REALLY not liking my SR right now...

[AsleepAltima]

shit is so annoying. stuttering at wot in the 1st three gears. reinforced the coil pack grounds, checked coil pack resistance - .7 across the board, grounded the head, checked fuel pressure - 38ish w/o vacuum, checked gaps - didnt matter if it was .022 or .028.

new build sr - s13 black top
87mm pistons
cosworth 1.1 head gasket
arp head studs
j30 maf
jwt ecu
gt2871
bc stage 2 cams
740cc injectors
cant think of anything else that should matter, for specs


http://www.youtube.com/my_videos_edit?ns=1&feature=vm&video_id=Bmuek3r0KDE

[Edwin562]

Check if maf is good?

[future]

You chEck everything but the maf, nice one

[AsleepAltima]

You chEck everything but the maf, nice one
maybe i forgot to put that down? think of that? nice one.

i checked the maf, tried grounding it too and checked for voltage - both good.
also, tps is set to .45 and idle is perfect.

[chetacheese]

What kind of fpr are you running? And is it adjustable. If so, is it adjusted?

Is it a chipped ecu? Was it dyno tuned?

More info can help us help you eliminate some possibilities.

[ultimateirving]

How about Boost leak, When was the last time you pressure tested the entire system? Also BOV leaking at boost can cause horrible shuttering

[JDMRIDDAZ]

the coilpack could still be bad even if resistance checks out
use a spark light...
this hasppened to me,,,
fpr should be 3bar
41-43 psi

[KiLLeR2001]

Could very well be a bad coilpack if it happens around 4000 to 5000 rpms. Also does it matter if the engine is cold or at operating temp?

[AsleepAltima]

im running an aeromotive fpr - boost reference. the fuel pressure is 43ish with vacuum - just like it should be per the fsm.
i replaced all of my couplings and pipes to reduce the amount of couplings that i had before because i did have a couple boost leaks. its a jwt ecu set for everything im running.
it ran well initially and then developed this problem. its pretty damned annoying to say the least. i was talking to cody ace the other day and i will be replacing the coil packs - with ls2 coil packs. i think its an electrical problem at the moment.

[itwillboost]

LOL should have stayed KA :wall:. I would pick up LS2 truck coils, they will fire much stronger, just remember you need to buy the whole harness. Are you set up for data logging if so email me the log. Hopefully it works out.

Did you change downpipe's recently ? How far from the turbo is your o2 sensor ? That or the coil is my guess. Your A/F's don't dip at the higher rpm's right ?

[AdamR]

Didn't watch the video. What is the AFR like when it happens?

[AsleepAltima]

Could very well be a bad coilpack if it happens around 4000 to 5000 rpms. Also does it matter if the engine is cold or at operating temp?
im blaming a coil pack too, at the moment. im going to do it old style and replace each coil one by one till i find it. i dont think its a multiple coil problem. it doesnt seem to do it as bad when its cold, but its still there.


i dont know what the afr's are - i dont have a wideband installed. it may sound silly, but i never ran a wb in my turbo altima because the jwt ecu seemed to be so spot-on, so i didnt bother with this one either. reading my plugs however, they dont look lean or rich - they look just right. i do have a wb sitting here though, i just havent decided if i want it in my evo or the 240 just yet.

[AsleepAltima]

LOL should have stayed KA :wall:. I would pick up LS2 truck coils, they will fire much stronger, just remember you need to buy the whole harness. Are you set up for data logging if so email me the log. Hopefully it works out.

Did you change downpipe's recently ? How far from the turbo is your o2 sensor ? That or the coil is my guess. Your A/F's don't dip at the higher rpm's right ?
its the same setup that i ran before the rebuild. it ran smooth as silk until the piston swelled up and killed the rings.
and as far as the ka goes - i loved it on my altima, but i love the simplicity of the sr much much more. :)

[Jesse SR20]

How about Boost leak, When was the last time you pressure tested the entire system? Also BOV leaking at boost can cause horrible shuttering


This.

Especially since you mentioned re-doing your piping/couplers.

[AsleepAltima]

i dont have a boost leak setup anymore but i was pretty careful about these couplings going on. i used new clamps and pliable couplings. the old ones were brittle and the clamps were iffy. i also switched over to a hard intake pipe instead of the soft flexible one. it did this before swapping the clamps though, although it did soften it a bit. the boost leaks were very obvious before, but now its pretty tight.

[AsleepAltima]

lowered the boost to about 18ish and the problem is gone. im pretty sure its all coil related now. changed each coil out with a known good coil and there was no difference whatsoever.

[TheRealSy90]

So its obviously not the coil.

[KiLLeR2001]

Whats the spark plug gap? Check spark plugs for any irregularities.

[AsleepAltima]

So its obviously not the coil.
how so?
i think its even more pointing to it now.

[AsleepAltima]

Whats the spark plug gap? Check spark plugs for any irregularities.
brand new bkr7 iridium ngks with less than 500 miles on them. the gap is .028. i tried all the way down to .022 and no change whatsoever. :(

[jr_ss]

Need to upgrade your ingition system. You need more dwell time and you can't do that with factory coils.

[AsleepAltima]

Need to upgrade your ingition system. You need more dwell time and you can't do that with factory coils.
i agree with you. i bought some lsx coils yesterday and they should be here to me in a couple days. :)

[AsleepAltima]

i took a look at my jwt ecu today and i dont see the recommended fuel pressure on it like the ka-t jwt ecu i had. is it the same? 3 bar? looks im gonna have to call jwt again...

http://img.photobucket.com/albums/v610/AsleepAltima/turbostuff2.jpg

[AsleepAltima]

anyone what the "12mm" thing is for?

[TheRealSy90]

Because you said you changed each coil out with a known good coil, and it didn't make a difference. So its obviously not the coil.

[AsleepAltima]

Because you said you changed each coil out with a known good coil, and it didn't make a difference. So its obviously not the coil.
im taking back what i said about "known good coil". the one i have with the most resistance made each cylinder it went into, miss. now im not even sure i have a good set of coils. lol

[srvnt]

bad 5th gear position sensor can do that also

[AsleepAltima]

not happy about what i found just now - lowered the boost the other day and it was fine... then today, it started doing it again. so i went out to check and double check the fuel pressure again. while i was there, i took a look at the ignitor and the dude that wired it up before i had the car, on the bundle after the ignitor on the engine side, used electrical tape and ran it under the regulator. so i grabbed one of the wires and INSTANTLY, the idle dropped and the engine started to stumble. pinched a couple other wires and the same thing happened... im going to be just as pissed as i am happy if it turns out to be shoddy wiring... well, when the lsx coils get here tomorrow or the day after and i have to eliminate the stock ignitor, i will fix the wires and solder/heat shrink it properly.

[PureRush]

It's the timing. My Ka was doing the same thing cause it was too advanced

[AsleepAltima]

i checked and rechecked the timing. it settles right in at 14/15ish.

[bb4_96]

im always surprised at the amount of shoddy wiring there is out there.

[AsleepAltima]

im always surprised at the amount of shoddy wiring there is out there.
right??? when i did the ka-t harness and the sr harness on my coupe, i soldered and heat shrank EVERYTHING. when i had to convert my obd 1 car to obd 2 - i heat shrunk and soldered all 60+ wires. its a lot of work, but it needs to be done to have piece of mind and to also not have a freakin fire! i wish people would understand that. this means that now im going to have to go thru all of the wiring and fix all of it. i already fixed some, but now im going to have to hunt down ALL of it.

[Bentleyness]

no one said timing. it should be @ 15* this fixed both my friends sr, the screw wasnt tight on the dizzy so over time it advanced to 25*

[di-devol]

anyone what the "12mm" thing is for?

It's mentioning your are using the skinny O2 sensor for feedback, I asked the same thing lol.

I had the same problem, but it was the injector wiring. Good luck!

[GroundPerformance]

Does sound like ignition related. LS Coils definitely would be a great upgrade. But personally fixing the wiring and adding a 30amp relay for the coils to get its power source direct from the battery may have helped.

Similar to this config that Yashio sells.
http://www.yashiofactory.co.jp/cam_p/okachan_tenka/n_t_harness.jpg

[AsleepAltima]

thats a good looking harness. i might do something like that to clean the bay up a little. im going to check my injector wiring too while im at it. i havent gotten my coils yet, but when i get them, im going to take my time and wire everything up real nice.

[hartig]

knock sensor? mine acted terribly for a while too, disabled the knock sensor, and it runs perfectly

[AsleepAltima]

id be nervous about disabling something like that on a turbo'd engine.

[AsleepAltima]

question - im reading that some people wire in their uego's to send a signal to the ecu and eliminate the stock o2 sensor... can we do that with the sr20 ecu? i went thru the instructions for my aem uego and it has an output but im not sure the ecu can read from it since its looking for a narrow signal.

[spartanmisfit]

Do you have the problem only under boost?

[AsleepAltima]

Do you have the problem only under boost?
only wot. i can boost semi-aggressively all the way to redline but it will sputter here and there if its wot or too aggressive.

[jr_ss]

Most wide band O2s have a narrow band output to be wired into the factory ECU if you wanted.

[budderigs]

it sure sounds like your on the right track. in between running alot of boost on stock coils. not to mention a possible electrical issue. a stutter and miss is going to happen.

food for thought, if the new ls coils dont solve the issue.

on my setup, lets say I have my car tuned to run at 15psi. then I decide I want to turn it up to 25 psi. as soon as it builds boost over 15psi it will run super rich and wll miss badly.
it does this because the higher boost setting draws more air through the maf.

i am sure your case will be a little differnt sense you have a rom bur and I am using a piggy back. but a maf controled engine is a maf controled engine. if that ecu is rom burned to run at 15 psi with turbo of (x cfm) and you are running higher psi or turbo with higher cfm flow. it is going to run richer. and once it runs to rich it is going to miss.

if the ls coils dont fix the issue I would suggest dynoing the car with a wideband on it. or install the wideband you have and watching what it does.

I would suggest getting a vehicle specific tune for your car no matter what.

[JDMRIDDAZ]

Does sound like ignition related. LS Coils definitely would be a great upgrade. But personally fixing the wiring and adding a 30amp relay for the coils to get its power source direct from the battery may have helped.

Similar to this config that Yashio sells.
http://www.yashiofactory.co.jp/cam_p/okachan_tenka/n_t_harness.jpg
i made this for my sr20det..but i used heavier wire and i used a relay per 2 coils...^^^^^^^^^this sells for like 100..something ....
it cost me like 15 worth of materials...and i made it tougher then this
this is a relay for a chinese fog light

[AsleepAltima]

it sure sounds like your on the right track. in between running alot of boost on stock coils. not to mention a possible electrical issue. a stutter and miss is going to happen.

food for thought, if the new ls coils dont solve the issue.

on my setup, lets say I have my car tuned to run at 15psi. then I decide I want to turn it up to 25 psi. as soon as it builds boost over 15psi it will run super rich and wll miss badly.
it does this because the higher boost setting draws more air through the maf.

i am sure your case will be a little differnt sense you have a rom bur and I am using a piggy back. but a maf controled engine is a maf controled engine. if that ecu is rom burned to run at 15 psi with turbo of (x cfm) and you are running higher psi or turbo with higher cfm flow. it is going to run richer. and once it runs to rich it is going to miss.

if the ls coils dont fix the issue I would suggest dynoing the car with a wideband on it. or install the wideband you have and watching what it does.

I would suggest getting a vehicle specific tune for your car no matter what.
yeah a modified tune is definitely in the works. funny thing though, the last time this car ran was about 2009 or so, it ran at 20-22 lbs boost and didnt have this problem. when i got back from deployment and started putting this car back together, late last year, i went from the stock pistons to the 87mm pistons and 264 cams. thats the only major change in the setup. maybe the added flow is causing it? not sure. i kept the compression the same, so hopefully its not that and this car only sees 93 octane. i installed the wideband yesterday and just need to get the bung welded in now. the coils came in today so i gotta get those mounted and wired in now too.

on to the wideband... i was reading the instructions and i know which wire is the 0-5v output (not like its hard to find. lol) and was wondering, can i just wire that into the ecu harness now? using pin 19? will the ecu (jwt burned) see that signal and use it? just need to make sure so i dont get the bung welded in if i really dont need to.

you guys are a great help - hard to get help from zilvia sometimes and the nissan forums i moderate are not very sr20det heavy so not much help there.

[jr_ss]

Yes, you can run it to that pin. However tge ECU still sees it as a narrow band reading so you cant rely on it to tune.

[ultimateirving]

question - im reading that some people wire in their uego's to send a signal to the ecu and eliminate the stock o2 sensor... can we do that with the sr20 ecu? i went thru the instructions for my aem uego and it has an output but im not sure the ecu can read from it since its looking for a narrow signal.

Yes you can run this, the AEM should have a simulated narrowband output.
Also, Knock sensor is useless above 4k rpm for SR, if yours is damaged/missing it will cause issues. BYPASS IT and be done. There are many write ups on how to do it. And I personally bypassed my own.

Check back after fixed.

[AsleepAltima]

Yes, you can run it to that pin. However tge ECU still sees it as a narrow band reading so you cant rely on it to tune.
understood. cody ace pointed me in the direction i need for logging thru the port. im not trying to tune with the narrow band, i just need it to keep sending my ecu the required signal. at least now, i dont have to get that bung welded in. i really really didnt want to pull the downpipe. lol

[AsleepAltima]

Yes you can run this, the AEM should have a simulated narrowband output.
Also, Knock sensor is useless above 4k rpm for SR, if yours is damaged/missing it will cause issues. BYPASS IT and be done. There are many write ups on how to do it. And I personally bypassed my own.

Check back after fixed.
you know, i painted my block after i had it bored out, acid cleaned and checked. i was careful to clean the area the knock sensor mounts to but it could still be a problem area now... ill try disconnecting it and see what happens - before i do the coil packs.

[AsleepAltima]

i kinda answered my own question too... the 0-5v IS a narrow band signal... right? lol

[cotbu]

i kinda answered my own question too... the 0-5v IS a narrow band signal... right? lol
No! it's not!

[AsleepAltima]

No! it's not!
cant just say no, its not - gotta say why it isnt...

[cotbu]

it should have been obvious! The wide band signal is 0-5v.

Narrow band
http://www.google.com/url?source=imglanding&ct=img&q=http://antzone.web.id/wp-content/uploads/2011/10/NarrowbandOutputGraph.jpg&sa=X&ei=QSXyT9rfI6PJ6wGnq7GtBg&ved=0CAwQ8wc&usg=AFQjCNHn0rkMMDSm03lKDW00Bx4H8cXBmg

Wide band
http://www.google.com/url?source=imglanding&ct=img&q=http://cherrypicker.tripod.com/sitebuildercontent/sitebuilderpictures/widebando2.jpg&sa=X&ei=QCXyT-fuHcLG6gGJhu2EBg&ved=0CAwQ8wc&usg=AFQjCNEPk2Fhus7kpP9OyqOPNMZNwmeLBg

[AsleepAltima]

got it.
figured it out - last question for the output wire is - which setting on the back of the gauge should it be set to? both p3 and p4 are 0-1v outputs, but i need to know if its autronic or nernst?

[AsleepAltima]

car is fixed. dont know if anyone is even reading this, but the lsx/truck coils fixed the stuttering and the wideband revealed a new problem. power was there but at 5k rpm, it would go lean. i checked fuel pump voltage and it was low. jumped it from the battery and the problem is absolutely, completely gone. car now, in boost, is at 11.2-12.2 on the wideband and it pulls like a pissed off raped ape. also, the setting for the ecu to read the narrow band signal from the aem wb gauge white wire is p4. i removed the jumper and am putting together a relayed circuit that i will install in the morning. definitely a learning experience but im very pleased with my sr for the time being. :D

[ANDY black s13]

Some good info there on both the coils and the pump feed,And glad you sorted the problem

[jr_ss]

Some good info there on both the coils and the pump feed,And glad you sorted the problem

Generally speaking, if you have a boosted motor and an upgraded pump you need to do the fuel pump wiring upgrade. Use the factory wiring as your relay 12v switch and wire the rest with larger gauge wire and directly from a battery. That way you no longer have psi drop under heavy load.

[AsleepAltima]

Generally speaking, if you have a boosted motor and an upgraded pump you need to do the fuel pump wiring upgrade. Use the factory wiring as your relay 12v switch and wire the rest with larger gauge wire and directly from a battery. That way you no longer have psi drop under heavy load.
yeah i didnt expect there to be a problem because it wasnt there pre-build. i wired up a spdt relay last night and will install that today. it was definitely what the car needed. lol