Hey guys,

I just got my hondata base map from my tuner over the weekend and fired up the motor for the first. It's a B16B swap into a 97 DX. Motor was rebuilt with new rings/bearings, a valve job and new valve guides. I used an OEM honda headgasket

I loaded the tune, started it, and the engine seemed to run fine but the idle was rough. It was hunting between 400-600rpm. I set the timing to 16 degrees, set the idle via the instructions from Hondata, and it did not get any better. It actually got worse and would no longer idle on its own. It would hold rpm if I started it with some throttle and held it, and it revs freely, but it would die after I let off the gas all the way. I also wasn't able to clear the IACV check engine code, and it didn't show up in my DTC codes on the SManager

I cleared the ECU and reuploaded the tune and it was idling better after that and the code went away, but now when it idles, there is white smoke coming out of the exhaust. A lot of white smoke. It just smells like fuel, though. When I step on the gas a puff of black smoke comes out, and the car either dies or catches itself after falling to 250rpm and comes back up.

The base map has idle set to 1000rpm with a slightly increased duty cycle for the IACV. If I increase the duty cycle by 50% it idles great but when I step on the throttle it doesn't do anything or it shuts off. When I put the duty cycle back to where the tuner has it, it idles a little rougher but usually catches itself when I let off the gas and I'm able to rev it out.

I bled the coolant and did have to add a bit. The idle got slightly better. It will sit at 1000rpm for a few minutes, then drop between 750-950, then jump back to 1000.

I tried knocking the IACV but it didn't do anything. I shouldn't have any vacuum leaks because all the hoses were checked and replaced if necessary.

Does anyone have suggestions? Is it possible the map is just too rich and that's why it's falling after pressing the gas and why I have white smoke coming out of the exhaust? I don't think I'm burning any coolant. It just smells like fuel and the oil looks fine. Also, is it possible the ECU is bad? I'm not sure if it's holding the tune. Sometimes the SManager will not read anything when I try and datalog. When I hit download it does bring up the map so I assume that means it's holding the tune.

 

basemaps are always too rich.
is it a stock rebuild?

bring it to a tuner

 

yeah stock rebuild. i'm not super concerned about the idle but the white smoke bothers me. unless it's extremely rich it seems like it would be a different issue. I know it's not coolant so I don't think it's anything major. I'm wondering if the IACV went bad when I upped the duty cycle or if the PCV is bad and it's burning oil vapors. It's just strange that it didn't smoke when I first started it, but did after I reuploaded the tune and tried to fix the idle.

I think it's beyond my capabilities at this point so I plan to bring it to the tuner to do a diagnoses and inspection before he tunes it.

 

just a bump for the future if anyone stumbles upon this thread.

It was just a vacuum leak, bad o-ring on the MAP sensor and I somehow flipped the MAP and TPS connectors. I labeled the harness off the old engine so idk how I managed to do that, but I did lol.

Otherwise the swap went well. Have pretty good compression for a rebuilt engine. 205+. should get better after the dyno and some more break in. It'll be tuned soon. excited to see what it makes. I haven't seen too many B16B dyno numbers from the US. I'll be very happy with anything in the 160s. If I touch 170 that would be awesome but it's not a race car so as long as it's well behaved I will be happy.

 

I've seen the MAP and TPS sensors mixed up before.

Glad you got a successful swap, hope you make some good numbers on the dyno. Cheers!