Idling Issue

[IslandBoy]

Recently i did an engine swapp on my Nissan FWD Sentra, basically stock CA 18 Det converted to FWD , on starting the car it idles fairly ok but after a while @1000 Rpm idle it jumps to 2500Rpm & cycles in between both after the engine temp is hot .i,ve tryed diffrent ECU,S but same result .Can any one ofer some suggestions?

[teddy]

your surging description sounds like a vacuum leak. check all your vacuum hoses to start.

[IslandBoy]

i serously doubt it because whenever i rev the engine it seems to decrease a little & when driving it attempts to want to stall.

[boost_boy]

Recently i did an engine swapp on my Nissan FWD Sentra, basically stock CA 18 Det converted to FWD , on starting the car it idles fairly ok but after a while @1000 Rpm idle it jumps to 2500Rpm & cycles in between both after the engine temp is hot .i,ve tryed diffrent ECU,S but same result .Can any one ofer some suggestions?

Could be, but not limioted to:

Idle air regulator could very well be a vacuum leak in beteen where the butterfly sections are seperated.Could be a bad CAS or bad tooth on the exhaust cam that turns the CAS causing the timing to move around at will.

It could be too many things, but I suggest you get a can of carburetor cleaner and with the engine running, start spraying and checking for leaks.

Dee

[F3600]

try to disconnect the AIC just behind the TPS.

i got mine idling perfect at 850 900 by this way ... if i keep it connected the idle is staying at 1300 1400. Maybe that can help you.

good luck