Can someone tell me what can cause this to happen. The motor is a b18a1 we just swapped it into my friends 98 civic ex but it isn't running right.

 

Look up what code the ecu is giving you..

then check said sensor.

my guess.. code 14. IVAC on the back of the intake.. ?

 

every time ive seen that happen, it has been distributor related. sometimes ist a faulty sensor in the dizzy, sometimes, its the wiring. id make sure there are no shorts in the wiring first, and then find a friend that has a good dizzy and try it and see if the problem goes away. if it does, u need a new one, or rebuild the one you have, which is not so easy most of the time.

 

Are you using the stock harness? That car is wired for vtec stock and your putting a non vtec motor in. You using full a1 w/stock harness or what?

 

Another thing to check is your cam gear timing. Make sure nothing is off, even by one tooth.

 

wow theres alot of non running LS swaps aren't there? ok, you can't use an obd2 harness on a B18A1 or B1. take it off, sell it buy yourself a B18B1 engine wire harness.if you don't already have an Obd1 PR4 ECU you will need that. that should fix any problems.

 

disregard this above advice.
You use the harness that came with the car and modify it appropriately.

But yeah, what ECU are you using now?

 

He's right, modifying your stock harness is the easiest way to go. Get the correct ecu and your car will be fine.

 

check ur plugs going on to the fuel injectors and see if they are loose, mine was just barley touching and it would do the same thing i couldnt rev it past 3500