WS6_Veteran

iTrader: (6)

Okay, so I recently got home from deployment about a month ago. I have been driving my '02 ws6 transam (with 90k and an M6) my wife picked up for me while I was in the stan. Since I have gotten home I have filled up the tank 3 times, I live on base so I only travel about 5 miles to my work and then other various places on base and I am only getting about 120 miles to a tank before I fill up at the 1/8 mark.

The first time I drove the car I got about 110 to the tank, near the end of that tank I did multiple things: install in NGK TR55's, MSD Wires, PCV (also added catch can in the process), also did the fuel filter, changed oil along with installing my suspension and changing trans and rear end fluid. I noticed a little change helping the fuel mileage but not what I expected (like 5-10 miles to tank after my next fill up). O and I also installed a catback slp lm1.

So I got to reading on the forums on here and read that if the air system air valve is stuck in the "open position" it is constantly throwing in air into the exhaust making the o2 sensors think its running lean cause it to throw more fuel in causing it to run rich. Also since I have owned the car I can smell it running rich when I stand on the side and in the back of the vehicle. So the beginning of my third tank I removed the air system and I just filled up today at roughly around 130 miles to the tank.

I realize I do drive city about 80% of the time, sometimes I go off base to go to town and get some stuff so I get it up into 6th gear but 3rd and 4th gear are my friends on base. But only around 120-130 miles to a tank is ridiculous, I am really about to park the trans am and only drive my wifes pontiac vibe (which she doesnt like incase she has to go somewhere).

The owner I got the car from only had it for 2 months and barely drove it and the owner before him had it repo'ed from him so previous owner had no knowledge on things done to the car.

The only thing I can think now is that a previous owner had something done to the fuel curve on the pcm or maybe the O2 sensors are going bad (probably stock the plugs were stock denso's at 90k). I'm not riding up the rpm's and I have only gotten on the car twice since I owned it and the second time I got pulled over because the cop said I went from 0-60 (SL was 55 on the road) too fast and broke traction a little bit which is bs but no more of that for me save it for the track and no I didnt see the cop anywhere he came up behind me 2 miles down the road and pulled me over lol. I'm just totally stumped and I cant keep affording to put 91/93 fuel in this car to burn a tank up that fast.

Anyone have any input that might help, thanks!

abrahamkay

Have you run any injector cleaner? Did your wife start it up and/or drive it while you was in the stan? Also welcome back fellow Military member. What service are you in?

WS6_Veteran

iTrader: (6)

I am army with 3rd Brigade 1st Infantry Division. My wife doesnt know how to drive a stick but a good neighbor of mine who owned a camaro went with her to check it out and do a good look with it. It was a 200 mile drive back from where they met to buy the car, my wife said she had to fill up the tank about 25 miles outside of home and they got it with full tank so highway it got around 175 miles before I was able to get ahold of it(this is me adding up the math now forgot to mention it sry a lot of factors and changes to the car soon as I got it). I put injector cleaner in on the first tank, a bottle of lucas.

I forgot to mention I installed an SLP lid and bellow when I did the rest of my mods, after I did this I got a check engine light for the MAF Sensor, guessing it got dirty because it was a PITA getting it to fit into the SLP Lid so i used soap and water and heated the lid so it could of gotten dirty. I did clean it with MAF Sensor cleaner, and while I was doing that I also sprayed a whole can of intake cleaner inside the intake while it was off (just looking at the butterfly) it was disgusting it ran rough a little bit and missed but after burning out all that cleaner she ran fine.

rperk

How many gallons of gas are you putting in at an 1/8 of a tank? Is it close to 11.5 to 12.5 gallons? If not, your sending unit in your tank could be faulty, and you could be showing an 1/8 when you actually have a half a tank.

abrahamkay

I didn't think about that being possible to with what rperk said.

VandykeT/A

The gas hand on my camaro would read fine until about 3/4 of a tank and then it would start falling toward empty. Mine has a faulty sender but alot of guys have them get stuck from the gum in the tank. If it truely is getting 120 mpg. I would try cleaning the MAF sensor and the throttle body. If that doesn't work I'd go for the upstream 02s. I would have thought they'd thrown a code by now though. I'd have the codes checked whether you have a light or not. I've seen cars with the wire cut. It just stores a code for a ground in the computer.

WS6_Veteran

iTrader: (6)

Im putting like 11-12 gallons in at around 1/8th. so im pretty sure this isnt the problem.

I have a reader on my computer that will show me the voltage each o2 sensor is reading I just need to know what they are supposed to sit at at when.

WS6_Veteran

iTrader: (6)

And the only check engine light im throwing right now is for my air system delete.

jaxcam02

iTrader: (1)

Thats insane man. I get 200 miles a tank in the city and I thought that was bad. I know you just changed the fuel filter but I would try to pour a can of seafoam in the gas tank and fill it up, Only thing I can think of is some issues with the injectors or something in the fuel system. The seafoam will clean alot of gunk out of the gas tank and may foul up the fuel filter so I would change that again. I just recently seafoamed my tank after replacing the fuel filter and I just changed the filter last week. My filter was extremely heavy compared to the first one I took off and the new one. Im assuming I flushed the majority of that crap and the filter did its job. Good luck fixing the problem, 93 octane is hella expensive so I feel your pain. Hopefully someone will have better suggestions.

peterock98

iTrader: (25)

Change your 02 sensors before the cats.Also once you put the top end cleaner in your intake your plugs should be changed.

VandykeT/A

Maybe it has something to do with air system. I've deleted it in my camaro and t/a and never got a code at all.

WS6_Veteran

iTrader: (6)

I have run lucas and was thinking about seafoam, but if the car was running rich (which I can smell) and the pcm was throwing in TOO much fuel why would the injectors be clogged? If they were clogged I feel like I would have missing or knocking problems from preignition in the CC from not enough fuel.

The plugs were changed after spraying the intake cleaner so I am good there, as for upstream O2 sensors this will be my next fix. If this doesnt work the car is getting parked until I have a highway trip to do so I can gauge my fuel usage off the highway trip.

chrysler kid

iTrader: (14)

this sounds dumb but my car ran pig rich when i had the intake air temperature sensor go out. because the density of air changes in cold weather the car doesnt know the density of air passing by the maf to adjust the fuel curve. it also did not trigger a check engine light. might want to look into getting a new one, they are $15 at autozone.

Also another dumb thing to check is the gas cap. if your system isnt properly sealed it can effect that too.

symptoms of a leaky injector would most likely include a hard startup which you havent described.

jam01

Oxygenates are fuel additives that contain oxygen, usually in the form of alcohol or ether. Oxygenates can enhance fuel combustion and thereby reduce exhaust emissions. Some oxygenates also boost gasoline octane.

The Clean Air Act requires use of oxygenated gasoline in areas where winter time carbon monoxide levels exceed federal air quality standards. Without oxygenated gasoline, carbon monoxide emissions from gasoline-fueled vehicles tend to increase in cold weather. Winter oxygenated gasoline programs are implemented by the states. The links below provide information about oxygenated gasoline, winter oxygenated gasoline areas, oxygenates (such as ethanol and MTBE), and health effects testing of oxygenates.

i dont know if your state makes you use this worthless garbage, but it is worse than the unleaded gas were forced to use. im not saying this is your problem but may be part of.

MrOrange360

I am having a similar issue. My Car is stock and has 63k on it. I need help.

WS6_Veteran

iTrader: (6)

I might replace this, if its only 15 bucks it can eliminate one of my what-ifs. Thanks for this.

Also when I go to autozone to pick it up I want to get a set of new upstream o2 sensors, does anyone know the best ones to get for our cars from a parts dealer like this? Will they have the factory Denso's?

jaxcam02

iTrader: (1)

im pretty sure any parts store should have the densos just stay away from bosch. and btw your probably correct on the seafoam thing, i just figured it would be helpful to have a fuel system clean of debris. and i think i remember reading it kinda helps clean out the catalyst to but that would effect more of the post cat O2s so it shouldnt effect air fuel that much.

WS6_Veteran

iTrader: (6)

Nevermind, picked up factory denso O2 sensors from RockAuto.com and the stock air inlet, these guys are awesome and pretty much manufacturer price cheap. Those 2 upstream right and left and Air Temperature Sensor only cost me 82 bucks after shipping... Autozone wanted over 150 for the exact same part.

jaxcam02

iTrader: (1)

good find, i usually look at rock auto too, ive got a couple parts from there. Let us know how those work out.

Onyx_Black_Z28

iTrader: (2)

WS6_Veteran, I'm having a similar issue that I just posted a thread about. You are much further into the diagnostic process than I am (read: I haven't started yet). Sorry to hear about your issue. I'm subscribing to this thread so I can hopefully share in your outcome. Looking forward to hearing how swapping the O2's turn out.