2002 Protege5 won't start.

Car ran just fine the day before yesterday. No problem at all starting. I was working on it yesterday (nothing that would cause it to not start, was messing with the VTCS and o2 sensor) and when I went to start it, it wouldn't turn over so I checked the battery and it had a low voltage (around 10v). The battery is old and probably needs to be replaced, but decided to have AutoZone check it out and they said it seems fine. They charged it up and I came home and installed it, car turned over just fine, but it will not start now. Did some Googling and tried a couple of different things. I cannot find an alarm override switch (I'm not sure if this car even has one) but I repeatedly unlocked the driver side door with the key and I also shifted between park and drive back and fourth a bit. Neither made the car start.

Any ideas on why it wouldn't start after the only real thing I've done is disconnect the battery? Could it still be the battery even though they said it held the proper charge fine and has no problem turning over the engine for an extended period of time?

Are your battery terminals clean?

Yeah they're clean.

you battery might be failing , check the battery again

Did you unplug anything? o2 sensor?

I unplugged the o2 sensor to back probe it to test whether or not it was functioning properly (i have a p0421 code on the car). It was plugged back up though. I also unplugged the VTCS to clean the contacts (error code p0159). It was plugged back in as well. I determined the solenoid was bad. Other than that, no. Nothing has or is unplugged. Everything is in the condition it was when it was running.

Won't start even when jumped (just tried). Don't think it's the battery.

Also is it normal for this model car to have the temp gauge go to max with a cold engine and the key just turned to the on position? My Sonata does not do this and I noticed this earlier while trying to jump the car.

IAmSupernova said:

I unplugged the o2 sensor to back probe it to test whether or not it was functioning properly (i have a p0421 code on the car). It was plugged back up though. I also unplugged the VTCS to clean the contacts (error code p0159). It was plugged back in as well. I determined the solenoid was bad. Other than that, no. Nothing has or is unplugged. Everything is in the condition it was when it was running.

Won't start even when jumped (just tried). Don't think it's the battery.

Also is it normal for this model car to have the temp gauge go to max with a cold engine and the key just turned to the on position? My Sonata does not do this and I noticed this earlier while trying to jump the car.

Click to expand...

No, that isn't normal. Check the wiring going to the ECT, and follow it back a little ways to make sure it's not pinched or broken.

What exactly did you back probe, and what did you use?

I would start with checking all of the fuses.

The back side of the connector of the o2 sensor (sensor side). I used a manufactured back probe, basically an alligator clip with a needle sticking out the back that is almost entirely insulated.

Never got around to testing it and we're on a time limit to get it inspected so we can get it titled and registered, so I just went ahead and ordered new o2 sensors and pre-cat. So if I somehow caused damage in the probing, it'll be replaced soon anyways. Don't want to run out of time by trying to get it to run and then running the test I planned they both likely need to be replaced anyways. But if I can get it back to running in the mean time, all the better. If I can't after I get the stuff done I already know needs done I'll just have to take it to the shop and have them figure it out. Would like to figure it out myself though.

As part of my planned tune-up/maintenance I also ordered new ignition coils, spark plug wires and will be replacing the spark plugs themselves.

Too dark to go checking on the ECT now, I'll have to do it tomorrow. Planned to check the fuses too, but with my luck it seems like a long shot so figured I might as well get a head start on finding out what else could be the issue, rather than report fuses as good and then wait around extra to get other ideas.

So far I've got a pretty good list going of what to look for, but figured seeing as this is a Mazda specific forum there might be something someone could offer that a general search wouldn't bring up. Like any weird quirks this car has that could be responsible. Plan to check fuses, and replace the ignition system, plan to check the fuel system. I've never had a car that had a bad battery that couldn't be jump started though so I don't think it's the battery, although I know there's still some kind of chance it is.

Have determined the engine is not getting fuel. Cannot hear the fuel pump turn on at any point, the relay for the fuel pump is not clicking. If I spray starter fluid into the air intake, the car does try to start. There is very clearly ignition going on with the starter fluid, but absolutely no sign of it otherwise. Trying to figure out why it's not pumping fuel now.

Figured it out. Was a fuse labeled "Engine" in the passenger compartment.