Question about 2004 Cadillac SRX
I AM AT THE END OF MY LIST WITH THIS...CAN YOU HELP..ANY IDEAS....I HAVE RELACED UPSTREAM 02 SENSORS CATALYTIC CONVERTER, FUEL FILTER, SPARK PLUGS, COIL PACKS, INTAKE GASKETS, HAVE DONE AN INJECTOR SERVICE, FUEL PRESSURE MAINTAINS 58 TO 60 PSI, PERFORMED SMOKE TEST ON ENTIRE SYSTEM FOUND NO LEAKS, SPRAYED COMON AREAS WITH BRAKE CLEAN, ADDED PROPANE GAS THRU INTAKE BEHIND MAF SENSOR TO TRY AND RICHEN THE SENSORS ......CHECKED ALL WIRING TO AND FROM FRONT O2 SENORS, AND MY READINGS ON THE O2 SENSOR REMAIN TO BE STUC AT 36 TO 40 AND THE LADA READINGS ARE STUCK AT .002......ANY IDEAS WOULD BE APPRECIATED.........THANK YOU CHRIS
Code p 0171 refers to system too lean bank1===causes ---intake /exhaust leaks--AIR system---MAF/VAF sensors --fuel pressure/pump--injector/S=== HO2S
code p 0174 refers to system too lean bank 2====causes intake /exhaust leak---fuel pressure/pump---injector/s---AIR system---hose connection/s
the fuel pressure is adequate
The HO2S is the heated oxygen sensor in the exhaust manifold /pipe before the cat converter
( is responsible for the fuel ratio settings )
you may have to pull the injectors to have them cleaned and tested
the maf/vaf sensor may have to be replaced as well
Posted on Apr 11, 2017
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Posted on Jan 02, 2017
it sounds like the mass air flow metering sensor thats in the air intake pipe ,but any more than that iam at a loss as none of these cars here in spain so i cannot tell you exactly where to look
Posted on Jun 15, 2010
Your fuel pressure is WAY to low, it should be at least 55 PSI, (spec is 55-62 PSI) You will need to replace the fuel pump and the fuel filter then clear the codes and retest, the fuel pump is located inside the fuel tank, the fuel tank must be removed to access the pump. after the fuel pump is replaced if any lean codes come back from the O2 sensors the intake maniold gaskets will need to be replaced as well, they are a common problem as well but your main problem is very low fuel pressure, this alone will set all the codes you have.
Posted on Oct 28, 2010
SOURCE: Will a bad catalytic converter
you have numerous problems to address, the cat could cause the car to smoke, but only because something is getting in it, heating up , and causing the smoke, normally if its white its due to water, and blue or gray due to a fuel issue , as far as a head gasket, if it was bad your cat could be bad too, so could the MAF sensor,, the alternator could work into this mess just due to the sensors not providing the correct signals to be sent to the computer in the car ,, but I doubt its bad , it can be simply checked, if you have a known good battery ,, use a meter and place the leads on the battery terminals, you should see a reading of between 13.5 and 14.5 volts, ( with the car running) if you do the alt is good, if not,, its probably bad,, There are two common types of mass airflow sensors in use on automotive engines. These are the vane meter and the hot wire. Neither design employs technology that measures air mass directly. However, with an additional sensor or two, the engine's air mass flow rate can be accurately determined.
Both approaches are used almost exclusively on electronic fuel injection (EFI) engines. Both sensor designs output a 0.0-5.0 volt or a pulse-width modulation (PWM) signal that is proportional to the air mass flow rate, and both sensors have an intake air temperature (IAT) sensor incorporated into their housings. When a MAF is used in conjunction with an oxygen sensor, the engine's air/fuel ratio can be controlled very accurately. The MAF sensor provides the open-loop controller predicted air flow information (the measured air flow) to the ECU, and the oxygen sensor provides closed-loop feedback in order to make minor corrections to the predicted air mass.
Both approaches are used almost exclusively on electronic fuel injection (EFI) engines. Both sensor designs output a 0.0-5.0 volt or a pulse-width modulation (PWM) signal that is proportional to the air mass flow rate, and both sensors have an intake air temperature (IAT) sensor incorporated into their housings.
When a MAF is used in conjunction with an oxygen sensor, the engine's air/fuel ratio can be controlled very accurately. The MAF sensor provides the open-loop controller predicted air flow information (the measured air flow) to the ECU, and the oxygen sensor provides closed-loop feedback in order to make minor corrections to the predicted air mass.
Posted on Sep 20, 2011
SOURCE: I have a 1991 Cadillac Deville with a V8. It won't pass smog. Has high co. I replaced the egr valve, charcoal canister, spark plugs, spark plug wires, cap and rotor, catalytic converter, oxygen sen
Hello! when you say you checked the MAP sensor what do you mean? Did you take voltage readings at idle ? A vacuum leak is the likely culprit, especially to the MAP...The minor shake at idle being the major clue...Send a comment...guru..saailer
Posted on Dec 24, 2011
Hi Armindo, Check and clean the mass air flow sensor and then check the intake manifold for any leakage of air. Check vacuum hoses for cracks, loose fitting or damaged connections. Also check the manifold for leakage. Regards John
Posted on Oct 20, 2012
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