So hoping this might be normal. We just swaped in a jdm B18C from a 96 type r. Had it running in the shop to flush the coolant and notice most of the time when you give it a rev it will backfire. Most of the time its just a little pop but sometimes its a good little snap. The old motor didnt do this but it was a 92 B17A1 motor. The old old motor had a much lower compression ratio. So i was leaning towards it and being about 5PSI high on fuel presure.

Only things mods are the adjustable fuel presure regulator. About 5PSI high right now. Skunk2 ALPHA header, open exhaust with a thrush muffler, and a MSD ditributor. And all of this was on the old motor.

I didnt check the timing yet, plan to. But the old ditributor was set in the middle so i set the MSD one in the middle. Starts fine. Runs fine. Just pops and snaps. A/F gauge shows around 13 at idle and 12 under load. Also the gas in the car should be 99 Octain.

 

B18B from a type r?
ECU the same as the B17?
swapping out stock components and no tuning?
Might be a good idea to take it and have it tuned at a shop.

 

The 96' ITR was powered by a B18C, not B.

Like said above, you need a good tune. You won't be able to run it properly with a B17 map.

 

LOL. I messed that one up. Its a B18C. And running on the 96 ITR ECU. All came from Hmotorsonline.com Only part that was switched was the harness. Its a 95 delsol VTEC (B16A) harness. We are using RyWire Alt, dist, ecu and injector jumpers.

 

Ok still sounds like you need to tune it.

 

I will check the timing this weekend and turn the fuel down to wear it should be. Really hoping that will solve it. The hole reason we went with the type R setup was because we didn't need to tune the car. Lol. I know we have the wrong temp plug in but that shouldn't cause this. We have a factory NGK #6. I ordered #7 temp plugs today from honda.

Thanks for the help thou. Don't want to burn-up the motor first weekend.

 

Double Check Timing yes, but before you do that:
Let the car idle and listen to the exhaust for a "putter." Sometimes you can even put a piece of paper over the exhaust and see if the exhaust ever sucks the paper in. after that, I recommend you double check the continuity of your Spark Wires and ensure they are completely connected to the Spark Plugs. If there aren't any issues there then inspect (check for oil, excessive black soot, any damage) your spark plugs make sure one of them isn't fouled. Best way to narrow this down is run the car with the hood up and bring up the rpms and see if you can narrow which cylinder the backfire is coming from.
If the car idles with no problems but bring up the RPMs creates the issue then it may be fuel related.