Just swapped in the D15B, very low and jumpy idle when motor is warm..

[sutton]

hey everyone, i finnally got the D15B swapped in, and everything went pretty good. now that we got the motor up and running, im trying to get all the little bugs worked out. 1st question is, my motor starts up great and idles good when its cold, its just that when it warms up, it BARELY idles or stalls out and if it does idle, its kinda jumpy. The ECU is throwing no codes but im running a stock P06, chipped for vtec. I was told it might be my PCV valve but right now, its bypassed. Anyone have any idea of what this can be? other than this, the motor runs great and pulls pretty good, other than the fact that i gotta get it tuned because its set to cut out at 6500 :TD: thanks everyone!

[crazkene13]

Sounds like a vac leak to me, got access to a smoke machine?

[Chiovnidca]

A vacuum leak will usually cause them to idle high.

Have you checked the ignition timing? Cam timing? Does the idle air bleed screw cause any changes?

[97civic123]

would anything else cause it?

[sutton]

hey, i just got home from work, im gunna go out tonight and look at it, im gunna check for vacuum leaks and im not sure weather the timing is off. ill try adjusting the idle and see if that does anything, its only at idle that it does it, it runs perfectly fine when its cold.

[DOHCDX]

yep, as above, make sure the base timing is right and adjust the idle screw on the t/b

[sutton]

ok, no dice on the idle screw, im thinkin the timing might be off a bit seeing that the distributer was off of the motor before it was swapped, so ill check that out somtime, thanks for the help guys!

[JaredKaragen]

it wouldn't hurt to check the cam timing too if you changed the belt (you shoulda done the timing belt and water pump before installing the motor... it's cheap insurance for a motor that has been sitting!

[superdewey58]

make sure the iacv is working and clean along with the ft.. i duno what its called but tis on the back side of ur intake mani

[K2e2vin]

make sure the iacv is working and clean along with the ft.. i duno what its called but tis on the back side of ur intake mani

I'm pretty sure the IACV is working, if it's not, the idle would be low all the time(IACV causes the high idle when cold).

[superdewey58]

good point, stil cudnt hurt

[Chiovnidca]

I'm pretty sure the IACV is working, if it's not, the idle would be low all the time(IACV causes the high idle when cold).
I thought the fast idle valve did that.

[K2e2vin]

If I recall recorrectly, the Fast Idle and IACV work the same way, exhaust Fast Idle is triggered by temp, while the IACV is controlled by ECU.

[EG_GSR_HB]

I have the same problem with my D15b. only at idle and when warm. Mine hasnt stalled out on my yet its just jumpy when warm. Im running a p28 chipped

[civic510z]

it seem like the iacv is not letting enought air get into the motor. MAYBE when it cold the fitv let in air but when it get warm,the fitv close and the iacv dose not open up eonugh for the air the engine need. THIS IS ALL IN THEORY. cuzz when you the car is warm and you block the IACV, the engine is not getting enough air and it just stall out and turn off.

[DOHCDX]

your AFRs at idle are probably crappy. right around stoich seems to be the best

[mikecrx1990]

Check your vacume lines from the map sensor mine did the same thing and I hade theim switched one gos to TB the other to the charcole canister.

[SOHCpower]

mine sounded like a wrx idling til it warmed up and it still didnt run right, i found out i forgot to put all my ground wires back one, had one connected to the ps pump and that was it. connected them all up and it ran great...