S14 Ka24DE Cold start- Rough Idle - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

nurevem1 · 03-25-2011, 08:46 PM

I have a 1997 s14 with a turboed Ka24de. When the car sits overnight or for a few hours in the cold weather (below 55 degrees) i go to start it up... starts up fine and rpms are at about 1,200rpm and after about 20 seconds-30 seconds the idle will drop. When the idle drops the car will throw the rpms from 800-1100rpm. My wideband is reading extremely lean (reading over 17). Once the car starts to get slightly warm (movement shown on coolant temp gauge) the idle smoothes out (for ex. after driving a mile down the road or reving the engine for a few minutes at about 2000rpm). If the weather is nice out (above 60 or 70) the idle problem does not exist. I have replaced the idle air control valve, dizzy cap and rotor, and plugs. I have monitored the colant temp sensor with consult 2 and the reading was showing about what the air temp was. I have cleaned the z32 MAF with MAF cleaner and have checked all piping and connections to and from the throttle body. i have tried adjusting the set screw on the IACV while the problem is happening and that did not help the issue. Anyone have ANY ideas what this could be?

Mozoby · 03-28-2011, 06:44 PM

maybe try cleaning the O2 sensor?

if that was the problem im not sure it would get better when the car warms up.. but its worth a try

statickx991 · 03-28-2011, 06:58 PM

what is the car tuned with? reason im asking is, could be a bad cold start tune since some ecu's like my old pfc went by degrees i belive. i could be wrong tho

nurevem1 · 04-04-2011, 01:47 PM

the o2 sensors are both reading and im sure would throw a code if they were out of spec.
The car is tuned with the Apexi AFC NEO. I was also thinking that the tune could be the issue but wasnt sure. maybe i should take it to the performance shop near me and see what they think

03-25-2011, 08:46 PM	#1
nurevem1 Join Date: Oct 2010 Location: PA Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	S14 Ka24DE Cold start- Rough Idle I have a 1997 s14 with a turboed Ka24de. When the car sits overnight or for a few hours in the cold weather (below 55 degrees) i go to start it up... starts up fine and rpms are at about 1,200rpm and after about 20 seconds-30 seconds the idle will drop. When the idle drops the car will throw the rpms from 800-1100rpm. My wideband is reading extremely lean (reading over 17). Once the car starts to get slightly warm (movement shown on coolant temp gauge) the idle smoothes out (for ex. after driving a mile down the road or reving the engine for a few minutes at about 2000rpm). If the weather is nice out (above 60 or 70) the idle problem does not exist. I have replaced the idle air control valve, dizzy cap and rotor, and plugs. I have monitored the colant temp sensor with consult 2 and the reading was showing about what the air temp was. I have cleaned the z32 MAF with MAF cleaner and have checked all piping and connections to and from the throttle body. i have tried adjusting the set screw on the IACV while the problem is happening and that did not help the issue. Anyone have ANY ideas what this could be?

03-28-2011, 06:58 PM	#3
statickx991 Zilvia Member Join Date: Jan 2008 Location: Pa Posts: 210 Trader Rating: (0) Feedback Score: 0 reviews	what is the car tuned with? reason im asking is, could be a bad cold start tune since some ecu's like my old pfc went by degrees i belive. i could be wrong tho __________________ im a f18 bro

03-28-2011, 06:44 PM	#2
Mozoby Join Date: Aug 2010 Location: Here Posts: 35 Trader Rating: (1) Feedback Score: 1 reviews	maybe try cleaning the O2 sensor? if that was the problem im not sure it would get better when the car warms up.. but its worth a try

04-04-2011, 01:47 PM	#4
nurevem1 Join Date: Oct 2010 Location: PA Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	the o2 sensors are both reading and im sure would throw a code if they were out of spec. The car is tuned with the Apexi AFC NEO. I was also thinking that the tune could be the issue but wasnt sure. maybe i should take it to the performance shop near me and see what they think