Ok, I have a 00 Si and I am having this horrible problem. When I start her up you can smell the gas and she smokes. While I drive she pours out gray to dark gray smoke. Upon acceleration she may sputter but not always. When I decelerate she backfires like crazy. And after I engage VTEC I will get a P1259 (VTEC Malfunction) Code. Oil is full, screen clean, etc. Timing is dead on, fuel pressure is correct brand new NGK plugs.

Here is a list of mods done to the car.
Rebuilt B16a2
Buddy club valves, valve springs and Toda Titanium retainers.
New VTEC lost motion Assembly.
Stock bolt ons other than intake, header, magnaflow cat (5 years old) and exhaust.
Weisco, high comp pistons and eagle rods.
Stock fuel injectors, stock ecu, which is the P2T.
02 Sensors are maybe a year old, but they are denso.

What can cause all of this?? At the same time anyways, lol.
Please help, this is irritating the **** out of me, lol.

 

try changing the dizzy. it may clean up the backfire. why wouldnt you get a tune after rebuilding your block ?? this could be the problem considering your running a stock ecu on a block with a higher compression and im assuming you have aftermarket cams with that valvetrain. i think you should get a tune!!

 

I have stock cams. And when I built the block first I never had this problem. Even after I built the head I did not have the problem. This started happening recently.

 

Replaced the fuel filter, regulator, dist, and rotor. The dist and rotor were trash, lol so I replaced them. Car still smoking. No imput guys? I know one of the ht members is gotta have an answer to my issue, besides a tune.

 

How's the coolant reservoir, are you loosing coolant or is it an off color? You said the timing is correct. You checked both valve and ignition timing? Does the problem get better after the car's warmed up? I'd perform a compression test.

 

I am almost positive that your ringlands are shot. This may be due to the fact that you pretty much built your engine and DID NOT GET A TUNE. Your car is running crazy lean due to the higher compression. This is the dumbest thing to do when investing any amount of money into your engine. Sorry to be the only one to post this bad news. I dont know how anyone else did not say this already. TUNE TUNE TUNE always

 

Since re reading this post, maybe its not the ringlands being the pistons are forged but it could be a cracked sleeve or something of the sort. you need to pull the head to be sure

 

I know I need a tune by I never ever had this problem on this built motor. And the coolant is fine, but it is white smoke, and it actually got worse and I barely drive the car as it is. I put a fell pro head gasket on it when I built the head, which was a dumb mistake. And not to mention I re-used the stock headbolts, so they could have stretched or what not. And a tune isnt really an issue because I have had this built motor for over a year and it never did this, and I never needed a tune. So, trust me, a tune is not my problem. So im replaceing the gasket with an OEM Honda gasket with ARP headstuds. This should fix my issue.