ka24e engine help

[wasab1z]

So i recently i got a state ref on my sr20det, for illegal emission. So i decide to try to get my 240 back on the road. So i went to go buy a ka24e because my 240 is a 1989. Did the whole engine swap and and now the ka24e is in the 240 and is working, kind of. I try taking it to a smog check to see if there is any problem because when i put a cat on it the engine light turn off, so i thought i would be able to pass smog with it. Then the engine light pop up and when i show him the engine he said, there was a vacuum leak, its misfiring, and that the timing look like it was off by the way the distributor look. I had a friend do the timing and the idling according to the sign on the 240 hood.
So basically my question is that what could possible be causing the misfiring and what step would i do in order to try and find the vacuum leak? like is there a manual or a book to help me? or if i uploaded a video of my car to help you guys get a better picture, please help me its been a year since the state ref.

Also should i just bring it to the state ref or take it to a smog then a state ref?

[StryfeS13]

The timing is off by the way the distributor looks..? I mean, the only thing I get from that is that the distributor is turned all the way to one side to get it to time correctly...right?

If that's the case your chain is off a tooth somewhere.

The misfire can be because it's timed wrong, needs new plugs, plugs arent gapped correctly, wires are old, bad ground, vac leak, loose connection somewhere, bad/worn rotor and/or cap..etc. can be lots of stuff.

[wasab1z]

The timing is off by the way the distributor looks..? I mean, the only thing I get from that is that the distributor is turned all the way to one side to get it to time correctly...right?

If that's the case your chain is off a tooth somewhere.

The misfire can be because it's timed wrong, needs new plugs, plugs arent gapped correctly, wires are old, bad ground, vac leak, loose connection somewhere, bad/worn rotor and/or cap..etc. can be lots of stuff.

Yah exactly, the dude said the timing looks off because its all the way to the right, but the timing on the gun said its right, and if that is the reason why it is misfiring, me changing the timing would make the missifiring stop? but would i still be able to pass smog with an incorrect timming? i think it says on the hood of my car that its 15. So is there a place where i can get that all checked? or a book that i can follow and just sit down with my car and go over it?

[Frank_Jaeger]

Yah exactly, the dude said the timing looks off because its all the way to the right, but the timing on the gun said its right, and if that is the reason why it is misfiring, me changing the timing would make the missifiring stop? but would i still be able to pass smog with an incorrect timming? i think it says on the hood of my car that its 15. So is there a place where i can get that all checked? or a book that i can follow and just sit down with my car and go over it?
Download the FSM for the 89-90 year 240sx.

Get a timing gun to check timing.
Get starter fluid to check for leaks

Mechanical timing could be off, however the distributor could also just be off a tooth.