Mazda 626 93 V6 turn key, click-k-k-k under dash, all dead, then back on - relay?

Almost sounds like a bad ignition switch.

What worries me is the car goes dead for a finite time when it happens

- then everything comes back on. That sounds like some immobilisation timer on the old factory alarm. It has gone from "twice a year" over the past 5 years to twice today with extreme difficulty in getting it started until it did "by chance". I could not find cause & effect in what I did.

It could be a failing immobilisation circuit or corroded connection, but I am surprised the factory alarm shuts the entire car down - as in door lights, headlights, interior lights? However I wonder if there is a relay which controls the whole car - when you start the car the relay shuts everything off so the maximum current can go to the starter motor?

These security systems can be complicated and touchy to diagnose.

I have a car like this that I may have to either give to Heritage for the Blind or burn in my front yard.

Save yourself some time.. Go to an expert.

Or, I can get you the telephone number for Heritage for the Blind

That's an awful idea. We already have _enough_ blind people driving, the last thing we need are more.

--scott

Mid '90s Nissan Maximas used to act something like this when the grease in the starter got dried out/stiff and the throwout bearing stopped throwing out. The symptom would be "turn the key, nothing, after several tries it would finally start as if nothing is wrong". What was happening was the piston in the starter was not moving far enough to contact the switch to engage the starter. When you tried it enough times, eventually it would connect and work fine until it cooled off and the grease stiffened again. The fix was to take out the starter and either re-grease it (essentially free repair) or put in a new starter.

With the car in the driveway...

Last night it started 4x in a row, battery voltage 12.92V. Today it started 3x in a row, battery voltage 12.56V before starting and 14.50-14.51V with the engine running.

However, the car has not been moved - just started.

Examining the battery terminals I find the Negative connector is not factory - it is a generic with two pozidrive screws clamping down on the factory fine copper conductors which are dark and not well clamped at all. It should be a moisture-free crimp, instead it looks like a trashed mess. That does suggest a poor negative terminal could be responsible, along with plenty of other grounds elsewhere. The battery negative terminal goes to the bodywork, not a great fastening and on somewhere else - would that be to the starter motor to give a low resistant start, thus I also need to check the starter terminals?

If the voltage drops low enough during starting I do know the alarm shuts down the car from past experience of failed batteries.

Picked up spray contact cleaner, battery terminal cleaner brush and looks like I will have to go right through all the grounds including under the dashboard. The fuse & relay box could do with things unplug- replug as it has never been touched (someone remind me why they stick them under the hood?!). Checked under carpets, no water evident.

One thing I *think* I noticed when it would not start 4x in a row (click-k-k-k, everything dead, came back a minute later probably as the alarm/immobiliser triggered by low voltage ran through their timeout). I think the negative battery terminal post & clamp were warm... does that point towards a high resistance negative... or is the starter just yanking the voltage down low enough to give the alarm/ immobiliser undervoltage (which makes them go into anti-theft mode)?

Ah, one thing I DO recall in the past.

Occasionally I would turn the key to start and get nothing (not even a sound). I would try the key again and the starter would run ok. Do cars use an ignition relay - or is that just corroded starter terminals?

If something can pull the voltage down low enough, the alarm/ immobiliser will obviously go into "anti-theft" mode. Just a matter of pinning it down.

Well just to followup.

#1 - The battery negative terminal had been butchered by a Previous Alarm Installer (TM). The twin-screw clamp expected 50-70mm cable not the factory 16mm. So in order to hold together and bulk up the fine strands so they would sit under a screw he tried soldering, with too small a soldering iron, insufficient flux, despite cold-flow under a screw, despite "warm- flow" being highly probable with a starter motor!

Cable cut back, crimped to new tinned-copper cable via copper-tube butt-crimp, then crimped to a battery lug, with new tinned marine battery terminal with M8 stud.

#2 - The clutch change circa 1998 involved unplugging all the main ECU harness plugs on top of the gearbox and the factory 16mm negative connection (yellow stripe on black cable jumped out at me). The main dealer mechanics, bless their cotton socks, had cross- threaded the M6 screw into the top of the aluminium housing so the

16mm negative lug could be wobbled up & down and around with ease. Suffice to say it looked rather worse for wear re abrasion and the numerous small ground cables in the area probably had little to ground to. The engine mounts & exhaust mounts are all rubber, I did not notice any other engine-to-body ground - even small 1mm never mind 16mm. None of the factory plugs/sockets were properly fitted back on their brackets.

Used a rethreader on the hole, chucked the mangled screw (which I also suspect was too long), cleaned off the oil, used a socket-cap stainless (all I had) so it is now very visible (aluminium & stainless are not ideal, but it does not have to last another 12yrs). The wiring harness clip brackets partly obscures this terminal for anyone looking, but the 16mm black with yellow stripe earth wire to the car battery is glaringly obvious.

The difference? The car starts better and for certain the engine does run noticeably better (no continual dot-dot-dot hesitation). There has been no repeat of the problem today despite 17 stop-starts. I hurled the car through S-corners again and again, stopped & restarted, let it a while and repeated, and the same stop-start along a very rough road... probably need new rims and teeth it was so rough :-)

I suspect those responsible use a nail for the welder's fuse... or have progressed into working with 400kV or at a nuclear power plant on the electrical shutdown side.