Have a 93 mx 6 188/k miles that stopped running last weekend. Check engine light (CEL)was on, and as soon as I turned the key to "on" one of the engine cooling fans came on. Ran a series of checks, timing belt OK and turning, distributor getting 12 volts and turning, cranking over, getting gas, but NO spark. Got a new distributor and put it in yesterday and the car started up after a few cranks, drove around about 15 mins and let sit and same problems as last weekend. With key in on position CEL light on dash on, cooling fan on. Cranking over and NO start. Let sit over night and the same thing this morning. Disconnetd the battery and cleaned the terminals and now it starts and runs (ran it for 10 minutes). But in turning it off and on the CEL light comes on at times and stays on and it runs real rough till I get the idle above 2,500 RPM and then it seems to smooth out and run OK. Think I still have a problem but what is it? In the interest of full disclosure am having some "hold" light problems with the automatic transmission and perhaps that is impacting the engine. As an FYI the trans is a MAZDA reman replaced about 60/k and the fluid has been changed 3 times. But my main concern now is the engine problems noted above and appreciate any help on that anyone can offer.

V6 or 4 cylinder? Retrieving the code that is turning on that CEL should help to narrow down possibilities. When running rough below 2500 are you able to narrow it down to any specific cylinder by pulling plug wires one at a time?

It is a 4 cylinder Dual cam. Understand retriving the code is not that easy. How is best to get the code? So far when runing rough (and that is the case now ... if it will start) have been on my own and it is enough just to keep the engine running. Will try to get some help to see if I can get it down to any one cylinder. Late yesterday (Sunday) afternoon .. the last time I went to start it it was popping .. no power and would hardley get to 2000 rpm.

Code retrieval not difficult. The diagnosis connector is next to your battery and should be labeled on top of cover. Will post a pic. On the underside of the cover is a diagram of the connector with labels for each pin. You want to use a jumper wire or whatever other means to ground the pin labeled TEN. Will post pic of this pin as well. Once you have connected a ground wire to that TEN pin then turn the key to the 'run' position and the CEL should start flashing a one or two digit code. If say a code 8 is stored then light will flash 8 times, pause, and then repeat. If say a code 23 then will be 2 long flashes followed by 3 short, pause, and then repeat. Try that and see what you come up with.

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Thanks for the post and the pictures. Your right it is not difficult. Followed your instructions but did not have any luck getting any code to flash out. I tried the ten to ground at least five times and even went to the "GND" in the connector. Each time I turned the key to run the CEL light stayed SOLID ON .. no flash at all. Also each time I did the procedure the cooling fan (closest to the battery) continued to run the entire time I had the key in the "RUN" position. Even tried leaving the key ON (RUN) for a minute or so but no flash at all from the CEL. One time it seemed like a relay was clicking in/ near the "fuse" box next to the diagnostics connector. Ever run in to this situation where the fan stayed on the entire time and NO flash from the CEL? Any thing else to try. Thanks for your help!!!!!

Babyhuey, hope you are still reading my posts. Tried to check the codes again last night and continue to have the same results, solid "ON" check engine light (no flash) and one radidator fan runs continously as long as the key is in the run position. Believe my connections between TEN & GRD are good in the diagnostics plug and am very puzzled as to why no cdes from the CEL. I went to my local Maza dealer yesterday and spoke with them as to why the (one) radiator fan runs with the key in the run position. They noted two sensors in/near the water outlet (on either side of the temp. guage sensor) that could be causing the fan to run. One (to the front of the car) they tells me controls the fan (it is 2 prong/ grey plastic on the sensor/ grey plastic on plug that goes to it) is mazda # FS 01 18 840 and the other one (to the rear) they tell me goes to the computer (it is 2 prong/green plastic on the sensor/ green plastic on the plug that connets to it) is mazda # B3 C8 18 840. Any experience with these sensors going bad or how to diagnose them? With the key in the run position I have disconnected both of these sensors and the cooling fan continues to run. The sensors are about $60 each so am reluctant to just start throwing more new parts at the problem. Appreciate any help you can offer.

Still here Jimm. Did not get on the computer last night as was swamped here at work. The dealer info is right. The one towards the front is the one that is used for fan control. Brown w/ Yellow stripe wire and Yellow w/ Blue are the wire colors. Your part number FS01-18-840 is ok but only show retail of $39.10. There are several ways that fan will run with key on all the time. With the TEN pin grounded and throttle slightly open the fan should run with key on as a sort of self test for the system. The computer also has a fail safe in case of faulty fan temp signal in that it will run the fan all of the time. Looks like you may have a bad fan temp sensor. If you have a way to check resistance of sensor here are some specs for resistance between the two pins of the fan sensor with connector unplugged. At 68'f should be 2200-2700 ohms, 176'f should be 290-350 ohms. If you do not have a way to check resistance then pick up a 50 cent resistor from radio shack that has 2000 ohms or so and plug both legs into the connector. You will be fooling the PCM into thinking that it is cold so fans should not turn on.
If not getting the CEL to flash then maybe there are no codes stored. Sounds very odd if your CEL will stay on with the engine running but is not storing a code. Try disconnecting the Mass air flow sensor at idle and see if the runability improves. This works on later years but don't remember if engine will run with Maf disconnected. Am working on a 96 now with a bad maf that bogs out badly when revving but is fine with the maf disconnected. The other thing this will do is make sure that your PCM is recognizing engine faults as it should set a code 8 and 10. Give those a try and see what happens.

Babyhuey and any others following this. Was not able to get back to the car till this past weekend. Checked the sensors near the water outlet and the one to the front of the vehicle controlling the fan had a reading of 31,000 ohms when the other was in the 2500 range. Replaced the sensor and started the car it seemed to run OK (it would idle) for a while and then started running very rough again. Was surprised to see in replacing the sensor the one cooling fan continued to run with the key in the run position. For a short time the check engine light was out but it came back on once the engine started running rough again. Still no codes at all being reported with grounding the ten pin. Engine ran rough even with disconnecting the Mass Airflow Sensor.

Way things ended for the day; car will not idle, giving a bit of gas engine runs rough/"pops" CEL light on, sometimes stepping on the gas up to about 3,000 rpm's the engine will smooth out (CEL light will go off) but letting off the gas it will hardley idle/ not idle and shut off. When starting the car as soon as the key is placed in the run position the one cooling fan starts to run, the check engine light comes on. BUT with the TEN grounded NO CODES reported. Should also note with both of the water temperature sensors DISCONNECTED with the key in the run position the one cooling fan continues to run. At the end of the day both of the sensors were giving readings in the 1,700 ohm range so gather they are OK. Any thoughts as to what to look at next? I thought replacing the one sensor would fix it but I must have another problem.

jimm, was having a thought on your car. Are you sure it is a 93 and not a 94? In 94 model year, Mazda used Ford engine computer and diagnostic capabilities in the 626/Mx-6 4 cyl with auto trans. If that is the case then we will never get codes from that TEN pin. Take a look at the 17 digit VIN located on the drivers side lower corner (will have to look at thru windshield). Should start with 1YVGE****. Count over to the 10th digit. If the 10th is a P then it is a 93 but if is an R then it is a 94. Also look next to the battery around the area of the coolant overflow bottle and see if there are two connectors that look like what I will post a picture of below. These are the Ford style diagnostic connectors.
After disconnecting the mass air flow sensor were any codes stored. Should have set a 8 and 10.

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Babyhuey looked at the VIN and from what you tell me it is a 93 model year. Vin is 1YVGE31A1P******* The sticker on the door frame on the drivers side has a manufacture date of 9/17/92. I do not notice any connector that looks like the picture you attached in your previous post. Never got any codes after disconnecting the mass air flow sensor and that is the most confusing thing about all of this ... not getting any codes at all. Are there some real basic things I should check that would not set a code? Thanks for your help!!!

UPDATE --- worked on the car today. Went out this morning around 11am. Noted in putting the key in the run position that the fan came on and the check engine light (CEL) went out. Started it and let it warm, up the one cooling fan stayed on as it has (was running at high speed) but the CEL stayed off and the car idled normally. Turned it off/ back on about 4 times and the same result as noted in the prior sentence. Checked for codes (jump TEN and GRD) and when I tuned the key to run, the fan stayed on the CEL light went out, and I finally got a code --- CODE 69 -- which according to what I have is the coolant temperature sensor for the fan used by the computer. Got an aftermarket sensor (Standard TX 40) that cross referenced to the dealer part number and put it in. Did the process for clearing the code and started the car. But NO LUCK it would hardley start, would not idle/ popping/ running very rough, kept cutting off, and would not take any gas at all (could not rev up) and no power. The CEL light was on and the cooling fan was running all of the time. Tried for code, jumped the TEN/ GRD --- once in run position fan and CEL light stayed on and NO CODE as I have been experiencing. Put the old sensor back in continued to run rough, fan and CEL light on and tried for a code but did not get one. The car had sat about a week before starting/ running well this morning around 10 am... was cooler in the morning then when I put in the sensor at 2:30 pm this afternoon. Any thing that could impact the running due to the temperature going up a bit in the afternoon? Thought I had it fixed with getting the code but I guess not. Apprecaite any suggestions you may have.

This car just does not want to run does it?[:@] So cold this morning it idled and ran fine and CEL was out. Pretty much all back to normal? Then this afternoon it went back to the same old problems. Try starting again when it is cold and see if that is making a difference. Just let it run and maybe rev engine some to see if the warming up changes something. The other thing that might have made the difference could be disturbing the engine harness in the process of changing that temp sensor. While engine is running try to wiggle the harness, connectors, and maybe even tugging lightly on individual wires at connectors for distributor, air flow sensor, thottle sensor, etc. Any place that might have been disturbed by replace of sensor or other place you may have been. Maybe a wire is pulling out or shorting somewhere that was fine untill you moved things?? HOPE. I was beginning to think that maybe cam timing was off but if it ran fine this morning then probably not. The not outputing a code during a forced failure such as leaving MAF or Throttle sensor unplugged is pointing towards a fault in the PCM. fan running all the time is another possible indicator as it is controlled by the PCM. Might even want to try pulling the center console and checking the wires and wiggle test them. If all ok and you have engine running ok when cold then heat up the PCM with a hair dryer and see if that suddenly makes it run rough. Wish there were some better answers instead of guesses!! Sounds like the temp sensor for fan was definitely out at 31k ohms and back to normal but why is fan still running. Faulty signal will put PCM in failsafe and run fan on high all the time. Wiring problemf or PCM? Good luck jimm.

Babyhuey, tried sending a PM but dont know if it made it. Found a "diagnostic module" inside the car, drivers side, under dash above left foot. The box is blue, about 7 x7, flat, with two plugs and a bunch of wires to/ from it. Found a bracket had gone into the box and was resting on a circuit board. Pulled the bracket away from the box and started the car. It ran fine for a while (NO cooling fan/ check engine light), but after a while the cooling fan came on and gradually (cooling fan)increased in speed, the car started running rougher got progressively worse, the check engine light came on and ultimately it stopped runnng as the plugs fouled out. The box has a warning on it about "disonnecting wires" and some wires run up the steering column. WHAT IS THIS "DIAGNOSTIC MODULE"? Does it control the airbag? Anything else it controls/ runs especally as to the fuel delivery sytem?

Greatly apprecaite any insight you can provide.

thanks

Jimm

Hello again Jim,

Saw your post late last night but did not have a chance to reply. The blue module is the air bag diagnostic module. The wires you see running up the colum would be going to the air bag in the steering wheel center. The module has absolutely nothing to do with the way the car runs but only controls deployment of the air bags and fault monitoring.
However, the power supply to the air bag module is a different matter. It is powered continuously by the 30 Amp EGI INJ fuse in the under hood fuse box which also is power feed to the Main Relay which then powers up the injectors, PCM, and virtually every sensor in the engine.
The air bag module also gets key on power thru the 15 Amp ENGINE fuse in the under dash fuse box. This fuse also supplies power to the main relay coil, fuel pump relay coil and contacts, and all three of the cooling fan relay coils.
Hmmmmm. Am wondering if that bracket may have created a short to ground for one of the power sources and possibly melted a wire somewhere or caused a connector to overheat and create a poor electrical contact condition at the connector. When engine is started that connection is still cool so power flows thru just fine but after running for awhile the increased resistance in the connector begins building up heat that then increases resistance which creates more heat etc, etc, untill voltage is dropped to the point of being insufficient to power up running systems. Just a theory mind you. Still kind of stumped about that cooling fan just coming on and running though. Do you have any wiring diagrams of system?

Sent you a PM too