Ok, its been 4months since I was dyno tuned. I am still having the same idle problems. I'm sick of writing the list of things that I've replaced, just think... everything. My fuel trims are dead-on, WOT is great, power is great, but idle is horrible and inconsistant. All of this is confirmed by turboxs. So, I'm completely helpless at this point. My question is now, can I switch to engine management that can properly run modded stock injectors at idle, without destroying my wallet or do I need to "de-mod" my car back to stageII? I'm sure I left info out that would assist my question, but I'm tired and sick of thinking about how annoying my car is to drive right now.

I have an 03 wrx sedan stage 4 w/ modded injectors, tuned myself with no idle issues at all. People that have ridden in it are amazed that it idles and drives as good as stock, but much much faster.
What modds and what scaling of the injectors?

were the jectors recently cleaned/flowtested? were they ever?

ken

were the jectors recently cleaned/flowtested? were they ever?

ken

no, I was thinking about having them cleaned.

Having them cleaned(and then flow tested) would be a good idea. Also, did your car ever idle properly? Usually a tuner will try to make sure you get a rock solid idle before they start messing with anything else..

Having them cleaned(and then flow tested) would be a good idea. Also, did your car ever idle properly? Usually a tuner will try to make sure you get a rock solid idle before they start messing with anything else..

I think TXS would be considered a tuner LOL. Like he said, they've already touched on everything from software to hardware. I don't see having them cleaned and flow tested doing the trick but that's just me. Based on experience of having the same issues, "some" of the Subarus aren't taking well to the modded injectors. Going stand-alone, you'll be fine!

He didn't say that TXS tuned the car though--just that they "confirmed" everything.

Not to attack you, but how would going with a stand alone affect an apparently unidentifiable idle issue?

Theres no point to asking "why am i having idle problems" until you get your injectors flow tested and cleaned. From there there diagnosis of your problem will be much easier. :)

He didn't say that TXS tuned the car though--just that they "confirmed" everything.

Not to attack you, but how would going with a stand alone affect an apparently unidentifiable idle issue?


Oh yeah, I've spoke to sharko through PM's and he had indicated that TXS tuned the vehicle which I thought he was also stating above.

Concerning the stand-alone route, you've got far more flexibilty and control of course. Unlike the UTEC, the stand-alone has complete control over idle where UTEC piggy backs and intercepts. I've got some experience with the SDS system (although I'm not a fan) and had no problems on a VW 1.8T setting the idle with large injectors. I believe having the OE ECU/UTEC combo in place is why some of us are having issues with idle but WOT power is dead on.

By the way, no attack taken.

So what do you classify as a bad idle? I have modded injectors and my idle isn't 100% perfect on cold startup, but I dont expect that with injectors 2x as big as stock and a stock idle RPM. My idle is still bearable and very close but I dont think you will ever really achieve a perfect idle with any large injector.

cdvma - if memery serves correct, sharko's idle were more than just a poor idle. He was stalling too (correct me if I'm wrong sharko)?

In the other "modded injector" thread that we went through recently we were having the same probs (two different cars). I guess flow testing them would confirm if it's just a particular car not dealing with these injectors well or maybe it's the injectors flowing at different rates?? However, why would various cars idle fine (or close to it) where others do not? Why would WOT be spot on but doesn't have an acceptable idle and stalls out? Also, he stated above that his ST/LT fuel trims are good. When I see a "stall" about to happen when logging, it loads up/dumps fuel and goes extremely rich off the WB and sputters to a hault. Seems like a tug-a-war match between the UTEC and ECU?

The first time I was at txs, they had a hard time stablizing my fuel trims. They thought it may be caused by an uppipe leak or o2 sensor. So i left there the first time with a crappy idle. After I replaced (ready? here it goes): front o2 sensor, IAC, IAC gasket, TB gasket, all pre-turbo exhaust gaskets (no leak), superduper grounding, a bad coilpack, spark plugs, Cleaned every sensor I could find, check torque specs on everything I have touched.

At this point my crossover was horrible and my idle seems to have gotten even worse, so I took it back to them. They re-road tuned it (Thanks Jermaine), crossover better but, not fixed(still extremely annoying), and the idle is still horrible. That is when they confirmed my normal, stable fuel trims.

My idle is rediculously horrible on cold starts, it floats and shakes. At normal idle, it shakes the car more than normal and the vaccum will flicker up and down at random (normal vacum levels while not flickering). Not to mention, my horrible crossover going up hills in a higher gear. The ecu is trying to run 42+ degrees timing while cruising ( this is what jermaine was battling). This car is depressing to drive around town, as I'm sure nathan/jermaine would agree. WOT is great though!

To be honest with you; my car idled fine after installing the injectors/pump/turbo (wot sucked though). I didn't notice the idle problem until I installed the FMIC, maybe it was just me. So far, Tmarcel seems to be the only one suffering from a similar problem. I'm 100% out of ideas. I mean, how much money should I spend on troubleshooting?

i have a feeling it's not the injectors so much as it is the massive mafv offsets necessary to tune for them... the oem ecu is "seeing" so little air it's essentially freaking out.

i have a feeling it's not the injectors so much as it is the massive mafv offsets necessary to tune for them... the oem ecu is "seeing" so little air it's essentially freaking out.

Question is... why are there so few cars that have such a drastic problem, while most run flawlessly. Turboxs basically told me they have never seen a car act the way mine was acting. Has anyone seen any of the professional utec tuners on this board addressing this situation?

Ok, so anyone have any suggestions on what path I should take. Keep spending money on attempting to make my car drivable or just demod it? I know nothing about hydra, would this potentially take care of this problem?

You could always try some injectors that actually atomize the fuel at lower rpms... RC/PE....

You know with large injectors it's always hard to get the car to idle smoothly. Just think about it. They are huge and you don't need very much fuel at the lower rpms. With the modded stockers I am sure that the issue is a little worse as it's a laser beam of fuel which has very little time and heat to fully atomize before it reachs the cyliners. This is great at higher rpm's but I am sure it effects combustion at lower rpms.

Maybe an actual larger injector that does some atomization will help with the issue you have.

Just thinking out loud.

mick_the_ginge
Scooby Newbie

But feel free to ignore the newbie

mick_the_ginge
Scooby Newbie

But feel free to ignore the newbie

I don't normally pay attention to those anyway. If someone provides solid,logical, or proven data/info; why does it matter how many times they've posted. You have always added intelligent insight to my questions.

What you said in the first post makes plenty of sense. Why would these injectors have huge differences between cars. Theoretically, if I swap modded injectors w/ my friend who was tuned using the same methods by the same people, but idles perfectly: they should idle fine in my car. Then what is physically different about the injectors at that point?

Is safe to assume these injectors can NOT idle on my car, considering 2 attempts by turboxs to make them run? I just wanna know if I should give up. I really don't wanna spend hundreds on pe's and tuning or tuning tools, and still be stuck w/ the same problem.

I don't think you can do anything else. Maybe just YOUR car with these injectors, UTEC, OE ECU combo ain't workin'. You've still got choices though. I don't know that much about the Hydra but don't think that it uses the MAF at all and still uses the factory wire harness. Correct me if I wrong. Or you can just get some other injectors for now, as Mick suggested above. Some that have caps on them to better atomize for combustion. I don't know if TXS said, but what's your AFR do when the rpms return back to idle? Mine goes very rich to 9:1 in some cases, usually resulting in a stall if that happens. Other times, will just stumble and hopefully catch itself and come back stoich'ish AFR.

You could always try some injectors that actually atomize the fuel at lower rpms... RC/PE....

You know with large injectors it's always hard to get the car to idle smoothly. Just think about it. They are huge and you don't need very much fuel at the lower rpms. With the modded stockers I am sure that the issue is a little worse as it's a laser beam of fuel which has very little time and heat to fully atomize before it reachs the cyliners. This is great at higher rpm's but I am sure it effects combustion at lower rpms.

Maybe an actual larger injector that does some atomization will help with the issue you have.

Just thinking out loud.

well if it make a difference i believe is the utec.....i pull the PE injectors out of my car about a month ago for the same reazon as el~sharko. verry poor idle ,car stalling and so on. but at wot it was fine.
I'm not cuttin corners no more stand alone it is.
el~sharko swap does injector for stock ones turn the boost down and enjoy your car again.

Maybe you have a bad injector(s)....

For the price you saved by modding the stock injectors, you could have bought others....

What if you bump the fuel pressure a touch. Say ~10%. That "could" help with the fuel atomization some.

Just a thought.

TMS

TMS-

Not to hijack sharko's thread but I thought about this too. When I get my car back on the road I will through on a gauge and see what happens (this is three WRX's now with identical problem's, actually more than three as others seem to have had similar results). The theory makes sense just wonder if it'll work.

u.scotty -

Anthing is possible. I may have them tested. I wonder if the heat created from the cutting disk could have damaged (warped) one of the injectors? Creating a condition where the injectors still work, just not correctly.

i have a feeling it's not the injectors so much as it is the massive mafv offsets necessary to tune for them... the oem ecu is "seeing" so little air it's essentially freaking out.
This is definitely something to check out. Sometimes, very little to no correction is needed at idle. You might even try *positive* correction in the UTEC.

Also, if you're running an FMIC, you're obviously running an intake... which one?

i've heard it said that the modded stockers flow proprtionally less at low on times.. iow, they act like smaller injectors than their full flows would have you believe.

the only way you can adjust for this is zero column tuning. relying on the global injector scaling is too broad a stroke.

i've heard it said that the modded stockers flow proprtionally less at low on times.. iow, they act like smaller injectors than their full flows would have you believe.

the only way you can adjust for this is zero column tuning. relying on the global injector scaling is too broad a stroke.

How about an example for us draw-it-out people LOL.

You could always check your blow off valve, depending on the number of washers or how tight or loose you ahve yours set that can throw off your idle immensly, its very commonly overlooked, because most people think the blow off is only good for sound and releasing pressure, but it can also control how well your car idles, give it a try, wherever you ahve it now try to loosen it and see how that works and then try tightning it, i think it sounds like your BOV is to loose and is releasing pressure before it should, jsut my opinion and a problem i ahve run into.

i've heard it said that the modded stockers flow proprtionally less at low on times.. iow, they act like smaller injectors than their full flows would have you believe.

the only way you can adjust for this is zero column tuning. relying on the global injector scaling is too broad a stroke.


...you would think someone at TXS would have thought of that one....BUT....seems like a good thing to check, to me....

You could always check your blow off valve, depending on the number of washers or how tight or loose you ahve yours set that can throw off your idle immensly, its very commonly overlooked, because most people think the blow off is only good for sound and releasing pressure, but it can also control how well your car idles, give it a try, wherever you ahve it now try to loosen it and see how that works and then try tightning it, i think it sounds like your BOV is to loose and is releasing pressure before it should, jsut my opinion and a problem i ahve run into.

This was actually adding to the problem, I tried 0-10 washers on the turboXs bpv. They gave me a new spring, which is about twice as long, but has roughly half the tension as the original. Although I get some surge from this new spring, it immidiately improved my idle issue as well as my crossover issue.

-Uncle Scotty, I realize the injector cost, had gone w/ pinks which is all I would need for the turbo I am using. At the time, I planned to go larger in the future, and since I was getting tuned anyway, I figured I'd give the modded stockers a shot.

You could always check your blow off valve, depending on the number of washers or how tight or loose you ahve yours set that can throw off your idle immensly, its very commonly overlooked, because most people think the blow off is only good for sound and releasing pressure, but it can also control how well your car idles, give it a try, wherever you ahve it now try to loosen it and see how that works and then try tightning it, i think it sounds like your BOV is to loose and is releasing pressure before it should, jsut my opinion and a problem i ahve run into.

This was actually adding to the problem, I tried 0-10 washers on the turboXs bpv. They gave me a new spring, which is about twice as long, but has roughly half the tension as the original. Although I get some surge from this new spring, it immidiately improved my idle issue as well as my crossover issue.

-Uncle Scotty, I realize the injector cost, had gone w/ pinks which is all I would need for the turbo I am using. At the time, I planned to go larger in the future, and since I was getting tuned anyway, I figured I'd give the modded stockers a shot.

-Tmarcel, Have you compression or leak-down checked any of these cars?

-Tmarcel, Have you compression or leak-down checked any of these cars?

One has been tested and the other one which hasn't is a ringer anyways. The one which was tested made between 152 to 158 across all four.

One has been tested and the other one which hasn't is a ringer anyways. The one which was tested made between 152 to 158 across all four.

good, that makes me feel better. I will do mine when my coilpacks come in. I think I had another coilpack crap out on me today. Car misfires like my grandfather at idle, any throttle below 2500rpm and any boost above 7psi, yet i can rev freely off boost. Maybe my whole idling problem was a semi-bad coilpack up until this point. We can only hope :rolleyes:

Did you say that you're running the stock intake? If not, guessing you've got the accordian hose to a short ram? How long would you estimate that turbo inlet hose is from the turbo to the MAF (not including the filter or box)?

Did you say that you're running the stock intake? If not, guessing you've got the accordian hose to a short ram? How long would you estimate that turbo inlet hose is from the turbo to the MAF (not including the filter or box)?

I pretty much have all turboxs stuff including their intake (stock acordian) and a perrin inlet pipe