help h22a4 high idle issue.. - Honda Prelude Forum

Ghost Built · 03-12-2010, 08:39 PM

hey whats up guys, i have having a problem with my 98 h22a4 motor, the problem i am having is at start up it revs its self to 4500-5000 rpms and hold it for a sec and then drops to 1000 back to 4000 and back and forth, i am sure i dont have any leaks, cause i replaced all the gaskets with new ones again, i also checked a few times for vaccume leaks, and i cant find any, i can unplug the iacv and the tps and makes no differents, i checked for air bubble in the coolant and seems to be none, i changed the thermatate to see if that would help and it didnt, i used a brand new 1 i had from honda, and it didnt change, i sprayed carb cleaner all over where i can and nothin, the motor ran the same, do u guys have any other ideas.. thanks for the help..

indylude18 · 03-12-2010, 08:42 PM

Does the bouncing idle happen when the engine is cold, after it has warmed up, or both?

pjschmitt · 03-12-2010, 09:16 PM

Pull the air intake off the throttle body. See if covering one of the two holes inside there affect the idle. THere are a few things that can affect idle. You have covered a few of them but they may still be the culprit. The one that people often miss is the TPS or the FITV if your car has one. Other hondas like civics have these and they need to be tended to just like the IACV.

Are you throwing any CEL codes?

Did you spray carb or brake cleaner into the IACV until it ran out clear?

It is necessary to remove the screws for the iacv in order to clean it but not necessary to disconnect the coolant lines at all. Just use the spray tip straw to get into the IACV really well. You should be able to manipulate it around so that the spray can be run out.

The coolant needs to be bled following this procedure: Start engine and ensure that coolant is full. Add a little at a time until full. Then cap off and turn on heater to defrost and fan on mid to high. Allow the engine to run for as long as it takes to make the fan come on without touching the gas pedal. There is a small bleeder screw on the water neck or area where the lines from the iacv go to. You will need either a 10mm socket on an extension with a small breaker bar or a wratchet to loosen this nut. A wrench will work but the coolant is very hot. Not take the the socket and crack the screw open turning it to the left. Just enough to let the air and or coolant flow out. Immediately close the screw and observe any differences in the engine's idle. I waited about 2 mins and then the idle came right back down to normal. The air that came out was followed by a lot of bubbles in the coolant. I just shuit it back and left it. It ran much better after that.

I did have to recalibrate my TPS though, and then eventually had to replace it.

Thant is another story...

Ghost Built · 03-13-2010, 11:11 AM

thanks guys for the feed back, ya it does it cold or warm, ok i will give those things a try.. i dont have the fitv cause it is in a 00 civic and i put the b16a2 throttle body on it.. i am sure the sensor is ok cause it worked just fine on the b20b i just had in there, ya i put a meter on the tps and it said .47 ohms.. ya i will give the coolant a try.. thanks guys for all the help and i will keep ur guys updated on what happens..

Kronn 98SH · 03-13-2010, 11:48 AM

Go to Honda-tech.com and search for the idle surge thread in the FAQ. I'd give you a link, but I'm posting from an iPhone.

Ghost Built · 03-15-2010, 07:41 PM

thanks guys again for all the help, i found what was making it idle like that, but now the motor is idling at a constant 2400 rpms, i kinda adjusted the idle screw and it didnt change the rpms so i put it back to where it was, is it the tps that needs to be adjusted or something... i can put my finger over the iacv hole on the tb a little bit and the rpms drop, no cels, any ideas, thanks again..

pjschmitt · 03-16-2010, 04:07 AM

SOmetimes when the coolant is low or the iacv and fitv are messed with, they can trap air and prevent coolant from flowing. Now please forgive me if I already suggested this to you, but the procedure is thus:

Open radiator and fill. burp it if necessary.

Start the car and let idle until the fan starts and when it stops, you are at the right temp to bleed the coolant.

Take socket with extension on ratchet to bleeder bolt on top of water neck/lower hose returns to block.

CAUTION!!

Crack the bolt loose a little bit and see if air comes out or if there is a lot of air in the coolant.

Tighten it back up and wait a minute. Try it again. See if that gets coolant flowing through your lines.

Another way is to disconnect the line where it goes back into the engine and see if it was full of air or something else.

I had one full of what seemed like dirt. New hoses and it ran like a dream.

Good Luck.

Don't forget to keep that coolant full. If you are running without a thermostat, just watch the temp gauge til it gets about 1/3 of the way up from cold.