ok so here are the modds before anyone asks.
t3/t4 turbo, ported and polished heads, 1.1 mil head gaskets, modded stock injectors, short ram intake no maf due to when i plug it in the car dies cause i dont have the recirculating hose,bov external waste, mbc up pipe down pipe and full 3inch exhaust. dont flame me cause i dont have a afr gauge cause money is hella tight due to xmas..

so heres the prob the car has rock solid idle tuned with openecu flash and it runs ok and builds proper boost unitl 4grand in the rpm range after that it just feels like i have lost fuel but you get a real stron wiff of the good ol 91 octane... ive tried tunning tip ins and ive tried re doing my latencies but nothing seems to work any suggestions i would love to get a few reads with enginuity but im affraid to drive.. som one please help.:(

Trying to tune fueling without a wideband is really not helping but you know that anyway.

What have you got in for injector scalar? If they are modded 550cc injectors they may well flow at 850cc

Have you scaled the MAF curve? If so how?

First job is to get the closed loop fueling running right (or at least running) before moving up the rev range - to do this you will need to have the MAF sensor in there - without it, it doesnt know how much air is going into the engine.

Do you have a Perrin/Silicone Inlet?... are you saying you have no MAF plugged in at all??

ok so here are the modds before anyone asks.
t3/t4 turbo, ported and polished heads, 1.1 mil head gaskets, modded stock injectors, short ram intake no maf due to when i plug it in the car dies cause i dont have the recirculating hose,bov external waste, mbc up pipe down pipe and full 3inch exhaust. dont flame me cause i dont have a afr gauge cause money is hella tight due to xmas..

so heres the prob the car has rock solid idle tuned with openecu flash and it runs ok and builds proper boost unitl 4grand in the rpm range after that it just feels like i have lost fuel but you get a real stron wiff of the good ol 91 octane... ive tried tunning tip ins and ive tried re doing my latencies but nothing seems to work any suggestions i would love to get a few reads with enginuity but im affraid to drive.. som one please help.:(

if the MAF isn't plugged in, thats exactly what happens, the car will fall on its face around 4000rpms. plug up the hole in the intake and plug the MAF back in. your car is not setup for speed-density.

hmmm ok no perrin and i have been running without my maf for about 10 mnths but this new setup doesnt seem to wanna work proper i will try putting the maf back in will it act weird if i put it in backwards? i think maybe that is what i did!!

Yes, it will cause the car to stall if put in the wrong way.

hmmm ok no perrin and i have been running without my maf for about 10 mnths but this new setup doesnt seem to wanna work proper i will try putting the maf back in will it act weird if i put it in backwards? i think maybe that is what i did!!

the Maf connector goes towards the front of the car

hmmm ok no perrin and i have been running without my maf for about 10 mnths but this new setup doesnt seem to wanna work proper i will try putting the maf back in will it act weird if i put it in backwards? i think maybe that is what i did!!

No maf for 10 months?

I didnt know these cars could run that well without it.

That's one way to convert to speed-density! :lol:

I'm curious. How did you come to the conclusion it would be a good idea to remove the MAF sensor?

I'm not trying to offend you. But if you don't understand why it's a problem to not be running a MAF sensor with the stock ECU, then you really need to spend a little time reading before you start tuning. You have to have a basic grasp of engine management. You will also need a wideband O2. Spend a weekend reading a book or two and order a wideband. Your pistons will thank you.

There was a thread about this on Enginuity... the car will run with no (signal from the) MAF sensor, but it won't necessarily run well. It's sort of a rudimentary speed-density system, which was only intended to limp the car to a shop that can fix the MAF. It wasn't intended to run well that way in the first place, and all of the OP's other engine mods probably throw it off even further.

And I'll second DocDetroit's suggestion to read a book or two about engine management. If money is tight, try your local library.

ok before you start flaming me get it straight and dont tell me to go read book because i have been researching non stop for the past 2 months while my build was taking place so dont get all high and mighty on me i un hooked the maf because. from what i understand with the recirc valve on the car the maf compensates for that air. when i put the bov on i could deffinantly tell this was true due to when the bov was making its pretty sounds it would buck and kick so i un hooked it and it actually ran as thought it were stock.. i drove it like that forever until my turbo went out... however i did hook it back up and it appears to be running better but still falls flat on its face at 4500 rpm i dont know why i pulled the plugs and they seemed to have a little residue on them i plugged in enginuity and my knock was crazy -15 i dont know what is gong on here and ive been researching non stop one of my friends recomended mixing in some 110 octane with 93 and seeing if that helped.. only reason i bring this up is he has a 600 hp 400 rx7 with a 9 inch rear end and knows his **** but i dont know what im doing wrong i havent pluged enginuity in since i put the maf on but test runs only go about half a mile down the high way and then back because i dont want to blow up the new motor... im wondering if im not getting too much fuel with the circumsized injectors or to little? any suggestion or help of if any one would like to make a map at this point im up for anything....

ok before you start flaming me get it straight and dont tell me to go read book because i have been researching non stop for the past 2 months while my build was taking place so dont get all high and mighty on me i un hooked the maf because. from what i understand with the recirc valve on the car the maf compensates for that air. when i put the bov on i could deffinantly tell this was true due to when the bov was making its pretty sounds it would buck and kick so i un hooked it and it actually ran as thought it were stock.. i drove it like that forever until my turbo went out... however i did hook it back up and it appears to be running better but still falls flat on its face at 4500 rpm i dont know why i pulled the plugs and they seemed to have a little residue on them i plugged in enginuity and my knock was crazy -15 i dont know what is gong on here and ive been researching non stop one of my friends recomended mixing in some 110 octane with 93 and seeing if that helped.. only reason i bring this up is he has a 600 hp 400 rx7 with a 9 inch rear end and knows his **** but i dont know what im doing wrong i havent pluged enginuity in since i put the maf on but test runs only go about half a mile down the high way and then back because i dont want to blow up the new motor... im wondering if im not getting too much fuel with the circumsized injectors or to little? any suggestion or help of if any one would like to make a map at this point im up for anything....
First of all, bloody learn to write English!

Second, if you've been researching so diligently and still are asking such questions, please donate your car to the nearest charity.

Here's where you need to go from here:

1) Log the car at idle. If it's having trouble hitting stoich here, the rest of everything isn't going to be any better. Your AF Learning and AF Correction should total less than 5% to hit 14.7-14.5 AFR if the car is happy. Make sure your MAFv and g/sec make sense. I can't speak to specifically what _your_ car should be pulling at idle, but mine draws about 4.5g/sec at idle. If it pulls ANY timing at idle, Something Is Up (TM). Because you say the car has problems at 4.5kRPM, you should also use the throttle to SLOWLY increase RPM all the way to redline while in neutral (so the only load on the engine is internal friction) while sitting in your driveway.

2) Log the car at a very light cruise, say putting around the neighborhood at the 25mph speed limit in 3rd (or whatever gear you'd normally do this in). Again, watch for your AFL or AFC to be too large in either direction. Make sure you log IAM, FBKC, and FLKC so you can see what timing it's pulling and when. Make sure you're staying in vacuum. Again, if it's pulling timing under these conditions, something is wrong.

3) Log the car at a moderate cruse, say a little into vacuum. Look for all the same things as before.

If you see NO problems with any of the above situations, then cautiously explore higher levels of boost.

If you log diligently and post well-formated examples of each stage of the testing, then we can help you arrive at a diagnosis. Many of the possible mechanical problems you listed will show up in the logs as values that aren't reasonable. If you don't do this, any help anyone tries to give you is no more than a wild guess that could just cost you time, money, or your motor.

ok before you start flaming me get it straight and dont tell me to go read book because i have been researching non stop for the past 2 months while my build was taking place so dont get all high and mighty on me i un hooked the maf because. from what i understand with the recirc valve on the car the maf compensates for that air. when i put the bov on i could deffinantly tell this was true due to when the bov was making its pretty sounds it would buck and kick so i un hooked it and it actually ran as thought it were stock.. i drove it like that forever until my turbo went out... however i did hook it back up and it appears to be running better but still falls flat on its face at 4500 rpm i dont know why i pulled the plugs and they seemed to have a little residue on them i plugged in enginuity and my knock was crazy -15 i dont know what is gong on here and ive been researching non stop one of my friends recomended mixing in some 110 octane with 93 and seeing if that helped.. only reason i bring this up is he has a 600 hp 400 rx7 with a 9 inch rear end and knows his **** but i dont know what im doing wrong i havent pluged enginuity in since i put the maf on but test runs only go about half a mile down the high way and then back because i dont want to blow up the new motor... im wondering if im not getting too much fuel with the circumsized injectors or to little? any suggestion or help of if any one would like to make a map at this point im up for anything....

WTF?

I'm not flaming, but it's pretty obvious that you're in over your head. Let me make a few points here:

1. BOV's are generally regarded as a bad idea on Subies. They throw off the mix when they vent to atmosphere. Maybe you should go back to a BPV.

2. Your MAF is an integral part of how you car determines how mine fuel to use. It also contains the intake air temp sensor. What reading did you do over 2 months that suggested unhooking it was a better solution than keeping the stock BPV?

3. Your knock is out of control because your engine is mildly retarded. I don't mean timing wise, I mean since you're unhooking sensors that help determine fueling and timing, the engine is lacking information, and doesn't know how to correct for knock.

4. Your friend with the Mazda may be a genius. He may even be acquainted with his fecal matter. If you had timing that is too far advanced, higher octane fuel may help. Does he tune your car? Maybe you should talk to someone with more experience with Subarus. My cousin's a jet mechanic for fighter jets, I wouldn't want him working on a helicopter I was going to ride in.

5. Stop driving you car until you know what you're doing. Your ignorance (not a flame, look it in a dictionary if you need to) can get rather expensive. You're worried about damaging your new engine, go seek professional help.

6. Post a little more clearly. This isn't an English class, we're not a bunch of prissy grammar Nazis, but honestly, you could try a bit harder. Install the spell checker, it works. Break up different ideas into separate paragraphs. Use a bit of capitalization and punctuation where appropriate. This isn't meant to incite you to new levels of frustration, it's just that when the message is easier to understand, you'll get more and better responses.

to the previous poster your a ahole.. so blow me i asked for some help because im having some troubles tunning my car im sorry you were probably born driving and tunning your subaru right... im new to this whole ecu flash and enginuity software but im sure you were born with that implanted in your tiny little brain right? so shoot me ill just stick with kc subaru from now on

ok before you start flaming me get it straight and dont tell me to go read book because i have been researching non stop for the past 2 months while my build was taking place so dont get all high and mighty on me i un hooked the maf because. from what i understand with the recirc valve on the car the maf compensates for that air. when i put the bov on i could deffinantly tell this was true due to when the bov was making its pretty sounds it would buck and kick so i un hooked it and it actually ran as thought it were stock.. i drove it like that forever until my turbo went out... however i did hook it back up and it appears to be running better but still falls flat on its face at 4500 rpm i dont know why i pulled the plugs and they seemed to have a little residue on them i plugged in enginuity and my knock was crazy -15 i dont know what is gong on here and ive been researching non stop one of my friends recomended mixing in some 110 octane with 93 and seeing if that helped.. only reason i bring this up is he has a 600 hp 400 rx7 with a 9 inch rear end and knows his **** but i dont know what im doing wrong i havent pluged enginuity in since i put the maf on but test runs only go about half a mile down the high way and then back because i dont want to blow up the new motor... im wondering if im not getting too much fuel with the circumsized injectors or to little? any suggestion or help of if any one would like to make a map at this point im up for anything....

Translation from gibberish to English:

Ok, before you start flaming me, get it straight and don’t tell me to go read books because I have been researching non stop for the past 2 months while my build was taking place. Don’t get all high and mighty on me!

I unhooked the MAF because from what I understand with the BPV on the car the MAF compensates for that air. When I put the BOV on I could definitely tell this was true, due to when the BOV sounded off it would buck and kick. I unhooked it and it actually ran better. I drove it like that forever until my turbo went out.

However I did hook it back up and it appears to be running better but still falls flat on its face at 4500 rpm. I don’t know why. I pulled the plugs and they seemed to have a little residue on them. I logged with Enginuity and my knock was crazy, -15!

I don’t know what is gong on here. One of my friends recommended mixing in some 110 octane with 93 and seeing if that helped. The only reason I bring this up is he has a 600 hp 400 RX7 with a 9 inch rear end and knows his ****. But I don’t know what I’m doing wrong, I haven’t logged with Enginuity since I put the MAF on except test runs going about half a mile down the highway and then back because I don’t want to blow up the new motor.

I’m wondering if I’m not getting too much fuel with the circumcised injectors or too little. Any suggestion or help, of if any one would like to make a map at this point I’m up for anything….

to the previous poster your a ahole.. so blow me i asked for some help because im having some troubles tunning my car im sorry you were probably born driving and tunning your subaru right... im new to this whole ecu flash and enginuity software but im sure you were born with that implanted in your tiny little brain right? so shoot me ill just stick with kc subaru from now on

You know, I'm actually trying to help you. Maybe a thank you instead of a rant.

I'm fairly new to the tuning thing myself, and have only had my car a few months. So I understand the frustration you're going through. This is why I tried offering a few pointers in the right direction, rather than just flaming away.

While you were busy typing up your little rant, I was busy trying to translate your previous illiterate garble to something anyone else could understand, so you could get even more help!


You're on your own from now on, as far as I'm concerned. Hopefully anyone else who's thinking of trying to help you reads this and acts appropriately, as well.

Thanks for the translation reddoak Fergucustoms you say that you have. logged short drives do the logs show MAF and IAT values that look reasonable... if they look like garbage then probably there is something wrong with the sensor or the wiring that would explain why your car is running like crap and if you found that hard to read then you can see why that other dude suggested that you work on your english skills its hard to understand messages that have ****ed-up grammar and borken punctuation i hope you get my drift.

Fergcustoms - Don't get so defensive. No one was trying to flame you. As someone else said, it's very obvious by your misunderstanding of the purpose of the MAF sensor that you are currently in over your head. It happens to everyone at times! I get in over my head all the time. When there are a lot of people warning you that your current level of knowledge is insufficient, you should probably heed that. That's especially true when it's people like me who knows that my level of knowledge is insufficient.

That's the bad news. The good news is you can get enough knowledge in a short period of time if you are willing.

In short, the ECU needs to know how much air in entering the engine at any given time. This is known as load. Knowing how much air is sitting in the cylinder is the major determing factor for calculating injector pulse width (how much fuel to inject).

Different manufacturers and different cars use different strategies to figure out how much air is in a cylinder. Some ECU's try to deduce it by looking at the throttle position and engine RPM. That system is called Alpha-N. Some look at the pressure in the manifold (MAP sensor) and the temperature in of the air in the manifold (IAT sensor) and a table of volumetric efficienies at given RPMs to determine it. That system is called speed-density. Some cars actually attempt to measure the amount of air entering the systems using a heated wire or an ultrasonic sensor (MAF). This system is called mass-air flow. All those systems have their pros, cons, and individual peculiarities.

It turns out our WRXs and STis primarily use a mass-air system. However they also have a MAP sensor and an IAT sensor. The MAP sensor is primarily used for boost control and the intake air temp sensor is used for fuel enrichment/enleanment. But as you discovered the subaru engineers foresaw the possibility of the MAF sensor becoming disabled. In that case they apparently switch over to a rudamentry speed-density strategy using the MAP and IAT sensors to allow the car to be driven in for service.

The reason your car ran badly when you switched over to a vent-to-atmosphere blow-off valve is because of the way subaru determine fueling requirments. Air sucked in through the intake is measured by the MAF sensor. The ECU, based on the amount of air measured by the MAF, calculates how much fuel to inject. But then your blow-off valve opens and lets a bunch of that air out. The ECU doesn't know this and still injects the amount of fuel originally calculated which is now way too much for the amount of air going in the cylinders.

By unplugging your MAF sensor, you caused the ECU to go to it's back-up, limp home strategy of using the MAP and IAT sensors. This fixed the problem with your vent-to-atmosphere BOV because the ECU is no longer measuring the air before the BOV. It is now measure the air after the BOV. So if the BOV lets some of the air out, it doesn't matter. There are two problems with this. First because it's a limp home strategy, it's probably not going to be very robust or efficient. Secondly speed-density is based on a table of volumetric efficiencies. Because you have modified your engine, your engine's real volumetric efficiencies no longer match the volumentric efficiencies in the ECU's internal table.

So now you have your MAF sensor hooked back up which is great news for your ECU as long as it's working correctly. Because now your ECU can do a much better job of determining how much air is in the cylinders and can calculate the fueling requirements.

I believe you said it idles and drives under light load fine. Is that correct?

Then you said when you hit 4,000 RPM is falls on it's face and smells really rich. Is that correct?

I bet if you reel in the attitude a little bit, and post up some logs, people will jump in to help you out. I suspect getting your injectors and MAF scaled correctly will go a long way in getting you to your goal.

You are much too charitable, this guy has way too much attitude to deserve the level of help you are giving him. This is not new stuff that only enginuity deals with. If he had really researched for 2 months, he would know how a MAF works.


I suggest fergucustoms actually starts to read a little more on the topic of MAFs and BPV's. I also think he owes a few people an apology, the people that posted above don't owe you anything.

I hate people that argue against the advice that they ask for.

This thread is great fun.

I like how through the genius of enginuity, this guy was able to see haw moronic what he has done accually is. These guys are taking it easy on you.

you're all making tons of noise. address the singular issue which is his problem...

the stock ECU references airflow (measured by the maf) for nearly everything it does. the OP removed his maf, but is still trying to tune the car using the stock ecu. His car will never run correctly without the maf. reinstall the maf, or switch to true speed density.

/thread.

you're all making tons of noise. address the singular issue which is his problem...

the stock ECU references airflow (measured by the maf) for nearly everything it does. the OP removed his maf, but is still trying to tune the car using the stock ecu. His car will never run correctly without the maf. reinstall the maf, or switch to true speed density.

/thread.

isn't that what i said?

isn't that what i said?

Yeah. And me, too.

Classic.

BOV is bad for the car, so take out the maf, ask for help, then insist you're right.

:eek:

All the while running limp mode on a big turbo with no wideband.

:eek:

I doubt you'll listen to me, but plug your maf back in, get a nice BPV and recirc hose, then go get someone else to tune your car.

Yeah, when I read that the first time (I caught the thread about 20 minutes after the OP started it, before any replies) I subscribed just to watch the carnage! :lol:

you're all making tons of noise. address the singular issue which is his problem...

the stock ECU references airflow (measured by the maf) for nearly everything it does. the OP removed his maf, but is still trying to tune the car using the stock ecu. His car will never run correctly without the maf. reinstall the maf, or switch to true speed density.



/thread.

Classic.

BOV is bad for the car, so take out the maf, ask for help, then insist you're right.



All the while running limp mode on a big turbo with no wideband.



I doubt you'll listen to me, but plug your maf back in, get a nice BPV and recirc hose, then go get someone else to tune your car.

Translation from English to gibberish:

no flaming yo youre all making tns of noise address the singular issue which is his problemthe stock ECU references maf stuff for nearly all the stuff it do the OP removed his maf, but is still trying to tune the car using the stock ecuhis car will never run correctly without the maf put in maf thing or switch to true speed density/thread classic sweet sund BOV is bad for the car so take out the maf ask for help then insist your write all the while running bad on a big turbo with no wideband( to broke right now) I doubt you'll listen to me but plug your maf back in get a nice BPV and recirc hose then go get someone else to tune your car

I only hope this helps.

Seriously dude, hope you mellowed out a bit. Take it one step at a time. Get your MAF issue straightened out, then go on from there. You're probably a bit overwhelmed because you're looking at every problem at once. Take them one at a time.

:lol:

Oh my...

I believe that Master here in Washington has managed to rewrite some code/tune for running speed density; however it may have been on an STI. Perhaps contact him for a tune of your maf-less setup.

It would be far better, as everyone above has said, to get a bypass valve and plumb it in properly. Then pressure test your ic system, reattach all sensors, and start again with your stock rom. And you are playing with fire without at least a WB o2, and with your experience it sounds like an EGT gauge is in order too.

Log and post your results as many have said.

Good luck.

thanks for everyone who has chimed in.. i have re installed my maf for so u guess can stop telling me to do that thank you doc detroit for explaining i do understand the whole theory of reventing the air back into the intake track and have thought of doing this several times.. guess its time to just shut up and do it and reddoak i dont know if your a grammer teacher or and english teacher or what but you need to take some ridaline and calm down on making everyones posts better... last time i checked you didnt have to go to grammer school to work on a car or own a speed shop am i correct..

now back to everyone else.. thanks a mil for all the input on the maf like i said i re instaled and ordered a wide band.. i know i needed one money was just a hair tight.... and even with the maf in its falling on it face.. only got to do one pull but i will try and post some logs for everyone to critasize (sp) any ways like i said thanks to everyone who is actualy trying to help...

If it was nut for other peoples' translations I wd nt have contributed anything two this thread seriously the first thyme I red your first post I thought yo sed yu disconnected the MAF butt that seemed weerd so I figured I must have red it rong you should at least try pudding periods between your sentences that would help a lot we cant help f we cat unnerstand

If you found that hard to read, now you know how we feel.

sorry, NSFW and WeldingHank, you guys were correct. I suppose I was just tossing more gasoline onto your fire. :)

Oh my...

I believe that Master here in Washington has managed to rewrite some code/tune for running speed density; however it may have been on an STI. Perhaps contact him for a tune of your maf-less setup.


Oh really? I didn't know that. I thought the only person who had successfully recoded his STi ecu with speed density tables was Freon.

Oh really? I didn't know that. I thought the only person who had successfully recoded his STi ecu with speed density tables was Freon.

I may need to be corrected on who did the coding, but he had a thread on the enginuity board about how he managed to get the car to run pretty well. He even rescaled the map sensors input if I recall, to use one with a higher ceiling for more boost.

No disrespect to Freon if it was his coding work, perhaps my memory is having issues on who's thread it was. :D