02 Accord SE, 160K. Running great, then no start. Checked/verified basics; battery, spark, fuel pump, injector -both power/signal voltage - all good. No codes showing. Then just gave a try, pushed accelerator to floor and cranked - started up - ran at about 2000 rpm. Once foot off gas, stalls out. Is this sounding like the Idle Air control system? Can it be cleaned up as suggested in some forums- to verify as problem?

 

What happens when the engine is warm?

You can try to verify. remove the intake duct between the air filter and throttle body. try to start in this configuration (may be a clogged air filter or air filter box inlet). If it does the same thing then find the IACV hole in the inlet area of the throttle body, with your finger covering the hole and throttle closed, have a friend try to start it. Did you feel a vacuum pulling your finger? If no, the valve is probably stuck shut. Check all the connectors, vacuum lines, the pcv and egr if hasn't been recently cleaned. I guess this could be a fuel pressure regulator, did you measure the rail pressure?

If you clean the IACV be careful not to get TB cleaner in the motor.

just my 0.02

 

Thanks for the response and good pointers. I could not get it started to get engine warm. I only had it run once with accelerator fully pressed, and rpm was so high, I shut it down. Yes, checked Air Intake system - all good and clean (checked intake tube for a stuck rag/plastic bag etc too). I did not measure fuel rail pressure - but guess in future that equipment will be in my diagnostic kit. Did use method you described w vacuum port within TB, valve seemed to be stuck. Actually did this days ago by the way after reading up further on diagnosis. Ordered a IACV, installed and that fixed the problem. Followed your method so hopefully this thread helps someone else too. Appreciated the response greatly.

 

I had one that cleaning did not help so I threw down the denaro on a new honda part, glad I could help.