idling problem/running rough
idling problem/running rough
Hi! I have a 90`240sx (205Kmiles) ka24e with the following probem: The engine will start and run just fine at idle for about 1-2 minutes. (this is after the car has been sitting for a while and the engine is cold). Then after a while the idlling becomes irregular until the engine eventually stalls. I can start it up again right away, but I will have to give it quite a bit of throttle to keep the rpm up and it is running rough. If I take my foot off the accel. it will stall agin. (TPS is new.. on advice from previous owner) I have searched the FAQ`s on 240org thouroughly, but couldn`t find a problem quite like mine. I know you guys are sitting on a awfull lot of knowledge about this engine and I would greatly appreciate your help. Thanks.
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yellow_jacket
- Posts: 1355
- Joined: Mon Jan 13, 2003 4:43 pm
- Car: 95 240sx
It sounds like the coolant temp. sensor has gone bad and is telling your car it is always cold. This of course makes the car run rich and of course as it warms up it will begin to flood and run very poorly. The fsm should have the resistance curve or specs for the sensor. It isn't that expensive and is very easy to replace.
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ricebike
- Posts: 3381
- Joined: Sat Feb 15, 2003 7:03 pm
- Car: 1989 240sx se 5spd (donated to my brother in law)
2002 Quest
2005 Altima - Location: CNJ
B4 u replace another item...
suggest you do an ECU diagnostic code retrieval to verify if anything is stored there... code 13 is the coolant temp sensor circuit...
I've also heard that you can disconnect the coolant temp sensor & run the engine under fail-safe mode: the ECU will have a programmed set for that circuit & will most definitely store a code 13 after this. See if your car would run better that way. (Yellow, can u confirm this? i'm a noob @ this)
ECU would "decide" this: car just started ~68 F,and will go up to ~176 F after about 6 min.
resistance values for the sensor goes down as the temp increases soo grab an ohmmeter & measure the terminals b4 u start this process 2.1-2.9 ohms as it warms up to about 176F, the ohms should drop to ~.30-.33
other "darts" for your "dartboard diagnostics" are in this thread:
http://www.nissaninfiniticlub....15700
hey maybe the last resort/compression test would indicate that your rings are shot... i dunno...
how does a plugged exhaust system/bad cat may be also a "dart" to this problem? I'm just guessing this because after it warms up, the o2 sensor starts working & now the car runs in "closed loop" mode.
suggest you do an ECU diagnostic code retrieval to verify if anything is stored there... code 13 is the coolant temp sensor circuit...
I've also heard that you can disconnect the coolant temp sensor & run the engine under fail-safe mode: the ECU will have a programmed set for that circuit & will most definitely store a code 13 after this. See if your car would run better that way. (Yellow, can u confirm this? i'm a noob @ this)
ECU would "decide" this: car just started ~68 F,and will go up to ~176 F after about 6 min.
resistance values for the sensor goes down as the temp increases soo grab an ohmmeter & measure the terminals b4 u start this process 2.1-2.9 ohms as it warms up to about 176F, the ohms should drop to ~.30-.33
other "darts" for your "dartboard diagnostics" are in this thread:
http://www.nissaninfiniticlub....15700
hey maybe the last resort/compression test would indicate that your rings are shot... i dunno...
how does a plugged exhaust system/bad cat may be also a "dart" to this problem? I'm just guessing this because after it warms up, the o2 sensor starts working & now the car runs in "closed loop" mode.