I am going to try and sum everything up the best I can so bear with me!
Turbo kit is in, running low boost, IAP kit (pics and all will be up soon enough)…sortin the bugs out first.
Car starts and idles great. Vacuum is 18 steady idling, around 20 cruising. Idle set to around 950 RPM, and the car holds idle well, except for below issues. Greddy RS BOV, recirculated, set at medium hardness, but hard enough for compressor surge only (haven’t set it to release at 4-5 PSI yet). T3/T4 turbo. EGR system is totally intact. Car feels very good, smooth, fast and everything except for the following…just throw any suggestions you may have:
– Once driving the car has started, on occasion around 2,000-3000 RPM cruising I get a random bog that lasts about 1 second, somewhat pulls the car back and AF (narrow) goes lean for sec too
– Again once driving, only when warmed up, coming to a stop the car will either idle okay or try to completely and quickly die out…not like an idle-dip, but more like it may be related to the above bog…not sure. So even with a recirc’d BOV I need to continuously use the gas to keep the car alive at lights… :? So basically I hold 2,000 RPMs steady on the gas then suddenly it dips/bogs to 1,000 or so and goes back up, often repeatedly. Again, usually after car is warmed up and moreso after a bit of more spirited driving…if I let it idle, it either sits happily at about 950-1000 RPM or repeatedly tries to die out.
I haven’t gapped the plugs yet also FYI (I will)…but at higher RPM/under boost things are okay…could that still be the issue during this lower-RPM area?
Can you guys throw me any ideas/experiences please…because I have a feeling this is caused by one thing that isn’t right…
on an airflow based system you measure the air once, and fire injectors accordingly, however with a recirc you force high pressure air back into the intake
-----> you don’t meter it and you go quickly lean when you re-apply throttle
-----> you could be blowing air backwards through the afm causing it to re-meter the air and going rich at the same time blowing away some of your fresh air which now has to turn around and come back in
It may well be BOV related, and i’m going to look testing the adjustment screws tightness…but the thing is my BOV is NOT recirc’ing any air yet, it’s too tight. The way I see it, in my case, the only way the BOV could be an issue is if it’s leaking at idle. Also, recirculating is done to prevent metered air loss, thus generally making things run better, not worse.
And RyanCRX don’t worry, big writeup and lots of photos coming! I’d like to get all of the initial issues out of the way first if at all possible.
Also, recirculating is done to prevent metered air loss, thus generally making things run better, not worse.
metering air causes the ecu to react with more fuel, how long do you think it will keep adding fuel if it isn’t metering more air yet the air is there?
thats how you run quick lean, I advise against recirc on afm based, but not map based injection
there’s another aspect to staying rich by venting, when you are boosting and up-shifting quickly, that momentary surge of fuel helps keep you from losing power when you mash the go pedal after the shift, which is a good thing, the downside is when down-shifting but who really cares about that
compressor surge will also fuck up your idle, not just air. any unsmooth flow through the flow sensor will screw it up and cause the car to run shit for a sec. Loosen your bov and give it a stronger vaccum signal. Like posted above make sure you aren’t remeasuring the recirc’d air (before turbo after flow sensor)
about the bog, i’ve found this to happen sometimes as well. its often spark (check your wires/plugs/rotor cap).
if you miss your o2 will show lean, as it is 100% air, there is fuel ther but it is unburnt, so the o2 wont pick it up. I’m pretty sure about that anyways.
Either way, after such a big mod you’ll be looking for little things that are wrong so make sure the problem hasn’t been there for a while!
i’m not positive the ka’s ecu’s work like the rb’s But if the ecu hasn’t been reset in my rb for example, and i add a different turbo, exhuast and frontmount, the ecu will be trying to learn and adapt to the new setup and is ecentially having a “heart attack” trying to cope. I had a bog issue becasue of this for a solid 2 days after i started to fill up with 94instead of the “race gas” in the old s13.
The IAP stage 1 kit comes with the high-pressure Walbro 255 pump (or FMU, they recommend just the fuel pump and colder plugs), and i’ve got the Z32 filter and Ultra 94 gasoline. Marc from IAP swears just the pump being good to 7 PSI max (dyno’d to redline slightly rich), and i’m running 5-6 or so at the moment. I have an FMU handy as well just in case but it’s not in the car. I may even end up with 370’s and SAFC depending but for now what I have suits my needs and indeed shows rich (narrow though) all the way through.
But anyways back to the issue, I think Sasha might be right about it being caused by compressor surge or BOV settings…we routed the lines so the wastegate had it’s own line and the BOV read from the intake manifold, helped prevent a lot of stalling, but issue still occurs quite frequently.
Car’s throttle is really touchy also, I’m going to try adjusting the TPS’s sensitivity a little as well.
Car idles PERFECTLY, and warms up perfectly, but once having been driven it starts the random dipping/stalling, no matter how low the RPM is when clutching in.
So we’re going to reset the ECU overnight, and let the new O2 sensor and everything set in. Then, adjust BOV and play around with it a little, as there is currently a mix of surge and air releasing.
I want to add, that on boost, the car is AMAZING, like really smooth and really quite fast (yay for 11lb flywheel and equal-length manifolds!). But i’ll add all my comments and pictures etc later when I get her running fully.
Thanks for the encouragement. Hopefully I can get this stuff sorted out soon so I can get some media up. And yeah, i’ll likely hit the track once or twice next spring!
Changed O2 sensor and reset ECU, re-routed the vacuum lines so the wastegate has it’s own feed (IAP hot-pipe fitting) and the BOV now reads from the intake manifold/boost gauge.
Car runs several times better than before. This fixed JUST about everything. No bogging or stuttering seems to be present anymore! Vacuum is steady at 18 HG without leaks. The following are my remaining issues before I get her back on the road safely:
– Car usually catches idle fine when clutching in after a harder run etc…but from time to time once the car’s warmed up and I do a run (doesn’t have to be very hard at all) it will dip, try to recover, and then fall on it’s face and stall the car. This happens about 1 in 3 times when revving the car from a standstill as well…rev, catch, rev, catch, rev, “putt putt stall” kind of thing…my ideas on this are:
checking for stuck EGR, cleaning IACV, adjusting TPS, BOV adjustments, raising idle (more), or spark plug gapping to .32 or so.
– Other issue is the blow-off valve (Greddy Type-RS) doesn’t seem to be releasing air. When driving, I still get only surge. When revving from a stop, car sounds NA except for the turbo spool (which sounds real nice I might add! But no sound of air coming through air filter)…i’ve tried:
loosening BOV all the way (finger tight), no vac leaks at all, and still not blowing off…this is as far as the adjustment is recommended so i’m a little confused. Should I try tightening it against logic and instructions to see if this helps? We’re also going to try venting the BOV as a comparison in case the recirc is causing anything funny…
Thanks for reading, suggestions/ideas would be appreciated.
what source are you taking the bov/boost gauge from? if the bov isn’t opening then recirc or not, its still gonna drop idle when you clutch in. im running an safc and it has a decel air setting which compensates for this and i run my bov open without any stalling. if you are going to end up with 370s and safc like me, might aswell do it now to solve this problem.
my bov isn’t opening either. then again i haven’t adjusted it much. and im just running whatever the wastegate spring is for now. still runs kinda shitty. needs tuning.
BOV and boost gauge are tee’d to intake manifold source. I changed it this way, as Marc recommended I do so.
I guess I will keep playing with the blow-off valve until I can get it to do it’s job, and then see if i’m still stuck with the idle problem at that point.
I had to take out one of the springs in my type s to get it to open. Do you know if the rs has a dual spring setup. Maybe you should look into that, just a thought :-s
Indeed it does have dual springs (apparently)…however I realized that i’m going to have to “break-in” the BOV a bit too. So i’ll keep it on the loose/soft setting and see if it starts to open up. It did on my friends Type-S.
If not, I may look into opening it up and taking out the smaller spring.
Car is finished and very close to perfect (I guess it’ll never really get there though lol).
We installed a 8:1 Vortech FMU because as predicted AF was indeed starting to show lean spots with just the Walbro HP 255lph pump under full boost (6-7 PSI). So with the FMU in the car is not only faster now, but perfectly on the edge of rich throughout the RPM band (sigh of relief) without the trailing clouds of smoke. :twisted:
Mild cleaning of IACV helped a lot with the idle issues. Only problems currently remaining are minor:
– Occasional spots where the car will dip idle when clutching in or stopping, not even necessarily after boosting, and sometimes it cannot be caught and the car stalls out (this happens about 10-20% of the time I stop or clutch)
– Occasional minor stumble when cruising at 2500 or so RPM, usually in 4th
– BOV still not opening fully, it is pretty much half-surging/half-releasing (but i’ll be taking one of the springs out and re-adjusting it, this should do the trick)
I’m also going to get some NGK Coppers and gap them to around .032". Currently running NGK platinums with 6 heat-rating and the original gap FYI.
These are the only issues remaining, and as of today i’m driving the car on the streets! And wow, it really is great…it feels so tight & solid, very good and even pull…at last the work and planning starts to pay off!
But anyways, if you have any other ideas on the above, throw 'em my way!
