Weird Idle Problem - 96 vti

[Paolo123]

Guys, tagal na ng idle drop problem ng civic 96 vti ko,. Pero baka yung symptom na to ang makapagsabi kung ano talaga sira nya.

Here is the situation:
I followed the recommended steps by Honda on how to set the proper idling of my engine (as stated on their service manual: let the engine warm up, disconnect IACV, set idle to 450 +/-50, reset ECU,). I set the idle to around 470 I made sure na the rad fan is not on while I set it ha. So tama naman ginawa ko diba?

The Honda service manual said that the idle should be at 750 +/-50 without AC and 850 +/- 50 with AC (cant exactly remember pero around ganyan yung natatandaan kong figures). Kaso pag start ko ng kotse, yung idle nya is 1,100 RPM without AC, 1,200 with AC. Masyado mataas diba, pero hinayaan ko na lang since hindi na nagddrop yung idle. And sobrang responsive yung change ng idle kapag nag on ako ng AC, meaning pumipitik pataas yung idle ko pag bukas ng AC or headlight.

Then after my 50km trip to Novaliches. Bumalik yung idle drop ng auto ko. Hindi naman nagalaw yung idle screw kasi talagang tinandaan ko sya. I even put gasket around my idle screw to make sure na hindi sya gagalaw. My car is now idling at 800 without AC, and 500 with AC pag bagong bukas ang oto. Pero mawawala yung idle drop kapag naitakbo ko na. Magiging smooth na yung idle after running for 15 mins.

Tingin nyo guys ano na problema nito? Para sakin hindi IACV ang sira nito kasi pag bagong reset ang ECU ko, nagwowork sya ng maayos. Definitely hindi TB, IM cleaning ang solution kasi nagawa ko na sya 3 months ago.

ECU kaya ang sira? Vacuum leaks? Ano pa bang pwede? Thanks! Sorry medyo mahaba.

[v6dreamer]

You have done almost everything, but you never mention about checking an air leak in the intake system or any restriction related to vacuum, could be those hoses big & small check for crack, or loose, or the intake manifold gasket have a little crack even the PVC is not functioning. You cannot bring your car in operational condition if leak or blockage are present.

[bambino]

first things to check ; do a scan test , you may have a code ie. eld ( electronic load detector ) if there's no code , check for vacuum leaks , cylinder balance test, if there is an evident misfire . hope this helps

[Paolo123]

Actually you guys are right. I havent done any vacuum leak tests because I dont know how to. I read somewhere na try to spray the with carb cleaner then when the idle goes up, it means merong leak. But I dont know which parts to spray with. I only tried to spray the IACV and throttle body area but the idle did not respond so Im guessing there is no leak there. Hindi rin ako familiar kung anu ano yung vacuum hoses except for the one that connects the throttle body to the IM. Air bypass hose yata yun.

Sa casa ba ang suggested place na magpagawa nito because they have a special aparatus to do this? Or OK na sa suking talyer ko? I havent asked my suking talyer if they can do these tests.

BTW, is it possible that the ECU responds to the additional air coming in kaya ibinababa nya yung idle ko after ko sya ibyahe?

[v6dreamer]

Spray that carb cleaner into those small hoses and around the engine, intake manifold. Any place that has a vacuum lake will suck the carb cleaner and it change the idle, also you can also put a small vacuum guage on the oil dipstick tube to check an internal vacuum leak coming from the intake gasket.
By the way, have you check your PVC lately, if you shake it and it rattle still okey if not replace it or maybe the MAF sensor is dirty.

[Paolo123]

I havent checked these. Thanks for your input, will definitely try them

[speedyfix]

have you cleaned the tb and iacv? if you haven't then babalik lang ng babalik yung problem.