KA-T Won't go into boost?

[StryfeS13]

KA24DE
T25
FMIC
6:1 FMU (temporary till tune)

My problem is that my car will not go into boost. The perfect way to explain this is it feels like the speed limiter that happens when you top out a 240SX in it's stock form. Hopefully that makes sense. When boost kicks in at full throttle it falls on it's face, like vrooooom ---> boost kicks in ----> bwahhh bog stutter, etc.

Things I have done so far:

-Made a boost leak tester today. Found a leak at the outlet of the turbo, and a leak on the cold pipe where it branches off to the idle-air. Fixed both.

-Removed and cleaned injectors, put new seals on them

-Tried removing the air filter, possibly not letting the turbo flow...

-Changed my fuel filter

-As stated before, I fixed all boost leaks. I pressurized the system to 20+ PSI and no leaks were present.

Did NOT solve my issue whatsoever. It still won't go into boost, feels like it hits a wall when boost kicks in.

And now my car doesn't want to idle at ALL.

EDIT: Forgot to mention spark plugs are NGK BKR6E gapped @ .028, and I also put in a new cap and rotor.

[StryfeS13]

Possibly this.....? I have a knockoff bov (it's not stuck open) and it's a Greddy replica, maybe this is my problem? IDK I'm out of ideas...

http://i54.tinypic.com/eiob4o.jpg

[StryfeS13]

Figured it out I think.

My VC breather is vented to atmosphere...no hose on it or anything just the little pipe. (Didn't think anything of it)

SO, BEFORE I fixed my boost leaks my idle was fine, because the boost leaks caused the idle to raise. But obviously it wouldn't boost because the VC breather is sucking in un metered air.

but AFTER I fixed my boost leaks, the idle was shit, because obviously the VC breather is disconnected and un metered air is being sucked in.

So I need to router my VC breather to my intake...

I HOPE this is it.

[smbonn2005]

Think about this for a second.... How would air get into the combustion chamber through the valve cover? Thats not your problem, and normally you want VC breather vented anyways.

[StryfeS13]

I read this on KA-T. This is my exact problem.

Quick question while i was idling, i pulled the valve cover line thats routed to my turbo inlet pipe and it sounds like it starts dieing is that normal? From the setups i saw people dont run the valve cover to atmosphere with a breather filter. How are you guys able to do that with out irratic engine idle...I read this on NICOclub, which makes me think this is definitely my problem.

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.I read this on 240SXForums.com

thats your problem right there.

the breather.... the intake manifold sucks air straight through the crank case and if you dont have counted air goin through there, it will run way off.

you have to put a 5/8" hose from the valve cover to a port on your intake AFTER the MAF.

sounds like your BOV is too stiff or hooked up incorrectly.I'm pretty sure this is my issue.


What the VC breather does (to my understanding) is suck in air, goes through the engine, into the PCV system, and back into the manifold and being burnt. So, if the MAF detects a certain amount of air being drawn in, tells the ECU, and then the VC breather is sucking in un metered air, I'd imagine it'd cause a problem..

Have you ever pulled the VC breather off a KA when it's on a normal MAF setup? (Not MAP/Blow thru/tuned around it, etc) The whole car stumbles and the idle goes ba da dum ba da dum ba da dum...and when you plug it back in or block it off it runs normal....I never even thought of this when i installed my turbo parts and I really hope it's my problem.

[waxball88]

I'm not sure if that is your problem, its always good to have the engine set-up in its original form(as close as possible) when boosting to relieve crank case pressure (yes you can argue the shit out of this if you want) Best way to do it is route the VC breather to a catch can, and back to the intake post MAF to avoid getting oil in the intake/turbo/ic pipes/etc.

I ran a t3 setup on my ka-t and i left the VC venting to atmosphere with a small filter and never experienced any negative side effects.

[xxoreolovexx]

check you timing. if its too retarded you wont build boost.

[ChiSleepyEyes]

happened to me with my sr, check your injectors

[StryfeS13]

It's not too retarded. It's @ 17 BTDC. It's not my injectors, I took them out and cleaned them, tested them etc.

When I re routed the VC breather to the intake it fixed my IDLE issue. But it still won't go into boost...at all. It misses at idle, and misses like crazy while driving.

[StryfeS13]

Please keep in mind that the car was running perfect before the turbo install.

[nismoman]

What plugs are you running and what gap. Also check your ignition coil

[codyace]

Possibly this.....? I have a knockoff bov (it's not stuck open) and it's a Greddy replica, maybe this is my problem? IDK I'm out of ideas...

You want to leave that smaller lower port open, and to only use the top (as you have it setup). HOWEVER I would look into not T-ing into the FPR line...try your best to keep all source lines seperate from each other.

and normally you want VC breather vented anyways.

You most certainly do not want it vented. That's the 'worst' PCV/Evap setup you could ever run.

[unseen-forces98]

Do u think it can be the turbo actuator?

[StryfeS13]

@ Nismoman, I'm running NGK BKR6E plugs @ .035. I have tried .032, .028, and .025. Nothing fixed the issue. I also have a new rotor, new cap, new wires, and I'm not sure how to test the coil, let me search.

@ unseen-forces, I doubt it, I can move it by hand...it's not seized or anything.

It misses at idle, and misses when you hold it at a constant RPM. When you're normally driving around even slowly, it feels like it is towing an anchor. I have tried to disconnect the TPS, no difference. I adjusted the TPS per FSM specs, and the MAF is not the issue either.

I can unplug each fuel injector one at a time and hear a cylinder drop accordinly, until I plug it back in, so I think injectors are good. I have also taken them out and cleaned them and inserted new seals. It has a new fuel filter as well. No boost leaks, no vacuum leaks. Slight exhaust leak where the downpipe meets the cat, but I know that that is not causing this.

[codyace]

What injectors are in it

[hektik13]

im having the same issue, car runs god but doesnt boost... runs like stock minus boost

[StryfeS13]

What injectors are in it

Stock 270CC. Remember I'm on an FMU setup.

I think it might be the coil.

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.

-New spark plug copper core wires
-New NGK spark plugs gapped @ .035 (I've tried .028, .025, .032, everything feels the same..it's low boost)
-New rotor
-New cap
-New fuel filter
-NO boost leaks WHATSOEVER
-etc etc etc.

This is sort of what it does.... http://www.youtube.com/watch?v=_vAYf9J-4OU

but worse.

[codyace]

So the only thing you did, was install the turbo and intercooler pipes...stock ECU and all sensors correct? No difference in MAF location or anything like that?


A crappy coil or distributor could be the cause...I mean it's hard to tell without a video of your own with the issue. Spark could certianly be an issue. How do you the plugs look? Are they all black and full of fuel?

[waxball88]

For troubleshooting's sake, what fuel pump are you running?

[anarchyperf]

Do you have a wideband and can you confirm your tune was at least somewhere close? Checking the plugs would be a good indicator. Try unplugging your maf and see if it idles better. If not then maybe time for a compression test to see if you did any damage while trying to boost it.

[StryfeS13]

So the only thing you did, was install the turbo and intercooler pipes...stock ECU and all sensors correct? No difference in MAF location or anything like that?


A crappy coil or distributor could be the cause...I mean it's hard to tell without a video of your own with the issue. Spark could certianly be an issue. How do you the plugs look? Are they all black and full of fuel?

Correct.

I tried a friends coil and wires...no difference. Plugs look fine.

For troubleshooting's sake, what fuel pump are you running?

Stock. Will upgrade to walbro soon enough.

Do you have a wideband and can you confirm your tune was at least somewhere close? Checking the plugs would be a good indicator. Try unplugging your maf and see if it idles better. If not then maybe time for a compression test to see if you did any damage while trying to boost it.

No wideband as of yet. Already have been checking the plugs constantly, not lean, not too rich. I have unplugged the maf, it falls on it's face. The MAF is good.

Compression is 135, 140, 145, 135. 8:6.1 Supertech pistons.

--------------------------------------

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 only 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...)

Here are some pictures...maybe something's wrong?


http://i54.tinypic.com/15gp7io.jpg
http://i53.tinypic.com/332100h.jpg
http://i55.tinypic.com/2qm22yr.jpg
http://i52.tinypic.com/2ps3daf.jpg

AND a video: Listen before it hits boost...it stutters and the when you release the gas the blow off blows off.

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

[anarchyperf]

Fuel pressure set properly? Perhaps it's time for a new regulator if it's leaking.

[codyace]

First plug looks awfully rich. I can say from prior experience with big pressure rising rates (yo u said yours is 6:1) on older mustang setups, they do drive awfully crappy without tune. Soon as your car sees a lb of bosot it's dumping in 6 more psi of base fuel, 2 psi 12 more psi, etc etc. That's a ton of fuel to not compensate for.

How's it drive with the stock FPR?

EDIT: Does the BOV actually work? I know you mentioned it's a knock off...if it's pushing open under the slight boost, it's going to be SUPER SUPER rich and misfire like your car seems too.

[StryfeS13]

Fuel pressure set properly? Perhaps it's time for a new regulator if it's leaking.

I replaced the regulator...and it still leaks @ 20 PSI during the test. WTF

First plug looks awfully rich. I can say from prior experience with big pressure rising rates (yo u said yours is 6:1) on older mustang setups, they do drive awfully crappy without tune. Soon as your car sees a lb of bosot it's dumping in 6 more psi of base fuel, 2 psi 12 more psi, etc etc. That's a ton of fuel to not compensate for.

How's it drive with the stock FPR?

EDIT: Does the BOV actually work? I know you mentioned it's a knock off...if it's pushing open under the slight boost, it's going to be SUPER SUPER rich and misfire like your car seems too.

The plugs were like that even before the FMU.

Well I'm not sure how it drives the stock FPR, seeing as my car doesn't really drive...Lol. But before boost it ran fine with the stock FPR.

Yes the BOV works. It doesn't blow out any air during idle or anything. Only pops off when it boosts...like a normal BOV. like vroooom psh.




I've tried everything. fucking EVERYTHING.

Today I cleaned my maf, checked all grounds, replaced the FPR (the new one still leaks.....maybe there's a relief?), tested CTS for proper resistance, tested injectors for proper resistance, etc.

It wants to go in boost when the car is cold(still doesnt go at WOT but seems to be better)...and seems to run better when it is cold. The second it warms up it dies when I stop, and doesn't go into boost at WOT.

Found another leak today, at the throttle body...not even at the gasket, at the spring assembly thing. I'm sure that's not my damn problem anyway.

Shoulda went SR.

[codyace]

If anything at least you're going about trying to fix the damn issue! Better than most guys on here asking for help! Props for that!

TO me, I'd return things slowly back to stock to see where the issue is. That FPR would be the first thing I return to stock. We've turboed bone stock thigns and never had an issue, so long as the pipes are 'essentially' leak free.

The Non reciculated Blow off valve doesn't help either, but it's not going to cause it to break up like that in boost.

[StryfeS13]

Yeah...whenever I have issues I always search first, try out what I learned, and when I can't figure it out I post.

I think there is some confusion. I AM using the stock FPR. But it was leaking, so I replaced it with another stock FPR, that is ALSO leaking!! See picture. (picture is of an SR20 but you get the point..)

I have an SR20 FPR, so hopefully that will work. I know that the KA/SR FPR'S are both 1:1

Also, I decided to try to floor my car when the motor was cold, and it seemed ALOT better, but still broke up like crazy. It got further up the RPM range though, and had a decent idle. I thought it might be the CTS, so I tested the resistance and it was perfect. For peace of mind, I removed my CTS, and put it in warm water, and the resistance changed accordingly.

(the FPR is leaking air, not fuel) and it only noticeable if I spray soapy water on it, when the system is pressurized to 20 PSI during boost leak testing)

http://i56.tinypic.com/2zg7us6.jpg

[codyace]

Ah, I have seen some stock ones (altima is the same FPR as well) do that :( Nismo ones dont' seem to have this issue though so if you find a non leaking one, at leat you know the Nismo won't leak hehe.

Cold start certainly had more fuel and timing dumped in to help warm it up quicker as well.

How's it run without the 6:1 fmu on there?

[StryfeS13]

So they aren't supposed to leak there at all, lol?

If it had more fuel and timing, why would it seem better, since it already runs too rich anyway...

It runs the same without the 6:1 FMU. No difference at all.

Picked up some BKR6E copper plugs today, I'll try those.

[anarchyperf]

Yea try the new plugs... I have this hunch it'll idle a lot better... What are you going to be using to tune the car?

[StryfeS13]

So I changed the FPR, put in the new plugs, and screwed with the dizzy for a while and...

Good news....it goes into boost.

Bad news:

-Seems a little hesitant still. (spark gap maybe???)
-The old plugs were lean-ish on the tip, but PITCH BLACK everywhere else
-The turbo sounds as if it's on it's way out, which it never did before.

Anyone know how to fix the hesitation that is still present?

EDIT: I believe the turbo sound is due to a loose gasket where the downpipe connects to the turbo elbow, working as the *blowing on a wrapper* effect...hope you know what I'm talking about.

[waxball88]

Try and drive the car at a consistent rpm. If you experience a lot of hesitation/jerking i would really start looking into the fuel pump. If it isn't feeding consistently it could cause odd symptoms from when it IS working properly and when it ISN'T working properly. Making you chase other problems. Test fuel pressure/consistency.

[StryfeS13]

Update...

Tried BKR7E plugs..gapped them lower hopefully to prevent the hesitation I'm having.... No luck.

Tried timing @ 13,15,17, and 20. No luck.

It doesn't go into boost smoothly...I have to go 1/2 throttle up to 4Kish, then floor it, and it'll go.

Still misses when driving slowly, misses slightly at idle as well.

Slowly losing patience, I'm out of ideas. All turbo stuff is being pulled off tomorrow, and the car is being returned to stock. I have a job and college to worry about, I can't be hitching rides for the rest of my life, lol.

[hektik13]

any update on the problems u having?

[StryfeS13]

Yeah. I couldn't figure it out so I took it all off and now it runs mint.

[hektik13]

i was going say did u have compression surge from the turbo? also where or how did u make/get that coupler from the turbo inlet cuz i see in ur pics u have the wastegate line hooked up into it

[StryfeS13]

No not really. I had the BOV too tight so it had surge. With the BOV at a good setting it wouldn't surge.

You can make your own coupler like mine by getting a KwikTap over at ATPTurbo dot com.

[xxoreolovexx]

personally bro i would just save some pennies and get a walbro and a rom tune. I read your entire thread and I had the same issue. It turned out to be because my stock ecu was trying to pull out waaaaay too much timing when i tried to boost. As soon as I got an enthalpy tune and a walbro everything went away. Now on my KA-T im using n62 maf, gt2871r .86, And STI yellow top 550's. She boosts perfect and runs great. I had your exact same issue the only thing i was able to do was advance the timing to *25 and the ecu would drop me back down so it would boost but it was running a little rich still but would boost. is just my .02