1990 gtu
ill be driving down the road and sometimes the car will randomly shut down. nothing i can do can save it from stalling. voltage reads zero. headlights and hazards turn on. thrn usually after a while voltage goes up to 12 and car starts. usually. lately it can be hours and nothing happens. what could it be?

 

when the car shuts down, does everything loose power?

could be bad grounds.

fyi your signature is huge

 

lol yeah i know. but like i said the headlights and hazards work thats it. got a new battery and nothing. wont take a jump either. could it be my starter? maybe a relay over heating or my alternator? im stumped

 

It can't be your starter, that would cause it not to crank at all. It's not your alternator unless you need to jump it/charge the battery before it will turn back on. It could possibly be the relay, does it say anything about this problem in the factory service manual?

 

actually before now (now it wont start at all) if i had some one jump me it would instantly get the voltage back. but even if they didnt after at least an hour it would get its voltage back on its own. i havent had a chance to look up the problem since it just happened today. i started this thread on my phone on the side of the road waiting for help. but just for a recap here is how my car is as of now.

1. car shows voltage as zero even when the key is in the on position AND if someone tries to jump the car

2. car will not turn over at all.

3. head lights work, hazards work, but radio, sunroof and wipers do not work.

4. car was running fine earlier but while driving the car just cut out. voltage dropped to zero and motor sputtered to zero rpm didnt just die like when you turn off car.

5. got a new battery. nothing

so thats pretty much where i am now. its driving me mad. i do a delivery job so i def need this car to run! it has to be something electrical

 

Okay, the good news is that it's not your alternator... The bad news is, that leaves a lot of things it could be. If it were the alt, then it would sputter and die slowly, gauges going crazy, etc.. And the battery wouldn't have enough juice to crank it next time. Since it just "shuts off" and even with a new battery it won't crank, that means it's not the charging system.

I would start with the key cylinder switch, then look at the main relay if the key cylinder checks out.

 

if the main relay is getting to hot could that shut down the engine while i'm driving??? and if it happens too often could it just be fried?

 

You've merely lost the power to the BLACK wire on the ignition switch. It comes from the Engine bay fuse box with one connector inbetween. Make sure its connector about six inches below and inbd of the engine bay fuse box is not half *** connected.

You can prove this idea is valid or not. Next time you LOSE power as you say, turn the wipers on. If they do not work, I'm right. Or you can substitute wipers for TUIRN SIGNALS and get a clue of where the problem lies.

If the wipers and turn signals don't work, it's a problem with the power TO the ignition switch or power From the ignition switch to power the interior fuse box. MOST fuses in the interior fuse box do not have power UNLESS the key is put to ON or better.

The ENGINE fuse which controls most engine related items, is on the IG1 bus in the interior fuse box. That fuse and the others on IG1 are fed from..........the ignition switch via the Main Relay in the engine bay fuse box. YOU know the Main Relay is good so the problem would lie in the path of the black wire on the igniton switch to the engine bay fuse box. ONly one connector inbetween as described above.

Many keys on the igniton switch key ring MIGHT cause the problem by keeping the switch from being in the ON positon.

See wiring diagrams for what I just talked about.

 

ill check that out

 

One thing that could shut the engine off while driving is the main relay. Take it out, put it back in, make sure it and every other connection is secure and tight.

 

what happed to my Fc is the ignition switch, they seem to loosen up as time passes.. u should call ray at malloy mazda and order a new ignition & have him cut ur key as well with ur vin#.. that should solve ur problem

 

The ignition switch and the actual key cylinder are different things, Ander.. You can swap out the switch cheaply, without getting a new cylinder cut, it's only held onto the cylinder with two or three screws... That's why I suggested checking it at the switch.

 

that would be great but i live in florida bro! XD so yer car had the exact same symptoms as me?

 

I have the same thing going on this S4 I just picked up.If I come up with anything I'll send the info your way.

 

actually the issue was resolved! turns out one of my connectors had melted in the engine bay between the battery box and the fuze box. check all those connecters and make sure none of them have melted! i mean if i just jiggled the cable power would come back on. simple fix was to just cut off the connector and crimp on a coupler! what a pain in the ***! D:

 

glad to hear you got this fixed.

 

yeah.I'll be working on mine this weekend.Hopefully,I find the same thing.lol.There are a lot of connectors that need to be replaced or cleaned up