[mark jeansonne]

I posted about this before. ''Check engine soon" light came on and stayed on, so changed from 93 octane to 89 octane, p38 running great, but "check engine soon" light now back on. Shows code 1172, "too rich, banks A & B". Stealership no help, just discouraged me with "$95. per hour, your problem if we can't find it after several hours, your problem if we can't fix it and you are 100 miles from home ...." Local mechanic suggested changing oxygen sensors, but was guessing.

Anyone recall a fix for those codes? Suggestions? THANKS.

 

[Goswin]

Air FLow meter? O2 / Lambda Sensors? Or a big leak in your exhaust?

Could all be causes for your problem......

Regards,
Goswin

 

[mark jeansonne]

THANKS Goswin! That will get me started. mark j.

 

[allyv8]

If the ecu is logging rich codes then the oxygen sensors must be capable of switching - so forget them for now.A failing Maf reads low, which prevents the ecu giving a wide enough injector pulse to get the sensors to switch rich.An exhaust leak up stream of the oxysensors will give a lean reading.
I'd be looking at a partial misfire,dying leads or plugs is a good start.

 

[mark jeansonne]

Ok thanks for that great input. I will order some plugs. When you say "leads", do you mean spark plug wires? THANKS, mark j.

 

[pistonbroke]

Mark, does your car show signs of running really rich, like black smoke, heavier fuel use etc.? If so, suspect the airflow meter which is testable at idle. At idle(aircon off), stick a multimeter into the wires at the connector to the meter. You need positive lead to the blue/green signal wire and negative to the red/black earth wire. The third wire(brown orange) is 12V power. The voltage at idle should be 1,4 volts . If the meter fails ,it can read rich and the voltage may be 1,7 V or above.
A new meter is pricey but you can gyppo the system with a resistor between the signal and earth wires. A 10Kohm on mine restored the signal to 1,4V and the oxy sensors adjusted to clean running with good gas mileage.

 

[mark jeansonne]

No, I haven't seen signs of running rich. Only the code shows, I clear it, and it reappears, but only after appr. 75 mi. of driving.

Do you think I should still test the air flow meter??? THANKS, mark j.

 

[mark jeansonne]

Been appr. 2 weeks now, changed plugs and the "check engine light has not returned". So "too rich"codes must have been fouling plug. I think allyV8 called it right. THANKS. (of course, now that I have reported this, "check engine" light may come on tomorrow! and if you have never changed your plugs in the rover----- NOT easy! harder to get to than you would think!)

 

[mark jeansonne]

I mis-spoke. "too rich" code has returned. I changed the spark plugs and plug wires (used recommended Atl. British).

What would you do next?

 

[SID]

I mis-spoke. "too rich" code has returned. I changed the spark plugs and plug wires (used recommended Atl. British).

What would you do next?

What did the old plugs look like, black and sooty?
Have you checked the air filter, if it's full of dirt or wet through then the engine will run rich due to lack of air to mix with the fuel.

SID.

 

[mark jeansonne]

Thanks SID. I have a K&N filter I put in appr. 2 yrs. ago. Not much dusty roads, so the flow should be good. Need to check it though. I will also post under K&N filter b/c may be related to that. THANKS.

 

[viperover]

Clean airflow meter and toss in a proper paper element filter