ignition issue

[ElFenix]

car is a 2008 mazda3 with about 165,000 all original miles.

back in october the positive battery terminal got so corroded the engine wouldn't start. i cleaned it up, replaced the battery and mazda's Y connector end for the positive cables, and went on my merry way.

at the end of december it wouldn't start again. no visible corrosion, but this time i went to the parts store and got a kit with some anti-corrosion stuff, cleaned up all the terminals, wires, and the Y connector, and went on my merry way.

last friday evening it did it again. though i did get it started by holding the key in the ignition position (there was no cranking, no clicking of the solenoid, nothing) for a few seconds, at which point it fired right up. i'd previously tried leaving it in accessory for a bit just to make sure the fuel pump was primed, but it wasn't starting immediately.

saturday morning i went out to clean it, and decided to try starting it beforehand just to see. it fired right up. i turned it off, went to get my wallet and put on some pants because i needed to go get an inspection (and you can't get that with a recently disconnected battery), but when i went back out it would not start without holding the ignition for several seconds. again, no noises or anything during that time. at the inspection it started hard but immediately, so that was fine. brought it home and it's been sitting since.

there was a TSB for this car issued just about when it was manufactured way back when covering what seems like this issue. although you'd think that i'd have had this problem at some point in the past if that was the issue.

so, options? am i just fighting a bad bit of corrosion? maybe a worn ignition switch or cylinder?

 

[NutBucket]

I would certainly check that connection at the starter. I'm a bit puzzled how adding some length to the wire would alleviate the issue but what do I know. You can test the ignition switch by hooking a test light to that lead and seeing that it lights up whenever you turn the key. It is also possible there is an intermittent in the starter solenoid. Have you ever replaced the starter?

 

[pcgeek11]

I was also thinking starter solenoid.

You should be able to replace just the solenoid and not the entire starter. Lots cheaper.

 

[ElFenix]

I would certainly check that connection at the starter. I'm a bit puzzled how adding some length to the wire would alleviate the issue but what do I know. You can test the ignition switch by hooking a test light to that lead and seeing that it lights up whenever you turn the key. It is also possible there is an intermittent in the starter solenoid. Have you ever replaced the starter?

no, starter is the original.

maybe with the short cable there's some tension on it that pulls it out of the connector, so adding some slack keeps that from happening.

 

[pcgeek11]

Get a meter set it to DC Volts.

Check the large connection on the solenoid, it should read battery voltage all the time ( on or off ).

Check the voltage at the small coil lead at the solenoid. It should read battery voltage when the key is turned to the start position.

If you get both of these voltages and the starter doesn't turn the engine the starter is defective. You may be able to just replace the solenoid which is far cheaper that the entire starter.

NOTE: If you get a rebuilt starter from a parts house they are known to have a huge failure rate. Make sure they give you a warranty.

 

[Meghan54]

I've seen pos. battery cables that were so corroded internally, underneath the insulation, that the cable began to struggle to pass elect. effectively. Maybe look at that?