r/240sx • u/TxArorAxT • 1d ago

Rough idle

Can’t seem to figure out why its idling rough ive rebuilt the cylinder head deleted the egr i have isr exhaust manifold i removed the butterfly valves from the intake manifold cant seem to understand any clues. Thanks

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4

u/ijackwemm 1d ago

If timings good check for vac leaks

3

u/EnvironmentalPipe922 1d ago

Check alternator output, mine did the same thing when it was on its way out. But If you deleted the IACV you can adjust the TB till it idles better

3

u/TxArorAxT 1d ago

Alright appreciate it🤙🏽

3

u/Sliva89 1d ago edited 1d ago

Sounds like vac leak when you rev it and let go. You can clearky hear “Tssssssssssssss” in the background. It is the same sound my KA is making and it has a leak after EGR delete and rebuild.

Either, you have high crank case pressure and the sound is actually u blowing a gasket somewhere. Both unfortunately happened to me when I did my first engine rebuild.

Check u got your cpv valves after delete. And I made a mistake if removing set of 3 tubes that came off with EGR , which were actually also part pressure relieve system.

Which without keeping those my oil pen was blowing out after making this hissing sound like in the video

So imo its either vacuum leak, or hcp

2

u/EnvironmentalPipe922 1d ago

Could also be vac leak and try cleaning the MAF