My BOV has that too, apparently you're supposed to hook that up to your intercooler piping for a quicker BOV response.

Not completely necessary, but if you aren't using it you should put a cap on it just incase.

Razi wrote:My BOV has that too, apparently you're supposed to hook that up to your intercooler piping for a quicker BOV response.

Not completely necessary, but if you aren't using it you should put a cap on it just incase.

qft...

I have the exact bov, the diaphragm inside could have failed like mine(was having abnormal lag) swapped to my shotty little back up bosch and it picked back up. So I took it apart and found the rubber inside is less than half a mm. And that its a piece of fabric with rubber coating on both sides. I replaced it with just rubber almost 3x thicker... Works better than ever now

I'll put a cap on it. But I don't believe that this is the reason I am having this issue...

Yeah, it shouldn't be causing all these weird issues.

So Razi and I were talking on AIM and believe to have figured out the issue.

I have my VC breather vented to atmosphere, where as it needs to be re-routed into the intake. Hopefully this causes my issue, due to unmetered air.

Replacing it with a breather just makes the intake manifold cleaner, but ONLY will work properly if your running a MAP(manifold absolute pressure) sensor. Otherwise your car will act like it has a huge vacuum leak because of the unmetered air.

Open ur plug gap to .035, swap to a z32 fuel filter, check for air leaks. how close is your maf to the turbo? (should be atleast 12 inches) what is your fuel pressure? (should be 43.5psi with the vacuum line unplugged from the regulator if using an adjustable) what pump do u have? I read somewhere that the stock maf reaches max resolution around 17lbs a min of air. The sr t25 will flow about 24-25lbs a min of air. An safc can help with that by its ability to act as a translator so you can calibrate in an N60 or an N62. The FMU you have can help you correct any under fueling issues and the safc could help (a little) with any over fueling issues, just remember that the more fuel you take away the more timing the ECU will add. If this isnt the setup you intend to keep (which not to be a d!ck but I hope not) then Id recommend grounding the car until you can get a real tune and proper fuel (Walbro 255, Z32tt fuel filter, 550's, N60 or N62 maf and atleast and a rom-tune from someone like Jim Wolf Technology) I had a faqked maf on my CA once and the car acted similar to this. It ran so rich that it continuously fouled the plugs. It idled horrible, ran rough under normal constant throttle and spit and chucked and raised hell at WOT. Im not saying your maf is bad but if something is causing you to run exceptionally rich it can foul plugs in no time and cause some of these very symptoms.

you guys need to lay off the fmu, they are proven reliable. same with the safc. It all depends on who is using what and how that person uses it. guy who has hit 25psi+ on an afc... and runs it currently at 5~10psi(fresh motor with ebay headgasket......sketchy)

However a rom tune is generally the SAFEST option.. but pricey in comarison, my afc and fmu cost less than the equipment to tune myself let alone a "tuned" ecus price...



op go blow through and the vc breather is not an issue..

Routed the line back to my intake, idle issue fixed.

Still has a miss. When I remove ANY spark plug wire, it doesn't seem to make much of a difference on the motor.

Bad wires?

Bad wires or bad plugs. Pull the plugs and look at them. Black is rich, white is lean. Ideally they should be about cardboard tan, maybe a little lighter. FMU + SAFC does work, but rom tune is much better and safer. You have forged rods and forged pistons so obviously you didnt cheap out on the lower deck, dont cheap out on the tune.

I regapped my plugs to .035 like you said. Yeah I know what black/white means lol I know how to read plugs. They look normal, not rich, not lean.

Plugs are good...must be wires?

bad wires will deff make the car run like a butthole.

but plugs are the issue, they are fouled..

The plugs aren't fouled... and I got new wires, and it didnt change a damn thing.

Slight miss at idle, constant miss when held at a steady rpm.

just a quick question.. how is ur timing.. if i remember correctly, hopefully someone will chime on this.. if ur not running a safc or a tuned ecu, u supposed to retart the timing 1 degree for every 5psi of boost????.. or something like that but to hold me on that im not quite sure..

but anyways u need to leave it alone till u get urself a wideband n check ur afr's that may help u solve ur problem...

The timing is at 17 BTDC..

I'm thinking when I installed my new knock sensor, maybe I tightened it too much so it always thinks it's detecting knock, causing it to pull timing when boost hits? Can I unplug it and test it out..?

Car ran fine with new knock sensor before being boosted...

is the ecu throwing a knock code?
no way top test without a piezio thing(spell check lol)

well take the wires back then bro. Next step in the ignition would be the coil

does it kinda hit boost then break up then after you let off its good again till you hit boost? could be blow out

do you have a fuel pressure gauge?

you may need to reapair the fmu if it was used... I had to... I think I made a write up on here. Mine would not increase pressure with boost and over all pressure was way way high.

No. The only code it is throwing is 35, EGR temperature sensor...cause I don't have an EGR.
I have no clue what a piezio thing is lol.

I'll keep the wires, my old one's needed replacing anyway.

It kinda hits boost yeah...but when it reaches full spool it just dies down, and doesnt do anything else. The car does nothing.

I don't have a fuel pressure gauge.

The FMU is brand new from Jegs.

Spark plugs are NGK Iridium BKR6E gapped @ .035. Maybe I need copper plugs...?

Even while going slowly down my driveway in reverse my car is missing. It misses at idle, and misses whenever it's at a constant RPM. When driving slowly like 5 - 10 MPH it feels like i'm towing and anchor, and when boost hits, it's like it cuts spark or fuel..like the car stops, it does nothing.

I have changed the cap, rotor, plugs, wires, fuel filter, fuel injector o-rings, etc. Possibly a bad coil? I never had this problem when I was N/A. Maybe my N/A setup wasn't as demanding for spark as my T25 setup...?

I can't even drive it that's how bad it misses. I have to keep it on manually (rev it) when coming to a stop, and eventually after a while it gets so bad that it'll turn off and have a hard time starting/idling.

Sort of does this...but worse. I can't drive my car on the road like in the video, it'd die.

http://www.youtube.com/watch?v=_vAYf9J-4OU

Check the compression for me real quick.

Some pics of the engine bay/ic/maf/bov setup may help as well.

sounds like it could be blow out, coil might need a refresh, do the hotwire mod and see if it help(if it helps and doesnt fix it then the coil could be going) ka coils are generally a decent coil however it still a wear item.
well the fmu ~should be good~

try to drive it out of boost to 4.5k rpm(then get on it till 5.5k) if it hits vtech it could be the cts or knock sensor, on 12lbs I picked up like 50whp from bad knock sensor wiring... and that was a safe estimate.

the motor ran fine n/a and now it doesnt like boost. sounds like hes descibing a fueling problem. bad coil could cause some of his symptoms but the miss at idle sounds like it could be way rich and running out of steam at wot sounds like its leaning out. i think the stock maf is just freaking out for some reason. you could deff try another maf but im not entirely sure that will help. a turbocharged car will have a slightly more accelerated air stream passing thru the maf into the turbo. at idle your ecu thinks that your on the gas a little bit and as the turbo begins to make boost the maf is reaching max resolution and youre running outta gas. the fuel tables in the ecu of a factory turbo engine are programmed to see the faster air steam passing thru the maf at idle and can then correct it and of coarse has enough resolution to meter the intake air steam when on the gas at wot. i myself have never seen a ka run proper on all stock electronics when turbocharged. i know of many that have been boosted and run flawless on rom tunes with a larger maf. i could be wrong and there may be many that run great on stock electronics but none ive seen myself.

WDRacing wrote:Check the compression for me real quick.

135, 145, 140, 135

biggie wrote:Some pics of the engine bay/ic/maf/bov setup may help as well.

Here ya go...

neverlift wrote:sounds like it could be blow out, coil might need a refresh, do the hotwire mod and see if it help(if it helps and doesnt fix it then the coil could be going) ka coils are generally a decent coil however it still a wear item.
well the fmu ~should be good~

try to drive it out of boost to 4.5k rpm(then get on it till 5.5k) if it hits vtech it could be the cts or knock sensor, on 12lbs I picked up like 50whp from bad knock sensor wiring... and that was a safe estimate.

Tried a friends known working coil. No difference. Found a loose ground, tightened it. Cleaned up ALL grounds. No difference.

Doesn't go into boost using the method you just described. I changed out the CTS and the knock sensor is brand new.

s13drifter88 wrote:the motor ran fine n/a and now it doesnt like boost. sounds like hes descibing a fueling problem. bad coil could cause some of his symptoms but the miss at idle sounds like it could be way rich and running out of steam at wot sounds like its leaning out. i think the stock maf is just freaking out for some reason. you could deff try another maf but im not entirely sure that will help. a turbocharged car will have a slightly more accelerated air stream passing thru the maf into the turbo. at idle your ecu thinks that your on the gas a little bit and as the turbo begins to make boost the maf is reaching max resolution and youre running outta gas. the fuel tables in the ecu of a factory turbo engine are programmed to see the faster air steam passing thru the maf at idle and can then correct it and of coarse has enough resolution to meter the intake air steam when on the gas at wot. i myself have never seen a ka run proper on all stock electronics when turbocharged. i know of many that have been boosted and run flawless on rom tunes with a larger maf. i could be wrong and there may be many that run great on stock electronics but none ive seen myself.

Coil is good. I tried a friends maf, no difference.


I disconnected the wastegate actuator arm from the turbo. Now when I floor it, it does go. It doesnt break up or anything, but of course it's at like 1 PSI with the actuator off. It STILL misses at idle...

I also pressure tested it again, and found a leak at the blow off valve flange. Fixed that. I also found that my fuel pressure regulator leaked during the pressure test...not from the vacuum line but like from the regulator itself. (These tests were at 20 PSI....my car only runs 7...)

FPR leaking is no good. Would get an inline FP gauge to be sure.

Also I never messed with open atmosphere bov with draw through maf, but can't be helping.

Yeah, I'd recirc it.
People run into bogging problems with an open atmo bov with a draw through maf setup, but you should still be able to idle.

Do Greddy BOVs stay open during idle?

I'd also fix or replace the leak at the FPR. If it leaks at positive 20 psi, it probably leaks at negative 20 psi during idle.

The usual problem people have with an open atmo. bov on a maf car is the car will stall coming to a stop,(usually after being hard on the throttle, letting off, and putting in the clutch), not bogging, unless the bov is sticking open.(witch it doesn't seem to be doing)

BOV is not stuck open. And yes it does want to stall when coming to a stop...(like 450 RPMS) but it doesn't stall, it catches itself.

FPR definitely needs replacing.

Also, how well does your filter adapter line up with the MAF "hole"?

I have a spare, will replace tomorrow.

Lines up perfectly.

Here's a video. You can tell when it screws up cause it will stutter/bog/etc and then blow off.

http://www.youtube.com/watch?v=WaNMczoXBq8

everything youre describing spells electronics to me man. it sounds like to much push water down low and running out on top. if u want to try a cheap right now solution you could get an safc and an n60 maf and pigtail from a junkyard. select hot wire type sensor, set sensor number at 2 in 7 out, low throttle at 10% and high throttle at 30% and go from there. pull fuel down low and try to add up top. start with just adding fuel about 4k add 10% across the board and see what happens. if it makes a few lbs then you know ur on the right track. down low you can pull a little fuel and see if that helps with the miss by subtracting a little fuel. pull 15% at 1k and 7% at 2k just to get u started. see where u get from there. the safc also has a decel air feature so thatll help with any off throttle stalling. for a ka-t, id recomend retarding your timing to about 13-14 degrees as well