not at all?

[MAGN1T]

When a cylinder burns oil you end up with oil on the threads. It's got nothing to do with not being tightened.

Steve

[nmcgowan]

Check the fuel pressure. Sounds very similar to what my 20v Silvertop did when it had a failing fuel pump. My post is still floating around of all the troubleshooting I did at the time.