Hello all, I am looking for advice as I have just completed my first major engine bay overhaul on my 00 civic.

I started with a d16y7 a/t p2e ecu
And​​ ended with a d16y8 m/t p28 ecu

After the swap, I was able to start the car (only with the throttle cable over tensioned to keep the rpms at ~800). The only other issue was a dead spot between 1.5k and 4k rpms where once I hit 1.5k and tried to go past, the engine would fluctuate between 3k and 1.5k. Once enough pressure was applied it shot straight up to 4k.

I thought both these issues would be fixed with a new TPS and MAP sensor. I hooked on the new sensors and esured the TPS was properly calibrated (0.45V - 4.2V). After this, the car WOULD NOT STAY STARTED. After resetting the ecu it would just start momentarily and sputter. I even tensioned the throttle cable again but didn't help.

I managed to get it started by putting the old MAP sensor on and keeping the cable tensioned. It started decently so I reset the ECU once more and did a re-learn.

Which leaves me to where I am today. The throttle is partially open to keep the vehicle from stalling out and the dead spot still remains between 1.5k-4k.
I'm stumped
HELP


 

Your problem is the IACV. What combination of intake, throttle body, engine harness, ECU and chassis are you using ? Fixing this will solve both your idle and light throttle/low RPM issues.

 

I have a y8 intake and TB. I have an EJ6 body with a p28 obd1 ecu, running the y7 harness. What would be bad on the IACV? Can I just clean it or does it require a replacment?

 

Is it a manual Y8 Intake and T/B ? To identify this properly, the manual I/M will have a provision on the back of it to bolt on a 2-wire IACV, and the bottom of the T/B has barb fittings for coolant to pass through. The automatic I/M and T/B will be different... the I/M has the rear IACV ports closed off in the casting and the T/B has the 3-wire IACV mounted to the bottom of it. The P28 cannot control a 3-wire IACV, so you MUST utilize a 2-wire IACV for proper idle and low RPM/light throttle operation. Even if you have all of these proper components, you need to make sure that your wiring is correct. Did you do the black/blue wire move at the ECU plugs to make the IACV work in your Y7 harness ?

 

Yes it's the manual I/M and TB. I had to solder a 2 wire connector from my y7 harness to fit the iacv plug. Orange wire was left behind and the 2 other wires I believe I hooked correctly.

 

You could have just said you have a 1999 Civic CX H/B.

You may have fitted the new 2-wire IACV with the proper plug and wires... both the black/blue and the yellow/black (or black/yellow) wires and a two-wire connector, however, you still have to move the black/blue wire to a new position at the ECU plugs. It is possible that your conversion harness has both wiring positions connected together, in which case, the IACV should function appropriately. If not, you WILL have to move the black/blue wire manually. The original position in your engine harness is B6... you need to move it to B23.

 

What is the reason for this? I looked up the pinout for obd2b and I don't see pin 26 listed? And just to double check, when converting the harness to 2-wire, what's the orientation of the 2 wires?
Also i have the 4dr sedan, SE trim, 2000

 

https://www.hamotorsports.com/pages/...or-96-98-civic

 

The orientation of the two wires at the IACV plug is immaterial... the polarity works either way. To be clear, it comes with the black/blue wire on top (with the lock tab facing up) and the yellow/black (or black/yellow) 12v power wire is on the bottom. I am not sure of the source validity of where I looked up your "EJ6" chassis code (and it obviously wasn't correct, so the information I might have provided may also be erroneous based on this incorrect chassis), but as you can see, providing that because it sounds cool doesn't help ANYONE here assist you !!! I could care less what your VIN code is... all you had to say is "I have a 2000 4-DR SE". In the future, provide clear, concise information so that members here can assist you as quickly as possible.

According to the OP, this is still a 2000 model year Civic chassis, so the wiring positions that I provided above are still accurate. What you have offered is that from a '96-98 Chassis and is in fact incorrect... unless this vehicle is from another market (Non USDM chassis), which the OP did not specify. I believe you meant to reference this source page for a '99-00 USDM Civic (except the HX):

https://www.hamotorsports.com/pages/...or-99-00-civic

 

*SOLVED*

Yes I see what you mean now. My source may have been incorrect. none the less I looked into the pin locations at the ecu and switching the pin from b6 to b23 fixed the issue. Thank you for the help!