1997 Protege repair screwed up my gas usage??

[Trooper]

Alright, here's the story in all its strange glory.

I took my car in for a repair a couple of weeks ago. My alternator belt broke.

Before I took my car in, my car was very fuel efficient. I would fill the tank up once every couple of weeks. It was great.

The guys at the garage fixed the alternator belt, but noticed a cracked exhaust manifold. I had them repair that as well. 900$ CDN later, and I got my car back.

No more squeaks, screeches or vibrations. Great! Wrong...

My car now sucks gas worse than even the biggest SUV. For some reason now, the car is sucking gas like an alcoholic sucks down a bottle of booze.

At first I thought maybe they did something and I am leaking gas, but I drove around an abandoned parking lot one day with a buddy of mine who is a mechanic to see if there is any leak or trail as I drive. Nothing.

Even sitting there idle sucks up a lot of gas. I looked under the car after using nearly a quarter of a tank sitting there idle for an hour, and nothing under the car. nothing leaked.

I filled my tank up and drove around constantly for about 2 and a half hours and my tank was empty.

My buddy couldn't figure it out.

I called the garage that did the repairs and explained the situation. At first the guy laughed and thought I was just messing around. When I ensured I was serious, he had me bring it in.

I brought my mechanic buddy with me while they looked at it again. Everything seemed fine. They had the car running idle and searched everywhere for leaks. Nothing. All the fuel tubes were dry.

They had no idea what is now causing this. According to them, they didn't do anything that would affect fuel efficiency.

So now I have a 97 Mazda protg, a car that I used to fill up once every couple of weeks, that now has to be filled up at least 3 times a week and no one knows why.

Does anyone here have any idea what the hell is going on?

My uncles 2001 Blazer isn't even that bad on gas.

I am seriously considering just selling this thing off and cutting my losses...

 

[JZProwler]

Can you tell if the car is running rich at all? A few things that come to mind is a coolant temp sensor gone bad. If the PCM thinks the engine is cold, it will run rich until its at operating temp. Another thing could be an injector, even though it probably isnt, maybe the injector is stuck open? Other than that, Nothing comes to mind ATM, if I think of anything I'll be sure to post it

 

[solid_snake]

is the Check Engine Light on?

if so, have it checked because as JZProwler said, it may be running richer than it needs to hence wasting more gas
​

 

[Trooper]

Can you tell if the car is running rich at all? A few things that come to mind is a coolant temp sensor gone bad. If the PCM thinks the engine is cold, it will run rich until its at operating temp.

I think you may be right. Since I got my car back, my engine temp light is always at the bottom (cold), even after hours of using it.

Any idea how to fix this?

 

[Trooper]

By the way, what is "running rich"?

 

[solid_snake]

By the way, what is "running rich"?

when an engine runs rich is when it has more fuel than it needs to in the air and fuel mixture

 

[JZProwler]

Basically, an engine is running at its most effecient when there are 14.7 parts are to 1 part fuel. When there is less air, the mixture is rich, because there is more fuel, or less air.
If you havnt touched any connections or anything under the hood, it may just be that the sensor went bad, and just needs to be replaced. If your looking from the front of the engine bay, it should be behind the distributer, with two wires going to it.

 

[joesturbo]

Basically, an engine is running at its most effecient when there are 14.7 parts are to 1 part fuel. When there is less air, the mixture is rich, because there is more fuel, or less air.
If you havnt touched any connections or anything under the hood, it may just be that the sensor went bad, and just needs to be replaced. If your looking from the front of the engine bay, it should be behind the distributer, with two wires going to it.

Exactly -it may have happened before you took it in but did not notice it until you got the car back and you were more sensitive to "things".

Also when was the last time you replaced the 02 sensor? Scheduled maintanace on an 02 (replacement) will also keep you car running efficient.

Turbo

 

[mannydingo]

More than likely the mechanic disconnected something and forgot to reconnect it. He may have disconnected it by mistake and doesn't even know he did it. It obviously happened at the repair shop. Not 100% but way more likely than if the owner did it himself.

 

[Trooper]

This problem has long since been fixed. Apparently the engine was "running rich" and taking in more gas than it should have been because of a bad 02 sensor.

 

[mannydingo]

Funny it would happen immediately after being at the shop. It reminds me of a story my dad told me when he used to do body work at a dealership before he retired. One of the mechanics there came to him with a problem. My father explained what it was and repaired it by welding it. He then told the mechanic that the part broke because a bracket that helped support the part that broke was not there. My dad told him that if it broke before that now it could break even easier because a welded part will never be as strong as a never-broken one. He advised him to get the protecting bracket as soon as possible to help make that part stable. A couple of days later my dad asked him if he had ordered the part. The mechanic told him that an identical car came in for a different repair and that he just took the one off that car. In other words, someone may have gotten the o2 sensor from your car that they needed in hopes the problems your car would have would not be too easy to notice soon after returning it to you. I can't guarantee that but the possibility sounds good because it was immediately after you got the car back.