Jump to content

70 Miles: Half A Tank Of Gas?


peetah_lyn
 Share

Recommended Posts

I have a big problem with my 1995 Pathfinder (XE, 2WD). For the past two months, it was stalled when I come to a red light or whenever I take my foot off the gas. (I have a 5-speed)! I have read the forum for the past few months before I deciding to post my findings: Here is what I have done so far:

  1. I changed the fuel fliter: no change
  2. I used fuel injector fluid: no change
  3. Had the fuel pump tested: no change
  4. Went to a mechanic who said I needed a tune up. Tuned it up and NO CHANGE
  5. Had another mechanic say it was the Air FLow Meter. He changed the meter: NO CHANGE

Between the two mechanics, I spent almost $800.00 Lucky for me, the second mechanic returned my money and put the old air flow meter back on my pathfinder. This morning, I ran the diagnostics: I got error code 55--which means it did not find anything wrong. Meanwhile, with my 21 gallen tank, I am getting about 6 miles to the gallon. I have tried everything. My next option is to take it to the nissan dealer in my area. It runs rough at times, "coughs" and just dies!!

 

Help!

Link to comment
Share on other sites

Believe it or not, last year around this time I flushed my entire cooling system and replaced with new coolant... before I did this I was getting only about 270 to 280 miles to a tank of gas (which is I think about an 18 gallon tank give or take a few ounces, I'm not entirely sure). After I did this I was backup to around 315 mile per tank of gas, granite the coolant was really old and dirty but that coolant being old and dirty means you're putting more strain on the water pump which is driven by the alty belt and that will put more load on the motor. Make sure you drain all the coolant out of the motor and the radiator by loosening the petcock on the radiator and removing the two drain plugs on the block which are the front portion of both sides of the motor. Then use a cooling system flush to evacuate all of the impurities in the system. There are a few other things you can do to get the maximum mpg's out of that gas guzzlin' vg such as lighten your load, wheel bearings, spark plugs, air filter (possibly upgrade to k&n), tire pressure, boycott the oil industry, the list is almost limitless...

Link to comment
Share on other sites

Does it run rough after the engine gets up to operating temp? Say around 6-10 minutes of driving?

02 sensors sometimes don't throw codes - might be your 02 sensor.

Link to comment
Share on other sites

I get 14 to 18 mpg but the only time I ever killed a half tank in only 70 miles was on my last offroad trip. Anyway, is there an EGR valve on these? yea, I have a 95 but it's out in the parking lot and I don't remember. My van had similar symptoms and it was due to a clogged EGR valve. Just a thought.

 

Once you find the gremlin, please remember to post the solution so others may benefit from your experience.

Link to comment
Share on other sites

Does it run rough after the engine gets up to operating temp? Say around 6-10 minutes of driving?

02 sensors sometimes don't throw codes - might be your 02 sensor.

 

Yes, that it exactly what happens sometimes. Where is the 02 sensor?

Link to comment
Share on other sites

I get 14 to 18 mpg but the only time I ever killed a half tank in only 70 miles was on my last offroad trip. Anyway, is there an EGR valve on these? yea, I have a 95 but it's out in the parking lot and I don't remember. My van had similar symptoms and it was due to a clogged EGR valve. Just a thought.

 

Once you find the gremlin, please remember to post the solution so others may benefit from your experience.

 

I had not thought about the EGR valve. And YES, YES, YES!! I will definately post my solution to my problem

Link to comment
Share on other sites

Could also be the coolant temp sensor - that affects fuelling as well. Your symptoms are consistent with that problem - at least they were on the 300ZX, with the same engine. Common problem after all this time.

Edited by GhostPath
Link to comment
Share on other sites

Very true. ^^^

 

The cylinder head temp sensor (which is what the ECU uses to determine engine temp for fueling calculations) is under/below/outside the upper timing cover on the very front of the engine, to the right of the thermostat housing. It's a real PITA to get to. The O2 sensor is directly under the driver's seat in the exhaust pipe.

Link to comment
Share on other sites

My vote would be O2 sensor as well. But if you decide to replace the O2 sensor don't buy an universal fits-all unit. Make darn sure you get the right one for your application. As I recall our O2 sensors are the three wired-type. But what ever it is replace it with a like sensor or you're liable to have additional issues. Did you clean the throttle body and MAF sensor as per the stickie in the garage section as well? An old tooth brush a can of carb choke cleaner (I prefer Napa's Mac aerosol solution) and scrub the inlet to the throttle body it will eventually load up with carbon. The MAF sensor cleaning is a much, much more depecate cleaning process using isopropyl alcohol and a Q-tip. Both of these services will improve drive ability. If you consider doing these (assuming they weren't done by yourself or your mechanics) I'd suggest doing prior to changing your O2 sensor. Again if you choose to change the sensor that is. No sense in guming up the new sensor with some of the gunk that's liable to find it's way though the combustion process. Let us know how you come out.

 

M

Link to comment
Share on other sites

  • 1 month later...

quote name='peetah_lyn' date='Jun 14 2007, 11:09 AM' post='244412']

I have a big problem with my 1995 Pathfinder (XE, 2WD). For the past two months, it was stalled when I come to a red light or whenever I take my foot off the gas. (I have a 5-speed)! I have read the forum for the past few months before I deciding to post my findings: Here is what I have done so far:

  1. I changed the fuel fliter: no change
  2. I used fuel injector fluid: no change
  3. Had the fuel pump tested: no change
  4. Went to a mechanic who said I needed a tune up. Tuned it up and NO CHANGE
  5. Had another mechanic say it was the Air FLow Meter. He changed the meter: NO CHANGE

Between the two mechanics, I spent almost $800.00 Lucky for me, the second mechanic returned my money and put the old air flow meter back on my pathfinder. This morning, I ran the diagnostics: I got error code 55--which means it did not find anything wrong. Meanwhile, with my 21 gallen tank, I am getting about 6 miles to the gallon. I have tried everything. My next option is to take it to the nissan dealer in my area. It runs rough at times, "coughs" and just dies!!

 

Help!

 

In June I wrote the above about my gas mileage. Well, since then, nothing has changed. I have tried everything. On Thurday, I had the 02 Sensor replaced. It did not change a thing: I am still getting only 60-70 miles per half a tank. I read that I must reset the ECU but I have no idea how to do this. According to the instructions there is either an "off/on" button, which I cannot find on mine. I have included a picture of my ECU: perhaps someone can tell me how to reset it and where the "on/off" position is.

 

IMG_0673.JPG

 

I read that I need to clean the MAF?? If there is any advice I can get, it would be most appreciated. I am just buring too much gas!

Link to comment
Share on other sites

the 'idle speed' screw is the switch, all the way clockwise for on and all the way counter for off. to get into certain test modes, turn the screw all the way clockwise GENTLY! and wait for the light to blink the certain mode you want, then turn the switch all the way counter clock wise to activate that mode. to return to normal mode just turn the ign switch off and back on. to clear codes, either diconnect the battery or go into the read code mode and then return it to normal mode.

Link to comment
Share on other sites

the 'idle speed' screw is the switch, all the way clockwise for on and all the way counter for off. to get into certain test modes, turn the screw all the way clockwise GENTLY! and wait for the light to blink the certain mode you want, then turn the switch all the way counter clock wise to activate that mode. to return to normal mode just turn the ign switch off and back on. to clear codes, either diconnect the battery or go into the read code mode and then return it to normal mode.

 

Thanks much--I will try it. Right now, the screw is half way between "off and on".

Link to comment
Share on other sites

[*]Had another mechanic say it was the Air FLow Meter. He changed the meter: NO CHANGE

 

 

I read that I need to clean the MAF?? If there is any advice I can get, it would be most appreciated. I am just buring too much gas!

 

FYI those are the same part. So cleaning it will probably be useless for your issues.

 

You did have a tune-up done, what all parts were replaced?

Link to comment
Share on other sites

I had similar symptoms. It was the cpu in my case.

 

I have a big problem with my 1995 Pathfinder (XE, 2WD). For the past two months, it was stalled when I come to a red light or whenever I take my foot off the gas. (I have a 5-speed)! I have read the forum for the past few months before I deciding to post my findings: Here is what I have done so far:
  1. I changed the fuel fliter: no change
  2. I used fuel injector fluid: no change
  3. Had the fuel pump tested: no change
  4. Went to a mechanic who said I needed a tune up. Tuned it up and NO CHANGE
  5. Had another mechanic say it was the Air FLow Meter. He changed the meter: NO CHANGE

Between the two mechanics, I spent almost $800.00 Lucky for me, the second mechanic returned my money and put the old air flow meter back on my pathfinder. This morning, I ran the diagnostics: I got error code 55--which means it did not find anything wrong. Meanwhile, with my 21 gallen tank, I am getting about 6 miles to the gallon. I have tried everything. My next option is to take it to the nissan dealer in my area. It runs rough at times, "coughs" and just dies!!

 

Help!

Link to comment
Share on other sites

CRC makes an aersol MAF sensor cleaner available at most parts house for about $6. Follow the destruction on the can. I just used this on my '91 last weekend as well as a thorough scrubbing of the TB. It feels smoother now. Tough to say which made it smoother. I will check for mileage improvements at the next opportunity.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...