I'm after swapping a b18c type r motor in to my EK shape civic. I ran the engine with no header and no o2 sensor plugged in and it seemed to run ok, well the idle was fine and the only cel it was throwing was for the o2 sensor. I let it warm up and got air out of the coolant lines and switched the car off till my new ex.manifold gasket came. After putting the header on and connecting up the o2 sensor I started it and it ran ok when cold but after a short run and it had reached operating temp the idle is rough. One second its sitting around 1k rpm and the next it bogs down to like 400-500rpm not far from stalling and keeps repeating that. Any ideas to the cause of the problem? I tried checking the ignition timing but I cant adjust it as when the rev's drop its going back to 0tdc mark. I'm going to try removing the IACV tomorrow and cleaning it...

 

I had the same problem with my b18. Mine turned out to be my thermostat that was causing the idle to hunt around.

 

The actually water thermostat in the housing?

 

Yeah the thermostat in the housing, i was like WTF, that's a first.

 

Ill try changing that for another one I have and see. Another thing I noticed was when I left it and came back to fit new gaskets (engine was cold at this stage) the radiator expansion bottle was empty? and it doesn't seem to be leaking

 

The car was left idle for a couple of months and i also changed fuel pump back to standard pump as there was a up rated pump in it before when it had the turbo engine so could the fuel be gone bad from been left there so long? Should i drain the tank and put new filter in to try solve my idle problem?

 

Ok so another problem has occurred. When the car is hot and driving at below 3-4k rpm some times when you WOT it the car splutters and doesn't want to rev its also back firing through the exhaust. Any help as to solving the problem?

 

Is the CEL ON?

I would start by topping off the radiator with coolant and then bleeding the cooling system.

 

No there is no CEL on. What is the best method to bleed the cooling system?

 

Bleeding the cooling system:

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push the dash heater lever/**** to MAX heat.

3) Follow the directions in the diagram below (skip the bleed bolt step if you don't have one):

 

Thanks for that. Ill give it a try again tomorrow.

 

check your ignition timing again

 

Tried that but can't set it right because the idle is too low. its hovering around the 1st of the 3 marks on the crank pulley

 

Problem turned out to be the idle adjust screw on the throttle body was turned in to tightly not giving it enough idle speed.

 

awesome you fixed it