Engine Rum Problems
 

For the past 2 months my FD has been shutting off on me randomly. The whole car dosen't shut off, just the motor. If I go to restart sometimes it will start right up. Other times it may take a few minuets to get going again. The motor just cranks and cranks. When It does start again it dosen't labor to start, I starts right up and run's fine. I don't get a check engine light. I replaced the fuel pump but the car does the same thing. I checked the engine grounds and cleaned all the battery connections. One thing that the car did not do before that I notice now is when I go to start the car, even when it is cold, The fans come right on with the key. It seems like the car won't start when the fans are running-- most of the time. Anyone seen anything like this? Any help would be appreciated...

try replacing fuel filter?? could be severely clogged....but it sounds like it's more of an electrical problem. You could check the coils/plugs, or it could be an ECU problem. You may want to try swapping in another ECU, or disconnecting the negative terminal on the battery and allowing the ECU to reset (disconnect for 5 minutes, then reconnect and start). The only reason I would do this is because of the fan thing you mentioned, I have heard before that with ECU problems, there is sometimes a "limp mode" that comes into effect. I had this happen to me a few times years ago running the PFS purple motor eater computer, and simply had to disconnect it, wait a few minutes and then reconnect. It happend once when the car tried to overheat on me, turned out I had an air bubble in the coolant system and the PFS computer didn't like it, so it freaked out. Try to purge your coolant while your at it, when the motor is cold, turn it on and take the filler cap off, let it cycle through a few times while squeezing the lower radiator hose...., probably not a fix for you, but you never know. I don't know what mods you have, but apparently, the airbubble in my system was sitting at the coolant temp sensor and the air heated up to really high temps, telling the PFS computer to shut the engine off.
Just remember there are three things that make an engine run....air/fuel/spark, if you don't have one, the engine doesn't run. You can be pretty sure that you are getting air, so maybe it's spark. You can check the spark plugs one at a time to make sure they are firing by removing the fuel pump relay fuse( to stop fuel from pumping so the engine won't actually start), and cranking the engine a few times. Hold the plug in your hand and point it towards the inner fender well about two inches away, if you are getting spark, you should see...well....a spark. Do this to all 4 spark plugs, and while you are at it, make sure you have the plug wires on the proper plug, leading on leading, trailing on trailing, in the proper order. The fuel filter is a few bucks from mazda, and if you haven't replaced it, now is probably a good time. See if you can get a different ECU from a buddy and swap it in, your ECU may be bad, it does happen. You basically just have to rule out one thing at a time until the car runs properly.

OK, so I looked for my origional post last night and I didn't see it?! This morning I found the link to search all my posts. Sorry. Anyway I tried swapping out the ECU without any luck. I'm going to try to re-bleed the coolant system but I think i'm with you with it being a electrical problem.

it's a long shot, but you should also check the alternator for voltage.....