msilvia

Breaking in a new mazda 13B and new-to-me 99 twins, so everything in the engine bay has recently been touched. The car drives great, everything feels good, the first ~500mi went by without incident. But three times now the car has died while stopped or at low speed, and has been unwilling to turn over for some period of time (15m-60m range in these instances) afterwards. The car won't try to crank at all. You don't even get the initial relay click when you turn the key. Eventually it starts right up and runs fine.

Note also that:

• I've tried bypassing the clutch starter switch at the clutch pedal with no effect
• The security starter wire (blue connector) in the driver's footwell has also been bypassed for years
• I recently replaced the ignition switch in the steering column, and had figured that fixed it. Nope.
• Twice the car died at the exact same spot going ~30 on a neighborhood side street. Once at a red light while stopped.
• Each time was on a hot day, and after the car had been driven somewhere, parked for a bit (head soaking) and then been on the way home. Not sure if it's related but this issue didn't pop up in the spring.
• Voltage seems fine and car starts immediately when it finally does crank.
• Running a power FC, if that can help to diagnose anything.

I'm thinking it's heat or vibration related going by the above. But where do I start looking? What would cause the car to die and then also to not crank, and then resolve itself after some period of time? Could a relay be going bad? Loose wire to... starter? Would that make the car die? Something else? I'm assuming if it was fuel/spark/air the car would turn over.

provels

Similar happened to me once. Was the battery cable, neg I think, Terminal was too large for the post. Fixed with a lead cap from the farm store.

msilvia

Thanks. I'm going to nut-and-bolt everything, but I do seem to have strong electrical power even when the car dies.

msilvia

If I had an issue with the starter/starter solenoid, is there any scenario where that could make the car die when it was already running?

FDAUTO

iTrader: (4)

3 things:

1: I had a problem similar to this on my own car a long time ago. Starts up cold and warm perfect, ran perfect for whatever period of time BUT when it got hot (not overheating hot) and you turned it off, it would NOT start until it sat for at least an hour. It would crank all day but never catch.

The problem ended up being the o ring at fuel pump hanger.

2: in my other fd, cold and warm it would start fine all day. After any extended drives, it would struggle to crank as if too great of a load was put on the battery. The lights would dim A LOT and the starter just acted like low voltage. Come to find out it WAS that the load was too great because one day the MAIN fuse in the fuse box popped while trying to crank.

Checked over everything you could think of until I suspected the starter. Tested a theory with a long drive and got the starter hot. The cranking issue was there. I sprayed the starter with water to rapidly cool it and then when to try and start the car, cranked over clean and perfect. Replaced the starter and the problem hasn't been back since.

3: on the same car before it was fully tuned, after a good drive and shutting it off allowing it to heat soak, it wouldn't start. It would crank and crank and crank but never catch as it wasn't getting any fuel. Did some tests and suspected the issue was the air temp being too high from heat soaking. Went into the map, corrected the fuel compensation for cranking when heat soaked.... boom.... fixed.

now of the 3 scenarios none of them directly share your issue but in this case they were all temperature related which yours seem to be. Maybe try forcing some temperature variations on certain components to isolate your issue.

Also want to mention in both cars the flasher relay will bug out when it's too cold. In one car it will flash the seat belt light and the windows will work intermittent of the flashes. In the other, it will rapidly flash the air bag and seat belt lights along with some occasional beeping from under the dash. Both of which confirmed to be temperature related because if I put the relays in the fridge, the symptoms return and if I heat them up, they go away.

Hopefully something here is useful to you and can help in your troubleshooting

msilvia

Thanks! I'm thinking: perhaps a ground issue is the culprit? I know ground issues can cause the starter not to fire, and I'm assuming it's also plausible that a grounding issue could make the car die. Maybe the heat is just adding resistance to an already-marginal grounding system. I'll go over the grounds, make sure they're good, and possibly run an extra engine-chassis ground or two to see if that helps.

The car seems to run ok, but I do have some issues sometimes with light throttle bucking that I know can indicate an grounding issue.

DaveW

http://www.rx7club.com/showthread.ph...condary+sensor