Hey guys, I put a fresh B20 from hmotorsonline into my 1994 Integra. It ran GREAT for about 600 miles, but the fuel injectors I put on it were from my old B16 civic and apparently they were leaking badly when the engine was off, bleeding excess fuel pressure directly into the cylinders and past the rings into the oil. I changed oil, put new injectors on, blew the extra fuel out, and tried to start it. It backfired HARD through the intake and snapped a rocker arm on one of the intake valves on cylinder 2. At this point in time it also jumped time a tooth on the intake cam AND started up all at once. It ran ok minus one valve but it was ticking pretty bad so I pulled the v/c and saw the broken rocker immediately. Luckily it wedged itself into an oil return hole and was out of the way of the valve springs etc. The cam was a little scratched, but not on the peak of the lobe. So I replaced the rocker and reset timing and now it runs great when you're driving it, but it misses/pops/crackles a LOT at idle once it's warmed up.

I don't have a leak-down tester :-( but compression on all cylinders is consistent and good. Multiple tests reveal around 180-190psi in all cylinders on a cold engine. The engine doesn't backfire or seem down on power at all while driving either....it's only at idle. I am really wondering if the valve or valve seat was bent or damaged when it backfired? Or did it blow out a section of the intake gasket? It sounds great and runs fine down the road though.... what do you guys think?

 

Pics? Never heard of all that happening just from a backfire

 

What would you like a picture of? I can take a video of the car running, but I'm not sure how to post it up here. You can only hear the popping from the exhaust...it's not quite a backfire, but quite a bit of popping and misfiring on at least one cylinder once she's warmed up.

 

re check your timing. one timing tooth can equate for a BIG difference in timing. and replace the intake gasket. most times when these little motors blow a flame, it burns the intake somewhat. after that throw some seafoam into it via booster hose and let idle again. gl man