MAF Or O2 sensor?

[pilfflip]

These were the Symptoms while my car ran (at this time it won't start);

1. Rough idle - Occasionally when I start my car is idles high, anywhere between 1,800RPM and 3,300RPM. Usually this can lost anywhere from 40 seconds to 10 minutes, I know that they sometimes are known to do that becuase of EGR but this was a little excessive.

2. INCREDIBLY rich - My exhaust gas smells like gas. My sparks plugs and plug wires also went out in just a few hundred miles.

3. Trouble starting - When it was running some times it was really finicky about starting. (this was very hit or miss) Sometimes it would start immediately and others it would take it anywhere from 10 seconds to 30 seconds of engine turn over before it would start. During this time it would reek of gas and when it would finally start it would pour out smoke from the engine bay and the exhaust that smelled of gas.

4. CEL - Although I didn't have the chance to get the codes pulled recently, when I cleared out my CAT it threw a code and it was an O2 sensor, but that was more than 2 years ago.

Now, my car won't start at all. It turns over but nothing after that. It sounds like it wants to start and if I turn it over long enough it'll sputter and start but that'll only last between 4 to 6 seconds and it'll slowly die. Then it'll start from square one again. It smells of gas in the engine bay when I'm trying to start it. I checked all of the vacuum lines-nothing.

I was thinking that this may be a MAF sensor, but I don't get the feeling from my searches that a MAF could keep a car from starting/running but I could totally be wrong. What I did come up with though is that it could be an O2 sensor, but none of the posts that I read could really put a definitive finger on which.


Any ideas?



~Mike

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[seowitz]

Check that you don't have any vacuum leaks too.

[pilfflip]

I checked for any vacuum issues and nothing that I could tell wasn't where it should have been, i also checked the MAF sensor and it looks relatively good. I'm still at a loss. I think I'm going to check the coil pack and ignition sensor.

[wadia]

I've had my MAF and O2 sensor go bad on mine and neither incident gave that dramatic of symptoms. I had a camaro with similar problems that died in the same way - I could start it and floor it to get it running to about 2k rpm but as soon as I let off the gas it would quit. After I gave it away, then that guy sold it for parts (he threw alot of parts in it trying to get it to run), the next guy figured out it was a bad catalytic converter.

[pilfflip]

I've read a couple of things on here about that being a possibility but both of my cats are gutted, so there's really nothing to go bad...

[wadia]

What about your injectors? Original? There are many places you can send them out to have them cleaned and flow tested. Maybe one is not closing when it should.

[Huffer]

Disconnect your MAF and see if the car starts.

[pilfflip]

If I disconnected the MAF sensor and started the car like that it would run in fail safe aka limp. I was thinking about trying that but I had a friend tell me it wouldn't start at all. We were in the process of towing my car so I didn't really care to argue at the time-but i'm definitely going to try it now.

What kind of place would clean the injectors? How much does something like that cost? I guess it's not unreasonable to think that they could be carboned up from the fuel being so rich.



~Mike

[pilfflip]

Went to Autozone and rented one of teh OBDII readers, the an "Actron CP9135" and pulled the codes:

P0115 Engine coolant temp malfunction
P0120 TPS/Pedal position sensor A Circuit Malfunction
P0125 Closed Loop Fuel Control, insufficient coolent temp
P1700 Manufacturer Control Transmission
P0121 TPS/Pedal position Sensor A CKT Range/Perf.

And a couple of those codes came up a second time with a "pd" on the far right of the screen, anyone know what that means?

My brother checked his '98 and came up with:

P0133 02 Sensor CKT slow response bank 1 sensor 1
P1443 Manufacturer control Aux. emission controls



~Mike

P.S. Gonna go Search...

[Huffer]

Originally Posted by pilfflip

Went to Autozone and rented one of teh OBDII readers, the an "Actron CP9135" and pulled the codes:

P0115 Engine coolant temp malfunction
P0120 TPS/Pedal position sensor A Circuit Malfunction
P0125 Closed Loop Fuel Control, insufficient coolent temp
P1700 Manufacturer Control Transmission
P0121 TPS/Pedal position Sensor A CKT Range/Perf.

And a couple of those codes came up a second time with a "pd" on the far right of the screen, anyone know what that means?

My brother checked his '98 and came up with:

P0133 02 Sensor CKT slow response bank 1 sensor 1
P1443 Manufacturer control Aux. emission controls

Sounds like you have a bit of problem there - have you tried resetting the car (unplug the battery) to see if those codes reappear? Sounds like you might have a problem with the thermostat in your coolant - it might be malfunctioning.

I would check the thermostat and replace that and the coolant, reset the ECU, see if the car starts.

Try unplugging the MAF and see if that starts the car too. It's worth a shot.

[Huffer]

Sorry, "pd" on a OBD scanner means "code PENDING".

[Dodik]

im not a pro at this but it sounds like some is worng with fuel system to me at least with electrical aspects of it, thermostat has nothing to do with starting the car but check just in case and please dont buy the generic ones they barely ever work for subarus get one from dealer they are not to expensive. mainly though i would check all fuses just in case all those codes are electrical maybe you have a short somewhere or something. because of gas smell id check ingectors, fuel pump, and other electrically operated parts of fuel system. and fuel filter. without maf you car should start but die shortly after at least my old BD did. hope my opinion helps.

[SailRacer]

It could be something small and silly like a fuel filter or a ground.

Check everything, steam clean the engine so that you can see everything.

[pilfflip]

Okay, it all had to do with my thermostat and then it just snow-balled from there. I had a OEM thermostat that I drilled a hole in so I could get the air out of the system (my brother did this and he said it worked great so he did me a favor by doing it to my thermostat for me) Problem lies in the fact that he put Anti-freeze and water wetter in his and I just put water.

My car was running WAY WAY cold, as in it usually sat around the bottom line and wouldn't get much warmer than that unless it sat still for a minutes at a time i.e. downtown driver. This caused an issue with my coolant temp sensor to freak and and try to compensate for the issue, causing start problems, rich gas, and funny idle problems.

I found a thread posted by a guy who had the EXACT same symptoms and codes as I did and he took care of it with a new coolant temp sensor. I don't know why his went bad but I'm gonna throw anti-freeze in my car and change the sensor (i have about 4 or 5 of them I know work).

I cleared the codes out of the car and I'll let you know if that changes the problem.



~Mike