legacy is acting wack

cruisen_15 · #1 11-08-2008, 12:03 PM

ok my car is acting weird. heres some symptoms

-when engine is warm idle is extremely bad like missing is occuring
-if i stop the car to quick the engine will die
-my power mode engages literly every ten seconds and i havent even pressed the throttle more than an inch
-fuel cut is occuring when i hit 10psi and when powermode goes on
- check engine light came on the other day but went away and says air sensor ( abnormal voltage input entererd from air sensor)but i have cleaned it already 3 times... do these symptoms say mas or is it something else?

SoCal LS-L · #2 11-08-2008, 12:25 PM

Sounds like a faulty MAP sensor, although I dont have that much experience with the H4's.

cruisen_15 · #3 11-08-2008, 12:28 PM

yeh, i think its the maf too but they are expensive!

b3lha · #4 11-08-2008, 03:54 PM

Power mode is engaged by the TPS signal. If your power mode keeps randomly engaging, it would suggest a problem with the TPS or its wiring.

Manarius · #5 11-08-2008, 04:35 PM

I beat the MAF is dead. I'd get a TLeg MAF used off of http://bbs.legacycentral.org.

SoCal LS-L · #6 11-08-2008, 08:20 PM

Quote:

Originally Posted by cruisen_15

-fuel cut is occuring when i hit 10psi and when powermode goes on

Is this a turbocharge mod or are you talking about fuel pressure?

Manarius · #7 11-08-2008, 10:37 PM

Quote:

Originally Posted by SoCal LS-L

Is this a turbocharge mod or are you talking about fuel pressure?

His Legacy is stock turbocharged. I definitely think this is MAF related however especially since he said he's getting fuel cut at 10psi.

b3lha · #8 11-09-2008, 07:09 AM

He said that his power mode keeps engaging. A faulty MAF cannot cause power mode to engage. The MAF is not connected to the TCU in any way. A faulty TPS can cause power mode to engage and can also have adverse effects on the ECU.

SoCal LS-L · #9 11-09-2008, 09:45 AM

Correct me if im wrong..... but dont almost all turbocharged engines feature a Manifold Absolute Pressure sensor (MAP) to detect the amount of vacuum or boost in the intake manifold? I only bring this up because it threw a code for an "air sensor", which could mean either MAF or MAP. MAP's tend to clog with fine dust, especially if a high-flow air filter is used. Unsure about the power mode problem, could be a combination of both sensors causing the symptoms.

cruisen_15 · #10 11-09-2008, 11:38 AM

thanks for the help guys. its not the pressure sensor btw. this happend before after i had put my td04 turbo and intercooler on, but somehow it just all disapeered after 2 weeks. so the real problem is that one of you is saying dead maf and one of you is saying tps... well i dont want to spend money on the wrong thing here

SoCal LS-L · #11 11-09-2008, 11:40 AM

Cool, if youre sure that MAP is good, then next I would try B3lha's suggestion and suspect the TPS. You can actually test the TPS with a multimeter capable of resistance metering. Im sure you can find the correct terminals to probe and resistance values in the how-to or with the online SVX manual. Beats just buying a new one outright.

cruisen_15 · #12 11-09-2008, 12:25 PM

ok so last night i was driving it and another code came on... now i have codes 23 and 49...

23 = abnormal voltage input entered from air flow sensor
49 = use of improper air flow sensor

Manarius · #13 11-09-2008, 04:35 PM

Quote:

Originally Posted by cruisen_15

ok so last night i was driving it and another code came on... now i have codes 23 and 49...

23 = abnormal voltage input entered from air flow sensor
49 = use of improper air flow sensor

This even further confirms my idea that your MAF is broken. What MAF do you have? Do you have the metal MAF found on all the Turbo Legacy's?

cruisen_15 · #14 11-09-2008, 09:51 PM

im using the metal one.

i cant seem to reset the codes, ive tried leaving the battery off for an hour but they still stay on the ecu. and one of them keeps coming up while driving but i dont know what one it is because i cant get the codes cleared

heres the codes i have on my ecu

22 = knock sensor (abnormal voltage produced)
31 = throttle sensor (abnormal normal signal)
45 = atmo. sensor and pressure sensor, also pressure exchange solenoid
49 = air flow sensor (use of improper slow sensor)

Hondasucks · #15 11-09-2008, 10:13 PM

Okay, so I'm guessing this is a newer car? But your codes look like the codes for the early (91-94) turbo Legacies.

If it's a newer one, leaving the battery off WILL NOT erase the codes, only way is to use a scan tool and clear the codes. I'd start with connectors, make sure all your connectors for the affected circuits are tight, and none of the pins are bent, etc... and make sure you don't have any busy mice in there gnawing on your wiring. If you post more details as to the year of the car, I could probably post some troubleshooting/diagnosis info.