ywsek

y7 manual from 98 dx into 96 cx, also runnning manual ecu. the problem is the idle fluctuates from 800-2000/2500 (no tach). I tried both IACV from both motors, and bought a third throttle body with IACV, map, tps and still same problem, new gaskets, coolant bled.
I've read something about auto has 3 pin for IACV and manual has 2? but didn't find the answer. what wiring could possibly cause this problem?
next step would be trying a new manual ecu but probably just to find out the problem is still there.

Sloshy

try the manual ecu, if ti doesnt fix it come back

Sloshy

here it is for the plug https://honda-tech.com/zerothread/1171263 after you install manual ecu

ywsek

i got a previously working manual ecu in there, just cannot find another decent priced manual ecu at the moment. ok, so from that thread i read the 3->2 pinout is only for non vtec to vtec swap. but this was the same engine, just different transmission.
at first i was getting code 14, but after changing the IACV the code is no longer there but the idle still is.

sicones

for you not doing your research

MonkeyPuzzle

Sounds like the 2/3 wire difference is your problem.

If that doesnt solve it I had a similar problem after my auto-manual swap. Mine turned out to be that two of the wiring harness plugs on the intake are the same and I had them swapped. Map plug or something like that I think.

ywsek

monkeypuzzle, was your swap nonvtec->vtec when you did auto->manual?
yea, i found that there are 4 sensors alike.., i mean, 2 are similar, and another 2 are similar. map and another is similar, and two other are similar. the map usually is the problem with wrong connections, but i cannot plug the one i plugged into the map to the other similar one because it will not reach..along with that there is a plug taped together with that plug that runs to the intake box.
so what im saying is if i did switch it, that intake box plug would not reach at all.
the fluctuation goes away when i disconnect the map sensor. but this is just because the CEL comes on, right? (i've also triggered the CEL another way which fixed the fluctuation)

sicones...i appreciate the help.
dont get me wrong, i've been researching for a while now.
but read line 2 under "IACV fix explained".
my situation is a non vtec into a non vtec. d16y7 replaced with d16y7. from a 98 dx ek into a 96 cx ek. so the 3->2 pinout would be for non vtec to vtec. if a vtec motor was installed, i could see that the IACV on the vtec motor would need a 2 pin plug, and quickly realize that the original 3 pin plug would not work.
or am i missing something else here?
do i just unpin A12 because in the diagram it says EX, HF and not "all 96-98 models"?

just some additional info is
i dont believe it is a vaccum leak because i have checked with carb cleaner
also when i plug the iacv hole in the throttle body, the car almost dies, which probably means there is no leak elsewhere.

in the 98 dx, there is a sensor running back to the fuel pump and attaching to the gas tank. it sits underneath the tank towards the driver side. the 96 cx did not have this. my brother ran this sensor to the ecu. this did not change the idle at all.

we tried to correct most differences of the two models, such as changing canister, radiator,..

but i am retaining the cx intake manifold because it was in better shape.
i've read that o2 can also lead to a fluctuating idle?


Modified by ywsek at 4:08 AM 10/13/2006

sicones

well if the engine your putting into the car had a 3 wire IACV then there is no need for the 2 wire fix

that sensor in the back of the car is either the fuel tank pressure sensor, or the evaprorative bypass solenoid valve, these things are not on every chassis some are even on coupes and not on sedans, I dont know what honda was smoking..you better get a helms to figure this **** out