fuel trim problems

[bmxcoolcat1]

i recently purchased a 98 gst spyder it needed a motor so i put a used motor with 100,000 miles in it.
car runs perfect but when at 1/2 tank fuel and i take a sharp curves fuel cuts out or when im at 1/4 tank or below and i get on it hard fuel cuts out.
so my check engine light is on and its reading a fuel trim malfuntion.car is all stock i heard that cracked headers will cause this problem so i replaced them same thing now im thinking maybe fuel pump i order a walbro 255 but havent installed it yet

 

[kenamond]

I'm not sure about the fuel issue. Maybe there's a problem with the fuel pickup in the tank.

If you have a logger, check your front O2v during idle. If it fluctuates around 0.5v, that's normal. If it doesn't, it might be your O2 sensor is bad. The fuel trim code I'm aware of is due to the ECU having to add so much fuel that it maxes out the "legal limit" of the LTFT and throws the code..

 

[spyderturbo007]

Mack is correct. 98% of the time, the Fuel Trim Malfunction (Bank 1) CEL is due to a dead front O2 sensor. That's the first place I would start.

 

[DSMopar]

Uhhh no guys, in this case it sounds like he's having a fuel sloshing problem, the fuel trim code is likely because it goes lean when hes cruising (around sharp corners like he mentioned) and the comp can't compensate (obviously because of a fuel pressure problem).

My bet is someone had that fuel tank apart at some time and didn't put the fuel pump in right or bent something and it's not in the right location causing it to suck air... obviously at half tank it shouldn't be sucking air...

 

[asexton6969]

ive seen that pickup tube crack and suck air. Now when you say fuel cuts out. Are you meaning fuel cut as if your getting on it. Or like how you said on curves, your just cruising, going around the curve and the car sputters like its out of gas. Help us narrow it down to like previously suggested o2 sensor or an actual fuel delivery issue.

 

[spyderturbo007]

in this case it sounds like he's having a fuel sloshing problem, the fuel trim code is likely because it goes lean when hes cruising (around sharp corners like he mentioned)

Good thinking and something that didn't even cross my mind.

To the original poster:

Do you have access to a logger? If so, check your fuel trims, if they are maxed in the negative direction, then you're most likely looking at a dying front O2 sensor. If they are maxed in the positive direction, I would look at what DSMopar has pointed to.

 

[kenamond]

Hmmm...

I'm not sure about the fuel issue. Maybe there's a problem with the fuel pickup in the tank.

 

[asexton6969]

Gee Kenamond, why didn't you think of that.

 

[bmxcoolcat1]

i dont have a logger is there anywhere i could go that migt be able to test my front o2.
And it cuts out as in it acts like it dyes out of gas at1/4 when i get on it as if i take off fast or im cruisin at 70 and floor it to pass the common asshole that cuts me and at 1/2 tank only around curves. I could cut out the fuel pump ? by installing the walbro but after reading these post the 255 might cause me more trouble since my car is all stock except for headers any suggestions on that

 

[bmxcoolcat1]

eBay Motors: WALBRO HP 255 FUEL PUMP MITSUBISHI ECLIPSE 95-99 2G DSM (item 120381835711 end time Mar-03-09 08:18:20 PST)

heres a link to the fuel pump tha i purchased

 

[gbradley]

Sounds like rust in the fuel tank clogging the pick up screen. Maybe time for a new tank.

 

[kenamond]

I'd pull the pump and see what you see.

 

[bmxcoolcat1]

well i have to tighten my timing belt up today so i will pull the pump while im at it and i have another question dont the timing belts suppose to have automatic tensioners cause on mine i cant find a bolt or a hole or nothing to push it in and its a pain in the ass because i have to tighten my belt every 3 weeks

 

[bmxcoolcat1]

so i pulled my air box cleaned the maf with a can of maf spray replaced my filter and sprayed off my front o2 sensor with a can of ether trying to get some of that build up off of it then reset my light. car ran great then bam cel but now its not saying fuel trim malfunction (bank 1) its reading a maf sensor code and a innsuffienct coolant temp closed loop code any ideas?