2004 Mazda RX8
Very good car.......

Well, I don't want to have to take this car apart to find this issue....here it is.

We've had this car 6 years, this problem has been recurring for 2 years.
At the first frost (or when it gets cold outside) in the morning, when you turn the key.....the starter does not engage.

Here is the sequence of events:

Get in car. Lights work
Insert key into the ignition.
Turn key to first position, good, I can hear things working....dash lights up properly
Turn key to second position, other things seem to work properly
Turn the key to engage starter, you can faintly hear a switch click (I'm assuming its from the engine compartment,
but setting in the driver's seat, sounds like it is behind glove box), but nothing happens.

HOWEVER ! ! After temperature rises during the day, it starts fine.

There is no parasitic drain.
Battery good (new)
Charging system works like it should.

We believe it is an electrical problem, possibly contacts in some switch move slightly when it gets cold and prevents contact.

Any suggestions??

Thank you!

 

Have you gone over all connections at the batt and the starter. Make sure it's all tight and clean.

 

I have not checked the starter connections.....I know my mechanic put new end on neg battery cable...but he did not mention checking the starter connection.
It was cold this morning, it would not start.
It will start this afternoon, as usual.

I will check starter connections.....
Thx

 

Sounds like moisture ingress somewhere that's minor, until the water freezes and expands, pushing whatever far enough apart to prevent adequate contact. TN isn't exactly tropical, so I wouldn't expect a ton of moisture in the cab. I'd be looking at contact areas related to the starter circuit outside the cabin, and especially in lower points where moisture can collect.

 

Sounds logical.
One thing......I'm not sure moisture has anything to do with it. I know I used the word "frost" in my initial message, but it is garaged.
The only thing I know of that gets to it, is the cold.....
Thanks!

 

I'm sticking with the starter connection right on the starter. Or the main ground under the battery box. The cold could be doing it's thing to the metal making the connection weak.

 

Likely your options are either the key... the relay or the starter solenoid connections

Check those first. After that there are lots of other things in the immobilizer system like the key coil or module. Never seen the key coil fail that way... but could i suppose.

If you are mechanically 8nclined you could jump the solenoid to 12v and see if it triggers the starter... if it does you can go backwards up the wiring looking for issues.

Check the relay by swapping it with another one and see if that helps... I think the fog relay is the same...just don't use something the car needs to run

 

If this only happens when it is below freezing then there is the possibility that there is water or moisture inside the starter solenoid or the starter itself, a small amount that is frozen can prevent movement of the parts. I have experienced this several times in the past and usually it was the solenoid.

 

I'm willing to bet the solenoid in your starter that pushes the gear forward has gotten weak with age, and now is stuck or binding when its cold. As the day warms up and the part warms up it sounds like its loosening up enough to operate somewhat normally. I'm thinking this is a mechanical part failure, not electrical. Replace the starter is what I would lean towards solving your problem.