portaman03

Okay well heres the scoop.

1997 Civic DX
d16y7 engine

Looks like a y8 intake manifold, but Im not sure how to check and see if the WHOLE HEAD is y8? Can someone tell me how to identify the head? It says p24-5.

Here is my original thread with the beginning of my troubles.
https://honda-tech.com/zerothread?id=2306284

I bought the car and it was running "okay" with a check engine light.
I pulled the codes (MAP, IACV, o2 sensor, and FTPS).
Since the FuelTankPressureSensor code was read, I was like wtf? cuz 97 DX isnt supposed to have that.

I pulled the ECU and it was an INTEGRA LS ecu.

I replaced it with the correct 97 DX ecu, and the FTPS code went away. However, I still have the 3 other codes and to add to my troubles:

Since I replaced the LS ecu with the correct DX ecu, the engine now revs up to 2000rpm and bobs up and down from 1500-2000rpm. It WILL rev past this if I press that gas pedal down further.

What could cause this? I replaced the spark plugs and wires, thinking the fuel wasnt being burned, smells a little like gas. Would the faulty o2 sensor cause a rich condition, causing the whacky revving?

Or could this be an issue with the IACV? I took it off and cleaned it out, but then realized that nothing happens when I unplug the IACV.

Here is also where I need help. Since the kid who had the car me did the y8 intake manifold swap, I think he also swapped over the entire y8 engine harness, considering it has numerous dangling connector and also a 2-wire IACV connection.

Would it be possible for somebody to show me the pinout on both the DX ecu and the ecu connector, so I can check and see if I have a connection for the IACV?
There was a link for the y7->y8 manifold swap and necessary ecu pinouts, but I lost the link.

I am about to try and sell the car and want this annoying revving to go away so I can get top dollar. Somebody please help!

portaman03

I also read that this may be an issue with the TPS, like the TPS and MAP connectors might be switched around. Gotta check it out.

Fafsa Racing

Same thing happen to me and it turned out that it was the Idle control valve...

portaman03

I unplugged the IACV and nothing happened, so I'm not sure if thats it or not. I am starting to think that I need to re-pin the ecu for the IACV (3-wire to 2-wire)?

Fafsa Racing

Check you Personal Mail box...

racerxh00

ok first off. its the ecu throwing the iacv code so its searching for the idle. the valve itself is ok but to fix the problem you neew to wire it and remove the oranve wire from the a13 slot and move the black/blue wire to the a12 slot. and make sure you have the wires right on the IACV. this is the fix if it has the VTEC (d16y8) head and the P2P ECU (EX). if its all stock d16y7 you should have the P2E ecu (Cx/dx) i have one laying right here if you need it. the y7 is a 3 wire plug so make sure the wires are all pinned right. there is a pinout for the IACV fix just google it. after doing the ecu swap, IACV wire fix and all mine still does it but i dont really care anymore.

Luserkid

Take a picture of the head and we could tell you what head you have. If there is VTEC solenoid then its a head that requires a 2wire IAC (minus auto y8). If its y7 this requires a 3wire IAC. This is control through the ecu you have. Take a picture of the engine and we could help you further, but it sounds like you are using the wrong ecu/IAC setup.

TPS and MAP could be crossed, no way to know since we are not there, tell use the color wires of each plug.


Edit: Just saw the other thread that has pictures. That is an OBD1 non VTEC head. Because of this you have 2 options. 1. run the DX ecu, and find yourself an auto y8 throttle body as well as a DX harness. Option 2 is convert to obd1 and run a DX ecu, you will be allowed to stay 2 wire IAC like it is on your harness now.

confucioussae

iTrader: (1)

^^x2 Make sure TPS and MAP aren't mixed up. Swap them, and if it runs better then leave it. If no difference, then keep your problem how it originally was. We really do need more information.

Is your current IACV mounted on the back of the intake manifold, or on the throttle body? You'll know by the coolant hoses. Have you tried running an EX ecu?


edit: just saw luserkids response. You could also use a y7 throttle body (may be easier to find) in addition to the DX harness, and swap the throttle body spring/plate. I'm using my y7 tb on a y8 mani.

is there no way he can run an obd2 ecu on an obd1 head problem-free? i havent done my obd1 homework


Modified by confucioussae at 11:10 PM 7/8/2008

94EG8

Theres a slight chance thats a vtec head, but i think i don't think so, i can see the distributor plug in one picture and the corner of the valve cover and i don't see a solinoid so i'm quite sure its non-vtec. This brings us to point 2, thats not an OBD1 non vtec head, with OBD1 the plug wires go towards the back of the valve cover on non vtec engines, on vtec engines and OBD2 non vtec SOHC engines they go towards the front of the engine. If i were in your position i'd get a Y7 intake and IACV and make sure your wiring harness is wired for a 3 wire IACV. Use the DX ECU you bought

hondamark35

i responded to your original thread, you have a y7 head with y8 manifolds.

the other computer that was screwy, could run the iacv correctly because you're running a y8 iacv on the back of your manifold.

when you went to the y7 computer, it corrected other problems but you were still using the y8 iacv, and a y7 ecu can't operate one of these. the y7 uses a rotory type 3-pin iacv on the TB.

when you unplugged the iacv and nothing changed... that was your big "lighbulb" moment. you're idle should drop when you disconnect the iacv, if it's working properly.

if you're tps and map were swapped the car won't get you down the road. i am assuming you can drive but when you come to a stop or put it in neutral the idle fluxuates.. you need to resolve the iacv issue

what you can do, if the y7 wiring is still intact... find any y7 TB, or a y8 TB from an automatic. these both have the 3-pin iacv that will let your engine idle normally. you will have to improvise the coolant bypass hoses to the iacv. unless you have a good hook-up, just get the right diameter hose by the foot at an auto parts store

two more minor details: 1) you'll need to block off your y8 iacv... i just took a piece of aluminum roof flashing, trimmed it and put holes in it to match the y8 iacv mount flange, applied a even layer of grey RTV to both sides and installed with iacv.
2) y8 TB gasket and y7 TB gasket are different... one will leave a gaping hole, the other will work fine. i think the y7 is the right one, but pay close attention and see what will work.

portaman03

Ok fellas...

So I know that a malfunction with the IACV (and also esp. since it's throwing that code) will cause a rough IDLE. Aka wandering idle, erratic idle, etc.

HOWEVER, my issue is ONLY when I depress the gas pedal. It will fluctuate almost like a rev limiter between 1500-2000 rpm, but if i depress the gas pedal further, it will rev past that.

It's almost like saying 1500-2000 rpm is the "hot spot" where it has the whacky revving.

So do ya'll really think this is the IACV issue?

Majority say yes, but I just wanted to clarify the issue that I am having...

Because my idle seems fine!

94EG8

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by portaman03 &raquo;</TD></TR><TR><TD CLASS="quote">Ok fellas...

So I know that a malfunction with the IACV (and also esp. since it's throwing that code) will cause a rough IDLE. Aka wandering idle, erratic idle, etc.

HOWEVER, my issue is ONLY when I depress the gas pedal. It will fluctuate almost like a rev limiter between 1500-2000 rpm, but if i depress the gas pedal further, it will rev past that.

It's almost like saying 1500-2000 rpm is the "hot spot" where it has the whacky revving.

So do ya'll really think this is the IACV issue?

Majority say yes, but I just wanted to clarify the issue that I am having...

Because my idle seems fine!</TD></TR></TABLE>

That is definately an IACV issue, i've seen if before, first time I was ever involved in an engine swap we mixed up the plugs for the IAT and the IACV and it did the very same thing, couldn't control the engine speed at all as soon at hit 1500 and all the way to 2000 rpm, after that it was ok. once we figured that out it was fine. I did the same thing one other time on my own car. I check a lot more carefully now when i plug stuff in obviously and check wire colors. But yes, definately IACV issue.

fernruffryders

are u running a 2 wire iacv or a 3 wire... if u have the 3 wire, switch the two outside wires... that was my problem... . hit me up if u want more details

hondamark35

wire switching only works if you're running the y8 ecu. i think he said he's got th y7 currently

confucioussae

iTrader: (1)

how many wires on your IACV did you say you were running, and on what ECU??

portaman03

The IACV is a 2 wire. On a p2e DX ecu.

94EG8

disregard this post read one below

94EG8

get a Y7 intake and throttle body, and a 3 wire IACV. follow this link http://technet.ff-squad.com/ under ecu and wiring tech, then obd2a you'll see 3 wire IACV fix, do this reverse of this and change the connector at the IACV with the 3 wire version.

portaman03

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94EG8 &raquo;</TD></TR><TR><TD CLASS="quote">get a Y7 intake and throttle body, and a 3 wire IACV. follow this link http://technet.ff-squad.com/ under ecu and wiring tech, then obd2a you'll see 3 wire IACV fix, do this reverse of this and change the connector at the IACV with the 3 wire version.</TD></TR></TABLE>

I dont understand how that would fix it. Essentially going back to stock? If I ran the y7 intake mani and TB with y7 iacv and y7 3 wire harness, i wouldnt have to repin the ecu - because it plugs into the y7 3 wire harness right?

Or are the connectors at the ecu not part of the y7 harness?

I would rather keep it semi the way it is, as in.. keep the y8 intake mani, find the appropriate TB and IACV combo, and then fix the wiring.

From what I've gathered, here are my options:

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Luserkid &raquo;</TD></TR><TR><TD CLASS="quote">That is an OBD1 non VTEC head. Because of this you have 2 options. 1. run the DX ecu, and find yourself an auto y8 throttle body as well as a DX harness. Option 2 is convert to obd1 and run a DX ecu, you will be allowed to stay 2 wire IAC like it is on your harness now. </TD></TR></TABLE>

and

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by confucioussae &raquo;</TD></TR><TR><TD CLASS="quote">You could also use a y7 throttle body (may be easier to find) in addition to the DX harness, and swap the throttle body spring/plate. I'm using my y7 tb on a y8 mani.

is there no way he can run an obd2 ecu on an obd1 head problem-free? i havent done my obd1 homework</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondamark35 &raquo;</TD></TR><TR><TD CLASS="quote">what you can do, if the y7 wiring is still intact... find any y7 TB, or a y8 TB from an automatic. these both have the 3-pin iacv that will let your engine idle normally. you will have to improvise the coolant bypass hoses to the iacv. unless you have a good hook-up, just get the right diameter hose by the foot at an auto parts store

two more minor details: 1) you'll need to block off your y8 iacv... i just took a piece of aluminum roof flashing, trimmed it and put holes in it to match the y8 iacv mount flange, applied a even layer of grey RTV to both sides and installed with iacv.
2) y8 TB gasket and y7 TB gasket are different... one will leave a gaping hole, the other will work fine. i think the y7 is the right one, but pay close attention and see what will work. </TD></TR></TABLE>

So either:

- y7 TB or autoy8 TB, with DX harness and ECU. Then block off the IACV that USED to be attached to the back of the y8 intake mani (new one Im assuming mounts to the new TB).

- or convert to obd1? I dont understand that part, would it be cheaper? What parts needed?

Basically trying to go the cheapest route possible to fix this pesky *** issue!

confucioussae

iTrader: (1)

Click on this image to enlarge it. View the section on IACV.

The cheapest method will be to get a y7 tb or a y8 auto tb with a 3 wire iacv and harness still attached. Repin the 3 wire harness to accept the old two wires, and use the existing left over wire from the 3 wire harness to attach to your cabin harness (and hook up to your ECU).

In essence, you will be ghetto rigging one wire into the cabin (not so bad if you don't do mickey mouse status.) Keep in mind, you said cheapest, not best method.

Ideally, you'd want to swap back to a DX harness with dx or y8 auto throttle body and continue using the DX ecu.

Does this make sense?

imzjustplayin

Have you done a compression test? Leak down test? My friend had the EXACT same issue with his 240SX, couldn't figure out what the problem was until his friend brought his 240sx over. I can only vaguely remember the details but it turned out he was missing some rubber washers, seals or whatever that was basically causing a vacuum leak. I vaguely remember my friend pointing to what I think were the fuel injectors, it's hard to say but maybe I could ask him. Anyway his car performed exactly the same as you're describing yours and I know they're completely different vehicles but I think it's worth a shot to check out if you have any leaks.

One thing that made it semi easy to spot was putting the back of his hand near parts of the engine and you could feel a slight breeze when you did that. I believe there are better methods with this same concept such as bringing white smoke nearby and seeing what happens to it. I don't know how you'd do this so hopefully someone could elaborate on this.

bpkmrtoes

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by imzjustplayin &raquo;</TD></TR><TR><TD CLASS="quote">One thing that made it semi easy to spot was putting the back of his hand near parts of the engine and you could feel a slight breeze when you did that. I believe there are better methods with this same concept such as bringing white smoke nearby and seeing what happens to it. I don't know how you'd do this so hopefully someone could elaborate on this.</TD></TR></TABLE>

You can use brake/carb/throttle body cleaner and spray around any suspicious places that might have a vacuum leak... you would find the culprit when idle changes when you spray the spot. But usually you would be able to hear a vacuum leak quite easily... well, to me it is.

portaman03

I understand what you are saying. However I am still a little confused.

If I am running the DX ecu with a EX harness (2 wire) cant I just do the re-pin fix at the ecu? Or do I really need the 3-wire iacv to work in conjunction with all 3 pins on the ecu? Because in the image it says that one pin will be rendered useless anyways.

ARG.

94EG8

you need the 3 wire IACV, the IACV fix in the pic is for when you want to go from a 3 wire to a 2 wire after an D16Y8 or B series swap, what your doing is exactly the opposite, so just do the reverse of what it says. or get a DX harness and you wont have to repin anything.

hondamark35

basically a Y7 ecu is looking for a 3-pin, no matter what wires are linking it. they're just wires.

it's like if you tried to fly a helicopter like driving a car... you don't have a steering wheel in front of you with a shift lever and the like. you've got gages here and there, a stick, a lever for throttle... see where i'm going? the ecu is designed to recognize the "controls" of a 3-pin.

on a different note: i found a spare Y7 TB with the iacv still on it if you decide you're in the market for one.