Ignition problem.

[BlueAstina]

My Astina is driving me nuts right now. It's had a problem for months where the engine just dies while I'm driving for no apparant reason. Sometimes the revs just stop and then return to normal in a second, sometimes the car completely stops and I need to restart. Sometimes it stops and doesn't start straight away.

I've taken it to ultratune and the guy there said he can't really determine what the problem is without it stopping for him. When it did stop for him he determined that there was pulse but no spark.

He replaced the ignition module (he called it a transistor). But that doesn't seem to have fixed the problem as it was back to its old tricks a day later.

So my question is what could the problem possibly be? And will I have to sell my kidneys to pay for it?


Car is 1991 1.8L SOHC 323 Astina

[Cosmo Dude]

Ummm, don't care for your sence of humour.

But

The ECU should have an error code to tell what the problem is. Problem with places like Ultratune is that they set their margins so low hat they don't have the time to diagnose and/or repair actual problems. Mazda will fix it at a premium price (fixed and fixed right with service backup). Try a private Mazda workshop in your area.

[EVOlution]

What sense of humour
I'd be checking the error log too, I'd also drive with my trusty Scopemeter in the car too, maybe even plug into a few engine signals and watch for the culprit.... but most ppl can't do that so your best bet might be to try mazda - you will pay but you will get it done right.

[ROB-80E]

"transistor"!!! lol man I like your sence of humour, but honestly, as the boys have said, taking your car to Ultratune is no laughing matter.

First thing to try is take the plug of the AFM (DON'T UNDO THE SCREWS!) and clean the contacts on the AFM side. Failing that, replace the AFM or atleast borrow one to see if that fixes the problem.

You got any mods done to the car?

[BlueAstina]

I guess I'll have to check out some Mazda places then.

Only thing done since buying the car (an old lady was the previous owner) was to put a CD player in.

Oh, and if I take it to a Mazda place would they be able to tell me what is wrong even if the car does not stop for them? It is an intermittent problem and it can go for weeks without problem then one day it can stop half a dozen times on a short trip.

[dfvadr]

they plug into ur computer an if there is an error it will tell them straight away , not only what it is but where
good luck

[Dogo]

easier for new cars.

the old ones weren't made OBD-II compliant so they need to run a mazda-specific test.

[jrp928]

there is a diagnostic socket there - bridge TEN to GND with a wire (pref insulated). Fit a 12V diode across B+ to FEN. Turn on ign, diode will glow for a few seconds, then go out, then flash the codes, as a long flash for ten, short for units (like morse). eg long long short = 21. longer pause between codes. When all have been shown it will repeat. When done, remove diode and jumper. Check any MX5 site for more details. Works for me on both .
Yes, the ecu will retain the code until you disconnect battery, turn on ign, hit brake pedal, leave a few mins (to make sure any charge left in any caps is gone). I would bet the cam angle sensor is the culprit (inside distributor), as this is most common fault in MX5 code 2,3 or 4. Does the tacho drop to zero first then you notice power is gone? BTDT. cheapest fix is a new guts from Petroject, fit yourself.
jp
FAULT CODES
1 Ignition pulse – from ignitor circuit on inner wing or in coil pack up to ‘94
2 Ne signal
3 G signal
4 SGT signal (1.8L)
8 Airflow meter
9 Water thermistor
10 Intake air thermistor in airflow meter
12 Throttle position sensor
14 Atmospheric pressure sensor
15 Oxygen sensor (output too low)
16 EGR function sensor (1.8L)
17 Oxygen sensor (output not changing)
25 PRC solenoid valve (1.8L)
26 Solenoid valve (Evaporative canister purge)
27 EGR solenoid valve (vacuum)(1.8L)
28 EGR solenoid valve (vent)(1.8L)
34 Idle air control (1.8L)
36 Idle speed control valve

[Dogo]

need to make sure thats light-emitting-diode ( LED ) else you wont see anything at all.

[Cosmo Dude]

Originally Posted by Dogo

need to make sure thats light-emitting-diode ( LED ) else you wont see anything at all.

A 12V lamp will do the same as an LED but they cost more.

and ..|..

[BlueAstina]

So where exactly do I put the LED? Diagrams or pictures would be most useful.

[ROB-80E]

if you have no idea about electrics, i'd forget getting error codes. You need and LED, you need a dropping resistor and the LED has to go in the right way to light up at all.

If you don't use a dropping resistor, you will blow up the LED. Also, you cannot use a globe because the ecu cannot supply more than 100mA of current to the diagnosis connector, so you may also do damage there.

[jrp928]

Theres a bit here
http://www.mx5club.org.nz/maintenanc...e_diagnostics/
The diagnostic socket is on pax inner guard, but I cant find a pic anywhere - its maybe 40x30mm with DIAGNOSTIC moulded on the top - lift the lid, it has a map of the connection codes. I used a 12V led from Dick smith, buy them 6 at a time...If you dont get a steady glow with ign on, reverse the legs as they are polarity sensitive (wont blow though). The TEN->GND jumper needs to be used also to adjust base idle or change static advance, then remove for normal use.
jp

[BlueAstina]

Just a follow up on this. I took the car back to ultratune because they weren't going to charge me more to look at it. They found some dodgy wiring from what I believe was a car alarm that had been installed and removed. They fixed the wiring up for no charge. Hopefully this will fix the problem. If not I shall take to Mazda repairer.

[schematic]

Hi I'm new here but have same problem checked every thing so reading this went on maplin site they have a led that needs no resistor 4v-30v price £1.99 so I'll go for that and see if I get code 2

[BlueAstina]

This problem resurfaced last weekend.

Took it to Mazda dealer for service. The receipt says:

Check vehicle unable to fault at time of test carried out self test on vehicle no fault codes evident. Carried out wiggle test on wiring loom found engine to slightly hesitate on wiring loom near coil. Removed and untapped wiring found poor solder connection in wiring loom where someone else had repaired. Added new wire between coil & PCM. Carried ou extended R/T all ok at time of test. Owner to monitor"

Cost $181.50.

[zappy65]

awesome hope thats not one of your kidneys though ( I like your humour) well at least you know it was someone elses fault and that your car isnt falling apart....