big_johnson Posted January 5, 2007 Share Posted January 5, 2007 I've had an increasingly present problem on my 97 pathfinder. At high altitude (9000 ft+) and cold weather, my pathfinder seems to flood itself and then not want to start. This first occurred in the spring...it started, fluttered, then died. I tried it again, and it just cranked over, didn't catch. It took several hours (we had no idea what was wrong), then a combination of cranking it and flooring the gas pedal and letting off for it to finally fire up. The exhaust smelled very rich for a while after it started. The other day at a resort, the same thing happened. It started, fluttered, then died. Then refused to start. We tried several times to start it with a combination of cranking it over and flooring/letting off. Initially, it didn't do anything. Eventually, we got some response. It would start, then die shortly thereafter. We finally just had my friend hold the throttle cable in the engine wide open when it fired up, and didn't let the car idle till we got home. The following morning in the mountains, it almost died upon startup. The exhaust has a very rich smell everytime we start it up, that goes away after a bit. This only happens in the mountains, at higher altitude. It basically feels like when you start up a basic 2 stroke engine that is flooded...just doesn't want to run. Down home (around 6000 ft) it starts up just fine. Mods that may affect the fuel flow include: cold/ram air intake, and performance muffler w/ larger 2.5" exit tubing. Basically, it seems like the pathfinder is flooding itself in thin air, the computer gives a wierd air:fuel ratio or something. Anyone have this or have any ideas? This is really a pain, not knowing if I'll be stranded when I go snowboarding. Thanks, -Chris Link to comment Share on other sites More sharing options...
zonianbrat Posted January 5, 2007 Share Posted January 5, 2007 Chris, My truck suffers or suffered from the same kinda problem except it was last year and it happened here in ft. collins same symptoms though. It only happened once this year right before thanksgiving but the weird thing was I parked it in my yard at a good angle and next day it started then died and would not fire but only turn over. I sprayed starter fluid and it did not help. I had to hook up another battery and just keep turningi it over until if fired then then it smelled really rich. So I think we might have the same problem except that I was up in the mountains a couple of weeks ago and it started and ran fine. I wonder if it could be the maf sensor??? This problem happend like 5 or 6 times last winter then this summer I got a K&N cone filter and I cleaned my Maf sensor at the same time so I am a little cornfused. Have you ever cleaned your maf sensor?? Link to comment Share on other sites More sharing options...
nissandoms47 Posted January 5, 2007 Share Posted January 5, 2007 O2 sensors could cause it to run rich and your exhaust grounds. check the grounding straps. Link to comment Share on other sites More sharing options...
zonianbrat Posted January 5, 2007 Share Posted January 5, 2007 what are these grounding straps you speak of? Link to comment Share on other sites More sharing options...
nissandoms47 Posted January 5, 2007 Share Posted January 5, 2007 things that i didnt have after i started taking it offroad. there should be a metal strap that goes from the body to the manifold and then again from the body to the intermediate flange (inbetween the front and rear doors) Link to comment Share on other sites More sharing options...
Trainman Posted January 5, 2007 Share Posted January 5, 2007 With most fuel injected motors (not sure about the Pathy though) if the motor floods, if you floor the pedal and HOLD it while cranking, it will trip the computer into a special mode that should get rid of the excess fuel then allow the motor to start. This happened a few time on our 1996 2.5l Mystique and the flooring thing worked on it (and it was O2 senors on it). So next time, try flooring it and holding while cranking and see if you can at least get it started. Good luck. Link to comment Share on other sites More sharing options...
big_johnson Posted January 5, 2007 Author Share Posted January 5, 2007 trainman- yea, that's essentially what gets it going each time, it just takes quite(!) a bit of cranking. Good to know exactly why it works though, I wasn't aware it affected the computer, just thought it let in more air for a given amount of fuel mechanically. Zonianbrat- good to know someone else has heard of this. I also tried the ether spray, with little effect. I did a half ass cleaning of the MAF sensor the second time my truck gave me problems, but other than that I haven't touched it. Strangely enough, my car has also been at angles when this problem arises. Wonder if there's a connection? Also, is there any specific trick to cleaning the MAF sensor? (The plug that connects right after the airbox, right?) So sounds like o2 sensors may be the culprit? I was thinking along those lines....someone want to refresh my memory on the process for replacing those? I remember reading about these a long time ago, but have forgotten. Also...am I looking for anything specific with the grounding straps? Or just that they're attached? Thanks for the quick and helpful replies...I need to get this fixed! Link to comment Share on other sites More sharing options...
nissandoms47 Posted January 5, 2007 Share Posted January 5, 2007 seriously 02 sensors can really screw up your car if they're not working right. go with the stock nissan ones if your replace em they are worth every penny over the universal ones. Link to comment Share on other sites More sharing options...
4x4le Posted January 5, 2007 Share Posted January 5, 2007 Well in my owners manual it highly suggests very low octane fuel at high altitudes. I suggests anything as low as 84 when its avabiable. My truck will not start up when i hold the gas down all the way but maybe thats because its not giving it enough fuel then. Link to comment Share on other sites More sharing options...
turbopath Posted January 5, 2007 Share Posted January 5, 2007 (edited) there was a tsb on high altitude problems...gotta find it though. Edited January 23, 2007 by turbopath Link to comment Share on other sites More sharing options...
big_johnson Posted January 6, 2007 Author Share Posted January 6, 2007 turbopath- thanks for the info. I did some more research and found at least 2 other TSB's on this problem... The nissan tech said a couple of things: - run higher octane at high altitudes. Not sure why this would help though. - use the "cold start' method. Apparently this entails turning the car's electrical system on for a few seconds, and lightly hitting the gas pedal, before cranking it over. Again, I'm not sure how this would help? - He suggested the airflow sensors (meaning the o2 sensors I'm assuming) may be bad, but would likely throw a code if they were faulty. - He also recommended a fuel injector cleaning...which goes along with the TSB turbopath posted Any more insight? Link to comment Share on other sites More sharing options...
DJ Dank Posted January 6, 2007 Share Posted January 6, 2007 Haven't seen you around for a while johnson! Glad to hear that you still got the Pathy! Link to comment Share on other sites More sharing options...
zonianbrat Posted January 6, 2007 Share Posted January 6, 2007 (edited) Big johnson, Glad to hear you talked to a tech about this problem. I thought that since it was fuel-injected that pushing the gas pedal did not have any affect? the few times my truck would not start only once did I floor it and it actually fire up. I find it odd that you said your truck had trouble starting at a weird angle. See my truck started giving me this problem last year then all of a sudden it stopped and worked perfectly unti one day out of the blue I parked in my yard with the passenger front being up considerably higher than the left front. Then the next morning it would not fire up. I finally did get it cranked and it has been working great ever since. I always thought that bad 02 sensors would throw a code, but maybe they are just not funtioning badly enough to throw a code?? There is a great write-up on this forum about cleaning the Maf. It is really simple, but hell if your in town, just give me a call and stop bye and we can clean the sensors on both trucks and I'll provide some homemade beer. Edited January 6, 2007 by zonianbrat Link to comment Share on other sites More sharing options...
big_johnson Posted January 8, 2007 Author Share Posted January 8, 2007 DJ- yea, I've been spending my time with the mountain bikes lately. Not neglecting the pathy though, actually installed some OME springs recently! Zonian- Strange about the angles, mine was also driver side low. I had also just filled up with gas..I wonder if there is some kind of leak that occurrs? I'm not sure about the o2 sensors and codes, but they are expensive to replace (if you get the OEM Nissan ones), so I won't look to those first. I may have to take you up on your offer though! I guess it depends on what they do/say when I take it in this week. Link to comment Share on other sites More sharing options...
zonianbrat Posted January 10, 2007 Share Posted January 10, 2007 Let me know what they say. If you wanna stop by for a brew let me know. This sunday might be my last day off for awhile. I am going to be spending the morning bending my bumper out!! fun stuff. Link to comment Share on other sites More sharing options...
big_johnson Posted January 10, 2007 Author Share Posted January 10, 2007 higher octane should help Why is this? It's the rule of thumb that you can go to a lower octane in higher altitudes... I'm not sure why higher octane would help. But I'd have no problem finding 87 or 91 if need be. Link to comment Share on other sites More sharing options...
FUELER Posted January 11, 2007 Share Posted January 11, 2007 Why is this? It's the rule of thumb that you can go to a lower octane in higher altitudes... I'm not sure why higher octane would help. But I'd have no problem finding 87 or 91 if need be. I was wrong, you are correct. You can safely drop octane in higher altitudes. I was all mixed up, I used to chat with some Colorado street racers who talked about it all the time, sorry for the confusion. Taken from the internet: "Higher compression engines need higher octane. Higher altitide reduced air pressure and compression. At higher altitude, most engines can run lower octane. (An exception would be a turbo charged engine.) The only drawback of running higher octane than needed is the car might be harder to start. The drawback of running lower octane is the car might start pinging and pre-detonating. This can cause bad problems in an engine." Link to comment Share on other sites More sharing options...
big_johnson Posted January 22, 2007 Author Share Posted January 22, 2007 (edited) So I have an update- Went to the dealer and had a bunch of things done: - Adjusted the Idle Air Valve - Flushed Fuel Injectors - Replaced spark plugs - Some other maintenance items Those first two relate to the TSB on the subject. The Nissan tech (who I now beleive is an idiot) said a couple of things: - Use 87 octane as it should help the car start easier (nevermind the fact that it is harder to compress...). Apparently I should be able to notice how much better it starts...more on this in a bit. - Use the cold start method (this entails turning the key to "ON" but not cranking the motor, and slightly tapping the gas pedal before starting) - He said the above mentioned services performed and those techniques should make the problem go away. The results: - After filling up with 87 octane, the car is noticeable HARDER to start. Takes usually a couple of extra cranks to get it going. - My gas mileage has gone to CRAP. I'm talking like <14mpg, down from 16-17. -I went to the mountains yesterday...and the car did the same exact thing! It ended up starting, but almost died initially, and appeared to be flooded again. So NOTHING fixed! - Apparently the next step is to replace the ECU and Idle air valve, to the tune of $1500. Super. :oops: Edited January 22, 2007 by big_johnson Link to comment Share on other sites More sharing options...
88pathoffroad Posted January 23, 2007 Share Posted January 23, 2007 They like to throw parts at problems, don't they? Link to comment Share on other sites More sharing options...
turbopath Posted January 23, 2007 Share Posted January 23, 2007 eh, I run 85 octane at higher altitudes and have never ever knocked. I would be thinking more along the lines of ecu reflash or getting the "boost sensor" checked out. I wonder if the ecu takes a baro reading off of that on startup like some other cars. Link to comment Share on other sites More sharing options...
4x4le Posted January 23, 2007 Share Posted January 23, 2007 slightly tapping the gas pedal before starting lol, he acts like its carberated. Just run lower octane next time. He must have never even read the owners manuall Link to comment Share on other sites More sharing options...
XPLORx4 Posted January 23, 2007 Share Posted January 23, 2007 (edited) lol, he acts like its carberated.Just run lower octane next time. He must have never even read the owners manuall You do realize that the "gas" pedal, actually the accelerator pedal, is really an "air" pedal, right? In other words, pressing the accelerator moves the butterfly valve on the throttle body, allowing more air into the engine. It doesn't add gas. If the butterfly valve is sticking (for whatever reason), tapping the accelerator will help unstick it. Edited January 23, 2007 by XPLORx4 Link to comment Share on other sites More sharing options...
Pavelow Leaks Posted January 23, 2007 Share Posted January 23, 2007 On older carbed cars, hitting the gas pedal puts gas in the motor, if the cars not running, you're not adding air, just gas, usually flooding the car, cuz the motor isn't sucking any air....I think thats what 4x4le was getting at. Everytime you hit the pedal you squirt gas, although you are also opening the butterflys, you're not really adding air if the motor isn't running. Link to comment Share on other sites More sharing options...
XPLORx4 Posted January 23, 2007 Share Posted January 23, 2007 Yeah, I should have qualified my statement with "For fuel-injected engines..." Link to comment Share on other sites More sharing options...
big_johnson Posted January 24, 2007 Author Share Posted January 24, 2007 Yeah, I should have qualified my statement with "For fuel-injected engines..." Ha, well this really makes me think he is an idiot. When I asked him why the cold start method helped, he specifically said "it just gets a little fuel into the motor to help it start". Needless to say, this made me a little doubtful that it would help my FLOODING problem... Link to comment Share on other sites More sharing options...
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