f20b idle problem

[nathan007]

Hello everyone!

I just almost finished swapping a f20 manual in my 01 accord f23a1, and i am running into an annoying problem. I will specify i am running the f20 ecu, did my wiring and research before!!

When i start the car up, the engine revs to 3000rpm, then back to 1000, then bounces back to 3000. I did not let it warm up and shut it down. I checked my TPS wich was already replaced (probably a Dorman part), calibrated it (it really was out of spec). Tried again and same result. (3k rpm/1k/3k...). I unplugged the IACV and started the motor back up, now the idle was bouncing from 1k to ~1.5k like normal iacv issue. I still got research to do, but any idea of what could be the cause?

thanks alot!

 

[2002CG3coupe]

I'm assuming you burped the cooling if not do that and check for any air leaks and poor connection too to start as your basis.

 

[nathan007]

checked for vacuum/gasket leaks with a shop vac, everyting is perfect. Coolant line to IACV is looped (no coolant), connections are good. Tried with f23 ecu, same issue. Tried blocking passages in throttle body, caused car to die if i blocked both, no change if only one blocked. I was running out of ideas so i made a el cheapo blockoff plate and plug the iacv on it, result; car would start and die. But it did keep running as it should with my foot on the gas. So yeah i'm happy i found my problem, now i just have to fix it!!

 

[nine23]

I was running out of ideas so i made a el cheapo blockoff plate and plug the iacv on it, result; car would start and die. But it did keep running as it should with my foot on the gas. So yeah i'm happy i found my problem, now i just have to fix it!!

i am having the same problem.... do you have any pictures of what you did?

 

[nathan007]

Sadly i did not take any pictures, but it's pretty easy to do. Remove IACV from intake manifold, i used a piece of radiator hose cut open so i was sure it sealed well (it was just a temporary fix), and reinstalled the iacv, with the ghetto block-off plate to block the passages.

Now you can do the same thing but using gasket material. Starting from there you can adjust your own idle, check out there on google there's a few threads about it.

 

[nathan007]

little update; i simply shot throttle body cleaner in the removed IACV, then made it a gasket with gasket making sheet (cut the same pattern but didnt bother with the coolant passage), plugged it on the car and it idled perfectly. Now i just have to fine-tune it (a part of the valve is slightly adjustable just like the replacement TPS)

edit: the original rubber gasket was pretty old and cracked in a corner (near coolant zone), it may be the source of the problem.

 

[nine23]

i just got my car's battery system where it will start every time...that has been a ride in itself! but im gonna check this out either tonight or tomorrow hopefully that is what the problem is.... but the thing with mine is that is revs back and forth a couple times and then it idles at 3000 steady...

 

[nine23]

So I have mine running and everything but now it idles at 3000... I took the iacv off and cleaned it and let it air dry... It doesn't bounce around or anything it just starts up and goes straight to 3000 rpms.... I read a thread about possibly getting power to my tps but that is all good...Any suggestions? Sorry to tread jack just figured it would be better than starting a new one over a similar issue

 

[nine23]

So the only thing I've found that changes the idle is unplugging the map sensor... Any suggestions

 

[nathan007]

f20b?

do you have the original throttle body? f20b does not have an idle adjustment screw so;

if your TPMS is original, you might want to check if it's giving .5v closed throttle, and 4.5v at WOT. If it's a replacement (wich is adjustable) you definitely want to check it out.

next, make sure your throttle body is fully closed when throttle off (someone might have messed around with the stopper screw)

if nothing does, try a block-off plate for your IACV, leave it plugged in but dont let if function (hence the blocking plate). If you see any change, you know for sure you got a problem with it. You may try taking it off, cleaning it, make sure the gasket is in good condition, and you could try adjusting it (two screws on the side of it facing driver side of fuel rail). it does affect the way the car idles.

other than that,..?