2G P0170 code etc

[la-panocha]

Hi all. I have done my searching of threads and tried advice given to others for similar problems and no luck.
Trying to keep this short n sweet...
I bought 96 GSX from a lady who was original owner($500) After popping hood I found numerous leaks, basically I ended up replacing TB shaft seals, TB gaskets, Int.Man. gasket, replaced injectors(stock) put in 1gen BOV, BISS o-ring, and boost gauge, fuel presure reg. solenoid, new wires and colder NGK plugs, K&N+int pipe. After all this I did a pull down the street and the T25 hit 18psi...cause is WG act. solenoid under MAF. Did straight connect from turbo to WG actuator and then only hit about 11psi.
The car was running really rich for her with gas mileage around 12mpg, after I cured all leaks and WG act. solenoid bypass the gas mileage is about 14mpg.
Also she stored car for summer and used as winter car, not sure if that's relevant.
I just got done replacing turbo with an EVO3 16G and new exhaust manifold since old manifold had 4" long crack and T25 had ALOT of shaft play and squealed a bit.
After putting about 60 miles on new set-up and mild boosting I get P0170 code which I am leaning towards O2 sensor which I know can cause poor mileage but unclear why it would throw code now and not before turbo swap.
There are no leaks and holds 10psi from turbo to motor. Cylinder compression is even across the board.
I even checked the grounding strap on exhaust.(not sure why that would cause bad mileage but seen that in a post)
Any help would be greatly appreciated.
I have an Actron scanner on the way as I have a few vehicles I work on.

 

[jcart953]

http://www.dsmtuners.com/forums/newbie-forum/348754-p0170-error-code.html

http://www.dsmtuners.com/forums/maintenance-repairs/404552-code-p0170-fuel-trim-bank-1-a.html

DSM Forums - Search Results

 

[la-panocha]

Thank you for reply Jcart, I have read just about all the searches.
I will be replacing O2 in a few days but am confused why CEL never came on before now.
Also one thing I neglected to mention is this, there are 3 solenoids on firewall. Far right is the FP reg sol. and not sure what other 2 are but the middle one will pulsate/tick tick tick. I believe it is part of the evap system. The ticking comes and goes but has done it since I got car.
I assume since she had car sitting in storage I should expect solenoids have gotten sticky or dried out etc.(FPR does not have gas smell in vac lines)
Can an O2 sensor be almost bad but on the edge so CEL won't come on?

 

[nickk90]

I would look for pre o2 exhaust leaks and vacuum leaks first. Dont you have a logger or scan tool to read o2 voltage?

 

[josh1095]

dude forget ## problems!! a 500 dollar 96 gsx??? you gotta be kidding me. congrats! id pay 500 for any eclipse with a blown motor and tranny.

 

[la-panocha]

haha Josh, that's why I jumped at the chance to get it.
I also neglected to mention that the tranny was in limp-in mode and she was thinking of junking GSX. All it was, a blown fuse.

I've done vac leak checks and checked pressure from O2 housing to top of turbo before install and everything is great.
I have the Actron CP9580 OBD2 scanner on it's way and could post data from that...

Is there a link someone could post for the ideal readings on an Actron I should see after I put new O2 sensor in please?

She is a dog off the line but once rpms get up and turbo spools she sounds good, and when I get to about 5K boost gets too about 15 and she pulls F'n hard

 

[wicked98gsx]

Wow... Im glad I looked this up. You have had the EXACT same problems I'm now having with my 98 gsx. I just threw this code last night. Are or did you have have any fuel cut issues when you put on the 16G? Mine hits 18 psi and fuel cuts. No boost leaks or anything.... I cant figure it out. sorry to ask this on your post but Everyone on this site is smarter than me.

 

[la-panocha]

I just replaced the O2 sensor (upstream) and put about 75 miles on GSX today. No CEL.
This car had many many many issues when I got it and poor gas mileage was one of them. I think the tipping point for the old O2 was the turbo upgrade.

I only have max boost at 14 atm, no fuel cut

 

[derek97gst]

What would some other symptoms of a bad o2 sensor be? I currently have a check engine light an i ran the code and it showed the p0170 bank 1 and another for my mdp sensor. But im not noticing any changes with my car. I have noticed a decrease in mpg but nothing to severe i guess. I do have a catless down pipe so i figured that was my reason for that? Any input please?