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View Full Version : GT25R install finished, got some problems



Brad
03-17-2004, 09:49 PM
hey, well i just finished my GT25R install, planned to "do it over spring break," but didnt plan for it to take up my whole spring break with problems. heres my mods:

-z32 mafs
-sard 550cc injectors
-hks ssqv
-custom radiator hose/rubber elbow from compressor to hotpipe
-hks actuator
-safc ii, set to -33% correction, 1 in 6 out
-gt r fuel pump

i think thats all the mods that are pertinent to this situation

oh well, lets see if anyone has the answer to these questions:

bov is very quiet, even shifting when its at full boost. shifting before full boost results in either no sound or a tickatickaticka of compressor surge

wont rev above 6500 rpms, when i get that high, feels like a misfire or something, not sure

car idles kind of lumpy, not sure if this is how its supposed to be with bigger injectors

ive got the hang of the afc, and can play with the in/out settings to make it not die, even tried changing them on the fly to see if it helped, but no dice

ThonG
03-17-2004, 09:59 PM
changing s-afc settings on the fly interms on in/out doesn't work. The s-afc has to be turned off and back on for the settings to take effect.

Anyway, sounds like maybe you hooked up the maf wrong...did you check your plugs also? which ones are you running?

Thon

NOSTALGIC_HERO
03-17-2004, 10:05 PM
you did alot at once. not good for troubleshooting. ask revlis.

i helped him solve his loss of cold idle. it didnt do anything with the inectors that he installed . but was a step he totally forgot he did (messing with the wires at F10)

did you do anything timing wise? did you play with wires at all? did you change plugs? ... Enthalpy once had a bad ignition problem (Breaking up in boost) when he installed his HKS twin power.. he was totally aggrivated when we went driving cause his install was soo clean. and i asked him the simple question if he changed his plugs.. he was like EUREKA! he used incorrect plug type (resistor/ non resistor type)


maybe it is something simple? think of everything you did.

Brad
03-17-2004, 10:11 PM
yeah thats what i was thinkikng, installing all that stuff at once, so i tried to do it in stages. i made sure the mafs would work, and drove it a bit on lowest boost possible, but really didnt get into it. installed the injectors last

i was thinking about plugs too as i was writing the original post, ill probably try some new ones asap. unfortuntely i dont have enough for a twin power, but newer plugs should be a step in the right direction

havent done anything with timing, not sure what wires you were talking about, but the only ones i changed were the mafs and injector wires, which were just splices.

thanks for the help though, im just not even sure what to start checking besides plugs

revlis240
03-18-2004, 12:26 AM
-33% fuel? for both low and high? its funny bradimus you and i have always had very similar setups, HKS everything, and now even the sard injectors. im running the SAFC at -25% for both high and low maps, and it runs well enough for now. when i was running -10% for the high map (rich so that i wouldnt blow up before i got to tune it) it would not rev above 6500 and misfire JUST like you said. so what does your high throttle map look like?
have you tried 2in 6 out?

-Abe

Brad
03-18-2004, 01:24 AM
hmm thats strange...it smells like im running super rich. i had the car backed into the garage, and when i started it and finally got it to idle, it would intoxicate anyone who was inside of it http://forums.freshalloy.com/images/graemlins/grin.gif. but youd think that -33% would be less rich than -25%. maybe i dont understand how the safc works. i will give it a try, starting to get frusterated. -25% it is. also going to get some new spark plugs tomarrow as well.

high and low maps are both -33%, enthalpy hooked me up with them. i kinda hinted that i only needed the bare minimum to get me to the dyno this saturday...but now i kinda want to feel a little power

oh yeah, safc on 2 in 6 out doesnt idle very well, and backfires at around 4-5k. i was running 3 in 7 out when i had my old hks filter just dangling on there. now i got a real 3" cone filter on tehre tight and had to switch it up.

thanks for the help tho, ill post back with what happens

oh yeah, on the safc in/out settings, i dont want to turn this into a moot arguing thing, but im 100% positive i was able to change the in and out settings on the fly. i originally had it on 2in 6out, and it was stumbling and barely keeping above 200rpms, so i started messing with the settings, and 1 in 6 out seemed to work ok. better bust out the wiring diagram again, my kanji is pretty crappy so i might have confused the tomei wiring diagram

revlis240
03-18-2004, 01:44 AM
its funny that your car was doing that misfire up high w/ -33% up there, you sure it was -33% up high? 25% is richer than 33% so i dont understand what is happening w/ your car. at 33% your misfire isnt because its running to rich like mine was. i dunno.

also, the SAFC will change settings on the fly, it just takes a second to do so. for example, if i change my setting to 6in6out itll stuble and attempt to die, and if i change back to 2in itll take a second, but itll be fine.

this whole safc thing has got me tied up in a bunch, cuz ive got thon over here ADDING fuel (makes 0% sense to me) and i seem to be at some kinda decent spot at -25%, and if i take anymore fuel out the useless af gauge goes to the lean side at close to wot (useless but still scary i guess). BLAH time to steal an LM1

-Abe

ThonG
03-18-2004, 08:00 AM
haha I'm adding fuel cuz I have a larger turbo with more boost:)

At 1k RPMs im at -30% (for my 480cc injectors) and its tuned for a correct a/f at idle (like 14.5:1)

thon

Brad
03-18-2004, 02:43 PM
ok well, headed over to autozone for some new plugs, they dont have any. ill try to get those before saturday (dyno tune), but i figure if im running rich then it will just foul the new plugs too, right?

oh yeah...i think im running heat range 6 plugs...bout a year old...i know...dont beat me massa http://forums.freshalloy.com/images/graemlins/tear.gif

also, i loosened up the bov, and its a little more active now. i guess im just used to the ssqv being so active with the t25, but i can get the full pshh sound once i get into the powerband a bit

hey what do you guys think about a bad o2 sensor? i know anyone whos pulled their manifold and has a/c knows that the o2 sensor and the a/c lines become close friends...repeatedly http://forums.freshalloy.com/images/graemlins/shocked.gif

rednerd
03-18-2004, 02:52 PM
The BOV thing bothers me more the the SAFC / fuel problem. Are you sure you have all of the vaccum lines hooked up right. If the FPR isn't seeing vaccum you would have idle problems because the fuel pressure would be to high. It would also be a vaccum leak which is never good for idle and might be messing with your BOV depending on the type that that you have. Check your turbo gaskets and clamps while you are at it.

revlis240
03-18-2004, 02:56 PM
wont the reading of that much more air through the maf = dumping of that much more fuel anyway by the ecu, thon?

-Abe http://forums.freshalloy.com/images/graemlins/confused.gif

ThonG
03-18-2004, 06:54 PM
no the ecu doesn't adjust that much, i dont understand why you're having a hard time grasping the concept http://forums.freshalloy.com/images/graemlins/smile.gif

thon

MATT_BACK_VASS
03-18-2004, 11:11 PM
in 2 out 6 for an N62 maf

MATT_BACK_VASS
03-18-2004, 11:11 PM
in 2 out 6 for an N62 maf

revlis240
03-19-2004, 03:46 AM
i would like to pride myself in being rather smart im most matters, im not tooting my own horn, but im no idiot. i just cannot still to this day grasp how a bigger maf makes sense, and i guess another one to add to that list, why you are adding fuel. i understand that bigger turbo = more fuel is needed. but pretend for one second you have an emanage. that thing just asks you injector size and bam, takes out 33%, car should run fine, and need FINE tuning. but if you ask me, adding 33+% fuel isnt FINE tuning, its massive changes that just doesnt click upstairs with me. with the pulsar turbo, you are pulling in lets say 500cfm of air at 3000rpm. im pulling in 200 cfm w/ my T25. these are hypothetical numbers, but isnt that what the maf is for? 300 more cfm of air, = more voltage = ecu gives more fuel? jeez what am i missing here. ima go crawl into my hole now, and wonder if i shoulda taken the short bus to skool

-Abe http://forums.freshalloy.com/images/graemlins/frown.gif

ThonG
03-19-2004, 04:30 AM
under load i add fuel because its adding a lot of air (18psi from a gtir at 4k rpm is like 35 lb/min as opposed to 14psi from a t25 is like 28 lb/min)

i guess it does seem odd that im going from subtracting 27% (in my car) to adding 33% at 4k rpm (for a difference of 60%+) but thats just how it works, and works well. But the voltage stays the same with the Z maf, opposed to the t25,atleast im fairly sure the voltage range stays the same, it just pulls more air in at any given voltage. Where's asad when we need him?

Thon

Enthalpy
03-19-2004, 07:48 AM
OK,

I have been watching this thread for a few days here and finally decided to chime in.

Bradimus. sounds like you have a N60 AFM. the N60 is identical in appearance to a N62. look on the upper right hand corner of the sticker on the MAF. also try in 4 out 6, with -33% across the board that would be the proper base calibration for 555's and a N60.

revlis240. the maf can output mroe than 5v...this is true. but if the ECU sees more than 5v then it wil shut down down the engine due to a percieved sensor fault. if you still dont understand, then go check my answer to this thread which you started about this very issue...

S-AFC, MAFS, and Injectors explained (http://forums.freshalloy.com/ubbthreads/showflat.php?Cat=&Board=UBB21&Number=67511309&page =0&view=collapsed&sb=5&o=365&fpart=1)

lastly, a less restrictive MAF also allows the compressor of the turbo to operate more efficiently. compressors operate on a pressure ratio...incoming to outgoing. if you have a mroe restrictive maf it will be pulling a vacuum before the turbo...making the incoming air 13.7 psi (absolute0 instad of 14.7 psi (absolute)...then if you want to run 14.7 psi (gauge) of boost you actually have to compress the air 15.7 psi to get there.

for many reasons...the Z32 maf is a very nice maf to run.

Scott

revlis240
03-19-2004, 02:31 PM
scott, i love you guys and am not trying to argue. my basic 'argument' is that, ok lets say thon is stock at 7psi. now he ups his boost to 14psi, hes flowing (in an ideal world) double the air correct? he doesnt have to make any changes to his a/f, he just boosts, maf adjusts and he calls it a day. WHY is it when he adds a bigger turbo (its just more air, just like upping the boost), now he has to ADD 60% more fuel? doesnt that seem a little odd? *60%*?

-Abe

ThonG
03-19-2004, 02:49 PM
uh no no no

If i add 7psi of boost i do have to correct with the s-afc (atleast with the z32 maf). or atleast i think its wise and best for performance to do so.

i know the car will run, but you really should be adding fuel when you up the airflow. When you go from 7psi on a stock maf (i imagine it'll do the same for z32 maf) to 14psi, the ecu goes into what i call 'freak out mode' and dumps fuel. This is not as efficient or safe as tuning the a/f's.

Just goto the dyno, run your car with a sniffer untuned on your safc and get a number, then tune it and compare your a/f's and powerband. I guarantee its smoother and makes more overall power (not peak necessarily)

thon

Enthalpy
03-19-2004, 03:08 PM
Abe, no worries mate...lets try and get to the correct answer...i can see where you are coming from here.

Yes Thon's numbers do seem a bit odd. but....there are a few things you need to know. the air meters are non linear. they respond on a exponential curve. that is you can get 1v at idle (.5 hp) 2.5v at crusing 10-20hp and 5v at max power 550whp. so you can get into situations where you need to add more than you would anticipate because the MAF signal (even after the S-AFC modifies it) is into a part of the map that doesnt really correspond with the right amount of fuel. now...having said all that....

i think Thon has an issue with his car if he is running the following setup:

480's
Z32
GTi-R turbo.


and he has to add 30% fuel on a stock computer to get to 11.5-ish afr's.

Base calibration for 480's and a Z-32 is:

-23% high and low throttle.
in 2...out 6


that should get you close. if you are at +30% then you have something wrong. usually you have to lean it out a bit off the base value.

Brad
03-19-2004, 04:09 PM
welp....heres an update for me (continue your discussion too if you want i dont mind)

new plugs, bcpr7es ngk. still breaking up around 5700+ rpms, no backfires or anything, just stumbling and such.

i did check the mafs, its an N60 or whatever, but the safc settings for 4in 6out makes the car die. it will only run ok on 1in 6out. could be mafs wiring, ill double check that tonite. but the tomei plug has color coded wires and everything, so it seems pretty hard to screw it up.

the main thing i noticed, is that it only does this at higher boost settings, and it appears the higher the boost goes, the earlier it breaks up. stock .5bar can rap all the way to redline no prob. i test drove it a few nights ago at .7 bar, and it broke up around 6500+. now its around 5700+. im going to stop driving hard cause i know it cant be good, but i just wanted to feel a little power to keep me going on this car.

ok so any ideas?

Enthalpy
03-20-2004, 09:26 AM
bradimus,

forst off the N60 MAF is a maxima maf. only has about 300-330 whp capacity....it is NOT the same as Z32 MAF. you dont need to change it....but just know it isnt a Z32 (550 whp) maf.

second. you need to look at your MAF wiring. it should be like this...disregard anythign else you have ever read on Z32 MAF wiring . this is the truth and it works the best:

ther are 6 pins on the maf. labeled a,b,c,d,e,f on the housing of the maf. wire it according to these pin names. heres how.

a - no cconnection
b - sensor signal (SR harness white wire)
c - sensor gound (SR harness black wire)
d - no connection
e - sensor power (SR harness black/white wire)
f - no connection.


if you have it wired any other way..change it to what i listed. no wire need to go to the chassis. that is wrong...yes i know what the tomei connector does...but it isnt necessary...and it is wrong http://forums.freshalloy.com/images/graemlins/smile.gif

nissan_s14
03-20-2004, 12:08 PM
no wire need to go to the chassis. that is wrong...yes i know what the tomei connector does...but it isnt necessary...and it is wrong http://forums.freshalloy.com/images/graemlins/smile.gif






Really? No wire needed to chassis? Maybe thats what's wrong with my Z32 MAFS. Harness work was wired by srswap..they left a wire for ground to chassis.

bl200sx
03-20-2004, 02:06 PM
bradimus,

forst off the N60 MAF is a maxima maf. only has about 300-330 whp capacity....it is NOT the same as Z32 MAF. you dont need to change it....but just know it isnt a Z32 (550 whp) maf.

second. you need to look at your MAF wiring. it should be like this...disregard anythign else you have ever read on Z32 MAF wiring . this is the truth and it works the best:

ther are 6 pins on the maf. labeled a,b,c,d,e,f on the housing of the maf. wire it according to these pin names. heres how.

a - no cconnection
b - sensor signal (SR harness white wire)
c - sensor gound (SR harness black wire)
d - no connection
e - sensor power (SR harness black/white wire)
f - no connection.


if you have it wired any other way..change it to what i listed. no wire need to go to the chassis. that is wrong...yes i know what the tomei connector does...but it isnt necessary...and it is wrong http://forums.freshalloy.com/images/graemlins/smile.gif





Humm....all of the wire digrams I have seen for the Z32 MAF have you use the 2 grounds from the Z32 to the SR harness black ground wire.

Thats how mine is wired.

Brad
03-20-2004, 08:39 PM
yeah still no dice, with the wiring you gave me scott. might be a bad mafs....im going to look around locally to see if i can borrow someone elses real quick.

DRAG_LIMITED
03-20-2004, 08:43 PM
I am falling behind bad in the HKS bling categorie, oh well, gotta get my ish running. Tell me how you like this turbo when ya get it running good bradimus!

Drifting Ricer
03-22-2004, 12:59 AM
I'm very interested in knowing the outcome of this thread. I too have set up pretty close to what you have and experiencing maf problems. Except, I didn't install the injectors, because they ordered the wrong ones, (shop). I ran the car around 7psis on the 370cc. For some reason I have to run 1 in 6 out on street (there is allot heastation around 3k RPMS) and 4in 9out (But it dies everytime I let go of the throttle for too long) on the highway. The car will stall out when the RPMS drop from 3k and above.... Yes I did follow Scott’s wringing diagram, which improved the idle a little bit.

I wanna keep this post alive, cause is helping me too. http://forums.freshalloy.com/images/graemlins/grin.gif

AZ_Dave
03-22-2004, 01:24 AM
Brad you REAAAALLY need to solder the maf wire connections. It is a very anal sensor and interferance and bad connections can trip it up.

Brad
03-22-2004, 01:58 AM
yes i know this, i will solder them tomarrow to see what happens.

i actually switched the wires (im still using the tomei plug, just using the wires in terms of the pin letters) and i got it to idle nicely on 4 in 6 out. wouldnt rev above 2k tho

i was just waiting to try and re-solder the connections tomarrow before whoring this post back to the top

Enthalpy
03-22-2004, 08:41 AM
solder is important on MAF wires. but it is also important to know that you will probably need a dyno tune to get your car runnign right. without a wideband you wont be able to tell if you are lean or rich.

Bradimus, what are your AirFlow %'s at idle and at 2000 rpm when it stumbles?

still trying to help you man!!

Brad
03-22-2004, 07:52 PM
k well heres the deal, i dont know if it was the solder of my temper but it looks like ive made a step forward

i just switched the mafs in and out settings while driving (cause the right ones wont let me idle), and it bogs and [censored] before 4k...but after that its insane. i crapped my pants. so yeah, sounds like its rich below 4k, ill try to tinker with the fuel, but i want to wait for a dyno

it will actually idle on 4 in 6 out, sounds pretty crappy and cammish.

oh yeah my knock sensor was reading 200s when i was boosting at .9 bar, but i didnt hear any audible knock or ping. i know the knock sensor is pretty crappuy on the SR, but i was getting 60-100 at most with the old T25...do i need to be worried?

Brad
03-23-2004, 04:44 PM
bah i hate to bump a post but maybe some of you guys missed it before it slipped to page 2 http://forums.freshalloy.com/images/graemlins/grin.gif

need to get it somewhat driveable so i can finally get back to driving it just say no to a geo

Enthalpy
03-24-2004, 07:18 AM
go to a dyno!!! you need to figure out what that thing is doing.

KmanSilvia
03-25-2004, 10:03 PM
hmmm poor idle / low load and good at high rpms.... sounds exactly like the problem i just solved on my car by making sure I had 14" of smooth pipe in between my Z32 MAF and GT25R turbo inlet.