My idle starts at 3k when started and eases up to 4k rather quickly...I have replaced all of the vac lines(2 of them). When I unplug the tps and IACV the car dies and gets the proper code. The car is a 93 CX Hatch with 94 b18b motor...I am running out of things to check...no codes until everythign is replaced...anyone have any ideas?

 

 

EESH.

Are we supposed to be psychic? WHat kind of motor is in your Hybrid rex?

Is that the car you are asking about?

What kind of intake is on the car. I dont the big silver RICE CANNON either. I am asking if your car os Throttle Body, or MPFI...

These are the kinds of details I need before I can start to offer help.

starting at 3K? Did you ever take off your fuel supply line? I did on my TBI intake, and put it on backwards. Its 90 Degree bend was backwards, and help the throttle open slightly. It took me nearly 45 minutes to figure this one out...

DETAILS MAN. DETAILS!!

THen we can help

 

93 CX Hatch with 94 b18b motor

Can't say it anymore.

Look, the car drove fine one minute...then just started doing it all of a sudden. All stock intake, have not removed anything. Or messed with anything other than trying to adjust the throttle out to lower the rpm.

 

This I had saved from a previous post on h-t. It came from hondaswap.

Fixing an Erratic Idle

By: Adam

Let me give you some background on my del sol if you haven't been around long. It will be a year ago in March that I put my JDM B16 SIR II into my del sol. Since the day it went into the car, it would not idle correctly. There was always a surge. The following is a list of steps I took to cure my idle problem.. it took me just shy of a year to get it to work properly, but it's done!!

1) Check the voltage on your Throttle Position sensor. Sometimes when doing swaps, you have to use your old throttle position sensor because the one that came with the swap is almost always broken. The Honda ECU looks for .5 volts when the throttle blade is closed and 4.5 volts at wide open throttle. You can measure this with the aid of Hondata or an Apexi Vafc, or a handy old voltmeter.

2) Unplug your Idle Air Control Valve (IAC), which is located on the back of the intake manifold. Doing this SHOULD cause the idle speed to increase if it functioning properly. If it does not increase, then you have found your problem... go get a new one. If the idle speed does increase, begin to turn the bypass screw on the throttle body and bring the idle of the car down to like 500-600 rpm, then plug back in your IAC valve. This should bring the speed back to a normal 800 or so rpm. In the event that doesn't work...

3) Check your ignition timing and make sure it is at the stock spec. Usually 16*... see my article on cam timing.

4) Chances are now that you have a vacuum leak somewhere. Trace all of the vacuum lines and make sure there is no leak anywhere. Some people use a little bit of lubricant and spray it on the hoses to watch for bubbles. Personally I have never done this; so try at your own risk. If it still doesn't idle properly, keep reading.

5) Did your Throttle Body get bored out at all? Is Air bypassing the blade?

6) Another thing that sometimes causes cars to idle poorly is too much fuel. Do you have a Fuel Pressure regulator? Make sure that it has a vacuum reference and that it is within specs at static idle. Honda recommends 30-38 psi. So anywhere within there would be worth a try. To adjust your pressure at static idle, Hondata suggests that you do it without the car running. Turn the key to "ON" and the fuel pump will prime the system, then you can adjust your fuel pressure accordingly.

7) At this point I began to think it was my ECU causing the car to run poorly. I was running a p28 chipped with everything under the sun.. I had it all: skunk2 , mugen n1, jun, visions, spoon... all those reburned programs you can buy. None of them seemed to work. I looked into Hondata. Hondata is the savior of my idle... or so I thought. Apparently no one told me this, but Hondata had a problem running B16's with p28 ECU's for some reason. Well after several attempts of having new programs made that ran more lean at idle and generally just wasting my time... I found a lonely sole in Minnesota who had what he claimed was the magical map that fixes the p28/b16 idle problem. He sent it to me... I took it to Tom Payn at http://www.PaynTechnologies.com and had him write the program to my ECU and presto it's run great ever since.

The above is just a short list of possible things it could be ... but they are all things you can undertake without paying someone else to do it. Good Luck and if you need the hondata idle fix, or have any questions please email me: Pills@hondaswap.com

 

Here's another one. This came out of the H-T archives before they were disabled. If these don't help you you're out of luck!

Bad Idle Troubleshooting

This is mostly for high and roaming idles but may work for low idles as well.

First, terms:

TB – Throttle Body
IM - Intake Manifold
IACV – Idle Air Control Valve (also called the Electronic Air Control Valve or EACV)
FITV – Fast Idle Thermo Valve
TPS – Throttle Position Sensor





I finally got the swap (b18a) in my civic but unfortunately when I started it up it idled at 3k then when it warmed up it had a hunting idle from 2k to 2500 rpm. I stood over that thing for 3 days, testing and scratching my head. On top of that I did a TON of searching on the h-t, hybrid boards, and on here. I hope what is contained within helps someone. Maybe they wont have to go through as much work as I did.

The idle on our Hondas is a tricky thing. It is controlled by two main sensors: the FITV and the IACV. The FITV is a mechanical valve that is controlled by coolant temperature (there is no ECU plug to it). When the coolant is cold the valve is open and letting air into the IM through a hole in the TB before the throttle plate. This essentially creates a small vacuum leak which in turn lets the motor idle higher than normal (supposed to be around 1500-2k for warming up). As the coolant warms up the valve closes and no longer lets air in through the hole in the throttle body. All the while the IACV, which is ECU controlled, is letting small amounts of air into the IM through another hole in the TB. Any amount of extra air the ECU is not expecting will confuse it and you will get either a high idle or a roaming/hunting/fluctuating idle. On to the troubleshooting.

First things first, don’t skip any of these steps. From what I have read (and experienced) usually small dumb things cause these problems so don’t overlook anything. Also refer back up to the pictures if need be.

1) Check your vacuum routing. On the underside of your hood there should be a vacuum diagram. If there isn’t a diagram under there, there is one in a Helms, Chiltons, or Haynes manual for your car (you should have one of these anyway). Remember, ANY extra air will confuse the ECU. Check for cracked or bad vacuum hoses. If in doubt just replace the hose, they are cheap.

The PCV valve could also be the culprit. Take it out and examine it. If it is cracked it could be causing a vacuum leak. Replace the peice if you arent completely sure it is ok (the helms/chiltons/haynes manuals tell you how to check it).

2) Check to see that your throttle plate is closed all the way. Take your intake off at the TB and check to see that nothing is blocking the plate. If nothing is in the way and it isn’t closed all the way, loosen your throttle cable.

3) Check to see if the nuts holding the TB and the IM on are tight, this was the source of my idle problem. If they are loose, tighten them.

4) Bleed your coolant. Some air bubbles may throw the FITV off and keep the valve open.

5) Take the 3 10mm bolts out of the FITV (you don’t have to take off the coolant lines). Then take off the 2 8mm bolts off the plate on the back of the FITV. Once the plate is off you will see a white plastic thing, screw that all the way in. This causes a TON of people’s hunting idle problems (it’s a source of a vacuum leak). Put the FITV back on and start the car up. If it still idles bad go on.

6) Clean the IACV screen(s). See Oz’s write up elsewhere on G2IC.

7) Make sure your car is completely warmed up. With it running, take the intake off the TB. There are 2 holes right in front of the throttle plate, these are the holes that feed the IACV (top hole) and the FITV (bottom hole). With your finger, cover up the bottom hole (it should NOT be sucking if your car is warmed up). If the idle goes down the FITV is to blame, either get a new one or take it apart and screw the valve completely closed (I have only read of people doing this, so I don’t know exactly how. Also, you will have to keep the engine speed up yourself when the car is cold).

Next cover both holes up with your fingers. The car should sputter and die (or almost die). If it does then the source of your crappy idle is the IACV. Replace it. If you want you can test the IACV. Shut the car off and put + battery voltage to the blk/yel terminal (on the valve) and momentarily touch ground to the blu/yel side. When doing this the valve should click, if it doesn’t, replace it.

If, when covering both holes the car still has a high idle, you have a vacuum leak somewhere. Again check the IM and TB nuts. You can spray carb cleaner around those areas and if any gets sucked in (the engine will rev) you have found your leak. Another source of vacuum leaks are where the FITV and IACV connect to the IM. Either replace the gaskets or use silicone gasket sealant.

8) If nothing has worked you should test your TPS. Probe the middle wire on the TPS plug (with the key on but not running, and the plug still connected to the sensor) with the + probe on the volt meter, and the neg probe to ground. You should have .5v with a fully closed throttle plate and 4.8v with it wide open. If the TPS is off, replace it. My TPS was .425v to 4.55v and it idles fine now so I don’t know how big the margin of error is. Also, it is pretty rare for these to go bad.

9) If, still, nothing has worked you might want to try a new ECU. This also is very unlikely, but worth a try.

10) If it still idles bad, go through the steps again.

I really really hope this helps someone out. It was a pain to have this mysterious problem and very little info on how to go about troubleshooting it. Comments or suggestions are welcome.

 

So bascially, the unplugging of MY IACV causing the car to die, instead of increasing the RPM, means that my IACV is bad...that is what I am getting from that statement.

I forgot to mention thanks for the reply...gives me something to do tomorrow...thanks again Stevel.


[Modified by hybridrex, 3:21 PM 4/4/2003]

 

that's what i gather too. I'm having problems with my idle and i unplug my IACV and the car dies. I heard cleaning it ou makes a big difference. It's basically a rubber plunger in there letting air in. I stripped one of the screws on the bottom so I couldn't completely disassemble it but I cleaned it out pretty good and nothing. Also, like mentioned above: If you want you can test the IACV. Shut the car off and put + battery voltage to the blk/yel terminal (on the valve) and momentarily touch ground to the blu/yel side. When doing this the valve should click, if it doesn’t, replace it.

I forgot to do that but I don't think I ever heard mine click.

no problem!
s

 

So, to recap my car has a hunting idle from about 1000-1500 rpm and it will idle really low sometimes and the engine will stall out. Only happens once it warms up usually. I have 11.2:1 compression, skunk2 stage 1's on a b16a with stock TB, IM, yada yada. The cam gears are set to +1 intake, -2 exhaust. Nothing really different. I have the problem when the car is at 0,0 but it usually won't die out and it just exaggerated by the exhaust being at -2.

Ok, so I've tried almost everything on the two posts that I put up here. If I unplug the IACV on my car it dies so I figured it was my IACV. So I checked it by applying 12V to + and - and it clicks quite audibly. So it seems to be ok but I swapped in another one and the car actually idled a little worse. I checked that one and the "click" sounded the same when 12V was applied. Mine has been cleaned out really good. Checked vacuum lines and they seem ok, haven't found anything yet. TPS voltage is .44V closed and 4.45V WOT. I've swapped ECU's, not the problem.

I have heard that the OBDII-OBDI harnesses can cause this problem but that doesn't seem right to me. In the posts it mentions screwing in a white plastic screw on the FITV but it seems to be in a different location on my engine, a b16a2. Is it under the TB?

Anyone have any other suggestions?

thanks.

s

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRneXt &raquo;</TD></TR><TR><TD CLASS="quote">EESH.

Are we supposed to be psychic? WHat kind of motor is in your Hybrid rex?

Is that the car you are asking about?

What kind of intake is on the car. I dont the big silver RICE CANNON either. I am asking if your car os Throttle Body, or MPFI...

These are the kinds of details I need before I can start to offer help.

starting at 3K? Did you ever take off your fuel supply line? I did on my TBI intake, and put it on backwards. Its 90 Degree bend was backwards, and help the throttle open slightly. It took me nearly 45 minutes to figure this one out...

DETAILS MAN. DETAILS!!

THen we can help</TD></TR></TABLE>

Your not the sharpest tool in the shed are ya?