# 96 g20(det) Rough Idle / slow Boost? HELP??????



## cbr954rr_g20_j (May 18, 2004)

Thanks ahead of time for any help or insight anyone may have. I have a 96 g20 with a u12 det running US JWT ecu. I am getting the error code 12 which is the MAF sensor. I will get between .76 and .8 voltage reading with the car off. With the car running i get between 1.6 and 2.1. I have tried regrounding the MAF but that didn't help. I have 4 different maf's and all of them give me 12 code. The car will run really rough at idle and will not blow off. I set the BOV to as soft as possible and now it very slightly blows off. Normally it will just make a flutter noise which i know is the boost bouncing back in to the turbo which i know is bad. When driving it will boost up to 7lbs which is where i have it set at but it doesn't reach full boost till 3800 rpms and normally it reaches it at 2500 rpms. I have checked all of the relays and fuses and am at a complete dead end. Some one please help me with this problem. Thanks


----------



## James (Apr 29, 2002)

when you put the jwt ecu in did you make sure the harness is fully seated into the ecu?


----------



## cbr954rr_g20_j (May 18, 2004)

the JWT ecu has been in there for well over a year and has ran fine this problem just recently arose. thanks


----------



## chimmike (Oct 17, 2002)

you recirculating the bov? what have you changed recently?

I think you might have a boost leak somewhere. check ALL the connections on your intercooler piping


----------



## cbr954rr_g20_j (May 18, 2004)

i am not recirculating and never have been... i have checked my piping and i replaced a small peice that was questionable. Correct me if i am wrong but if i had a leaking pipe it would still idle fine just run bad under any acceleration. i know i am going to get flamed for saying this but the car not blowing off is not a mechanical problem it is a electrical problem.

I previously had a problem with my 02 sensor wires melting together. I belive it was due to the fact that i was using the incorrect 02 sensor and i had to extend the wires my self. I purchased a brand new 90-93 02 with the longer wires and installed that. I am not getting a check engine light for that anymore. But i am getting the check engine light code 12 which is the MAF sensor. i have switched back and forth between 4 differnt MAF's and nothing is working. I tried regrounding the MAF too and that didn't help. Previously when my car would run like this i would re do the wires on the 02 sensor and replace the Engine cont. fuses and the car would run great. But this time no fuese are blown and i checked Engine Cont. relay and it works also. 

This problem is pissing me off so bad i just want to drop my car off at the junk yard so i don't have to deal with this crap.


----------



## SUN-E (May 3, 2004)

Hey man, I'm sorta having that same prob. but I got a gti-r and I blew an engine control fuse, fixed it and now it idles off and at around 3200-3600rpm it flutters and almost stalls. Do u have that same prob. The thing is I just installed mine and have yet to have it work properly at all. My check engine light also comes on like yours and but tends to go off until I give it gas at like 3000 and ^^. I hope we can fix this crap lol but gl anyway!


----------



## chimmike (Oct 17, 2002)

actually, when I had a leak in the piping, the car wouldn't idle right at all....because you're losing metered air (after the MAF)


----------



## James (Apr 29, 2002)

get a vacum gauge on there and see for sure.


----------



## FourN2ner (Dec 10, 2003)

SUN-E said:


> Hey man, I'm sorta having that same prob. but I got a gti-r and I blew an engine control fuse, fixed it and now it idles off and at around 3200-3600rpm it flutters and almost stalls. Do u have that same prob. The thing is I just installed mine and have yet to have it work properly at all. My check engine light also comes on like yours and but tends to go off until I give it gas at like 3000 and ^^. I hope we can fix this crap lol but gl anyway!


u have a vacume leak look at your boost guage in that range and see if its bouncing around sun-e what state are u in u need a shop!


----------



## FourN2ner (Dec 10, 2003)

cbr954rr_g20_j said:


> Thanks ahead of time for any help or insight anyone may have. I have a 96 g20 with a u12 det running US JWT ecu. I am getting the error code 12 which is the MAF sensor. I will get between .76 and .8 voltage reading with the car off. With the car running i get between 1.6 and 2.1. I have tried regrounding the MAF but that didn't help. I have 4 different maf's and all of them give me 12 code. The car will run really rough at idle and will not blow off. I set the BOV to as soft as possible and now it very slightly blows off. Normally it will just make a flutter noise which i know is the boost bouncing back in to the turbo which i know is bad. When driving it will boost up to 7lbs which is where i have it set at but it doesn't reach full boost till 3800 rpms and normally it reaches it at 2500 rpms. I have checked all of the relays and fuses and am at a complete dead end. Some one please help me with this problem. Thanks


what maf do u have? look at your boost guage is it fluttering around ? have some one hold the throttle in the trouble rpm range and start messing around check all hoses AND the hoses on the ic piping and dont argue with us were just tring to help u !!! when someone asks 4 help and then doesnt atleast try it . we get discourged this is most likly stuff that happend to us and were passing it on to u to help u after all every install is diffrent and not a factory installed motor so theres no way we know :hal:


----------



## SUN-E (May 3, 2004)

Yeh I totally appreciate your help guy's!! I do need a freakin shop. I live in New Jersey and not sure of anyone around here. I don't have a boost gauge or any other gauges. I know I need them and I will buy them asap. I have checked all hoses but I have nothing to base my result's off of (no example) or another running gti-r. I wish I knew someone lol well I'll get some gauges and see what happens. Thank'z


----------



## cbr954rr_g20_j (May 18, 2004)

FourN2ner said:


> what maf do u have? look at your boost guage is it fluttering around ? have some one hold the throttle in the trouble rpm range and start messing around check all hoses AND the hoses on the ic piping and dont argue with us were just tring to help u !!! when someone asks 4 help and then doesnt atleast try it . we get discourged this is most likly stuff that happend to us and were passing it on to u to help u after all every install is diffrent and not a factory installed motor so theres no way we know :hal:


 I do appreciate everyones insight and help greatly. i have no problem looking into every single answer whether it is outrageous or well thought out. I have spent a couple months dealing with this problem so i 95% of these basic problems i have looked into. But again thank everyone for input on this problem. i just know that the problem is an electrical problem and nothing mechanical.

Off the top of my head the stock one that was on the car is a 53j01 and the other 3 i have are 53j00's. I ran the 53j00 for a couple months and it worked. I had to butcher the harness to get it to work but it did work. The boost gauge does not flutter at all. But when i driving the car it takes longer to get to full boost and then when i let off the throttle it does not blow off.

What happend was my 02 sensor wires melted together and that caused the problem. It had happened before and all i did was rerun the wires and it worked fine. This go around i bought the correct 300zx 02 sensor and that didn't solve the problem. But now i get the CEL 12 code which i wasn't getting before. If there is a wire that is related to both the 02 sensor and the MAF then i am willing to put money on it that that is the problem but i havn't yet found such a wire. 
thanks for the help, justin


----------



## FourN2ner (Dec 10, 2003)

cbr954rr_g20_j said:


> Thanks ahead of time for any help or insight anyone may have. I have a 96 g20 with a u12 det running US JWT ecu. I am getting the error code 12 which is the MAF sensor. I will get between .76 and .8 voltage reading with the car off. With the car running i get between 1.6 and 2.1. I have tried regrounding the MAF but that didn't help. I have 4 different maf's and all of them give me 12 code. The car will run really rough at idle and will not blow off. I set the BOV to as soft as possible and now it very slightly blows off. Normally it will just make a flutter noise which i know is the boost bouncing back in to the turbo which i know is bad. When driving it will boost up to 7lbs which is where i have it set at but it doesn't reach full boost till 3800 rpms and normally it reaches it at 2500 rpms. I have checked all of the relays and fuses and am at a complete dead end. Some one please help me with this problem. Thanks


 just reading the post again 
do u think that the maf reading could be reading off tps voltage 
i think the tps is off with jwt ecu u set it @ .5 closed and should be somewhere around 4.somthing @ wot that would cause rough idle and would read rich thinking it was open .....worth a shot easy to over look mine vibrated loose a few times


----------



## cbr954rr_g20_j (May 18, 2004)

FourN2ner said:


> just reading the post again
> do u think that the maf reading could be reading off tps voltage i think the tps is off with jwt ecu u set it @ .5 closed and should be somewhere around 4.somthing @ wot that would cause rough idle and would read rich thinking it was open .....worth a shot easy to over look mine vibrated loose a few times


I checked the TPS a while back and didn't see a problem but i will try it out a little more throughly today. and let yall know what happens. thanks


----------

