[Echo9Zulu]

Hi Guys.

Recently acquired a 2007 Xterra, probably the off-road trim. The person I bought it from had the vehicle sitting for three months in wet New England conditions. They are not car people and did not diagnose a failed brake line and a torn caliper seal leaking pressure. Remaining problem is burping gas at the pump. The nozzle at the gas sttion will only send a continuous flow at average presure for a moment before burping gas out of the filler neck. Seems to be fuel pump/sending unit related when coupled with a crazy drop in fuel efficiency. I am logging today but it seems like its probably down by eighty percent. In about 20-30 miles of driving I burned through a quarter tank.

Is it more common for sending units to fail in these vehicle or could it be a clogged cat issue? Looking at the walker diagram does not look good; however, snag seems to be that the OBD has not reported anything which should not agree with these symptoms. If the valve in the filler neck was clogged I should be getting something. I know that the tachometer on the dash it misaligned- I suspect that whoever did the aftermarket radio may have botched the wiring by dissembling more than necessary for that job. The owners said the previous guy did some work but not much, the radio being the work they cited most clearly.

As far as I can tell there are no misfires yet. After looking at the TSB for timing chain issues the sounds do not seem to meet the criteria. Also exhaust seemed to be a little bit white and engine smells of burnt oil after driving about three miles.

Pretty much I turned to the internet because these issues strike me as being specific to the Xterra and require, as most specific non-failure related problems, the wisdom of others.

 

[Brunnie]

May be that the charcoal filter is clogged. It is located on the driver side rear quarter panel, accessible from underneath. As for decrease in MPG... get a code reader and scan for codes. It is possible that you have a clogged cat. Soot/Burnt oil smell sounds to me like a cat that has destroyed the engine.

 

[CThoreal]

Fuel filling issue is likely the charcoal cannister or valve in the cannister. If the valve fails it can give a code, but its possible for the tank to not breath properly when filling, without a code.

As for the fuel economy hit. Is it also accompanied by a loss of power? A plugged cat should drastically reduce performance. If power is still ok, but you're getting white in the exhaust and oil smell, this can be a classic indicator of a bad head gasket, or a cat may have already came apart and sucked into the motor, damaging valves or a cylinder.

Assuming this is an automatic, how does the coolant look? You're right in the model years to be affected by "SMOD" (when radiator fails and mixes coolant with trans fluid) which would definitely affect fuel economy as the trans starts to fail, but this may not really explain the oil smell or white exhaust.

 

[Echo9Zulu]

Fuel filling issue is likely the charcoal cannister or valve in the cannister. If the valve fails it can give a code, but its possible for the tank to not breath properly when filling, without a code.

As for the fuel economy hit. Is it also accompanied by a loss of power? A plugged cat should drastically reduce performance. If power is still ok, but you're getting white in the exhaust and oil smell, this can be a classic indicator of a bad head gasket, or a cat may have already came apart and sucked into the motor, damaging valves or a cylinder.

Assuming this is an automatic, how does the coolant look? You're right in the model years to be affected by "SMOD" (when radiator fails and mixes coolant with trans fluid) which would definitely affect fuel economy as the trans starts to fail, but this may not really explain the oil smell or white exhaust.

Coolant in the rad and recovery tank are good.

Fuel filling issue is likely the charcoal cannister or valve in the cannister. If the valve fails it can give a code, but its possible for the tank to not breath properly when filling, without a code.

As for the fuel economy hit. Is it also accompanied by a loss of power? A plugged cat should drastically reduce performance. If power is still ok, but you're getting white in the exhaust and oil smell, this can be a classic indicator of a bad head gasket, or a cat may have already came apart and sucked into the motor, damaging valves or a cylinder.

Assuming this is an automatic, how does the coolant look? You're right in the model years to be affected by "SMOD" (when radiator fails and mixes coolant with trans fluid) which would definitely affect fuel economy as the trans starts to fail, but this may not really explain the oil smell or white exhaust.

Negative on the power loss. However my late 2001 Avalon- rest her soul- pack no where near the punch this thing does so maybe I am not used to have a more powerful engine with better torque delivery/4WD. I think I isolated the MPG hit; dry rot in the air intake hose after the MAF and before throttle body explaining why there have been no codes yet. Leak is pretty bad, replacement hoses coming in soon. I am a manager at my AZ and hot damn, its easy to forget how much cheaper rock auto is. I actually reccomend it to customers all the time lol.

Yes its automatic and the recovery tank and rad are good. Belt tensioner happens to be bad. I actually discovered a recall that doesnt come up under my VIN but the key symptom , reporting a 1/4 full tank, happened this morning. $11 from a blinking E does not add up to 1/4 tank haha. there happens to be NIssan dealaership down the road from my University so I am going there this afternoon. I have been hesitant to run an injector cleaner like cataclean to address clogged cats because, in my opinion, it does nothing for the diagnostic process if it works.

 

[CThoreal]

Good catch on the dry rot. Should make a big difference.

I had an '05 Frontier years ago that started reading 1/4 tank when empty. Replacing the tank sending unit cured it.