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?

 

is it possible that the iac is wired wrong ?

ususally an engine will only surge with a large vacume leak , like a wide open IAC

if for some reason the iac is wired backwards , then when the cu is trying to fully close it its opening it wide open

 

this is an in the dark guess, does the iacv have the 2 wire or 3 wire, i know you are supposed to do a mod to convert them

 

The kid sent the wiring harness to HCP. The TPS was wired wrong. They had 2 wires feeding 5V! The ECU thought it was at 100% throttle all the time. I wouldn't be suprised if the IAC was wired wrong. I'll try switching it around.

EDIT: Harness was done by HCP.


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

 

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 6:31 AM 1/21/2005

 

Anyone... thoughts?

 

perhaps the service connector is not making good contact? if its not flashing when connected it usually means a busted ECU, but whats the chances that both are busted eh?

and thats really unfortunate that the hasport harness turned out that bad.

oh yeah, the iac is a pulsed 12v wire, i forget it if was constant 12v and pulsed ground, or constant ground and pulsed 12v. Though I am pretty sure it should be pulsed ground.

The IAT is 5v and ground. the 5v is the sensor input to the ecu

goodluck with the swap

 

bump for a good reason

HCP did the wire harness too.

 

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


Modified by ranta18 at 6:31 AM 1/21/2005

 

all the sensors run to a common sensor ground, if anything, i would suggest you ground them to a sensor ground near the ecu. 12V ground and sensor ground are both pretty close, but for sensitive sensors like those I would go the extra step and ground them to a sensor ground just so that the ecu will be at teh same reference ground.

though if the harness is really taht crossed up, I would suggest you tearing into the harness to find the problem instead of going around the issue by running new wires, it usually jsut creates a bigger headache.

I feel your pain in this, i HATE working on modded harnesses, it takes more time to fix a screwed up harness than it does to just mod another stock harness to fit. I usually send my customers to a junkyard to get another stock harness if they come to me with a modded harness, but don't send GAccord away, he's special,

 

I am pretty sure its a constant 12v on one end, and the other end goes to the ecu pin.

 

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

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

 

hahaha, i only hate harnesses that dont work

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Eddiebx &raquo;</TD></TR><TR><TD CLASS="quote">but don't send GAccord away, he's special, </TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ranta18 &raquo;</TD></TR><TR><TD CLASS="quote">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 6:31 AM 1/21/2005</TD></TR></TABLE>

the fact that the cel stays on from the get go is what worries me. perhaps you should take the ecu out and open it up, and the use the library at pgmfi.org to see if you can tell if they converted a auto to manual ecu, and if they did it correctly.

that would be my first concern, a solid cel is an interal ecu problem. you should definatly open it up and use pgmfi library to look at the board and see exactly what they did

also what harness was used, sounds like the wiring is all F'ed up. use the faq at the top of our page, to check the p13 ecu pin outs

 

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

the fact that the cel stays on from the get go is what worries me. perhaps you should take the ecu out and open it up, and the use the library at pgmfi.org to see if you can tell if they converted a auto to manual ecu, and if they did it correctly.

that would be my first concern, a solid cel is an interal ecu problem. you should definatly open it up and use pgmfi library to look at the board and see exactly what they did

also what harness was used, sounds like the wiring is all F'ed up. use the faq at the top of our page, to check the p13 ecu pin outs </TD></TR></TABLE>

That could explain why it had a/t and m/t written on the ecu when I got it. Mike told me that the ecu was chipped as well, so it had been messed with at some point.

 

I don't think the solid CEL is from the ECU. We tried 3 other KNOWN to be working ECU's and they all did the same thing... solid CEL with no flashing when jumpered. It has to be something in the wiring. We went though each plug and check to make sure it was going to the right pin on the ECU and they all checked out ok.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ranta18 &raquo;</TD></TR><TR><TD CLASS="quote">I don't think the solid CEL is from the ECU. We tried 3 other KNOWN to be working ECU's and they all did the same thing... solid CEL with no flashing when jumpered. It has to be something in the wiring. We went though each plug and check to make sure it was going to the right pin on the ECU and they all checked out ok.</TD></TR></TABLE>

oh ok , i thought you were saying that no matter what you did with the jumper wire even without it you had a solid CEL,

 

Well, this is what happend... https://honda-tech.com/zerothread?id=1123450



Still a little surging at idle, but we think we have that narrowed down.

 

I'm going to replace the IACV when I get a chance and see if that fixes the problem. Hopefully it does.

ANyone on here have a spare H22 IACV they want to sell?

 

try hondaautomotiveparts.com, prices are good there

 

picked one up for $28.

 

different iacv didnt fix the problem. anyone have suggestions?

 

maybe try adjusting the fitv, and see if that helps

 

Fast Idle Vavle fixed it.