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back pressure?


Guest De Schmaydee

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Guest De Schmaydee

...been having probs since the install of this jwt (downgrade) ecu...

......since i put it in, the turbo (?) makes a noise like a goose fornicating when i let off of the gas....been told it was back pressure....sounds good to me...but it never did it before....i'm not talking about going full boost and slamming the throttlebody shut.....i cant hardly even drive the thing w/o it doing it when i shift....doesnt do it when i put the j-pipe back on.....

...i know a bypass would help/fix it (maybe) but i wouldnt think 1-2 psi should make it happen...could it be something else?.......s

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Sounds right to me. I hear a series of things happening when I get on the throttle. I've been systematically fixing leaks, like my old intake was leaking bad from the compressor bypass return, and on my new piping I forgot to tighten the clamp after my turbo outlet - "why won't it build boost?". But I can definitely hear the wastegate opening, and the release into the intake on a throttle lift - the old j-pipe setup was much quieter.

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Guest De Schmaydee

.....i guess it would be the same w/an external wastegate?....i have the bypass/pop-off 1/2 way in...i have an 1.5" hose routed back to the cold air plenum after the maf...but i'm having a hard time fitting in the valve its self....

...this is a kind of a "googling" sound not a "pssssssst".....skeered to drive it like that.....

....i had it in the same configuration before the jwt thing and would run 10psi no prob (no noise)...then i installed a cheapo msa (knob type) boost controller that didnt work (or i hooked it up wrong) and after that (and the jwt install) it started making noise.....i eliminated the boost controller but it still occurs......

....it may even be doing it w/o boost...if i shift @+3k it'll do it pretty loud even though i'm showing 0/1-2 psi boost......its pretty much not drivable...or i'm afraid i'll mess something up.....

....i'm gonna retube the wastegate...it still has the "T" in it where the msa was hooked up....maybe something is leaking..... .....s

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A possible reason it does it now is that the turbo is spooling faster than it did before even with the same total amount of boost. The crazy goose sound is the turbo back peddling. Anyway do as the other guys have said and plumb in a BOV and make sure it is adjusted correctly. If you are unable to adjust it correctly you might seek the help of a shop that has the tuners that can help you out with your setup. There are always cause and effect issues when you change as many things as many of us have done on your cars.

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Guest De Schmaydee

.....i'm trying to do too many things at once,overcomplicating it.....then getting tired and making mistakes......i have it to where she'll pull like a big dog once its warmed up (cant do it because the blow-off/bypass isnt in)....and i'm hoping the the cold start probs are the result of the air regulator not working (it gets it's +12vdc from the fp relay that had to be modified)...not getting any voltage now...but i've got a handle on that....hopefully it'll all fall into place once the air regulator is functioning and i retime it.......(except for the goose gaggle)....

.....my ecu was set fully counter-clockwise (or clockwise)...."opposite of the diagnostic ("codes") mode"......i've been told that is a diagnostic mode for the maf...and it should be set somewhere in the middle (but that might be for a stock z31)....i get 3 green led blinks (code) where its set now ......seems like i read somewhere that means something about the o2.....the diagnostic mode doesnt seem to give "possible" codes "both" leds blink on every code ...never does just 1 led blink by its self....but it seems like i saw somewhere the codes dont really work in our application.....anybody know about that?.......s

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Why are you messing with that? I have not ever touched the diagnostic deal in my ecu. Put it back where it goes and leave it there.

 

Man you are really making this more complicated then it needs to be. Why not just put the J tube on there, and concentrate on getting the ECU and stuff working properly before moving on to other things? Run lower boost, don't worry about the BOV, and get it running right.

 

I would not be to worried about the cold start either. The easiest way to check it is take it off the car and stich it in the freezer. after an hour if you can see thru the hole, it works. The 12 volts that goes to it is to help heat it up and make it close, so it really isn't critical to even have it connected.

 

I don't want to sound like I am being critical, but JWT does recommend having a technician install their set-up. You have to be very systematic about how you install it, you are taking a system from several different cars and putting it in a car that it is not supposed to be in. That doesn't always go smoothly and makes it complicated. Why do you think speed shops charge so much money to do this kind of work? Its a PITA, and it always takes longer then they planned.

 

I would start with getting the car running and timed properly with the J tube. Send the intercooler back to Bell and make him fix it, you cannot have leaks with a MAF car or it will never run right. Get the timing right, and drive it around and see what it does. Then start making changes, one at a time so you can keep track of the results.

 

Repeat after me, I will not make more then one change at a time, and will test that change thoroughly before making another one.

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Guest De Schmaydee

....didnt see anything about removing the o2 sensor in the literature i was sent......already did test on the fuel regulator you suggested....i dont know about leaving it unplugged...doesnt that let unmetered air into the system?.......its been timed (as well as can be seeing as that i cant get it to idle lower than 1k rpm).....

....at this point i only have 3 probs.....the unrelated?...back-pressure prob which should be fixed w/the bypass ...the fast idle and stalling/stumbling when its cold......

...i know the fuel regulator isnt getting the voltage to make it work properly...and doesnt it effect the idle?

...as far as what i work on and when.....i'll decide that..... when i work on the idle/stumble, the j-pipe is on and the car is in its stock configuration..... car runs well once its warmed up except for the 1k idle...

....i'm very greatful for any "constructive" info anyone has to offer....anything else isnt needed......save yourself some typing and just ignore my post...... .........s

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....didnt see anything about removing the o2 sensor in the literature i was sent......already did test on the fuel regulator you suggested....i dont know about leaving it unplugged...doesnt that let unmetered air into the system?.......its been timed (as well as can be seeing as that i cant get it to idle lower than 1k rpm).....

....at this point i only have 3 probs.....the unrelated?...back-pressure prob which should be fixed w/the bypass ...the fast idle and stalling/stumbling when its cold......

...i know the fuel regulator isnt getting the voltage to make it work properly...and doesnt it effect the idle?

...as far as what i work on and when.....i'll decide that..... when i work on the idle/stumble' date=' the j-pipe is on and the car is in its stock configuration..... car runs well once its warmed up except for the 1k idle...

....i'm very greatful for any "constructive" info anyone has to offer....anything else isnt needed......save yourself some typing and just ignore my post...... .........s[/quote']

 

What Lockjaw said is very important. Change one thing at a time.

 

As to the air regulator, you can test it in the freezer. Leaving it unplugged will not cause a leak. But it sounds like you have complicated things too much. Set the idle by blocking the hose to the air regulator, just to see if it's the problem - lots of options.

 

Breathe in, breathe out.

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Guest De Schmaydee

.....like i said in that last post when i'm working on the idle/stumble the car is in the stock configuration....w/the exception of the things i did (or tried to do) w/the jwt upgrade...the air regulator has been tested and the element inside of it too.....i havent plugged the hose to it but i did pinch it w/some pliers to cut off the air...didnt have any effect....so i dont think its my main prob...but it wasnt correct..i had connectivity to the ecu on the black wire and i've found another switched +12vdc to hook it up w/ to get it to work....

....i was talking w/jeffp he said he made up an air bypass to correct his idle and eliminated the all those hoses and check valve on the intake along w/the aac and egr (more or less get rid of everthing except the air regulator and block 'em off) and put an air bypass in....then check the tps and make sure the throttle plate is fully shut......so i think i'll give that a try....i can see having bumped the tps or throttle linkage trying to get the new injs in....i had a real hard time getting them on the barbs.....

...but i do understand what youre saying and agree...the intercooler wont be hooked up until i get the idle/stumble thing worked out (then i have an evc-4 to put in after that).....but i'm gonna have to have the bypass ready for when i do get the stumble resolved...the stumble goes away after it gets warm and the car runs well but its still undriveable w/all the back pressure on the compressor........s

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You can get mad all you want, but the bottom line is you are making the whole deal more complicated then it needs to be.

 

And while you are complaining, lets not forget you are trashing a system on an open forum, a system that is set-up by the premier Nissan ecu hacker/tuner in the USA. Not that I think its the best system invented, but it works good for me, JeffP, Cody, and at least one other person, as yours is configured.

 

You have posts in this section, the efi section, and on Zcar all complaining about the system, and you don't even understand how to test the air regulator. See the point?

 

You need to calm down, quite fussing, and get the kinks worked out, one at a time. Anything you put in there besides going back is going to require work, or paying someone else to do it.

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Guest De Schmaydee

lj ...i wasnt mad but i can get that way....who the hell are you?...and whats the crack about not knowing how to test the air regulator...you need to get a life man...if you want to offer and recv info... cool... if you just want to argue,insult and make smart ass remarks..which seems to be your reason for being on here....go somewhere else...i dont want your "help" and can get by w/o it.....

...as far as the jwt ecu i wont have a verdict about that until this car is running as well w/it as it was before it was put in...and i find out the reason its not.....i do know everything that was supposed to be done as far as what the install documentation said should be done and its not working the way they said it would.....

.......if i knew i would have to tear into,test and modify a bunch of subsystems (that were working perfectly before) i would replaced them all and had someone put in a tec3....

...that doesnt mean that its the new ecu thats wrong...could be something else wrong w/the car that didnt manifest its self until this was put in....or something i didnt do correctly.....but i do know they lied to me for 4 months about the delivery of this, didnt let anybody know about the mods needed for the injector plugs and havent responded to any of the emails i've sent them to work out a resolution for this..... ...s

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I am the guy who's JWT system works, and you have solicited my help in the past. As for making smart ass comments, that can be arranged, if thats what you like.

 

What you are doing by trashing someone's business is not right, and I think the real issue is you don't know enough about what you are doing, which is what I was trying to work you thru.

 

You can keep on complaining if you like, but that won't get your car working. Listening to some good advice from people running the sytem will, even if you don't like what they say.

 

And going the Tec3 route would be worse for you trust me. You would have to take the damper and front cover off, have them machined for the trigger wheel, mount the hall effect sensor, probably build the bracket for it, you would have to make a harness for the thing, and then program it, which requires a laptop and some dyno time. You would also have to make a cover for where the distributor goes, and then you are not even guaranteed all your instruments will work, like the tach. And I got to say, if you are having this much trouble with JWT's set-up, what makes you think the TEC3 would be easier? Plus I believe the TEC unit uses GM sensors, so you would have to adapt the TPS set-up to work. Its not as simple as you think.

 

If you want some help, PM me. You want to argue some more, PM me, but either way, I am done trying to help you if all you are going to do is complain about how the system sucks. The system works fine, and there are enough people on this board getting good results out of it to prove that.

 

Is it the ultimate set-up for a Z car with a turbo, no, and I have said so in the past.

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Guest De Schmaydee

...lock jaw (or better yet "rachet jaw") who do you think gives a shit about what you think (start your own post and argue w/yourself, i'm trying to get a car fixed)...and i'm not gonna get in a debate w/an idiot...as far as running a business down....who's business?...is it your business?....or is it none of your business.....who said anything about anything of your's...your ecu,car,you...or your mama...

....i dont know what you know about these cars and the ecu....(i think youre pretty knowledgable)....but i know you dont know squat about me or how much i know (or dont)...and if you werent hiding in bushes when i put in this ecu you dont know anything about that either.....

....i'm not real happy w/my ecu or jwt...time will tell.....i'll get to the bottom of this sooner or later and i'll know exactly what the probs were and what caused 'em..... cant rule myself out of it as a damned good "possible cause"......or a even a probable cause.....dont know yet...

....if this thing works it'll be a good deal for the money.....and seeing as that it is the only thing out there (short of a stand alone programable ecu) it could be a good consideration for a bunch of folks ....if it doesnt work as advertised or there are probs w/the product or w/jwt, people need to know that too.....i dont have time to listen to you mouth off....i got a car to fix...... .......s

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Well I may be an idiot as far as you are concerned, but I got a mid 12 second car, successfully running the system you can't install,what do you have?

 

And FWIW, you got 3 posts in the efi section, one here, and one on Zcar all blasting JWT. I don't need to hide in the bushes as you say to tell you don't know what you are doing, you have proven that already with questions about the air regulator, the intercooler, and the fact you think a Tec3 would be easier to install then a JWT set-up. Not to mention you think the compressor section has backpressure, that is the exhaust system.

 

I have been doing turbo stuff with Z cars for better then 10 years, and I dare say I was one of the first few people to put a ZXT engine in a 240. I have built plenty of engines, run cams, different heads, you name it. I know what I am talking about, and thats the real difference between you and I, I know what I am talking about, and you only know enough to be dangerous.

 

As far as trashing a business, it's wrong when the person doing the trashing isn't even capable of installing the sytem. You would be doing the same thing if you had a Tec3 because you wouldn't understand it either.

 

And as I said already, JWT recommends having a tech install their system, becuase the average Joe doesn't have the capability, ie you.

 

And just so you know, I have not had or felt the need to stoop to name calling as you have. I simply call it like I see it. If you don't like it, I hate it for you, but the truth is, you need to quit complaining and start listening, or take the stinking set-up off your car, and put it back to stock.

 

Whether you like me or not doesn't matter to me at all. I could care less. But I am not going to let you continue to trash a system I have had good success with because you lack the skills to install it.

 

:roll:

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....hmmmmmmm so the compressor is on the exhaust side of the turbo....?hehehe maybe thats what i got wrong.........s

 

I believe the term was backpressure, found in the exhaust side. Backpressure on the intake side is referred to as boost. ;)

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[quote="De Schmaydee

....at this point i only have 3 probs.....the unrelated?...back-pressure prob which should be fixed w/the bypass .........s

 

 

Lets see you are going to put a compressor bypass on the turbine side? I would like to see that, how about posting the pic's when you get it done.

 

That would be a first. :lol:

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