Fluctuating Idle Problem - 2000 Civic

[00Civic]

Hello guys.....it's that time when I need someone's help on here. First time too.

Anyways, here's the 411. I just bought this car 2 nights ago for pretty cheap. It's a 2000 civic ex with a D15b7 motor in it.

Two issues. Fluctuating idle and bad transmission. ( I'm not worried about the transmission ) - Buying a new one within the week.

The idle issue is where I'm stuck at. It's going from about 1400rpm to 2000rpm back and forth. I came across a disconnected plug that was supposed to be in the IAVC, so thinking I fixed it, I plug it back in, no luck.

I've never had to deal with an IAVC and was wondering if anyone can point me in the right direction? Thanks!

[00Civic]

What voltage reading should I get if I were to test it to the body ground with the key in the (int) on position? I want to make sure it's not an electrical issue.

[*EFilliated*]

are you sure that was the right plug that goes to it? its IACV by the way

[00Civic]

There are two that can both connect to it, and I've tried both and no luck.

[00Civic]

I've just now sprayed it with a throttle body cleaner and in about 30 minutes, going to re-install it and see if it does the trick. I wanted to take this opportunity and volt-test it. I was wondering if anyone knew what the readings should be

[00Civic]

No luck. No difference at all. I'm going to check electrical before trying a new IACV. Where should I test for voltage? Any suggestions would be helpful.

[smoknlegend]

Remove and clean the iacv with cleaner then reinstall. Also check to make sure your cooling system is air free, air bubbles in there can cause idle fluctuations.

[00Civic]

Remove and clean the iacv with cleaner then reinstall. Also check to make sure your cooling system is air free, air bubbles in there can cause idle fluctuations.

Already cleaned and reinstalled it. No difference. No air bubbles in coolant hose. I need to find someone around the Macon area with an IACV laying around to test it.

[Theycall_Metue]

I came across a disconnected plug that was supposed to be in the IAVC

1:iacv is not a plug, its a hose. if it was disconnected, you'll be shooting out anti-freeze/water.
2: d15b7 is a obd1 motor. i hope its jumped to obd1 ecu and not obd2.
3: like above, it hope its not on p2p ecu, obd2 d16y8 vtec ecu.

4: idle like that is normally iacv, or a extreme vacuum leak


i would check the obd conversion first.

[00Civic]

I just double checked with the ECU identification chart.

Now I have a P2E(OBD II ) ecu that's for a 96+ Civic DX

Now I guess I am on the hunt for a P06 ecu!

[*EFilliated*]

How do u expect to go from obd2 ecu to obd1 without a jumper harness?

I just double checked with the ECU identification chart.

Now I have a P2E(OBD II ) ecu that's for a 96+ Civic DX

Now I guess I am on the hunt for a P06 ecu!

[00Civic]

How do u expect to go from obd2 ecu to obd1 without a jumper harness?

I am getting a jumper harness as well when I get the P06.

[*EFilliated*]

kewl try that

I am getting a jumper harness as well when I get the P06.

[*EFilliated*]

Hmm yea u sir are wrong. Iacv does have a plug going to it so the ecu can determine location and compensate for any adjustment needed. If he doesn't have power/ground to it, it would cause this issue. And for 00civic I will try and find what readings u should get at the plug

1:iacv is not a plug, its a hose. if it was disconnected, you'll be shooting out anti-freeze/water.
2: d15b7 is a obd1 motor. i hope its jumped to obd1 ecu and not obd2.
3: like above, it hope its not on p2p ecu, obd2 d16y8 vtec ecu.

4: idle like that is normally iacv, or a extreme vacuum leak


i would check the obd conversion first.

[RBS]

2000 civic EX, if you are using a EX engine harness then you have a bad IACV or vaccum leak. if it is not a EX engine harness, you will need to move ECU pin B6 to B23 and remove B15

[00Civic]

2000 civic EX, if you are using a EX engine harness then you have a bad IACV or vaccum leak. if it is not a EX engine harness, you will need to move ECU pin B6 to B23 and remove B15

Wouldn't the P2E (obd 2 ) ecu be causing the fluctuating idle if I have a obd 1 manifold? The back of the intake manifold says P06 HF 5.

[00Civic]

if it is not a EX engine harness, you will need to move ECU pin B6 to B23 and remove B15

Is this in reference to a P2E ecu or an EX ECU?

[RBS]

you need a p2p OBD2 ecu, or a Jumper harness & OBD1 ecu. p2e is a Y7/3 wire IACV ecu.

[metalmatt47]

Hold on now, I'm confused. it's a 2000 model, but it's OBD1? I'm no Honda guy, but this makes NO sense to me. Maybe I'm wrong, but I'm pretty sure any car '95 1/2 and up were all OBD2, with some exceptions on '95/96 models.


Sounds to me more like a vacuum leak then anything. Either that or something is routed incorrectly.

[00Civic]

LOL, yes it's a 2000 model but the 92-95 civic motor is in it. Don't ask me. I bought it this way and couldn't pass up a good deal.

[metalmatt47]

LOL, yes it's a 2000 model but the 92-95 civic motor is in it. Don't ask me. I bought it this way and couldn't pass up a good deal.

Ahhh that makes sense then. Not sure why someone would go backwards on an engine swap though :P

[*EFilliated*]

HONDA owners

Ahhh that makes sense then. Not sure why someone would go backwards on an engine swap though :P

[00Civic]

You're telling me.

[00Civic]

RBS, you have aim or yahoo? real time messaging would be easier

[00Civic]

[00Civic]

RBS, someone already repinned the B plug. Exactly the way you said to do. So, do I need a new IACV or a P06 Obd 1 ecu?

[RBS]

RBS, someone already repinned the B plug. Exactly the way you said to do. So, do I need a new IACV or a P06 Obd 1 ecu?

try another ECU before anything else, you need a p2p (Civic EX Vtec) or a OBD1 computer.. any OBD1 will do

[00Civic]

try another ECU before anything else, you need a p2p (Civic EX Vtec) or a OBD1 computer.. any OBD1 will do

even OBD 1 automatic ecu's?

[*EFilliated*]

no it has to be 5speed

even OBD 1 automatic ecu's?

[00Civic]

no it has to be 5speed

That's what I thought, but he's the one who said " any obd1's would do ".

So anything that's obd 1 and 5 speed would work? are preludes, accords excluded from this?

[candycoated]

mine had the same problem, it was my coolant.

[00Civic]

I'm going to try a new IACV on there to see if it solves the problem. If not, then I will go from there.

[candycoated]

goodluck!

[Feriozfinest]

All u gotta do is clean the IVAC. They have video's on Youtube that show how to to do it step by step.

[Feriozfinest]

I had the same problem. Do waste ya money on a new IACV.

[00Civic]

So, here's my understanding / breakdown of what I've observed so far. I have a 2 wired IACV.

(92-95 civic DX motor ) used for 2-wired IACV's
(P2E ecu (96+ Civic DX ) for 3-wired IACV's - but there is not an orange wire ( which is used for the 3rd wire in the IACV )
(99-00 Civic EX harness ) used for 2-wired IACV's - No orange wire

At this point, it's looking like I might need to get a P06 ecu so that it won't look for the 3rd ( orange ) wire.

Here is the thing. The wiring harness that's under my hood is OBD2, would it be stupid to get an OBD1 ecu, or is there a way to keep this P2E ecu and solve this issue? Any suggestions/advice is welcomed.

[00Civic]

ORRR

Should I just get the P2P ecu so that it doesn't look for the 3rd wire?

[00Civic]

Anyone who can solve this issue will get $50. No joke. If your idea/suggestion works and fixes the problem, I will be more than glad to pay the $50 =).

[*EFilliated*]

put it this way when it comes to having stock motors, u use whatever ecu is meant for the motor regardless of what chassi it is in. once u get the correct ecu for the motor that is in your car u can start looking somewhere else if the problem remains, the ecu is the brain to how the motor will run period. without having the correct ecu to begin with, it will just cause you to waste money and time trying to diagnose a problem that may not be there.

[00Civic]

I've already made that suggestion to my brother and he said it would be a waste of money to do that, but the hell with it. I will just try my luck and go for it.

With that being said, anyone have a P06 ecu and a jumper harness for me to test it on? Long shot, but it's a start!