fernruffryders

Ok here's the specs:
-1999 honda civic dx stock
-slapped on a 1996 ex (d16y8)mani
-did the iacv 3-pin to 2-pin fix at the mani and at the ecu.

The problem:

-cel P1509
-car idles fine, but if I hold the throttle at any rpms steady, it fluctuates.

What I have done:

-went on mitchel on demand, and trouble shooted the code, only thing I haven't done is gave the iacv direct power to see if it opens or not, I'm worried about frying it (I plan on using my Power Probe III)

My main reason for this post:

-am I supposed to use a ex ecu? Or does my ecu work after doing the "iacv fix".

-at the mani, where does the yellow/blk and green/black actually go, to what pin on the iacv?? I tried flipping them to see if the iacv would open with the ecu signal and no luck....

I appreciate all the help guys...

fernruffryders

Anyone?

fernruffryders

... no one has any iidea??

mrbob1983

the y7 ecu is still looking for the 3 wire IACV so yes you will have to use an ex ecu or a jumper harness and an obd1 ecu

Luserkid

You have to use an Auto Y8 TB or your DX throttle body. either way you need a 3wire IAC hooked up.

fernruffryders

Ok either a ex ecu...

Or a auto y8 tb...

Or my dx tb...


Well I looked at my dx tb, n I thought about it... but if I slapped it on, the piece that is supposed to hold the throttle cable would not line u, its like upside down...

Luserkid

You cant use the EX ecu because you are not using a VTEC engine. You would throw a code for different sensors used on the VTEC engine.

You have to flip the throttle holder.

fernruffryders

Ok, well I am building a y8 head... it won't be slapped on for a while tho, so I guess ill hold off on the ecu... but the throttle holder, how do I go about flipping it?? Diy??

Luserkid

unbolt the Y7 one and put on the y8 one.

fernruffryders

Ok so I swapped out tb's and no more cel's ... but now I start it up and my rpms shoot up to 5k and then it drops and fluctuates between 1k and 2k ...what's going on now??

sql_civic

iTrader: (3)

Could be a vacuum leak.

A couple other points on the EX (P2P) ECU...

This ECU will expect to see a knock sensor and 240cc injectors. So if you decide to use this ECU you will need to wire in a knock sensor and also use a 2 wire IACV. The fuel maps in the P2P ECU expect the higher volume injectors so you should swap those in otherwise you may end up running lean.

fernruffryders

Hmmm.. Well I have the ex injectors in there, could that be causing me a problem?? I'm running the stock dx ecu...

NIGHTRIDER27

ditch the dx ecu and do a obd1 conversion. that's what fixed mine

fernruffryders

How much did that cost u and what all did u have to purchase

NIGHTRIDER27

conversion harness and the ecu, then its just plug and play, also when i did my conversion harness i had to move one of the pins in the harness so that the iac would be seen. i spent like 2 days racking my brain over why the iac wasn't beening seen by the ecu and then i looked at a wiring diagram and bam there it was. good luck

fernruffryders

Cool... thanks, areciate it guys...

Is there any ower advantages by going obd1 ecu??

hondamark35

you're idle fluxuation is because you used the wrong TB gasket.

honestly i can't remember which works, DX or EX, but which ever one you used, you need the other.

i've done the same thing to my DX and i love the results. i used the throttle cable-rotor (thing) from the y8 TB and swapped it to the DX TB. used stock ECU, stock wire harness, DX sensors and fuel rail.

no need to go put another $200 into it to get it to work.

fernruffryders

Heall yea... thanks man... I'm changing the tb gasket as I speak... is there anything wrong with using the 96 y8 fuel rail, pressure regulator and injectors? Cus that's what I'm running...