P0 174
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P0 174
could anybody answer this ?
took my 01 exp to auto zone, my sevice engine light came on . obll scanner said
the. PCM has determined that during the testing,the fuel system for bank 2 was too lean. (BANK 1 IDENTIFIES THE LOCATION OF CYLINDER #1, WHILE BANK 2 IDENTIFIES THE CYLINDERS ON THE OPPOSITE BANK)
could anybody explain this to me .
i check air leaks ,changed the pcv and hose , got rid of code 171,clean the maf ,changed air filter any other suggestion
thanks (open for thoughts)
took my 01 exp to auto zone, my sevice engine light came on . obll scanner said
the. PCM has determined that during the testing,the fuel system for bank 2 was too lean. (BANK 1 IDENTIFIES THE LOCATION OF CYLINDER #1, WHILE BANK 2 IDENTIFIES THE CYLINDERS ON THE OPPOSITE BANK)
could anybody explain this to me .
i check air leaks ,changed the pcv and hose , got rid of code 171,clean the maf ,changed air filter any other suggestion
thanks (open for thoughts)
Postmaster
Joined: Sep 2005
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From: Florence,SC
it could be plugs, then again if the o2 sensor is going haywire, then it could be sending false info to the processor and causing the "skip". when is the last time you did a tune up? if its been a while, then go ahead with the tune up.
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Vacuum leak, or Mass Air Flow sensor (try cleaning it)...
If it was an ignition problem.. you'd have a misfire code.. or maybe even a RICH code (ignition problems cause excessive unburned fuel = rich)
While possible, O2 sensors are rarely the cause for this.. they will usually set their own code when they go bad.
Check all the vacuum lines, especially for the PCV valve. Try spraying some carb cleaner around the intake and listen for an idle change in the process.
But first I would clean off the mass air flow sensor elements with some brake cleaner, or fuel injector cleaner spray (don't use carb cleaner on the MAF.. it leaves a residue which can confuse its readings)...
good luck
If it was an ignition problem.. you'd have a misfire code.. or maybe even a RICH code (ignition problems cause excessive unburned fuel = rich)
While possible, O2 sensors are rarely the cause for this.. they will usually set their own code when they go bad.
Check all the vacuum lines, especially for the PCV valve. Try spraying some carb cleaner around the intake and listen for an idle change in the process.
But first I would clean off the mass air flow sensor elements with some brake cleaner, or fuel injector cleaner spray (don't use carb cleaner on the MAF.. it leaves a residue which can confuse its readings)...
good luck
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Postmaster
Joined: Sep 2005
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From: Florence,SC
a vacuum leak will set a 171/174 code because the engine is lean not just one bank. same thing for the maf.
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From: SE Texas
Originally Posted by BowTieHatr
a vacuum leak will set a 171/174 code because the engine is lean not just one bank. same thing for the maf.
If you've got a leak close to the intake port of the head,then it'll come up lean on that bank.If you've got a leak upstream in the system,then you can still get a single bank lean code if the leak is small enough. The EEC throws a code after it attemps to correct STFT at a percentage that's programmed in the EEC. It's possible that the o2 sensor for one bank is old and is misreporting STFT by say...5-10% more than the other bank. If the leak is not big enough to cause the percentage STFT correction to set a code and turn on the CEL-you might have one bank over the STFT limit from the o2 sensor being old and out of spec,and you'll get a single bank lean code.
JL
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From: SE Texas
Originally Posted by BowTieHatr
um true but it is a expedition. the vacuum ports are center intake. i was not talking about in general or some intakes.
JL
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Theoretically, yes it would set both codes.
But I've seen leaks that only set one code before... one bank was just barely lean enough to set the code, and the other bank was right on the border...
Happens more often than you think. I wouldn't make that detemination sure without seeing the fuel trim readings.
But I've seen leaks that only set one code before... one bank was just barely lean enough to set the code, and the other bank was right on the border...
Happens more often than you think. I wouldn't make that detemination sure without seeing the fuel trim readings.
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