I have a 1996 Honda Accord that I'm running a stock 93 Prelude H23 in and the idle started surging last night. It will jump to around 2000 rpms and fall to around 1000 rpms and continue to do this if the clutch is pushed in or if the car is stopped. I've been told numerous things to check but want other opinions as well. I have bypassed the fitv and it still has the idle surge. Has anyone had this problem on these motors or know what the exact problem is before I start tearing it apart and dumping money into it?

 

it's called a vacuum leak...get a squirt bottle and spray a very fine "mist" around the intake manifold until the engine idle changes..then you found the leak. If you still can't find it after you have guaranteed spray every nook and cranny anywhere, the problem is probably the iacv or the base idle is set too high for the engine to handle.

 

got in it this am and the time i started the car i started smelling a strong scent of gas coming from my exhaust. i found no gas leaks anywhere. not sure if this is causing the idle surge or not. but it didn't do this before the idle started messing up.

 

thats weird about the gas smell. as far as idle it could be a few different things. maybe iacv or like he said a vacuum leak. also bad wiring or bad ecu.

 

I bypassed the iac valve on my car to fix the idle surging that I had. Now when I drive it, I have to basically rev it to almost 3000rpms for it to not sputter when I take off from a dead stop. Wth is going on with it? Yes I know it has a rough idle with the clutch pushed in. Its an h23a1a3 engine.

 

Gotcha. That's pretty crazy man. I don't think I can help you lol

 

You could have a fuel injector O ring leaking or a fuel line leak.

 

for the surging idle....check your tps sensor to see if it set properly.

 

If you don't use the iacv at all anymore the car is going to run in limp mode. I'm assuming it's throwing a code 14. If you just rerouted the coolant hose that goes to the iacv then ignore that.

Can you describe how exactly you bypassed the FITV and IACV valves ? I mean, exactly.

 

I just blocked off the IACV a few minutes ago. With it blocked off I don't smell the gas like before and it cold idles a little high, but once you hit the throttle it starts to surge again. I honestly have no clue wth is going on with it. I don't have anything bypassed now.