I've been wrenching for 20 years, and have been occasionally using writeups nearly as long. 7 out of 10 times, someone misses something important in their writeup. No offense, but the Y8 manifold swaps are no exceprion.

-My Y8 automatic throttlebody does not have a map sensor. The boss and threaded holes are there, but the boss is not drilled. Do I drill out the boss, or will I end up with a coolant leak? I spent a lot of time porting this trottle body out and would like to use it.

-YES you DO have to lengthen the harness so the throttlebody-mounted sensors can be connected. I have tried to make it work every way possible, there is NOT enough reach.

-You DO have to swap to a Y8 throttle cable, the Y7 cable is a few feet too long and makes the install look like s***. The more bends you have in a throttle cable, the more likely it is to get stuck.

Really frustrating. Any help would be greatly appreciated!

 

Searched all threads, cannot find a solution. About to take my code reader out and see whats going on. If this becomes a wild goose chase, I'm putting the other manifold back on.

Y8 manifold and tb from automatic
Everything hooked up correctly
y8 tb gasket
cannot swap throttle hardware, they rotate opposite directions
no vacuum leaks

 

Year Civic and year Y8 IM?

 

That's interesting to see that the throttle body doesn't have the hole for the MAP sensor to properly fit.

Since the MAP measures the manifold pressure it would be safe to drill the appropriate hole for the map sensor to fit. Looking at my throttle body its just a small hole/port that's not connected to any possible coolant ports.

 

Can you post pictures or provide evidence showing that the map sensor hole is actually blocked?

 

Just needed to drive the car for a few minutes, the ecu caught up.

In case this helps others:
pre-99 auto Y8 IM
my car is 98 Y7 manual, otherwise stock
reused Y7 MAP on Y8 TB (3 wire)
Used Y8 TB gasket
Y8 auto TB (DID NOT swap anything but MAP on it)
Sliced down wire loom keeper, added 8in of wire to purge valve connector wires.
DId not reuse steel tubing under fuel rail
THOROUGHLY bled cooling system
Will be getting Y8 throttle cable to replace excessively long Y7 cable.
Y8 purge solenoid
Y7 injectors
Y8 fuel supply line (they are slightly different)
Y8 rail
Y8 throttle bracket
Y8 manifold bracket
Y8 brake booster hose
Y8 fuel return hose
Y8 purge lines (all)

CEL came on initially. Surging idle +- 1000-1800rpm. Turned car off and vack on a few times. TPS low voltage code set. Erased code, drove car. After a few gears of load, idle normalized.

Some of this stuff was not mentioned in the swap threads, or information was convoluted hopefully this clears some things up. Was a very frustrating day.

 

so, I figured it out. What tripped me up was the Y8 setuo I pulled from a parts yard, never had a map sensor, or evidence of one having been there at some point. So I assumed it was just a boss. Upon further inspection, I found a small hole in the wall of the MAP sensor boss. So I swapped my Y7 map onto it. While it was running. I loosened the sensor, and it hissed, so I know it's getting a good reading. In the end, I got everything worked out. I will link my other post here.

 

https://honda-tech.com/forums/honda-...rched-3349131/

 

I merged your two threads as it's about the same car and the same process.

Easier for all if all the challenges before, during and after are in one thread regarding this IM swap.

 

Thanks, I appreciate that!

Another issue has popped up. CEL for IACV, idle steady at inconsistent rpm (sometimes 1200, sometines 3200, sometimes 2000).... The issue stopped after another drive cycle, but the light has stayed on. Despite normal idle, no IACV sensor data is coming up on my scanner during live data stream.

I guess I'll leave it for now and see what happens. I recall Honda ECUs being a bit picky sometimes especially with idle and throttle sensors.

 

Clear the code from the ECU and then go from there.

IF CEL turns on again after driving, pull the code and post it.

 

Will do next time I drive it. I can post freeze frame too if that helps anyone.

 

aftermarket throttlebody...nuff said....

 

To fix this issue? If so, I have been considering it.

Cleared the code, drove a few more drive cycles. It acted up on the second drive cycle after, but not the third, and no CEL. Have to drive another 170 miles tomorrow, at least two more cycles involved. I did notice there was no IACV sensor data available at all on live datastream, so the IACV may be totally toast and the computer is compensating with MAP and TPS. Wouldn't be the first time I've seen a vehicle do it.

 

You never provided the actual original IACV code. Was it P0505? If so, clean the IACV thoroughly, and then go from there.

 

Oh, crap you're right, sorry about that. It is P0505. I cleaned the tb and its orifices thoroughly but did not actually remove and clean the valve itself. I'll give that a shot.

 

I did a z6 intake and used the stock y7 throttle body. Never had a single issue, I just moved the throttle bracket over

****edit**** on the z6 intake manifold I had to use the z6 fuel rail, I also had to use the z6 fuel pressure regulator. The hose from the fuel filter was very snug, also the tps? Wire was a snug fit to move it over to fit

Next time just use your original throttle body and you shouldn't have any issues.

I went with the z6 because it was 75 shipped with everything on it including injectors and throttle body. A y8 automatic intake manifold with no extra pieces was going for over a hundred dollars on eBay at the time

Also just my two cents, I was going to do a vtec head swap because I just hated the y7 half intake. After factoring in the cost of a good cylinder head, new gaskets, new head bolts, an ecu, and the mess of converting my original engine harness, I decided that $600 in parts to gain 15hp was not reasonable.

 

I fixed the issue, as others had mentioned, cleaning the IACV was necessary. Runs just as it should now.

 

Update: issue is NOT fixed. When hot, idle starts climbing, first 2k, then 2500, then 3k, then -4500- rpm each time load is applied and let off. It got so bad I had to unplug it to get home safely.

I ordered a new IACV off Amazon. This was supposed to be a cheap and simple mod, it's not looking like it anymore.

 

Sounds like you just need to thoroughly clean the throttle body and properly adjust the throttle cable.

Any CEL codes thrown?

Avoid the expensive and risky approach of purchasing new parts in a desperate hope of finding a solution.

 

No codes, IACV has been cleaned repeatedly. No codes, but it doesntt show up on sensor data stream. The new IACV is 30 bucks. Poorly adjusted throttle cable would cause an issue on a regilar basis, not intermittently.


The risky approach was using sensors off a junkyard vehicle in the first plce, which I usually never do. For this reason.

 

Cleaning the throttle body and adjusting the throttle cable are not difficult and also may solve the problem without any additional parts purchases.

 

I see you used heat shield tape on your exhaust manifold. how well does it work? I have an 00 ex coupe with the cat conv underneath rather than at the neck. haven't been able to find a proper heat shield that bolts on.

 

i didn't do a swap but I had a similar issue. d16y8. there's a small vac line on the underside of the driverside intake manifold that controls the cruise control. I had the surging and the p0505 CEL. hooked the cruise control hose back and it settled everything. granted, after I cleaned the throttle body and replaced the IACV. I can't see your cruise control module in the pic to see if it has one or not. if not, you might want to check the int man for the vac nipple and plug it if you don't have cruise control. Just a thought.

 

Have already done that, as stated above. New IACV is on the way. Any time you use a sensor from a junkyard vehicle, you roll the dice.