P0171 code with freeze frame Data

[elderc]

Can any of you code guys tell me what to look for, I'am lost
I replaced the 0/2 sensor thinking that was the trouble but it came back anyway. Other wise the car seems to be running great . any ideas ?
(Seems stange LT & ST fuel trim are the same)

Thanks in advance

P0171 (lean)
Load valve 16.47%
Engine Coolant temp 201.20 F
Short term fuel trim 14.84%
Long term fuel trim 14.84%
Engine RPM 2151 rpm
Speed 39.15 mph

[maxgtr2000]

Does that o2 have heater wires? Sometimes the general code will be thrown if the ecu doesn't detect the heater circuit.

[Accord2nrz]

It's not strange that your LT and ST Fuel Trims are the same. What is strange is that there is soo much being added right now. You should be aiming for 0 i believe.

In any case P0171 is a heater sensor circuit malfunction O2 Bank 1 Sensor 1 for most cars I think. I agree with previous response, you should check your sensor wiring, is it possible a wire got frayed and disconnected?

[elderc]

Thanks for the input guys found out Mazda uses a "Boost sensor" on their n/a cars ? ( my oem ecu is n/a).... werid I know, they use it to measure Barometric Pressure changes in the intake manifold and since the Emanage Blue can't detect the oem boost sensor it can't modifiy that siginal so I'll just have to deal with it. from time to time. Accord2nrz your right LTFT & STFT can be the same (I did'nt know that). Also found out this is not an 0/2 sensor code on a Mazda (P1170 is). guess I wasted my money when I replaced the 0/2. I'am sure it won't be the last time I waste money LOL..................Thanks again.

[Accord2nrz]

I wonder if there is a way to wire in a resistor or something to only allow a certain amount of voltage to pass through it. this way the ecu would still see the signal as normal?

[elderc]

If I new the voltage that the ecu is looking for at a 14.7 A/F ratio then I might be able to reproduce that, what I'll do is strip the wires back going to the boost sensor and check the voltage at idle and say 50 mph and try to come up with something between the two maybe by using an adjustable pot.:confused:?

[Dzaster]

CG10DET seems to have a fairly decent background in electronics. He might have some suggestions.

[CG10DET]

Can somebody please re-state what has been said here, as I don't seem to see a question in which to offer any suggestions?

[CG10DET]

Right, just did some research to the fault code.

Do you have a wideband lambda sensor? If so what is the AF/R at the time when the fault code appears?

It seems that the P0171 fault code is produced when the engine is running too lean, so check your whole fuel delivery system, and if it's ok then check your fuel maps and AFRs.

It's common on a mazda for this to happen when the sensor is dirty OR is being maxxed out and can't compensate. Since you're boosting on a stock map sensor (which can probably only read 14.7 psi, which if boosting you will be above) this may be your problem.

[CG10DET]

Is it hot wire maf? if so you are either maxxing it or it is dirty, have you got it clamped?

[elderc]

Yes, its a hotwire I replaced the MAF two months ago, and I'am using a FM-0/2clamp. Heres what I noticed yesterday I was be driving along at 45mph A/F's steady in the 14's then for no reason (same TP under- noload) A/F's will drop into the 10's then back to the 12's 11's 13's @ the same speed and same RPM'S then will go back to the 14's for while its worse at 60mph A/F's will drop into the 9's (@ 6%TP " no load ) then will settle in the 12's I replaced the 0/2 sensor 500 miles back I can't thinks its bad already thats why I'am going to hard wire it in maybe I have a bad oem connector ?.......... I'am lost at this point. ( I'am now getting a P1170 code ? ) this stinks.

[CG10DET]

P1107 is sensor 1 fault.

[Dzaster]

So there is no air flow meter of any sort that needs to be clamped?

[elderc]

I know the MAF on the Miata will flow up to 300 hp (I'll never see that) so I only have to clamp the the 0/2 for lean tip in. Talked to a Miata tech. he told me that after looking at my LTFT he thinks I have a leak somewere in my intake system, that is showing up at higher rpm's not at idle, that maybe the reason I can't find it. and I should do a smoke test ?...... I have no idea how to do that.

[CG10DET]

apparently inlet manifolds can commonly leak on your car from research I found on the internet,.