Major Fuel Injection problem

[pacem]

1996 Mazda 626 ES 2.5L auto.

I replaced the starter, which entailed disconnecting the throttle body and stuff around it like fuel lines, coolant lines, accelerator cable, etc. When I got everything back together, the starter worked but the vehicle will not idle and runs very rich. I pulled the codes and I got:

P0100 - MAF circuit malfunction
P0110 - IAT circuit
P0125 - "Excessive time to enter closed loop fuel control".
PO135 - O2 sensor heater circuit malfunction
P0300 (Or PO303) - Random misfire detected on cylinder 3 - I replaced that spark plug and cleaned up the oil in its cavity so I don't think it's an issue anymore)
P1170 - Heater O2 sensor (Front RH (Inversion))


Any idea what any of this means? The car runs horrible, does not idle (goes anywhere from 0 to 2000 rpms) and gets less than 20mpg on highway instead of close to 30mpg.

I pulled the MAF sensor and looked at it, although not sure what I was supposed to look at.

 

[brianl703]

As many things as it's complaining about, I'd check for loose or not properly connected electrical connector.

 

[Kestas]

After checking connections, erase the codes, drive it some more, then see which codes reappear. It's not unusual to see spurious codes.

 

[surfstar]

definately sounds like a bad MAF connection. also check all vacuum hoses for correct connections/no leaks. MAFs are easy to mess up if handled roughly. Perhaps it got dirty and should be cleaned.

 

[Shaman]

Check MAF. Look for a fuse that might have blown.

Had it happen on my car, bought a new MAF, then was told that there was a fuse for the MAF. Spent $50 of a MAF to spend $.35 on a fuse.

 

[chrome]

The multitudes of codes you are getting can be related to possibly 2 major faults. You have the Mazda 2.5 V6 KL engine.

MAF and IAT circuits are together, in the airflow meter at the end of the throttle body boot. If both are reporting errors, I would suspect a malfunctioned airflow meter or possible a fault in the wiring/connector.

P0125,135,300 and 1170 are possibly tied to one problem, one of the O2 sensors. An inversion error for an O2 sensor would indicate the sensor is slow (lazy). P0125 is due to the fact the heater circuit has malfuntioned, causing excessive delays before the O2 is heated up. The random misfire could be due to the faulty O2 sensor on that cylinder bank.

If you have recently disconnected the airflow meter, check if you have connected it back properly and the connector is clean and tight. Sometimes the contacts can corrode, some cleaning may be required.

After checking the connector to the airflow meter, disconnected the negative terminal on the battery for a few minutes, and reconnect it. This will clear the error codes. Drive around a bit, minimum 10 miles, and recheck the codes again.

If the O2 sensor code persists, you would need to replace them, there are 2 or 3 depending on your location. If the MAF and IAT codes come again, you might need a new airflow meter.

 

[The_Jeff]

Also check all your temp sensors, water and if equipped intake air. You could also try unplugging the o2 sensor in case it's wonky... that'll force open loop operation which if it's better than before indicts the front o2. And check your grounds too.