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Gas mileage has always been horrable on the car not bad, I mean horrable like 12 MPG, with a light foot

92 Subaru legacy AWD non turbo wagon Automatic.

 

I've done many things to try to fix this problem.

 

1) Replace air filter

 

2) Mass air flow sensor

 

3) O2 Sensor (the one by the exhaust manifold)

 

4) Spark plugs

 

5) Seafoam straight through the injection with a tube and the can.

 

6) tire pressure and new tires

 

7) Oil changes

 

8) Replaced coolant temp sensor and sending unit

 

 

9) Replaced PCV

 

10) My wife has to smog the car since regestration is due, but of course if failed. :dead::dead::dead::dead::dead:

 

HC (PPM)

 

Idle

Max = 120

Measured = 230

2500 RPM

max = 140

Measured = 15

______________________________

 

CO

Idle

Max = 1.00

Measured = 1.65

2500 RPM

Max = 1.00

Measured = 0.05

 

 

If your have any other suggestions as to what I can do plz let me know.

 

This is from a previous posting that never got replied to.

 

Ok I changed out the PCV and the coolant temp sensor as well as the coolest temp sending unit underneath the temp sensor.

 

I plugged in the black connectors and got 2 error code readings

 

1 ) Bad coolant temp sensor

 

2) Bad cam angle sensor

 

anyways after I changed the coolant sensor 2 things happened.

 

1) check engine light is solid on now with no codes.

 

2) even in the cold morning if u turn the car on and drive 1 block maybe about 1/4 mile or less the car is already fully heated up. like within 1 min of starting the car.

 

Also tonight I took apart the IAC unit and noticed when I disconnected the PCV valve all the tubed are gunked up with gunk. Not like where air can't get through but nice cake build up on sides of tubing.

 

I also looked at the injector rings to see if they were leaking but I didn't see anything wrong with them.

 

Gas mileage is still crap any clues???

 

PLEASE DEAR GOD PLEASE!!!!!!!!! :banghead::banghead::banghead::banghead::banghead:

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....even in the cold morning if u turn the car on and drive 1 block maybe about 1/4 mile or less the car is already fully heated up. like within 1 min of starting the car.

 

How is the excelleration? Does it sound kinda like a jet at high speed? (some may know where I'm going with this).

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[...]How is the excelleration? Does it sound kinda like a jet at high speed? (some may know where I'm going with this).

If the car accelerates poorly under load (going uphill for example), it's possible there's a restriction in the exhaust system, perhaps due to failure of the catalytic converter.

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If the car accelerates poorly under load (going uphill for example), it's possible there's a restriction in the exhaust system, perhaps due to failure of the catalytic converter.

 

I had a car that had chunks of crap stuck in the cat and it wouldn't go over like 4000 rpm or it would start to choke. Do u believe that a car that has tons of power would choke going uphill due to a bad cat?

 

It been the only thing I can imagine besides the ECU that would be the cause but I kept ruling it out becuase the car seems to have lots of power normally.

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....even in the cold morning if u turn the car on and drive 1 block maybe about 1/4 mile or less the car is already fully heated up. like within 1 min of starting the car.

 

How is the excelleration? Does it sound kinda like a jet at high speed? (some may know where I'm going with this).

 

No car sounds fine nothing abnormal except what might sound like a pinging engine once in awhile or a cylinder missing. Definetly some kinda misfiring noise from the engine when idle or accelerating.

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I had a car that had chunks of crap stuck in the cat and it wouldn't go over like 4000 rpm or it would start to choke. Do u believe that a car that has tons of power would choke going uphill due to a bad cat?[...]
My response was a follow-up to where I thought Sonicfrog was going, and based on something you said in your PM to me (sorry, but for some reason my browser is freezing when I try to return-PM). Usually a plugged converter won't allow good performance in general, but sometimes the problem only shows up when loose material shifts, and going uphill might be the condition needed to cause that.

 

 

No car sounds fine nothing abnormal except what might sound like a pinging engine once in awhile or a cylinder missing. Definetly some kinda misfiring noise from the engine when idle or accelerating.
The high CO and HC readings indicate a rich condition. An intermittent misfire could be related, and since there's a code for the cam angle sensor, maybe it's not always triggering proper ignition, and should be replaced; check connections first, though.

 

On the other hand, it may be time to stop throwing parts at the problem and have someone do a real-time scan. Knowing for certain what the engine sensors are doing, and whether the management system is eventually going closed-loop would be very useful information. It's too bad the car doesn't have OBD-II, but even the earlier systems can be diagnosed. A vacuum and/or compression test also might be worth considering, just to check general health of the engine at 170,000 miles.

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My response was a follow-up to where I thought Sonicfrog was going, and based on something you said in your PM to me (sorry, but for some reason my browser is freezing when I try to return-PM). Usually a plugged converter won't allow good performance in general, but sometimes the problem only shows up when loose material shifts, and going uphill might be the condition needed to cause that.

 

 

The high CO and HC readings indicate a rich condition. An intermittent misfire could be related, and since there's a code for the cam angle sensor, maybe it's not always triggering proper ignition, and should be replaced; check connections first, though.

 

On the other hand, it may be time to stop throwing parts at the problem and have someone do a real-time scan. Knowing for certain what the engine sensors are doing, and whether the management system is eventually going closed-loop would be very useful information. It's too bad the car doesn't have OBD-II, but even the earlier systems can be diagnosed. A vacuum and/or compression test also might be worth considering, just to check general health of the engine at 170,000 miles.

Since everyone around this area is a frigin idiot when it comes to fixing subarus do u recommend I take it to the dealer? Maybe someone knows of a place in or around san diego that has the balls to say $50 bucks to diagnose the problem and not be like all these other retards that say 80 bucks an hour and who knows how long it takes.

 

I just hate going to the dealer everytime I do I feel like I'm walking in backwards while I'm spreading my buttchecks after applying glue and sand between them with a credit car in my hand. :eek:

 

Also if it wa the ca and loose crap was floating around in there would that cause the car to have crap mileage? maybe all the bad air wouldn't be passing through the system and the car would try to compensate by making the mixture richer?

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I would check out the injector for this problem. It may be leaking.

 

As far as the temperature gauge goes it sounds like either the sensor is not working as it should be or the thermostat is bad. The engine can't heat up as fast as 1 minute from a cold start.

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I would check out the injector for this problem. It may be leaking.

 

As far as the temperature gauge goes it sounds like either the sensor is not working as it should be or the thermostat is bad. The engine can't heat up as fast as 1 minute from a cold start.

 

I replaced the thermostat, coolant temp sensor, and coolant temp sensor sending unit. And the car used to heat up fast but since I replaced those it's REALLY fast now, as previously stated.

 

Would the injector be leaking through bad o-rings? I pulled those and looked at them, but they looked fine, unless it's some kinda hairline crack that normal human eyes can't see.

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The indicated temperature on the gauge may say one thing but I seriously doubt it is correct. My guess is the real temperature of the coolant is a lot cooler than indicated by the gauge. At least from a cold start. The only way I could see the temperature getting that hot, so fast, is if exhaust gases are getting into the coolant.

 

The injector may be leaking through the center pin, not the O-ring gaskets.

 

After thinking on this some more I wonder if you are loosing coolant. If so, maybe you do have a headgasket leak.

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The indicated temperature on the gauge may say one thing but I seriously doubt it is correct. My guess is the real temperature of the coolant is a lot cooler than indicated by the gauge. At least from a cold start. The only way I could see the temperature getting that hot, so fast, is if exhaust gases are getting into the coolant.

 

The injector may be leaking through the center pin, not the O-ring gaskets.

 

After thinking on this some more I wonder if you are losing coolant. If so, maybe you do have a headgasket leak.

 

Nope I had the car for I about a year and never had to put coolant in it. It's full everytime I check it.

 

Would u happen to know a way or a place that can test fuel injectors?

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I replaced the thermostat, coolant temp sensor, and coolant temp sensor sending unit. And the car used to heat up fast but since I replaced those it's REALLY fast now, as previously stated.[...]

Did you use original factory (OEM) parts? These are just the sort of things that are critical to operation, and if not closely meeting specs can really affect operation. For example, a coolant temp sensor could be within the "normal" range of resistance that the ECU "expects" (and therefore not throw a code), but inaccurate enough so that the ECU thinks the engine is colder than it actually is; that could lead to constant over-enrichment of the mixture, or even to the system running open-loop all the time.

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How hot does the car get, according to the temp gauge? If it's running hot, that can definitely cause a rich mixture. You've replaced many parts of the cooling system, but I notice you haven't replaced the radiator. A crappy radiator caused all kinds of grief with Murphy, the $500 87 T-Wag. Failed smog (rich mixture), was blowing hoses left and right. The last straw, last summer, was blowing a head gasket in the middle of the Grapevine on my way back to Fresno from San Diego.... on a 100 degree day.... with my Mom in the car. I still haven't told my little brother about it as he will give me no end of grief about it.

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Did you use original factory (OEM) parts? These are just the sort of things that are critical to operation, and if not closely meeting specs can really affect operation. For example, a coolant temp sensor could be within the "normal" range of resistance that the ECU "expects" (and therefore not throw a code), but inaccurate enough so that the ECU thinks the engine is colder than it actually is; that could lead to constant over-enrichment of the mixture, or even to the system running open-loop all the time.

 

 

Yes I got all my parts from the dealer

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How hot does the car get, according to the temp gauge? If it's running hot, that can definitely cause a rich mixture. You've replaced many parts of the cooling system, but I notice you haven't replaced the radiator. A crappy radiator caused all kinds of grief with Murphy, the $500 87 T-Wag. Failed smog (rich mixture), was blowing hoses left and right. The last straw, last summer, was blowing a head gasket in the middle of the Grapevine on my way back to Fresno from San Diego.... on a 100 degree day.... with my Mom in the car. I still haven't told my little brother about it as he will give me no end of grief about it.

 

No it's not running abnormally hot it stay right in the middle temp range and doesn't move. Just heats up hella quick. The more I think about it possably if it's a bad cat and the gases aren't escaping from the cylinders it's possable that it makes the car think it's heating up quicker, becuase new cold air isn't getting inside the engine.

 

What do u guys think?

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You may be able to inspect the injector yourself. Let the car sit overnight and then pull the injector out to inspect it. If it is wet with fuel then it may be the problem.

 

Yeah when I pulled them out b4 they looked nice and dry to me. But if a new cat doesn't fix the problem then I will have to check again

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Before you replace the CAT I would verify it is bad since thay are not cheap to replace.

 

The rich fuel mixture could be due to a bad TPS, or MAF. Have those sensors been checked to see if they are working correctly? I see you replaced the air filter but make sure there isn't something wrong with the airflow. A lack of air can cause a rich conditon.

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Before you replace the CAT I would verify it is bad since thay are not cheap to replace.

 

The rich fuel mixture could be due to a bad TPS, or MAF. Have those sensors been checked to see if they are working correctly? I see you replaced the air filter but make sure there isn't something wrong with the airflow. A lack of air can cause a rich conditon.

 

TPS??

 

I replaced the MAF and I know it's working correctly because I tested it.

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Before you replace the CAT I would verify it is bad since thay are not cheap to replace.
Agreed; that's why I suggested certain tests be run, especially use of a vacuum gauge. The $20 (sometimes even less) ones are perfectly adequate for the job, and can tell you a lot about engine-related things if you learn how to interpret them.

 

 

The rich fuel mixture could be due to a bad TPS, or MAF. Have those sensors been checked to see if they are working correctly? I see you replaced the air filter but make sure there isn't something wrong with the airflow. A lack of air can cause a rich conditon.
Mouse nest in the intake? :)
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