won't idle

bills1988 · 06-15-2009, 07:23 PM

I realize it has been a year since your post, but thought I would tell you what I know about the Idle Speed Control Valve. I am trying to solve a loping idle problem and when checking the ISC, I thought it wasn't moving until I realized that you must repeat the sequence S1-S2-S3-S4---S1-S2-S3-S4 over and over. With each sequence it will move slightly out. When you reverse the sequence S4-S3-S2-S1 (over and over) it will move back in.

By the way, anyone have a clue on intermittent loping idle around 500-600 rpm? Not getting any codes and ISC checks OK. TPS also checks out ok per TSRM. I have looked for vacuum leaks, but no luck except there is a hissing sound around the EGR vacuum regulator that I cannot pinpoint. I will check the EGR vacc reg per the TSRM (EC-13).

06-15-2009, 07:23 PM	#7
bills1988 Intake Join Date: Nov 2007 Location: Plano, TX USA Posts: 33	ISC operation I realize it has been a year since your post, but thought I would tell you what I know about the Idle Speed Control Valve. I am trying to solve a loping idle problem and when checking the ISC, I thought it wasn't moving until I realized that you must repeat the sequence S1-S2-S3-S4---S1-S2-S3-S4 over and over. With each sequence it will move slightly out. When you reverse the sequence S4-S3-S2-S1 (over and over) it will move back in. By the way, anyone have a clue on intermittent loping idle around 500-600 rpm? Not getting any codes and ISC checks OK. TPS also checks out ok per TSRM. I have looked for vacuum leaks, but no luck except there is a hissing sound around the EGR vacuum regulator that I cannot pinpoint. I will check the EGR vacc reg per the TSRM (EC-13). __________________ 1988 MK3 Supra; 7M-GE; Automatic; Sport Roof; Factory Original Last edited by bills1988; 06-15-2009 at 08:57 PM. Reason: add TPS check