help with idle

[Guest rikuo59]

have a 280zx ,auto trans ,headers, cold air intake, new engine, new trans, however intake is a dual butterfly throttle body, on a nissan naps manfold, have a high idle(2000) at start and drops to 1500+ when warm. Changed timeing did not help there are no adjustment that I can see also this manfold and throttle is nothing like I have seen on other z's! car is from japan ,had no problem for 20 years only when i put headers and cold air .any one got idea thanks

[woldson]

Vaccume leak?

[Broken-Z]

have a 280zx ,auto trans ,headers, cold air intake, new engine, new trans, however intake is a dual butterfly throttle body, on a nissan naps manfold, have a high idle(2000) at start and drops to 1500+ when warm. Changed timeing did not help there are no adjustment that I can see also this manfold and throttle is nothing like I have seen on other z's! car is from japan ,had no problem for 20 years only when i put headers and cold air .any one got idea thanks

 

When adding the cold air intake, you may need to re-adjust your air flow meter. Air flow meter now telling the ecu that you have more air to the engine,ecu compensating by richening up the fuel mixture,hence the higher idle. Just a guess. Here's a link to the EFI bible.Should help.

http://www.atlanticz.ca/zclub/techtips/EFI&fuel.htm

[luvmy280zxt]

Hey dude, I had the same prob except i have a turbo. It started at 2000 rpm then down to 1500rpm. I removed my throttle body and cleaned the hell out of it and installed a cold air intake. The only way i got it to fix was to adjust my AFM. try that bud. Good luck.