zack1978 Posted December 10, 2009 Share Posted December 10, 2009 Hi everyone, I am the original owner of my 1995 Pathfinder 5spd. The truck has about 190,000 on the odo (the odo stopped working at 182,000). I have two issues with the truck, and I assume that they are related. First, when you drive the truck for long distances over an hour or so, at random times the "cel" will light up, when it does light up the truck will buck and stumble. However it never lasts for more than a few minutes at a time, when the light is off it runs fine. It will ususally cycle on and off at random times. There aeems to be no codes stored, and a shop has attempted to fix this twice to no avail. The other issue is that currently the truck gets HORRIBLE mpg's! I don't know the exact mpg's because the odo is broken, but I can tell you that it is bad. A ride of about 30 miles or so drops a full tank to 3/4 of a tank. The exhaust does not smell bad, and it does not burn a drop of oil. I also just did a full tune up, with all OEM Nissan parts (cap, rotor, plugs, pcv, air filter, gas filter, oil and filer (Mobil 1 5w30 since new). I don't drive the Path much, but now it is snowmobile season, so she will be doing towing duties, and I can't afford to drive it six + hours the way it is. Any ideas? One year ago it did pass inspection without any problems. The truck is totally original. Thanks, Zack Link to comment Share on other sites More sharing options...
adamzan Posted December 10, 2009 Share Posted December 10, 2009 I would say check the wiring to your MAF sensor, and clean the sensor itself. Also check the o2 sensor, cylinder head temp sensor. Did you read the sticky in the garage on how to read the codes? Even if the CEL isn't on but it has been before the code will still be there unless you removed it. Link to comment Share on other sites More sharing options...
Precise1 Posted December 10, 2009 Share Posted December 10, 2009 Yep, Adam said it... B Link to comment Share on other sites More sharing options...
4X4pathy94 Posted December 13, 2009 Share Posted December 13, 2009 have you checked your calipers on your truck they could be sticking and slightly rubbing aswell. I had my front drivers side and back passenger calliper stick and i was getting horrible mpg's Link to comment Share on other sites More sharing options...
zack1978 Posted December 13, 2009 Author Share Posted December 13, 2009 I gave up......I dropped it at the shop today they will check it on Monday. I am sure they will charge me a huge bill, but I don't have the time and energy to deal with this. I will let everyone know what they come up with. Zack Link to comment Share on other sites More sharing options...
Tungsten Posted December 17, 2009 Share Posted December 17, 2009 coolant temp sensor. Link to comment Share on other sites More sharing options...
nismothunder Posted December 18, 2009 Share Posted December 18, 2009 I think kingman had the same thing wrong with his old pathy,I think he said he went like 20 miles and used half a tank of gas...I dont recall what was wrong with it though... Link to comment Share on other sites More sharing options...
Kingman Posted December 19, 2009 Share Posted December 19, 2009 (edited) 14 miles to a half a tank of gas. It was the ECU Coolant Temp Sensor, a different one than the gauge temperature sensor. It was pretty bad, it taunted me for months before finally completely showing it's colors. It was an $854 shop fix, but my mom had the money and said she didn't care how much it would cost to fix because I needed something to drive within 2 days. It would be fine for a while then suddenly start sputtering and almost die out, then when the engine cooled down it would be okay. It was on an extremely sudden cold day that it went completely haywire. It was telling the ECU that it was in the antarctic at -4856468516564 something degrees so it was dumping 100% of the injectors' capacity into the engine. I forget how many ohms of resistance the sensor had but I do know it was a crap load. Edited December 19, 2009 by Kingman Link to comment Share on other sites More sharing options...
zack1978 Posted January 2, 2010 Author Share Posted January 2, 2010 14 miles to a half a tank of gas. It was the ECU Coolant Temp Sensor, a different one than the gauge temperature sensor. It was pretty bad, it taunted me for months before finally completely showing it's colors. It was an $854 shop fix, but my mom had the money and said she didn't care how much it would cost to fix because I needed something to drive within 2 days. It would be fine for a while then suddenly start sputtering and almost die out, then when the engine cooled down it would be okay. It was on an extremely sudden cold day that it went completely haywire. It was telling the ECU that it was in the antarctic at -4856468516564 something degrees so it was dumping 100% of the injectors' capacity into the engine. I forget how many ohms of resistance the sensor had but I do know it was a crap load. UPDATE: Well the Path is still broken after $260.00 at the shop. When they checked the codes they came up with the O2 sensor code, so they replaced the O2 sensor. Well ten minutes after picking up the truck, the CEL was flashing again. Back to the shop it went. They pulled the code, and again it came up as an O2 sensor. At that point a vac hose also was off, so they cleared the code and fixed the hose and away I went. Well the light flased on again. I had to use the Path to tow my sleds, so I have not taken it back yet. But on the 6 hour road trip the light came on again, and it was bucking as usual when the light was on. Now the light has been on for over 400 miles, and the truck seems to be running ok, however the MPG's still suck. I think I am only getting about 10MPG (the odo is busted so I don't know for sure). I will mention the coolant temp sensor to them, or perhaps not? Should I let them figure it out, so that I don't get stuck with them replacing parts that are not bad? Zack Link to comment Share on other sites More sharing options...
zack1978 Posted January 2, 2010 Author Share Posted January 2, 2010 14 miles to a half a tank of gas. It was the ECU Coolant Temp Sensor, a different one than the gauge temperature sensor. It was pretty bad, it taunted me for months before finally completely showing it's colors. It was an $854 shop fix, but my mom had the money and said she didn't care how much it would cost to fix because I needed something to drive within 2 days. It would be fine for a while then suddenly start sputtering and almost die out, then when the engine cooled down it would be okay. It was on an extremely sudden cold day that it went completely haywire. It was telling the ECU that it was in the antarctic at -4856468516564 something degrees so it was dumping 100% of the injectors' capacity into the engine. I forget how many ohms of resistance the sensor had but I do know it was a crap load. Do you mean "EGR TEMP SENSOR"? That is the only part that I can find on www.rockauto.com You are not speaking about the coolant temp sensor right? Link to comment Share on other sites More sharing options...
adamzan Posted January 2, 2010 Share Posted January 2, 2010 Do you mean "EGR TEMP SENSOR"? That is the only part that I can find on www.rockauto.com You are not speaking about the coolant temp sensor right? No he means ECU coolant temp sensor. They are both a coolant temp sensor (in a parts list) but one is for the gauge on the dash and the other goes to the ECU. Link to comment Share on other sites More sharing options...
zack1978 Posted February 8, 2010 Author Share Posted February 8, 2010 Well the shop gave up, and threw in the towel. They checked everything they could possibly think of, including the temp sensors, and everything checks out perfectly. The computer is still giving an O2 sensor code.....The truck still has all of the originally noted issues. At this point I am going to drop it off at the Nissan dealer. They are going to charge 1 hour of labor ($100.00) to determine the issue, then I may or may not have them fix the truck, depending on the price. This is so annoying. Zack Link to comment Share on other sites More sharing options...
andreus009 Posted February 8, 2010 Share Posted February 8, 2010 Anyone try to check the condition of the catalytic converter? Link to comment Share on other sites More sharing options...
zack1978 Posted February 8, 2010 Author Share Posted February 8, 2010 Anyone try to check the condition of the catalytic converter? Not that I know of? The cat is original. How would or could the cat effect this situtaion? Thanks, Zack Link to comment Share on other sites More sharing options...
Kingman Posted February 8, 2010 Share Posted February 8, 2010 (edited) The O2 sensor is upstream of the cat, so it should not make a difference. The ECU Coolant Temp Sensor (code 13) WILL throw a code. I would remove the O2 sensor and see what condition it's in. If it's new it shouldn't be dirty at all. If it is, clean it up carefully and leave the battery unplugged overnight to completely reset it. Remember, these are learning ECUs so resetting it should make it forget about the problem and learn the patterns of the good O2 sensor. Edited February 8, 2010 by Kingman Link to comment Share on other sites More sharing options...
zack1978 Posted February 9, 2010 Author Share Posted February 9, 2010 Well the only two codes that it was throwing were 33 and 34, the O2 sensor and a knock sensor? It is at the dealer as I type this, so we will see what they find...................... Zack Link to comment Share on other sites More sharing options...
zack1978 Posted February 11, 2010 Author Share Posted February 11, 2010 Well the dealer has no clue except to say that they believe that it is in the wire harness (electric issue), and they no idea how to fix the truck. They only option they gave me was to have them start opening up the various wire harnesses to attaempt to find a needle in a hay stack......They don't feel it is worth it. It is still showing them the two codes, and they checked both the O2 sensor and the knock sensor and they check out fine. This issue is making me nuts! Zack Link to comment Share on other sites More sharing options...
Precise1 Posted February 11, 2010 Share Posted February 11, 2010 What if you try swapping out another ECU?? Not unheard of... What year, auto or manual and here do you live? B Link to comment Share on other sites More sharing options...
zack1978 Posted February 12, 2010 Author Share Posted February 12, 2010 What if you try swapping out another ECU?? Not unheard of... What year, auto or manual and here do you live? B Yup the last shop that had the truck did swap in a new ECU. My truck is a 5spd. The dealer thinks that there "might" be a bad ground somewhere? Zack Link to comment Share on other sites More sharing options...
R3DN1CK Posted February 12, 2010 Share Posted February 12, 2010 bad mileage and bucking, I am going to suggest getting a junk yard maf to try. $20 or so used. Worth a shot. I have an old I30 that would stall out. Was told it had bad grounds and that the ecu was toast. I work at a dealer and they were telling me this... took it to a performance tuning shop in the area and it was a bad maf. Changed it out, no more stall or bucking and my mileage couldn't be better. I tried cleaning it with CRC mass air flow sensor cleaner to no avail. Link to comment Share on other sites More sharing options...
Kittamaru Posted February 15, 2010 Share Posted February 15, 2010 Before you do anything else, unplug the battery, drain the system (pump brakes, turn on lights, etc). Let it sit for at least half an hour. I gave mine overnight. As was already said, these ECU's "learn" things, and if they have learned a bad habit, you have to help them kick it... resetting the ECU will make the truck drive a little weird, but should allow it to re-learn on the new O2 and anything else that was changed/replaced. Could make a hell of a difference. Link to comment Share on other sites More sharing options...
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