Ok i've searched this for months trying to figure out the problem but still am at a lose. About a year ago i swapped in a h22 everything was fine before that. When the car is warming up everything is fine with 0 problems. Once the car is warmed up i start to see issues.

once warmed up if there is no load on the engine and its just idling it will be fine with the occasion idle roaming nothing to serious. But if i roll the windows up the engines idle will dip real low and everything will dim and the whole car will shake. Also if im driving the car and press the clutch in/take the load off the engine the rpms will drop down to like 300 everything will dim for a second but then the rpms will come up and it will idle normally. I feel it is something electrical related and but i cant figure it out. While the car is idling the alternator will put out around 13.5 ish volts so i guess that is fine.( id like it to be higher) Battery is new. I've also tested the tps, cleaned the fitv and the iacv.

So if anyone can throw some ideas at me for what to look for or test next i'm all ears. Like i said it never did this with my h23 only the h22. Thanks guys

 

any ideas people??? i'm thinking about biting the bullet and just buying an alternator..

 

Take it to the dealer, seriously, if you ask they'll do a free battery/alternator/starter test. Other than that I had all but the lights dimming problem when I had a bad IACV, if you know someone else with a prelude that is running fine maybe you can ask if they'll let you hook theirs up to your lude to test.

Usually though if it's the alternator the battery light on the dash will come on when losing power.

 

true all good points...well i did discover somethign last night. My amp has a volt readout on it so i was looking at when i first started the car and it was reading 13.7-8 so i was like ok alt is working fine. drove it for about 20 min got to my destination and checked it again and it was right around 11.8- 12 volts with the car running. So i figured the alt is on its way out. End of the night i start the car up its reading high 13s volts, drove home and it was still reading high 13s but the lights were still dimming the whole ride home. So i dunno what to think. Maybe its a combination of things, cause the car runs completly fine until it gets up to operating temp which sounds like it would be the iacv so maybe i'll start off buying one of them.

Anymore insight on this problem or did anyone have any similiar problems?

 

I'd highly suggest trying to use a IACV from someone you know if possible before buying one since they start at $250+, don't wanna spend that for nothing.