Hey I have a question for you. My cousin has an 89 prelude that is failing emissions and there is a lottttt of pressure coming from the exhaust. Readings from the emissions test says that it is running really rich which you can tell from the smell.

The guy that did the emissions said that my cousin could come in and he would tell my cousin what the problem is. When he did that, he told my cousin that there was no compression in cylinder 1. Apparently at the time he did a compression test and the readings for that cylinder was around 5psi (yeah sounds like bs already). Also, when he pulled out the spark plug wire to cylinder 1 the engine didnt sound any different but there was a big difference when he did the other 3 cylinders.

Today, we redid the compression test and that guy is a complete moron. When the engine was cold the readings were about 80-100 in all 4 cylinders and about 130 with a cap of oil. We did the test again after driving the car for a bit and allowing it to warm up and all the readings were from 100-105. There is no way this can be low compression specifically in cylinder 1. When you pull out the spark plug wire for cylinder 1 there is not as noticible a difference as the other 3 cylinders but you can tell a difference.

New wires, new plugs, new cap and rotor. Any idea why there is so much back pressure? No codes either

 

are there any CELs? runing rich can be cause by alot of things. Did you check the 02 sensor?

 

Check the cam and ignition timing also.