PDA

View Full Version : 240sx KA24E idle surge on startup


cream
02-10-2021, 07:29 PM
Idle surges on startup does not matter hot or cold, full tank or empty. Replaced all vaccum lines, checked for vacuum leaks by injectors, intake, cleaned electrical plugs; maf, injectors, throttle body tps.. Possible fuel/injector/electrical issue?

https://www.youtube.com/watch?v=3aiff4Qrg2k

inferno s14
02-12-2021, 11:22 AM
you need some stickers on your car

Kingtal0n
02-12-2021, 12:10 PM
Idle speed controlled by airflow.

You have an air leak;

perform a boost leak pressure test (use pressure to find the leaks)

It might be a leak inside the IACV motor

Diagnostically:
1. disconnect & Disable (make sure its blocked somehow) or clamp the IACV line to determine whether the unwanted air is coming through the iacv or somewhere else
2. disconnect fresh air vent from crankcase to prevent seal blow out
3. pressure test intake system to (1-5psi for NA or 15-25psi for Turbo)
4. Don't forget to inspect the throttle body, throttle blade, for bent shaft or improper closing of the blade
5. During the pressure test I also recommend pulling the pcv valve to see if it leaks (and replace the pcv valve)

Find all leaks, repair leaks

cream
02-12-2021, 02:12 PM
Thank you for the insight! Will diagnose as directed and report back with results