ok I just swaped my b18b in and got it running pretty well. It has a lope in the idle and the valves seem to have a slight tap to them. I am gonna adjust them soon. What are the most probable causes for a loping idle. It also fluctuates a small amount while at idle.

 

Cams. Cams cause a lopey idle. Cams are great! :thumbup:

But seriously, you're probably misfiring. Check your base timing, and while your car is running, pull one plug wire at a time and see what difference it makes. If one of them doesn't make any difference in the way it idles, or less of a difference, that one's misfiring.

 

yeah cams. especially performance cams not tuned right.
is the 18b all original?

 

no the b18 has new rods and pistons and crank. It has be bored over .20 and other then that just cleaned up real good on the inside. I havent put a light on it yet, do you think that could make that much of a difference. Can the timing actually be off by a tooth and still crank?? Good points once again jafro.

 

Yes, and the motor can run if it's a tooth off; but that's valve timing... I was really referring to ignition timing. Put a timing light on the crank and see where it is. Follow your service manual for putting it in time... but if it's got a rough idle and feels like it's misfiring, you're going to have a hell of a time with it.

Once you get the car set to the right idle rpms, it should smooth out. If it's being caused by a misfire, stuck injector, bad valve adjustment, bad throttle body adjustment, clogged throttle body, clogged AICV or wrong valve timing (a tooth off), dead sensor, loose vacuum line or whatever then that actually needs to be fixed first before you mess with setting base ignition timing.

If you unbolt and rotate your distributor, you'll probably find that the idle speed changes, or you might even be able to make it stall altogether. I don't know what your car sounds like when it's idling. Did you try pulling the plug wires 1 at a time (Use a pair of pliers and don't touch the motor or you could make yourself part of the circuit(bad, ouch))?

 

i am gonna work on the car tommorow. So I am gonna check timing with light, adjust valve lash, tighten alternator belt, put washers in my shifter, and rotate my tires. When should I change the oil on the break in for a motor. It doesnt smoke any more and I dont like the metal shavings being in the oil if they dont have to. It has 250 miles on it. Should I change now or wait.

 

sounds goofy, but one thing that will kill your idle is the hose that runs from the bottom of the pcv valve. if it isn't connected back to the box on the back of the block, your idle is going to be chunky as hell... Other than that, Jafro has it pretty well covered.

 

I pulled the wires today just out of curiosity and it seems to make a difference in every cylinder. I dunno, maby I will figure it out soon.

 

That was my first thought, PCV valve. Also might want to see if the IACV is clogged.