OK, here is the full story, I'll include anything I can think of. I need help big-time. I've got a couple of ideas about what could be wrong, but I want all the imput I can get.

MY SETUP
1998 CIVIC EX
D16Y8
T3 - 60 trim
deltagate at 9psi
intercooled
RC440 injectors
VAFC
P28 with Uberdata
Eagle Rods
CP pistons .020 / 9:1
Stock ignition and everything else

THE SYMPTOMS
I just finished putting the engine back together and installing it about two weeks ago. I then went thru the break-in (mostly) according to the Endyn directions.
Everything is going fine and when I occasionally get happy and rev to far, vtec works fine, everything is cool.

When I first started running the engine I was getting cel 71-74, but I believe that was because the dizzy wasn't tightened down enough - it went away. I was getting map errors (code 3) on the hack on a regular basis, but not with uberdata. It has thrown a few o2 errors (1 and 41), but not recently. It once threw a code 54 which freaked me out, but it never came back. Lastly, I have seen a code 43 (fuel supply) a few times. If I turn the ignition off and back on it goes away and stays away, but it has happened a few times so this one has got me wondering.

FIRST when I finally finish breaking it in I notice there is a slight stumble around 4500 rpms. It only happens when I'm boosting and have the throttle at 100%. Also, it is only noticeable in higher gears (4, 5, well, can't really test it in 5th very well, but I assume it is there). At about 30% throttle or less I can take it all the way to red line ok, altho it does make a quiet high-pitched noise that doesn't really sound like the turbo spooling. But as soon as I floor it, it starts bucking and popping at high revs. I've been driving it and trying different things to fix the issue, but nothing has worked, in fact it has gotten worse. Now, it will stumble at somewhat lower revs (still not reall low, maybe around 3000rpm) and it will stumble in lower gears (2nd, haven't noticed 1st yet) if I take it to redline hard. The popping doesn't really sound like rich backfiring to me, but I could be mistaken. And it doesn't sound like a metallic knock at all, I'm pretty sure about that, but again it IS possible I'm mistaken. I can't rule it out entirely.

ALSO I've got some serious crankcase pressure I'm thinking. I've got a lot of oil from the breather filter on the valve cover.

LASTLY the car seems to have stopped going into VTEC. The light on the vafc stopped changing at least.

WHAT I'VE ALREADY DONE TO TEST
The TPS seems to be working judging from the VAFC display (goes from 0-100% ok)

I tried using my original obdII ecu with the hack, and it didn't change. I tried adding and subtracting fuel in that area using the afc, and it still doesn't change, except that if I add much, it pretty much cuts out completely, like hitting a soft wall in that area of the rev range.

I tried different uberdata maps with the P28, adding and subtracting fuel and spark in that area. Nothing seemed to make much difference. It felt like I was changing the intensity, or rpm of the problem slightly with my changes, but I couldn't change it much or get rid of it entirely.

I clearenced the valves (set lash) first of all since it wouldn't even start and I had no compression. Turns out the shop that did the valvejob didn't set the clearance when they were done. Go figure.

I inspected visually and verified that all of the plugs are getting some spark
I've tried stock plugs and 2-step colder plugs
I've tried gaps from .30 to .40
I visually inspected the wires rotor and cap - all look good.
Checked the resistance of the plug wires - looks good
Plugs have a light bronze/golden cast to them

Disconnected the vafc - no change (not a sloppy wiring or bad afc issue)

Disconnected the O2 - no change

Disconnected intake filter, then exhaust to make sure it was breathing - no change

I may have checked some other things, but that is all I can think of right now.
I've pretty much eliminated the electronics (ecu/vafc) and I'm pretty sure I wired the harness back up correctly when I reinstalled the engine.

Does anyone know what would cause symptoms like mine?


HELP!!!!!!!!!!!!!!!!!

 

the highest you can go with plugs and boost is 30 with a stock ignition. you only need one step colder plugs. it's 1 step colder per every 100hp extra that you add to the motor. it sounds like your car is getting too much gas. how did you route the pcv system? if you have a fucked up pcv valve, the motor is gonna get some pressure in the crankcase. when i got my car tunned it would do that, hesitate or bog when vtech kicked in cause it was way too rich. leaning it out fixed it.

 

when you say the highest you can go is 30 are you referring to the gap? The last thing I tried was gapping them .25 and that didn't help any either. My car is running rich, it runs fine everywhere else, so it isn't cel/dumping fuel rich, but it positively stinks sometimes and it does a lot of popping. I don't think it is bogging when vtec kicks in however, because sometimes it seems to do it when vtec is disabled, or at lower revs than vtec should engage. I dunno, I'll keep that in mind while I keep testing. How do I know if the pcv valve is good? And can anyone tell me where it is located on a d16y8?

 

yeah 30 at the gap i have mine gapped at 28, i step colder.
if it aint bogging above vtec then it's running way rich in
the lower rpms. when you adjust the vafc, you have to set hi-lo throttle position. wide/narrow throttle settings, that ---- has alot of settings. make sure you adjusted it how it says in the manual. and if you have an adjustable fpr and still can't lean it out enough, turn down the fuel pressure via the fpr. it's definately running way rich in the lower rpms. i have vtec set at 4500rpms on my vafc and it rocks as far as reducing spool up time.

 

Actually I'm not even using the vafc now. I had it disconnected entirely until I went out earlier to test vtec some more. Is the pcv valve mounted in the black canister in the back of the block? Because I've got two of them and I can try the other one if I need to. Would it hurt anything if I just pulled the valve out and let it vent?

 

You dont need that afc anyways, if you're using uberdata. Thats just silly.

When you bog out like that do you notice any smoke out the tail end of the car? if so what color?

 

go put a wideband on it and see what it looks like.

 

this is what I'd do first......why work backwards?