[Question] Car problem: won't start

[drifter]

Some background problems which may or may not lead to my current problem:

1. A while back the mechanic told me my valve cover gasket was leaking and would eventually need to be replaced. Told me he would just replace the spark plugs for now and to change the gasket later (this was 2-3 months ago?)

2. Just a couple days prior my key fob wouldn't open my car door. It's not the key fob, as my spare wouldn't work either (checked battery for both, looked fine).

So now my car won't start. I took the battery in to see if it was bad, they recommended replacing so I did. Still wouldn't start. Then the funny thing is I tried to start it today and it worked, but after giving it a little gas while idling it died. Right now I'm guessing that the gasket gave up the ghost and the spark plugs are fouled, but the key fob thing makes me wonder if it might be some kind of electrical problem. I figured I'd ask what you guys think before poking my head under the hood again.

 

[sixpackshaker]

Get your alternator checked.

And the battery you just had installed checked too. Some modern cars can't run with a battery with a dead cell.

Valve gasket should not affect the starting of the car. It will just ruin the car by letting oil into the anti-freeze or vice versa.

 

[PatrThom]

Second the alternator/alternator belt. The car draws power from the battery to start, but it's the alternator's job to provide the power that keeps the spark plugs firing while the engine is running. Recharging the battery is secondary. Most people think that the battery's job is done at that point, but really the purpose of the battery is to give you a reserve "tank" of electricity to keep your car running long enough to get to safety if your alternator dies. That's why you're supposed to find a place to pit as soon as you see that alternator light come on, because you don't know how much longer your car's going to run until it just...quits.

Valve gasket should not affect the starting of the car. It will just ruin the car by letting oil into the anti-freeze or vice versa.

Isn't that the head gasket? I thought all the valve cover gasket will do when it fails is spit oil out onto the engine, where it'll burn up and smell bad. I don't think antifreeze circulates anywhere up above the valves.

--Patrick

 

[Shakey]

When it won't start, does it turn over? Or does it do nothing?

 

[drifter]

When it won't start, does it turn over? Or does it do nothing?

Turns over.

Not sure if worth mentioning, but before I replaced the battery, noticed headlights seemed strong even with old battery. Car would turn over, then slowly die until only starter was clicking.

 

[Gared]

I'm going to throw in with the alternator/belt crowd as well, and throw in the one that bit me in the ass for good measure: the belt pulleys. The tensioner pulley for my serpentine belt failed on my last car, and it took two replacement jobs on the belt itself to figure it out.

 

[GasBandit]

Definitely alternator, or the belt that drives it.

 

[Shakey]

Turns over.

Not sure if worth mentioning, but before I replaced the battery, noticed headlights seemed strong even with old battery. Car would turn over, then slowly die until only starter was clicking.

You mentioned it started, but then died shortly after. Were you still able turn it over after that?

It doesn't sound like a battery issue if it's turning over. The battery is most likely dieing from turning it over too much.

The head gasket just keeps oil from splashing out into your engine, like @PatrThom had mentioned. I wouldn't think it would foul the plugs, unless it's splashing on to them and maybe oil is getting in to the connection and shorting it out.

It's hard to say for sure. Could be clogged fuel filter. Could be dirty throttle body. Could be bad plugs or plug wires. Did you get any sort of check engine light?

 

[drifter]

You mentioned it started, but then died shortly after. Were you still able turn it over after that?

Yeah, still turned over after that.

It doesn't sound like a battery issue if it's turning over. The battery is most likely dieing from turning it over too much.

The head gasket just keeps oil from splashing out into your engine, like @PatrThom had mentioned. I wouldn't think it would foul the plugs, unless it's splashing on to them and maybe oil is getting in to the connection and shorting it out.

It's hard to say for sure. Could be clogged fuel filter. Could be dirty throttle body. Could be bad plugs or plug wires. Did you get any sort of check engine light?

Well, I unplugged the spark plugs and 3 out of the 4 wells were dirty, two lightly and one moderately. Didn't pull them out and check because at the time I didn't have a spark plug socket. No check engine light

 

[GasBandit]

A cracked head gasket can foul a spark plug if the crack is near one of the plug apertures. But it's unlikely to get more than one, and even with 3 plugs the engine should catch and rev, albeit extremely roughly. Heck, even with two it should hiccup and fire and stutter. But if it's not catching at all, and just turning over and over and over until the starter wears out the battery, that makes me think there's a compression problem (which would also be easily explained by a bad head gasket) or maybe the engine timing is off - badly off.

I don't envy Drifter his upcoming repair bill. A head gasket alone is a lot of labor, and the rest of hunting down "what else is wrong" will likely take up some more manhours as well.[DOUBLEPOST=1512359517,1512359419][/DOUBLEPOST]

Well, I unplugged the spark plugs and 3 out of the 4 wells were dirty, two lightly and one moderately. Didn't pull them out and check because at the time I didn't have a spark plug socket. No check engine light

Dirty, or wet?

Could be the head gasket, you might also have piston ring problems.

 

[Shakey]

Dirty, or wet?

Could be the head gasket, you might also have piston ring problems.

Valve cover, not head gasket. I said it wrong. Valve cover is pretty simple.[DOUBLEPOST=1512360042,1512359831][/DOUBLEPOST]

Yeah, still turned over after that.



Well, I unplugged the spark plugs and 3 out of the 4 wells were dirty, two lightly and one moderately. Didn't pull them out and check because at the time I didn't have a spark plug socket. No check engine light

It's hard to say. If you could pull the plugs you could see if they have gas on them. Then you could tell if it's a fuel issue.
If you want to try something that could be quick and possibly easy, is replace the fuel filter. That's just a shot in the dark though.

 

[PatrThom]

First of all, let me say I'm not an auto mechanic. However...
If it continues to turn over but doesn't catch, then it's not the battery and probably not the alternator/alternator belt (though it can't hurt to check). My reasoning goes like this: the battery will still provide enough power to keep the engine sparking for a little while (a little Googling says a full battery can keep a car running anywhere from 30-90min depending on add'l electric draw like headlights, etc), so if it dies sooner than that, you have some other issue (or your battery started out really low and you DO have an alternator problem).
Other things I can come up with that will keep a car from starting/running:
-No spark/not enough spark (poor plugs, poor wires, short, bad coil/distributor if your car still uses one)
-No air (clogged/obstructed airway/filter)
-No exhaust (e.g., banana in the tailpipe)
-No fuel (clogged filter, out of gas, sugar/water/antifreeze in fuel)
...really, those four things are what an engine needs to run, so if it's not running, one of those things is impacted. Just gotta start eliminating things.

--Patrick

 

[drifter]

Update: the car starts... for now

So I decided to pull out the spark plugs and hit them with some brake cleaner. Put'em back in, car still won't start. But today, after checking this and that (nothing that would have fixed anything, I don't think) I decided to ask my dad to try and start the car while I took a look at the engine. Turned over a couple times, and then it started. According to him he gave it a little gas while starting, and I guess that did it? Anyway after letting it idle for a bit, turned it off and tried to start it again, worked no problem. So yay?

 

[drifter]

Update 2: so I took my car for a drive and it looks like I'm not off the hook yet. Sometimes when I let my foot off the gas, it feels kind of like the engine dies? Or is having trouble keeping going. Also happens when I am stopped. Funny thing is if I put it in neutral, engine revs back up. Also noticed when stopped that the belts will sometimes make a squeaking noise when the car is stopped/idling. Took a look at the serpentine belt earlier, but I guess I need to take a closer look. Bleahhhh.

 

[Gared]

Update 2: so I took my car for a drive and it looks like I'm not off the hook yet. Sometimes when I let my foot off the gas, it feels kind of like the engine dies? Or is having trouble keeping going. Also happens when I am stopped. Funny thing is if I put it in neutral, engine revs back up. Also noticed when stopped that the belts will sometimes make a squeaking noise when the car is stopped/idling. Took a look at the serpentine belt earlier, but I guess I need to take a closer look. Bleahhhh.

What make, model, and year are we dealing with here?

 

[drifter]

2004 Mazda 3

 

[Gared]

Did you try this forum?

 

[strawman]

All the bits and pieces put together point to the alternator for me, but I suspect you're facing a variety of problems and they're clouding the issue.

First, when you aren't pressing the gas and the engine is skipping I'm wondering if the alternator isn't supplying enough current. A new battery and it works for awhile then starts having issues after a driving test suggests that the charging system isn't up to snuff. Put a voltmeter on the battery or cigarette lighter and drive it around, if it ever drops below 13.5 volts, you need to check the alternator - either the belt tension as you suggest, or the alternator itself.

Even if the gasket is damaged it shouldn't prevent the engine from starting. Running rough, sure, but there's a lot of power in those cylinders, starting shouldn't be an issue.

The power could be part of that - during start the battery is under load, perhaps the ignition isn't generating a hot enough spark.

But your dad giving it gas also makes me wonder if your fuel rail isn't hitting proper pressure. Check the pressure on the fuel rail while the car is running, and if it's not within spec make sure your fuel filter has been changed.

As Patrthom points out, if you check the fuel, spark, and air you should be able to figure out which of the three are inadequate and then troubleshoot from there.

 

[drifter]

Did you try this forum?

No; did find the same answer from a different car forum, but not with such thorough instructions. Thanks![DOUBLEPOST=1513001161,1513001019][/DOUBLEPOST]

All the bits and pieces put together point to the alternator for me, but I suspect you're facing a variety of problems and they're clouding the issue.

First, when you aren't pressing the gas and the engine is skipping I'm wondering if the alternator isn't supplying enough current. A new battery and it works for awhile then starts having issues after a driving test suggests that the charging system isn't up to snuff. Put a voltmeter on the battery or cigarette lighter and drive it around, if it ever drops below 13.5 volts, you need to check the alternator - either the belt tension as you suggest, or the alternator itself.

Even if the gasket is damaged it shouldn't prevent the engine from starting. Running rough, sure, but there's a lot of power in those cylinders, starting shouldn't be an issue.

The power could be part of that - during start the battery is under load, perhaps the ignition isn't generating a hot enough spark.

But your dad giving it gas also makes me wonder if your fuel rail isn't hitting proper pressure. Check the pressure on the fuel rail while the car is running, and if it's not within spec make sure your fuel filter has been changed.

As Patrthom points out, if you check the fuel, spark, and air you should be able to figure out which of the three are inadequate and then troubleshoot from there.

So many possibilities to hunt down. Exciting!

 

[GasBandit]

This is getting beyond my limited car knowledge, but the fact that giving it gas during start makes it catch better makes me start to wonder about the injectors/fuel valves.

 

[drifter]

This is getting beyond my limited car knowledge, but the fact that giving it gas during start makes it catch better makes me start to wonder about the injectors/fuel valves.

Yeah, the purge valve solenoid mentioned in Gared's link controls fuel vapor to the engine. If that's all it is it'll be a relief.