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Intermittent knocking and misfire only @ temp! D16y8 [solved]
Hey everyone car is a 98 civic coupe, auto to manual swap. Got a new to me Y7 stock bottom end(checked before putting into car), with a Y8 head that got the head decked, valves lapped, BC springs and retainers. Skunk 2 intake mani, 1> year old dizzy, new OEM injectors, OEM oil pump, timing belt/tensioner/water pump, 1320 exhaust manifold, ARP head studs and flywheel bolts, and new Knock sensor, IACV, OEM vtec solenoid. Cometic head gasket kit as well.
problem I’m having is an intermittent knocking on the passenger side of the engine. It goes away past maybe 2k rpm’s? I checked valve lash twice, checked for exhaust leaks, and put my hand on each injector to feel if it was maybe then being noisy. Couldn’t find anything. It seems very odd to me the nature of the noise, sounds like popcorn going off in the top end. I unplugged the vtec solenoid thinking that it was intermittently engaging for some reason, no change. The noise only occurs at temp and is accompanied by a random misfire with the CEL. I ended up taking the rocker arm assembly off because the nature of the noise and location made me think to check that. I checked the cam and caps there is some wear but nothing significant. Swapped the rocker arm assembly from a known good head (the old one, cam cap threads for valve cover bolts cracked, this is why I got a new head and it machined) Nothing my fingernail would catch on at all. Got some LMA’s cleaned them up and let them sit in 10-30W oil for 48 hours as well, noise and misfire is still there. From here I did a compression test had 195 across the board +_5. Everything was done by spec from the FSM, this is my first “major” engine job, I’m lost, any help would be appreciated. And yes the motor is in time. Here’s a link to the noise
re: Intermittent knocking and misfire only @ temp! D16y8 [solved]
Couldn’t work on the car until recently… found out the issue. While it was unnecessary in hindsight, I swapped the rocker arm assembly. Used the same caps but swapped from a known good head. Did this because the head I had machined was new to me and I dunno I guess I just started doubting if it was a good head. Noise persisted after getting back into time.
found that the wire for the oil pressure switch was unpinned internally (if this makes sense). Wire wouldn’t untug from a previous owner gluing it into the connector. Fixed this and still had the noise.
second part to this was the “OEM” vtec solenoid I purchased was a knockoff. Verified from markings on the inside and overall just small differences in it and oem. Luckily when buying my block it came with a spare vtec solenoid on the head that wasn’t trashed and had NO metal shavings in it. Replaced screen and installed. Same noise. Swapped the oil pressure switch and voila! No more noise.
to add my head was spinning around with this issue because I was also battling a p1399 code that was from a bad coil, that ultimately completely failed resulting in no spark. Issues were unrelated but easy to think I had messed up something when building the motor (my first time doing a project of this scale) as well as installing some after market parts which I’ve never done as well (skunk 2 intake and tb, this was its own headache cause I couldn’t remember where all the vac lines went and whatnot). On top of the new to me trans, clutch and flywheel, full exhaust, and all the little ends and pieces, was just a lot going on at once.
Happy to report it’s running great now, compression still 195 +-5 across the board. Still gotta mess with TPS and ignition timing but finally coming to a wrap.
