Spoonerz

I searched the archives and found similar problems but different model vehicles. When i start my car it idles fine, but after it starts to warm up the idle problem starts by going from 2k to 1k rpm. I tried burping my coolant and still bad idle. When i take off the map sensor it idles without a bad idle but it comes back sometimes. This is a stock d16y7 with a Auto EX manifold. Need car to go to school. Any help will be appreciated.

Otherguy

your sensors might be bad... either that or something not wired up right

Z3120

Did you plug up the nipple (cruise control vaccum) at the rear of the manifold?

Spoonerz

yes i put a hose and plugged it with a bolt. the little one at the bottom right of the manifold. Also i don't have check engine light

Luserkid

What year manifold and what year engine? 99-00 manifolds have air injection thing that you have to cap if your going to use the manifold for anything other then 99-00. More then likely thats your problem or a cracked intake manifold gasket.

Spoonerz

d16y7 is a 96 and the EX manifold is a 96-98. I just put a new manifold gasket in. I used my sister's 96 civic EX as a guide and i've checked where all the hoses, vaccum and wires are suppose to go and they seem pretty much identical except that i do not have cruise control. Any more ideas what my idle problem can be?

Luserkid

Well the reason its fluctuating is because you have a vac leak. What throttle body are you using, the auto y8 or the y7?

Spoonerz

i'm still using the y8 throttle because i already had a EX throttle cable on my car and it worked with the throotle so i stuck with the y8. Can that cause a idle problem? was i suppose to use the y7 throttle or is the y8 one fine?

Luserkid

The auto y8 throttle body works best since its also a 3wire IAC. Check your gaskets im guessing one of them has a crack. Try the TB gasket then the manifold gasket.

EE_Chris

It sounds like a vac leak. And a vac leak doesn't always come from old gaskets...it can come from the IACV being stuck (happened to me). The fact that the idle bounces up and down is NOT an indication that the IACV is working. It bounces because the ECU is cutting off the fuel injectors and turning them back on because the idle keeps trying to climb past 1k with the throttle closed.

03akkord5spd

can you use a 99-00 y7 TB on a 99-00 y8 mani?

Spoonerz

I plugged the TB to see if i got a vaccum leak and the car stalled and died so maybe that indicates that i don't have a vaccum leak? I unplugged the clip that is underneath the TB, it's the olive lime looking one and the idle jumped even faster but not as high. Then i tried letting only a certain amount of air into the TB and the bad idle calmed down and stop? any clues of what it is still?

EE_Chris

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Spoonerz &raquo;</TD></TR><TR><TD CLASS="quote">I plugged the TB to see if i got a vaccum leak and the car stalled and died so maybe that indicates that i don't have a vaccum leak?</TD></TR></TABLE>

No, it doesn't. You can still have one.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Spoonerz &raquo;</TD></TR><TR><TD CLASS="quote">I unplugged the clip that is underneath the TB, it's the olive lime looking one and the idle jumped even faster but not as high.</TD></TR></TABLE>

If you unplug a 3-wire IACV, that's what usually happens. They don't close down like their 2-wire cousins...they stay open or actually OPEN FURTHER. They aren't constructed the same as a 2-wire.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Spoonerz &raquo;</TD></TR><TR><TD CLASS="quote">Then i tried letting only a certain amount of air into the TB and the bad idle calmed down and stop? any clues of what it is still?</TD></TR></TABLE>

Yes, a vac leak. The fact that you had to throttle the amount of air going in to make the idle come down and stabilize should tell you you've got air coming in from some other place. Whether that be from a mis-adjusted throttle plate stop screw or a mis-adjusted idle air bypass screw - it's coming from somewhere.

Spoonerz

i think i fixed it. It must have been a bad sensor or something. I just switch the TB and put my y7 TB on it with the plugs and sensors and it stopped having a bad idle when the motor warms up. I didn't notice it at first but my idle still goes up and down really slow and it's not noticeable if you don't pay attention to it. but right now it idles around 700rpm and i screwed the idle screw thing all the way shut. Would you guys think i will still be able to pass smog?

Beryun

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Ukrainamese

if it's still doing a surging idle, check the following:
1. check for a leak. use wd-40 or propane, and spray around the vacuum lines and nips, and the gaskets (if your engine revs up, there's your leak) (for me, it was a gasket leak, honda gave me one that fit the tb perfectly, but didn't fit the manifold properly "too small", so i made one to fit)

2. clean out your iacv with wd-40, throttle body cleaner or brake cleaner (could be more things you could use, but this is best)

3. check your sensors (if the sensors on your y8 are bad, just use the throttle rotor from the y8 tb and put it on the y7 seeing how the y7 should still be in working condition)

it has nothing to do with your idle screw, just an fyi.

good luck.