On my way home from the Dr`s office I noticed a little lack of power climbing the hill next to my house. When I got home the engine was making "putt-putt-putt" noises instead of the normal "HMMMM". Blown seal? Hasn`t been run very hard and I just had this "low mileage JDM motor" installed. 3 grand out the window. Now I have the old motor that stopped because of trash in the fuel to send off to be rebuilt. Hopefully, they can use the old parts. Is there something else that could be causing the problem to the JDM motor?

 

What model RX7?
What mods do you have?
How much boost are you running?

 

The car and engine are `90. The car is a convertible. It has 370 management and sensors. Boost at tge time was stock. I may have over-reved as I was between trucks and couldn`t hear the buzzer, ran fine tho` and got away from the trucks very quickly. Ran good after that (5mi or so) `til I came to the hill, pretty steep, about 3/4 mi long, and was putting down the driveway. I have a long driveway (country) and if I pressed it hard it would go but not quite the same

 

Perform a compression test. There are a lot of used J-spec engines that are junk from the start. Compression tests and thorough inspections are a very good idea before using one in any car.

If the engine was left stock, and all of the S5 TII electronics were used, it may not have blown through any fault of your own. Was the fuel pump upgraded to at least a TII pump also?