240sx Rattle

[shiro_neko]

89 240sx ka24e. Im about to have it overhauled but what concerns me is the rattle. Ive read that it might be caused by the chain guides but it lasts only 2-3 secs. Mine doesnt rattle at idle. it starts before 2000 rpm and peaks at 2500-3000 rpm then it goes away revving past that. My concern if this is caused by the valve or what. Because if does I wouldnt bother with the engine anymore.

My idle is at 900 rpm (cant lower it even by turning the idle adjust screw) and have a slight hesitation/stumble on hard throttle. Backfires at the exhaust at 4000 rpm

[OutToWinPAHC]

Could be as simple as a head shield. Old trick, get a wood dowel or broom stick and place on various ares of the car and place ear to the other end to determine exactly where the sound is coming from. Once you have that we might be able to help you more.

[Cone Junky]

Could be weak lifters. Once the car warms up or oil pressure rises they might quiet down. Make sure your oil is the clean and the proper viscosity.

The car has to be warm and the TPS sensor disconnected to set base idle

[shiro_neko]

Could be as simple as a head shield. Old trick, get a wood dowel or broom stick and place on various ares of the car and place ear to the other end to determine exactly where the sound is coming from. Once you have that we might be able to help you more.

I'll try that when I get home

Could be weak lifters. Once the car warms up or oil pressure rises they might quiet down. Make sure your oil is the clean and the proper viscosity.

The car has to be warm and the TPS sensor disconnected to set base idle

I havent changed the oil yet because Im set to have it overhauled this month. The lifters might be weak though because of the ticking sound. And I did disconnect the tps while adjusting the base idle just dont remember if it was warm enough. When I disconnected it the idle went down then went back again to 900rpm. I'll try to adjust it again later

I really want to make sure that its just a minor thing because Im not from the US and KA parts are scarce here

[shiro_neko]

I tried to adjust the idle while the engine is warm and tps disconnected and its still the same. The IAV probably needs cleaning or somethings making the ecu idle it higher. anyway thats another issue...

Ok I tried that wood dowel technique and the rattle doesnt seem to come from inside the engine. I even partially opened the oil cap but the rattling sound didnt came out from it. its somewhere in the passanger side pulleys it seems. I think the mechanic missed something when we removed the engine for repainting

[shiro_neko]

The rattling noise is coming from the bell housing. Im gonna have it checked for loose bolts or something. thanks for the reply guys