tommyb123

ok so i have attacked this problem in many areas for the past year and a half and have gotten nowhere but resolving the ticking that sounded like a valve by putting on a new exhaust. this will be a long forum and im going to apologize in advance because it will be hard to explain in text.

since i baught my evo i have had a huge problem with running very rich. i read hundreds of forums and tried everything that i thought could be it. the only thing that i havent tried is a boost leak test. yes i know that is the first thing i should have done, but i have just never got around to buying or building one because i have days where my car will run perfect with good AFR readings, crazy power that takes me by suprize and then bam back to running rich and sluggish. so i just dont think it has a leak. it will run great when cold but as soon as my car is warmed up it will run very sluggish with a huge decrease in power. higher rpms (3,000 + rpms)have very little pull (basically when turbo builds pressure, - pushing 18 - 20 psi by the way) i had it diagnosed and there was a bad o2 sensor. i thought for sure that was the problem, but nope.

i use to have a BOV that was just atmospheric vented that i pulled off my 94 celica gt coupe. i was still running very rich so i just assumed that it had a bad spring from the celica and read that could be the problem with the CEL i was getting when boosting. so i put a new dual port BOV that vents to atmos. and recirculates. that fixed that problem with the CEL but still running rich.

i put new plugs, 10mm wires, coil packs, MAF sensor, cold air filter, IAC Valve, injector seals, altonator & Battery, 3" cat back exhaust and still running rich. the plugs wires and coil packs made my cars fuel economy a LOT better but still loading up with fuel.
as soon as i build boost my AEM wideband o2 guage tacks straight to 10 then
right to --- from being so ri rich. when i come down to idle my car smells like gas BAD. spits and sputters, about stalls causing the oil light to come on for a send or two then jumps back up to 2k RPM and then idles perfect and the AFR reading will slowely come back down to perfect during that process (14.7)

would an exhaust leak be my problem? i would figure if anything that would make it run more lean. i had put the new exhaust on because the resognator in the center of the car literally blew apart when i spooled full boost. i tried to temporarily fix it but it still came apart. im almost possitive that the exhaust/internal wastegate 2-1 plate (not shure what it is called exactly, it makes my wastegate dump through my exhause) are not stock because the 2-1 deal just looks aftermarket and stainless, and the downpipe has a nut that is welded (professional tack weld) right before the 3" cat delete, which was aslo on the car when i baght it. there wasent anything in it so obviously it was a big exhaust leak. so i put my AEM wideband o2 sensor in that hole and it threaded in perfectly. but when i took it for a run that was when i blew my exhaust apart at the resognator in the center. so i thought my exhaust was clogged post downpipe/cat delete and baught a new cat back exhaust. but that didnt work, i plugged the hole again on the new exhaust (after i drove it unplugged so i could see the difference) and blew out the bottom of two of the brand new gaskets in the center of my car.i have no idea what the problem is. so i run it with nothing in the hole. i know its a pretty good exhaust leak but my car runs like crap with it plugged. also it sounds like my turbo is spooling way to hard for 20 pounds when it is plugged(i do have a boost guage as well in case some one asks), this isnt my first turbo vehicle and i know that it is spooling to hard. my turbo celica had a t3t4 turbo pushing 30 pounds and wasent even that loud.
when i say runs like crap i mean there is absolutely no pull, my old POS cavalier pulled harder lol.

i did some looking today and seen someone say an exhaust leak could cause rich running. which is why i explained the F'd up exhaust situation.

if somone could give me a few pointers that would be great.

llDemonll

iTrader: (21)

do a boost leak test. there's no point in anyone trying to help you troubleshoot until you do this

otherwise:
1. good job using paragraphs
2. get rid of whatever BOV you have on there and get a stock diverter valve or a tial QR or a synapse DV. anything that doesnt vent to atmosphere. venting to atmosphere will make the car run rich
3. your boost gauge is either not hooked up properly or you are brake boosting. if the car is making boost and is in positive vacuum, you will know it. i 100% doubt that you're making 18-20lbs of boost and the car isn't pulling
4. the stalling issue you're talking about is likely due to your BOV. get rid of it and get a proper diverter valve or get tuned on speed density and keep the BOV
5. get a tune

tommyb123

ok so why does my exhaust blow apart and blow gaskets if i seal that hole? something isnt right.
also i have tried a new stock diverter and it ran worse then it does now.

what about plug gap? everyone says something different. there at .027 right now.
i just dont want to spend any more money that i have to since i have blown so much just to not fix my problem. im in the process of making a boost leak test now to see if that is the problem, but that still doesent explain my exhaust problem. i forgot to mention that when i plug the hole my engine is insanely quiet. may be normal, just figured the new cat back would be a little louder especially with the cat delete.

Ev0ikon

iTrader: (18)

gap plugs to 0.020"

tommyb123

alright how big of a difference would that make out of curiosity?

tommyb123

i was lookin for carbon build up and seen a little around the little arm that the wastegate actuator is connected to. would that be considered pre or post boost leak? because from what i know about turbo systems it sounds like i have a post boost leak. i just dont understand why it would effect my car periodically and not all the time. a leak is a leak. and with it being worse when warm then there should be less of a chance of a leak with the expanding process that heat does to most engine parts causing a better seal. i dont know it all im just trying to put common physics into play and still im mind boggled.

llDemonll

iTrader: (21)

you can make an exhaust leak test the same way. just jam the pressurizer in the muffler and power it up. don't need much of a test, 5-10lbs is more than enough

and yes, gap your plugs to .020"