Okay, i just finished putting a nnewer better d15b7 into my civic sedan, i figured itd be a simple swap seeing as ive put a zc in my hatch. so aftre i get the swap all done, i turned the car on and the revs go to 2000 then down to 1000 then up to 2000 then down to 1000 and so on, whats going on?

 

sounds like a vacuum leak to me, check all the hoses going to the intake manifold. i bet one is leaking/or in the correct spot.

 

clean out your iac valve

 

doesn't the iacv cause a low idle, not a irratic idle?

 

iacv causes both irratic & lower idles, but 1000-2000 sounds like a vacuum leak for sure..surges, up and down, up and down...

 

oh yeah, try reseting the ecu also.

 

sorry to jack the thread, but i recently noticed that when i first go into neutral say while stopping at a light, my idle drop down to normal, but shoots up to 1500 and drops back down and stays there. possibly iacv?

 

or low on coolant, believe me or not, if you have an air pocket in the coolant system it will cause irratic idle.

 

yeah ive heard about low coolant doing that
though i know my iacv could use a cleaning, , do you know if you should bleed the system after cleaning it?

 

where is the iacv?????

 

back of the intake manifold..

 

there is lots behind the intake manifold lol, what does it look like?

 

its bolted to the back if the intake manifold

heres a link to a DIY, it has a few pics of it.

DIY IACV Cleaning

 

it's bascially the only thing on the back of it..

2 bolts has 2 hoses going into it from the bottom..

 

Thank u! Ill go do that now, ill let u know how it goes

 

tps adjustment maybe

 

so did it fix the problem Kieran?

 

i cleaned it all out but now my car isnt getting any power to start the car, its weird cuz i have to keep charging the battery all the time now and the alternator was working fine when i took it out of the old civic and the battery was working finew not too long ago, oh well, ill charge the battery upo toimoro and start it to see how it runs, and what is the tps adjustment????

 

???????

 

Throttle Position Sensor.. Don't touch that yet..

So you cleaned out the IACV and now not enough power to start the car?

Do this.. Get a Volt Meter and while the car is running, check the terminals. You should read about mid 14 volts. IF it's way lower then your alternator is NOT charging the battery. With the car off, your battery should read about 13 volts.

Check all your grounds on properly? Check tension on the alternator belt. Insure that all the connection on the alternator are on well. Try a different battery.. If it doesn't solve it, time for a new alternator. I did a ZC in a crx recently and the alternator was fine for a few days and then just died..

As for the IDLE up and down.. I would adjust the BISS screw. It's a little screw on the throttle body. Remember how much you turn it just incase, because if it doesn't fix the problem, you want to put it back in the exact spot it was before. My H22 did the same thing with Idle, I adjusted this screw a little and everything was fine.