So after 2 years, my car finally has a new engine and runs, but I have a very loud exhaust pop coming from the pass side. Doesn't seem to do it at idle, but as soon as i give it any gas, POP! With the cutout open it REALLY sounds like backfire, but not as bad with it closed, but still embarassing! Hesitates and seems to have low power. :eek2:

I degreed the cam upon install...twice, the timing set is dead on, as well as the opti is lined up correctly, and I adjusted the valves with 1/2 turn preload....all of this done on the engine stand before install to make sure was done 100% correct. What to check out for this, spark plug wires? Readjust the valves? Anything else?

It's my day off so I want to go out driving around in this car I haven't driven in 2 years!!! :drive:

 

Do you have it tuned for the cam?

 

Yeah I have a tune from Ion (madz28.com) for the cam, and since using E85, all I tweaked on it was the WOT tables so far. It's only coming from the passenger side, and sounds like unburned fuel igniting in the exhaust.

 

Found it to be cylinder #5 actually. I pulled the injector plugs one at a time until I no longer got a backfire, and #5 is the only injector that, when disconnected, causes the backfire to stop.

So I pulled the plug wire, visually looked fine, went ahead and readjusted the #5 exhaust valve, it was fine, could slightly move it side to side when on the base of cam, but, readjusted anyway. Next, I used a spark tester, clamping one end to the top of the spark plug and the probe in the end of the plug wire, and it made spark while the engine ran (injector unplugged). So I clean up the terminal of the plug boot, reinstall it on the plug, plug the injector back in and....POP!

So now that I have tested spark with a spark tester, readjusted the valves...now what???

 

Have you scanned it for codes and did you look at the plug itself ? Maybe that injector is bad, switch it with another. If that doesn't work and it's still #5, I'd do a compression check on that cylinder.

 

No codes, I'll pull the plug after work today, hopefully it is just fouled out. I'm going to pickup a new plug and set of wires today after work and see if that does it. If not I'll try swapping the injector to another cylinder.

 

We have a winner....and I'm a retard for not noticing it sooner! 5 and 7 were swapped at the opti. However, the #5 plug also was cracked, so that probably didn't help. Running smooth now!

 

wonderful !