Problems with P0505, two codes showing up?

Erny

New Member
So a couple weeks ago we swapped the engine in my 99 Civic M/T cause it got blown and the new engine came from a 99 Civic as well but it was an A/T. When we first got the engine in it ran fine no problems til i took it for a test drive and the engine light came on for the knock sensor , we replaced it and the engine light went away and the car ran fine again. I parked the car for 15 minutes and turned it on and a P0505 code as well as a P0420 cause the engine light to come on. I cleaned the IACv, there was a bit of carbon build up but not too bad. I reinstalled the IACv, and only the P0505 code for the IAC system came on but now theres two, on my OBD scanner one of the codes has the letters PND before the P0505. The car started to idle at about 1800, I turned the throttle body adjustment screw clockwise until it stopped, I couldn't get the RPMs to go below 1100 at idle. I checked the monitors on my scanner and it says the evap system is not ready. I unscrewed the map sensor on top of the throttle boddy and there was a bit of oil in between the sensor and the throttle body, is this normal? I've also checked all the vacuum hoses for tears and made sure they went where they were supposed to. The car also surges really bad in 2nd gear when beginning to accelerate again. Should I continue adjusting the idle by adjusting the throttle cable instead of the adjustment screw? Pardon my terminology if I said something incorrect.
 

Erny

New Member
Also the manifold and thermostat housing are both off of the manual.
edit: Also one code has Cnf infront of it and the other code has Pnd, both P0505, both say Idle Air Control System
 

Erny

New Member
Did you forget to reconnect the cruise control vacuum hose and/or the fuel injector air assist hose?
Nope, Cruise control worked fine last night, even with the light on. Car runs fine too other than high idle and the surging, But when i clear the code and drive it again the surging stops. Could this be over correction of a bad sensor? Smells like it runs rich too.
 


Erny

New Member
The hose that's attached to the straight up and down end goes to the top right of the intake manifold, and the hose that's attached to the end that protrudes at a 90 degree angle connects to the intake tube.
 

Erny

New Member
The top hose in the 2nd photo is the same hose that is connected to the FIA in the first photo
 

Restotech

Respected
Ok. Ihavnt worked on, or even set eyes on a y7 or y8 in prob 10 years. In the second pic, what is the hard plastic line across the intake labeled pvc that is joined 2-1 by what looks like heat shrink. What is that going to? Just curious. You swapped intakes to the new motor, did you use a new intake gasket?
 

Erny

New Member
Ok. Ihavnt worked on, or even set eyes on a y7 or y8 in prob 10 years. In the second pic, what is the hard plastic line across the intake labeled pvc that is joined 2-1 by what looks like heat shrink. Just curious. You swapped intakes to the new motor, did you use a new intake gasket?
Those are just my HID wires, havent found a permanent place for them yet.
 

Restotech

Respected
Those are just my HID wires, havent found a permanent place for them yet.
Oh. Ok. Obviously a high idle is due to to much air entering the engine from some where.
Those are just my HID wires, havent found a permanent place for them yet.
oh ok. Boofoo has more knowledge in 6th gens than I do. I would obviously makes sure the throttle body is not being held open by the cable by disconnecting the cable from it or checking the slack of the cable to the sheathing.
 

Erny

New Member
Thank
Oh. Ok. Obviously a high idle is due to to much air entering the engine from some where.

oh ok. Boofoo has more knowledge in 6th gens than I do. I would obviously makes sure the throttle body is not being held open by the cable by disconnecting the cable from it or checking the slack of the cable to the sheathing.
No worries, and thanks for the heads up on the throttle cable, I'll have to check it in the morning.
 

Restotech

Respected
Suspected external vacuum leaks can be identified by spraying carb, or throttle body cleaner in the suspected area and the idle will increase drastically.
 

Erny

New Member
You can also pinch vacuum hoses, using needle nose pliers, going to the intake and the idle will drop lower if you find the ciurcut introducing to much air
That's so simple I feel like it should've crossed our minds at some point haha, thanks for the tips.
 

civteck

Respected
Registered VIP
Suspected external vacuum leaks can be identified by spraying carb, or throttle body cleaner in the suspected area and the idle will increase drastically.
Iv seen even the best looking vac hoses have slight cracks that bleed air. Try this trick with the engine warm and steady idle, high or not, the engine should rev if a vac leak is sprayed. Go around all hoses and gasket surfaces. Did you set mechanical timing after swap? At this point with info provided 1) vac leak 2) iac sticking 3) timing. Let us know what you find

Sent from my boujea ass phone
 

Restotech

Respected
I agree with Resto on checking whether the throttle cable is adjusted too tightly. The cable should have some slack. However, that would not throw P0505.

Did you replace the IM and TB gaskets and torque the nuts and bolts to spec?

Do this test:
  1. Remove air intake.
  2. Start engine.
  3. Use your finger to cover the hole leading to the IACV.
  4. Does blocking air entry into the hole cause the idle speed to drop substantially?
I would try this first. I have used this method and found too much air through my fitv.
 


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