ls/vtec motor, 440cc injectors, JUN stage 2 cams, Exedy lightweight flywheel, all components upgraded, timing retarded... recently dyno tuned and we couldnt advance the timing bc the motor wouldnt run. oh well. brand new iacv, tps, thermostat, thermosensor, coolant flushed. the problem: when at a stop out of gear and without the clutch depressed my rpms will suddenly drop from normal idle to almost nothing, usually making me stall out. most of the time this happens, sometimes it won't at all. also, the motor struggles when the thermostat opens and the fans turn on. im about to give up.
open to opinions, willing to share more info if i missed something.
thanks.

 

Sounds like your idle air control valve is sticking shut.

 

Weak alternator/charging system?

 

I had that problem with my old light weight flywheel. Whenever the rad fans turned on or there was any load on the engine, my RPM would drop to nothing and stall. increase the idle speed a bit see if it helps. I went back to stock FW and problem went away.

It doesn't happen to every engine with a light weight FW. It depends on how loose the bottom end is. Mine was always a bit on the tight side.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Maxbore.com &raquo;</TD></TR><TR><TD CLASS="quote">I had that problem with my old light weight flywheel. Whenever the rad fans turned on or there was any load on the engine, my RPM would drop to nothing and stall. increase the idle speed a bit see if it helps. I went back to stock FW and problem went away.

It doesn't happen to every engine with a light weight FW. It depends on how loose the bottom end is. Mine was always a bit on the tight side.</TD></TR></TABLE>

It also depends on the weight of your flywheel. Like was mentioned earlier, adjust your idle speed. That should keep you from stalling at least.