dc4b20

engine is a d15b7. i just purchased the car and im fixing its problems. had a searching idle. i replaced the iacv and that fixed the searching idle. now the car idles around 2k when cold and at 1500 when it warms up. i checked the tps and its good. removed the ficv, cleaned it, adjusted it, and still the high idle. ive bleed the cooling system also. im running out of ideas of how to get this idle down. help!!!! i need to get this car smogged.

jbpnoman

Follow FSM procedure for adjusting your idle speed. You should be able to find a write-up in the FAQs sticky. Alternatively, get your hands on a FSM for your car. They're invaluable.

dc4b20

ill try that procedure tomorrow. any other ideas?

HondaPartsHero

Try that first. More than likely the previous owner had the idle problem and attempted to fix it with the idle screw and or hopefully not the base idle screw.

Hondaguy83

Check for leaks again around the USC gasket and make sure hoses goes where it belongs. Could be another bad iac.

dc4b20

Where is the "base idle screw"? The iacv was changed and fixed the up and down idle.

HondaPartsHero

Sorry should be called throttle stop screw. This should never be messed with, you can tell if someone did if the paint from the factory put on it is broken or looks adjusted.

dc4b20

So.....my throttle stop screw has been adjusted. There is a small gap between the gap screw and the throttle plate. And the yellow paint has been broken. Where do I go from here to get that idle down?

HondaPartsHero

If you can tell where the original paint stopped and started you can try to turn it back. I'd still try to do the factory idle adjust first and make sure that its right first.

Hondaguy83

I bet u got a slight vacuum leak or stuck open idle air control. Try cleaning by spraying cleaner in throttle body and hope it clears out the iac. Reset ecu if its obd2. See what happens.

dc4b20

Thanks for the help. I already checked for vacuum leaks, but I will re check that tomorrow and set it to the factory idle and see what happens. What should happen if I put my finger and cover the holes inside the throttle body? One at a time of course.

Hondaguy83

Car wil die. Don't do that. Sometimes u just gotta double check things twice or you'll be looking forever. Spray around gaskets and check for leaks around pcv valve but recommend changing it because if its stuck open it will cause that.

dc4b20

Pcv valve will cause it to idle high? Is there any way to check it, or do I just have to replace it?

Hondaguy83

Pinch off the hose n see if idle goes down. Should be a slight drop or take the valve out and plug with finger. It might idle lower than specs but gives you an idea.

dc4b20

Ok thanks. I'll try that today.

Hondaguy83

What I've learned from smog school is normal it should drop 50rpms if more than that ilu know the valve is no good and allowing more air than before

dc4b20

ok, i took off the valve and plugged it with my finger and the idle seemed to drop a little bit. noticeable by ear. is that normal? i also tried to set it to the factory idle adjustment as well and that did not work. if i unplug the iacv sensor, it seems to idle alot lower. is this normal?

moejoepotatoe

You should be adjusting the base idle ith the IACV unplugged and with the service connector jumped, well at lease that's how you do it on my b16a. Find the write up and you'll know for sure how to do it.

dc4b20

I tried searching "adjusting base idle" and found nothing.

Hondaguy83

Plan b.take off your intake arm and clean out your throttle body with throttle cleaner spray and hopefully it will clean out your iac too when the spray goes into the iac hole In Your throttle body.
Rev it up alittle while applying spray. See if that clears out and work.
If that don't work try this.

2. Test your coolant temp sensor if your car is obd2 u can use a scanner and read voltage and temperature. If obd1 u can try another method by finding resistance specs and calculating what temp and resistance it suppose to be at. Also check the voltage.

jbpnoman

Remember that part where I said "Get the factory service manual for your car, and follow the instuctions"? The FSM has a very comprehensive, easy to follow write-up on adjusting idle.

dc4b20

I don't really want to buy a service manual for this engine cause its gonna be swapped out before next summer.

jbpnoman

I never said buy, I said obtain. Borrow, rent, download, there are plenty of cheap/free methods that don't involve paying full price for a brand new one.