windman
Full Access Member
Hello again.
My first technical problems related post here.
It is 2004 Limited with v6 3.7 engine. I have duel fuel setup which utilizes LPG too.
I bought this car as used adn it is approximately 60K miles on its odometer.
I have a problem. I have a check engine light with p0171 code. I have computer to scan OBD codes and realtime data, also a scangauge car computer to do quick checks.
This problem is not related to LPG setup becasue, when i disable system and only operate engine on gasoline as it is used to operate on, engine stalls rarely.
Also its idle races slightly, sometimes it decreases and increases. when it decrease it i most likeliy to stall. It is acting like it has excess air after MAP sensor. why i know this is, once i owened a V6 Nissan, it has a LPG system hcih was installed wrong, and it could not receive enough LPG to idle at both V banks. It was trying to idle on only one bank. Also engine was idling fast due to cracked intake hose.
Now lets limti ourselves with gasoline only on liberty.
I start engine, it is cold outside, not problems, after warming up it is still ok. There is no significiant difference on idle. After heavy traffic and water temp is at highest possible level, higher than cruising temp of course, when i stop at red light, tachometer starts to go high and low slightly which is not normal. also it can stall without a hesitation like i turned it off.
after resetting ECU by removing battery leads and waiting, after 3 consecutive warm up periods, check engine light turns on, after 5 or 6 warm ups id dissappears. freeze frame data for DTC is P0171 each time i try this.
Bank 1 is lean.
I sprayed brake pad cleaner to PCV hoses, intake manifold, intake air control valfe gasket, pas sensor o ring. nothing happens. It stalls or idles as i have no effect on mixture ( as it should be). I do not hear hissing sound to indicate a vacuum leak.
I removed air control valve, cleaned every carbon or dust deposit, i cleaned idle controller, map sesnor pcv valve, responsze to throttle is better, no misfires, and idle is much smoother but problem is still there.
Any comments?
MAP sensor ( if it was, there should be both 171 and 174 codes simultaneously)
Fuel pressure? (it acts same way on LPG so this is not something we suspect)
O2 sensor on bank 1? ( i do not smell unburnt fuel at exhaust and no codes related to a specific sensor - also scanner reads similar values at both banks in terms on voltage)
Broken PCV hoses somewhere i cant see/find?
intake manifold gasket at bank 1 (which enlagers slightly when engine is warm)?
ECU problems?
any experience or insight on this issue?
My first technical problems related post here.
It is 2004 Limited with v6 3.7 engine. I have duel fuel setup which utilizes LPG too.
I bought this car as used adn it is approximately 60K miles on its odometer.
I have a problem. I have a check engine light with p0171 code. I have computer to scan OBD codes and realtime data, also a scangauge car computer to do quick checks.
This problem is not related to LPG setup becasue, when i disable system and only operate engine on gasoline as it is used to operate on, engine stalls rarely.
Also its idle races slightly, sometimes it decreases and increases. when it decrease it i most likeliy to stall. It is acting like it has excess air after MAP sensor. why i know this is, once i owened a V6 Nissan, it has a LPG system hcih was installed wrong, and it could not receive enough LPG to idle at both V banks. It was trying to idle on only one bank. Also engine was idling fast due to cracked intake hose.
Now lets limti ourselves with gasoline only on liberty.
I start engine, it is cold outside, not problems, after warming up it is still ok. There is no significiant difference on idle. After heavy traffic and water temp is at highest possible level, higher than cruising temp of course, when i stop at red light, tachometer starts to go high and low slightly which is not normal. also it can stall without a hesitation like i turned it off.
after resetting ECU by removing battery leads and waiting, after 3 consecutive warm up periods, check engine light turns on, after 5 or 6 warm ups id dissappears. freeze frame data for DTC is P0171 each time i try this.
Bank 1 is lean.
I sprayed brake pad cleaner to PCV hoses, intake manifold, intake air control valfe gasket, pas sensor o ring. nothing happens. It stalls or idles as i have no effect on mixture ( as it should be). I do not hear hissing sound to indicate a vacuum leak.
I removed air control valve, cleaned every carbon or dust deposit, i cleaned idle controller, map sesnor pcv valve, responsze to throttle is better, no misfires, and idle is much smoother but problem is still there.
Any comments?
MAP sensor ( if it was, there should be both 171 and 174 codes simultaneously)
Fuel pressure? (it acts same way on LPG so this is not something we suspect)
O2 sensor on bank 1? ( i do not smell unburnt fuel at exhaust and no codes related to a specific sensor - also scanner reads similar values at both banks in terms on voltage)
Broken PCV hoses somewhere i cant see/find?
intake manifold gasket at bank 1 (which enlagers slightly when engine is warm)?
ECU problems?
any experience or insight on this issue?