head swap on preulde question

[Tdub90]

i helped my friend swap a b21 head on his b20a motor. the b20a head snapped a cam shaft on previous owner. anyway we timed the motor correctly. put the new head back correctly. connected every plug and ground. started it up and it revs to high heaven. which is about 5000 rpm. i forget what we did but now its idleing at 4000 rpm. has anyone had this problem??? its a 91 prelude with 4 wheel steering

[mozzandherb]

moved: please post in the right section. Thanks

[Tdub90]

sorry about that i figured since it wasnt a cb7 related question. it would be off topic. thanks

[thepowderblue]

Is should have ben posted in swaps or technical.

[coupes]

Try adjusting the throttle cable.

[lx93f22a6]

check for a vacuum leak. something might have been overlooked or forgoten in the swap.

[PR CB7]

if its idling at 4k, its got a huge vacuum leak

check, your idle sensors to see if they're loose or stuck open
this engine has IABS too, so check the spacer between the manifold and plenum, for any leaks

use a water hose if you cant find the leak spray water around the manifold, and hear where the idle goes down, and hear a sucking sound

try not to use too much water, being that this big of a leak and water going through it could damage the engine

[deevergote]

Actually, this WOULD be Off Topic, since it doesn't pertain to the CB7. Even better, it should go in the Other Automotive Tech/Performance section. However, you need 30 posts to post it there.

Since you have 29 posts, Tdub90, I'm going to move it to that section. When you get one more post, you'll be able to reply to it.


However, very few people on here know about the B20 and B21... they are very uncommon motors (specific to the 3rd gen Prelude only), and they have nothing at all to do with the motors we are familiar with on here!