S13 1989 240SX Base Redtop Swap SR20DET, Strange Noise just after starting up

[95lstegman]

it starts up okay, and it has an idling issue, but basically it runs at 2000rpm idling basically 99% of the time, so here goes.

starts up after a few cranks (like 4), and it idles at like 1500, and i hear a metal-on-metal noise that sounds like rotating parts (it's cyclical), and it goes away after 5-8 seconds and the car resumes idling at 2000rpm. it sounds like it's coming from the front of the motor, so maybe oil or water pump? neither are new. i'm guessing it's the water pump, but maybe this is a fairly common issue or something. it ONLY happens when starting up from cold. if it has been run in the past several hours it doesn't do it. i live in FL, so it doesn't get REALLY cold here. ambient temperature does not seem to have an affect on it at all.

maybe sometime when you have LOTS of time you could meet me on AIM or something and discuss the idling problem. it seems to be very complex, as at least 2 sensors are malfunctioning and when i put a timing light on #1 cylinder wire loop it looks like 90 degrees off or more, and it won't run any other way.

[s13sr20chris]

if you suspect water pump, pull belts off and run it like that for a moment.

[95lstegman]

mmm good idea. i'm so stupid i didn't even think of that! that's the kind of answer that makes me want to kick myself . . . but thanks! i'll report back so anybody who searches down the road will find an answer.