KA24DE bouncing and high idle - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

xxleadxheadxx · 08-13-2012, 11:53 AM

i bought the car about a month ago, the idle was around 1500 when i bought it, drove it for a week or so and the idle went down to normal <1000 then it slowly started raising, not only would it raise but it would jump from anywhere between 3000 for a few seconds then randomly drop to like 300 and bounce back to 1000 then do it all over i replaced my tps, it was replaced properly and the idle went down to what its supposed to for a week or 2 then randomly jumped back up, it even cuts out on me sometimes like its getting too much or not enough fuel. would my extremely cool temp have anything to do with this also? i have no ac or heater hoses or components its just a shorter circuit within my engine

Phil80sxdet · 08-19-2012, 12:08 PM

Seems like a maf or vacuum leak. Check all the lines and make sure you have no loose ended lines. May need to cap a few off, also if a maf is not reading right or if you have a leak after the maf (from the connector next to the air box ) to the intake it will run like that. If there's a leak the computer will think its getting less air than it really is which could cause the high rpm. The computer fighting the way the car is running may cause the idle to drop and raise out of nowhere.

08-13-2012, 11:53 AM	#1
xxleadxheadxx Join Date: Jul 2012 Location: san diego Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	KA24DE bouncing and high idle i bought the car about a month ago, the idle was around 1500 when i bought it, drove it for a week or so and the idle went down to normal <1000 then it slowly started raising, not only would it raise but it would jump from anywhere between 3000 for a few seconds then randomly drop to like 300 and bounce back to 1000 then do it all over i replaced my tps, it was replaced properly and the idle went down to what its supposed to for a week or 2 then randomly jumped back up, it even cuts out on me sometimes like its getting too much or not enough fuel. would my extremely cool temp have anything to do with this also? i have no ac or heater hoses or components its just a shorter circuit within my engine

08-19-2012, 12:08 PM	#2
Phil80sxdet Join Date: Jan 2011 Location: Las Vegas Age: 35 Posts: 11 Trader Rating: (0) Feedback Score: 0 reviews	Seems like a maf or vacuum leak. Check all the lines and make sure you have no loose ended lines. May need to cap a few off, also if a maf is not reading right or if you have a leak after the maf (from the connector next to the air box ) to the intake it will run like that. If there's a leak the computer will think its getting less air than it really is which could cause the high rpm. The computer fighting the way the car is running may cause the idle to drop and raise out of nowhere.