When does the IAC Valve on a 94 gsr see voltage and is activated? Because when I start the car and check the voltage at the plug it reads in the 11 region and stays the same even when a/c is switched on. Im running hondata and when I switch the a/c on the rpms drop a good 100 when it should be raised. We checked the iac and when we give it manual voltage it does click on. We have no test harness like it recommends in the helms.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboTeG4 &raquo;</TD></TR><TR><TD CLASS="quote">When does the IAC Valve on a 94 gsr see voltage and is activated? Because when I start the car and check the voltage at the plug it reads in the 11 region and stays the same even when a/c is switched on. Im running hondata and when I switch the a/c on the rpms drop a good 100 when it should be raised. We checked the iac and when we give it manual voltage it does click on. We have no test harness like it recommends in the helms.</TD></TR></TABLE>

http://hondata.net/forum/viewtopic.php?p=8965#8965

 

Has it always done this? Or just since the installation of the Hondata?

From my understanding, it's always active even during cold start up when the FITV assists in raising the idle.

 

Well I swapped my engine with a Spark racing engine, and added the hondata, since then this is occuring as I dont remember it occuring before hand.

 

IACV works with ground (earth) pulses coming from the ECU. You will always have about 12v on the power side of the IACV regardless of the load of the IACV.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Turbogixxer &raquo;</TD></TR><TR><TD CLASS="quote">IACV works with ground (earth) pulses coming from the ECU. You will always have about 12v on the power side of the IACV regardless of the load of the IACV.</TD></TR></TABLE>Roger that, thats why do you think it could be a faulty main relay which is sending the ground signal, if only the IAC ground from the relay is not coming on cause everything else works fine? Is the IAC almost exclusivly for the a/c cause its not for the warm up

 

Well I changed the main relay with another one I had and same thing, idle drops roughly 130-140 rpms. How is the signals working???
Does the a/c have 2 signals 1 going to the compressor and one going to the iac in turn goes to the relay and grounds it??? The IAC has 2 wires one from the ecu and the other going to the relay.
Explain PLEASE!!!!!!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboTeG4 &raquo;</TD></TR><TR><TD CLASS="quote">Explain PLEASE!!!!!!!!</TD></TR></TABLE>

Well, honda's system has load detectors. What they basically do is let the ECU know that a load (thus drop in RPM) is going to happen. Your load detectors are for A/c, PS, and ELD.

You have a a/c input to your ECU (b5 on OBD1). When you push the a.c button, it going to a few relays and switches, if the relays and switches close the circuit, B5 will get ground, thus letting the ECU know the A/c compressor (also controlled by the ECU) will be turning on. The ECU will add more air (via of the IACV) to bump the rpms up so the motor does not bog/die.

The IACV is like a injector, then the ECU wants it to open more, it increases the pulses (duty cycle) to the IACV.

Damn, we-todd-did-racing is slow tonight, I have the troubleshooting charts for the IACV. I think.

 

Another strange thing is I was idling the car with the a/c on and the compressor stopped for a while, then came back on.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboTeG4 &raquo;</TD></TR><TR><TD CLASS="quote">Another strange thing is I was idling the car with the a/c on and the compressor stopped for a while, then came back on. </TD></TR></TABLE>

Depending on the a/c duty cycle (low and high side pressures) that maybe normal. You can have someone check your a/c for you (if it is in good condition)

 

So I guess my only available option is to take the car to a honda/acura dealer to troubleshoot? Looks like the signal is not going to the iac

 

You said it worked before - I'm guessing with a stock ECU? And all you did was replace the motor with another one and added Hondata? Are you re-using the old IACV from the known working motor? Have you tried (can you) the stock ECU again (or you chipped your stock ECU)? Have you verified the wiring just to make sure something didn't get pulled slightly out of its connector, which when viewed visually it looks fine but using a meter shows an open?

 

Im re-using my old IACV from my previous engine, and all I did was swap engines and use the hondata. I assume it was working fine because my stock motor was running at the stock 750 rpms at idle and when I used my a/c my engine never got near to stalling out, it would be at 550 rpms if it dropped 200.
Now with the hondata I adjusted my idle at 850 when the a/c switch is on the idle drops a good 200 rpms. Im running off a slightly modified base map for 440 injectors turbo from the hondata base maps.
My tuner also stated that he could not manipulate the the rpms through hondata, he said for me to check the Iacv. Hondalogger shows the a/c switch on and the a/c relay on, wire harness has been checked. Voltage does show on the IACV connectors but seems like the main relay is not grounding it which I also replaced.
Also today I drove my car and with the engine cold if I rev it the rpms drop to like 100, I stalled on the road when I pressed in the clutch as it went all the way down. I find that after it warmed up it did not do this, could this be from a faulty p28 hondata ecu. I do have my stock ecu but im now running 440 injectors and I dont think I could run the car that way in order to test the problem.

Now that I think about it could very well be the hondata p28 ecu since that is what will control the pulses to the iacv

 

Also why is the coolant going to the Iacv, cause the fast idle thermal valve is the one on the throttle body to regulate rpms during warm up???

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboTeG4 &raquo;</TD></TR><TR><TD CLASS="quote">Also why is the coolant going to the Iacv, cause the fast idle thermal valve is the one on the throttle body to regulate rpms during warm up???</TD></TR></TABLE>

Teh coolant going ot the IACV valve to to keep the IACV from freezing on cold days. In FL, I bypass it if I have to move the IACV (ex: install a h22a S2 manifold). I have never seen a problem with bypassing it in a warm place (FL, HI, CA).

Check the wiring too before you replace the ECU.

OBD1 ECU pinouts

This is a civic, but is damn close to a integra


Also, take the ecu covers off and inspect the ECU for damage (burn marks, broken parts, bad solders).

 

I tried my stock ecu with the 440's, it would idle(if you call it that)at 200 sputtering over rich but I put on the a/c and the engine Did not Die.
Thinking of trying to put my stock injectors on and the stock ecu and see what happens, or maybe a different chipped ecu.