i have changed from dpfi to mpfi, now the engine goes up and down. Idle is fine but when i cross 1500 rpm it jumps to 2000 rpm and back to 1500. Engine fluctuates 500 rpm, at anny given rpm

How can i solve this

Jelger

 

Either you have a vaccum leak somewhere or your IACV is bad.

 

First guess: TPS is wired wrong. When converting from DP to MPFI the outside wires on the TPS plug need to be switched.

http://hybrid2.honda-perf.org/tech/4gdxtozc.html

"Be sure to switch green/white and yellow/white wires on TPS"


Second guess:Warm the engine to operating temperature. Disconnect the IACV the engine should be idlng at 700-750 RPM. If not adjust the idle speed using the screw on the top left of the throttle body when viewed from the passengers side of the engine bay. Reconnect the IACV and it should idle smoothly. Most likely it is set too high causing the engine to "hunt" for a stable idle. If this does not work then it is most likely a vacuum leak.

 

if your tach is jumping, also check your ground wires and/or connections. A lifted ground wire can cause numerous problems

 

check a vacum diagram and if thats not it take off throttle body and thier shold be a plastic screw tightn it up and put on your throttle body agian that should help