ranta18

Just swapped this H22 into a Civic. It idles fine without the IAC electrical connector connected. But once you raise the rpm to 1200 or so it surges. After 2500 or so it runs fine. When its idling and you hook the IAC up it surges. I tried another IAC and it did the same thing. You can hear it sucking the air through the IAC hole in the throttle body when the IAC is hooked up. IAC wiring wrong? The engine was warmed up. The TPS and idle air control screw are good. The CEL is on, but for some reason his CEL won't flash the codes. We're going to try using a LED on the actual CEL wire from the ECU. Any ideas?

DirectPortEF

Replace the IAC

Turbogixxer

Now, I had the same problem as you. I tried a another IAC, same thing. I tried third a IAC, it fixed the problem.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ranta18 &raquo;</TD></TR><TR><TD CLASS="quote">The CEL is on, but for some reason his CEL won't flash the codes. We're going to try using a LED on the actual CEL wire from the ECU. Any ideas?</TD></TR></TABLE>

What are you using to jump the connector?

ranta18

I tried another IAC and same thing. This one is cleaned out too.

I will try those trouble shooting steps.

HCP did the wiring and wired the TPS wrong, so maybe they messed this up too. They had 5V going to 2 wires on the TPS! ECU thought 100% throttle all the time.


EDIT: Harness was done by HCP.


Modified by ranta18 at 10:23 PM 1/22/2005

Turbogixxer

What year/model harness and what car/trim?

Weird, it is hard to have two 5v sources go to the TPS. On the IACV, One wire is battery voltage. The other is the signal ground if the ECU. The ECU sends a pulse to the IACV when load is detected (Electric, Power Steering, A/c, and to control the idle RPM). Follow the steps, it will lead you the right way.

ranta18

Its a 94 Civic VX with a 92 JDM H22

What happens... Car is idling fine, no IAC connected, as soon as you connect the IAC you can hear it sucking the air through the TB hole and it lopes/surges. Its like its wide open. When the car is warmed up does it suck air through that hole in the TB?

Adam.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ranta18 &raquo;</TD></TR><TR><TD CLASS="quote">Its a 94 Civic VX with a 92 JDM H22

What happens... Car is idling fine, no IAC connected, as soon as you connect the IAC you can hear it sucking the air through the TB hole and it lopes/surges. Its like its wide open. When the car is warmed up does it suck air through that hole in the TB?</TD></TR></TABLE>

I know you are having problems with your IAC, but that sounds exactly like when I replaced my fast idle valve. MOD said something about it is a common problem where the wax that is heated by coolant, loose it's ability to completely cover the hole and thus rev surges at idle.

Turbogixxer

If you disconnect the IACV plug, it can smooth out the idle, even thou the IACV is not the problem.

Do this. Take the intake tube off so the TB is open. Look inside the TB, you will see two holes on the left side of the TB. The top one going to the IACV, the bottom one goes to the Fast idle valve. With the IACV plugged in, Place your finger over them one at a time. If you plug the top one and the idle goes back to normal, your IACV (or wiring) is bad. If you plug the bottom one and the idle goes back to normal, your fast idle valve is bad. Note: this test should be done on a warm motor, so that the fast idle valve should be closed. If you plug both of them and you still have the idle problem, it is something other than the IACV and fast idle valve.

fastwanabe

I bet that you have 2 sensor reversed. The IAT and IACV were reversed on my friends H22 and if he reved up to 1500 rpms it would sound like its hitting redline then stop and rev up fine.

TrnsferErr

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fastwanabe &raquo;</TD></TR><TR><TD CLASS="quote">I bet that you have 2 sensor reversed. The IAT and IACV were reversed on my friends H22 and if he reved up to 1500 rpms it would sound like its hitting redline then stop and rev up fine.</TD></TR></TABLE>
yup, sounds like same exact thign that happend to me. try swapping those two.

ranta18

Well I did some more work on it. The IAC was wire ALL wrong. I don't know what they did to this harness. After that I took the cover off the ECU and found out it was socketed and there is a chip in it. ECU says A/T, but also M/T on it. Code is some numbers P13-N51. Only 3 plugs for ECU connections. I plugged in the stock VX ECU and it idled fine and reved up fine with no surges. But after idling for awhile it started to surge just a little. Both ECU's throw a constant CEL from the moment the key is turned on and when I jumper the 2 wires under the dash to see the codes, none flash.




Modified by ranta18 at 6:29 AM 1/21/2005

ranta18

Anyone... Thoughts?

Adam.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ranta18 &raquo;</TD></TR><TR><TD CLASS="quote">Anyone... Thoughts?</TD></TR></TABLE>

Sounds like bad chipping and bad wiring. Can't you pull the codes from the vx ecu at least? If they are the same obd they should have the same codes come up.

ranta18

On the IAC, there is a 12V source and then the other wire goes to the ECU correct?


Modified by ranta18 at 6:30 AM 1/21/2005

Turbogixxer

The ECU ALWAYS supplys the ground. It is safer to get ground then power. The wire going to the ECU is the ground.

ranta18

Got it. Going to start over and re-think this harness.

Oh btw... I hate wiring harnesses! I'd rather just build engines.

Turbogixxer

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ranta18 &raquo;</TD></TR><TR><TD CLASS="quote">Oh btw... I hate wiring harnesses! I'd rather just build engines.</TD></TR></TABLE>

They are not that bad This is what I will do for you, I will print out the diagrams for the car and the motor and mail them to you. Sound good?

It sucks thou. Troubleshooting wiring harnesses is a POS if you do not have the right diagrams/info.

ranta18

Thats cool. Don't worry about it. I think I got it. Thanks though.

98TypeSH

Fast Idle Thermo Valve.

Only happens when the car is Cold trying to warm up right ?

Easy test for it. pull the intake arm off, and inside the throttle body you will see a cutout hole. Put your finger over it. Is it sucking in air or not? If not FITV is toast or needs to be cleaned.

GAccord

bump to fix my car.

ranta18

I think you'll be happy with this Tom... https://honda-tech.com/zerothread?id=1123451

Still some surging at idle, but we think we've got that figured out.