setup:
b16a
overbore ctr pistons
gsr cams
blox valve springs and retainers
head and block decked .001
stock fuel setup besides inline fuel filter (summit)
edlebrock victor x
stock tb
8lb flywheel
stock p28 (getting phearable.net chip on friday)

Info:
so my issue is I have a bouncing idle during the day and it will stall the car when at a light or between shifts. at night it will usually idle perfectly but sometimes it acts up at night as well.

issue started when i swapped to a victor x im, new (used) altenator, and added a/c (a/c has since been removed since the weather is getting nicer in AZ.

sensors and manifold worked perfect on the previous owners car (buddy of mine)

only cel I have is o2 sensor and that only comes on during heavy load

when I unplug the IACV it dies

blows smoke in vtec

engine has like 10,000 miles since full rebuild

stuff i have done:
tb has been cleaned
IACV has been cleaned and swapped
valves have been adjusted
timing is right
idle screw has been adjusted
distributor replaced
no vac leaks
spark plugs have been checked
FITV is deleted
coolant is bled
grounds are all good


any ideas before I start throwing more money at it?

my thoughts are replace:
tb/tps
fuel pump
injectors
o2 sensor
get ECU chipped until I can afford a tune

 

Wrong ECU. Why are you running an ECU meant for a SOHC on a DOHC engine? And a modified engine at that?

 

this being true it still ran fine before the manifold and altenator

answer: money... it will be chipped soon

 

check for vacuum leaks at the manifold and the tbody. spray brake cleaner and see if the motor reacts. check the chargin system. make sure it is charging.

and, of course the motor wont run right if you are running of stock ecu. Plus, o2 sensor has alot to do with driveability. Fix that problem first after checking for vacuum leaks

 

no vac leaks.

ill check charging system tonight.

o2 will be deleted on Friday when I send my ECU to phearable.net for chipping.

 

If your IACV is good then you have a vacuum leak. Look harder for the vacuum leak, it is there.

 

would the vacuum leak only be there during the day?

its weird it will run purrrrfect the second the sun goes down.

 

so I now have a Pherable.net chipped ECU and im still having the same issue with my idle...
now that it is really cold out the car barely wants to run at all

any tips?

 

Is this thing tuned? If this thing is not tuned than obviously thats a problem. especially if you delete the o2 sensor. Now the ecu doesnt even know the a/f of the motor. Its running of a guessed map.

And if you are wondering, yes, replacing the intake manifold with change the a/f ratio just like putting a header on.

 

pulled the head and found that 3 pistons were cracked below the top ring and one had a huge chip missing from the top.

I'm blaming bad tune

LESSON LEARNED