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Cold Weather Problems

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  • dmaljunkdmaljunk Posts: 160
    thanks div2. No, I do not see any air leaks in the hoses. I went to a knowledgeable mechanic. He noticed that when the car is warming up, the voltage being sent from throttle position sensor to the computer keeps changing, it starts at 0.60 and then drops to 0.46 by itself. He suggested that the computer needs to be reprogrammed. He says that when they put in a new computer they never reprogrammed it and therefore I have this problem. When you press the gas the voltage on the throttle position sensor climbs up, so the sensor itself seems to be working properly. That sounded reasonable and I went to the dealer to reprogram the computer but this morning the car was shaking a bit again. It wasn't that cold so i have to wait for a colder morning but it didn't seem to help. What's your opinion on this TPS thing? Thanks
  • div2div2 Posts: 2,580
    It would be nice if you could switch the TPS out with a known good one; failing that, I'd like to know just what the dealer's "reprogramming" is supposed to accomplish. If the TPS voltage is fluctuating at idle it sounds like the problem is the TPS.
  • dmaljunkdmaljunk Posts: 160
    well, I just got the computer reprogrammed. As with all previous repairs, it seemed to improve cold start up but not 100%. Reprogramming the computer seems to be a common thing for Maxima. I think they upload the latest software onto the computer, it's like upgrading BIOS on your PC motherboard. There are technical service bulletins released by Nissan where reprogramming is listed as the solution for certain problems, one of those bulletins talks about car stalling or idling bad in the morning when temp is below 40F and when you put it in drive and reprogramming is required. Well, it kind of sounds like my problem except for the fact that the car also idles bad in park as well... I have to wait for the really cold morning, so far it hasn't stalled on me and idled better but it was 38F outside, I usually get problems when it's 33F or below...

    As far as TPS the mechanic showed me that when he presses the gas the voltage climbs up on the TPS and therefore he concluded that the sensor itself is fine...
  • dmaljunkdmaljunk Posts: 160
    div2, I got an advise on another forum that I need to replace my thermostat. It kind of seems to be in the right area - cooling but I don't experience any problems related to thermostat, like bad heating or temp guage climbing up too slow, all of that is fine. I do get a suspicious noise only when the car warms up on cold mornings - when the rpms drop I hear a rattling noise or water-going-down-the-drain noise on the passenger side of the engine and then the noise goes away when the car is warm. Can that be the thermostat struggling to open or close? Will a lazy thermostat cause my cold whether bad idling problems? Thanks
  • div2div2 Posts: 2,580
    If the thermostat is stuck open or is opening too soon then the car would take a long time to reach operating temperature-if it reached it at all. However, have you checked to make sure that all the air has been bled out of the cooling system? That could be the source of the noises.
  • dmaljunkdmaljunk Posts: 160
    no, I didn't check, in fact they were using a machine, some sort of a pump to flush and refill the antifreeze. So, if I open the air release valve and start adding antifreeze into the radiator until it starts spilling from the air release valve, should that let any air in the coolant system out? Or should I replace all antifreeze again?

    You mentioned air leaks previously, how exactly do you find them. I don't see any with naked eye but may be I should listen to them or spray something on the hoses to see? Thanks
  • div2div2 Posts: 2,580
    So, if I open the air release valve and start adding antifreeze into the radiator until it starts spilling from the air release valve, should that let any air in the coolant system out? Or should I replace all antifreeze again?

    I'd use the procedure given in the Nissan shop manual.

    You mentioned air leaks previously, how exactly do you find them.

    Here's a good desciption of the procedure.
  • dmaljunkdmaljunk Posts: 160
    div2, mechanic inspected the car more thoroughly - no air leaks, he sprayed some stuff on all vacume hoses and they are all good. He found a more serious problem though - there is oil on one fo the spark plugs, I don't know how much but there is. When he was warming it up in the morning and got bad idle, he said that it sounded like one cilynder was misfiring and when he found oil on the spark plug he said that this is it - oil leaking into one of the cylinders. He said that he would need to do exploratary surgery on the engine, open it up and if it's just seals or rings leaking oil that it will be a $200 job but if it's more then that like pistons then I am better off replacing the car. I knew about this oil leak a year ago but never thought it could cause problems I am having simply because it never happended in warm weather but he explained that when oil is cold then it takes time for it to burn off the plug and when it's warm then it doesn't have time to collect in the cylinder. For $200 I think I should try and fix it and I do hope that it's just the seals/rings. What do you think about all this, does this sound like a cause for the cold engine idle/stalling problems I've been having? Can you explain what an oil leaking into the cylinder would be causing and why did it start leaking in the first place. I appreciate your help. Thanks
  • div2div2 Posts: 2,580
    Well, I don't see any way that you could get rings replaced for only $200, so your mechanic must be talking about just the valve seals. Has a compression and/or cylinder leakdown test been performed?
  • dmaljunkdmaljunk Posts: 160
    Not sure but would these tests determine exactly what the problem is and what is leaking?
  • div2div2 Posts: 2,580
    Either tests would give you a good indication as to whether the rings in that cylinder are in bad shape.
  • compression test can easily fool you into making false conclusions (for instance you can have good compression and lousy oil rings) but a cylinder leakdown test is pretty conclusive.
  • dmaljunkdmaljunk Posts: 160
    can you advise how the cylinder leakdown test is performed? Does it require disassembly of engine parts? Also, if I have oil on one spark plug and I have symptoms only on cold mornings until the car warms up then does that sound serious or as div2 suggested, can it be only the oil valve seals?
  • No no disassembly required. You just remove the spark plugs one at a time and insert a special plug that allows you to fill the cylinder with compressed air. You then measure the % of leakage over a period of time. The nice part is that if you make sure the tested cylinder is on TDC (both valves closed) then if there is a leak you can actually hear it out the tailpipe (exhaust valve) or air cleaner (intake valve, guides, etc.) or in the crankcase (piston rings).

    I'm not sure but I don't think cylinder leakdown is a good test for bad valve stem seals---you can test that easily on a road test....
  • Hey, I own a dodge colt 200GT '92. I've been having problems in cold (well, doesn't need to be that cold) weather. What happens is, I turn on my car and everything is running great. But, let's say I turn on my fan/lights/wippers, my car starts to make a somewhat loud screeching noise.

    I've tested this while being on the highway. At some point, it started screeching while I was driving. What I did is I turned off my plug-in heater (through the lighter), and turned down my fans a notch and the screeching stopped right away.

    Im wondering if my alternator could be starting to break down and if I should replace it. It seems that it only does this noise when I use a lot of electricity.

    Thanks for the help!

    P.S Feel free to email your answer ;D
  • dmaljunkdmaljunk Posts: 160
    OK, my cold weather bad idling and stalling issue was fixed. It was an EGR valve tube, which goes out of the manifold and into the EGR. It was clogged and that was causing too much pressure and eventually caused oil leak. The saw the oil leak and when the manifold was removed they saw the clogged valve and determined it to be the cause of my problems. I had that tube cleaned, oil seals and gaskets replaced and manifold gasket replaced as well. Not an expansive repair and the problem is fixed, car idles perfectly on a cold mornig. Thanks to all for your help. One question - what caused this tube to get clogged? Bad gas?
  • Nah, EGRs just clog up with age. But I don't think that had anything to do with your oil leaks. That's a PCV valve issue. EGR is exhaust gas recirculation. A clogged PCV (positive crankcase ventilation) valve can cause excessive crankcase pressure and oil leaks. So you're mixing two things up there---but no matter, the car's running great so that's good news.
  • dmaljunkdmaljunk Posts: 160
    Question, and this is pretty specific. They replaced the Valve Cover gaskets, both the main gasket and the spark plug tube seals. The mechanic noticed that the three original front seals are thicker then the rear three. The front valve cover seemed to have deeper wholes for seals then in the rear. However the set that they got from parts store had all six same spark plug tube seals. The seals from the set had "made in Japan" on them but it wasn't from Nissan, some aftermarket. Nissan dealer doesn't sell this set, they only sell it with volve covers. Now, is this possible that three spark plug tube seals should be thicker then the other three? Why would that be? The mechanic installed them because originals were leaking, they went in fine but he had his doubts. I am not experiencing any noticeable issues with the car right now but I don't know if a tiny leak at that seal would be noticeable any way...

    I will go to AutoZone to look at their gasket sets but let me know if this sounds strange to you...

    Thanks
  • It does sound weird but sometimes engineers will do weird things. I always try to buy gaskets strictly from the dealer for this reason. They FIT.
  • dmaljunkdmaljunk Posts: 160
    ye, agreed but Nissan sells the set with valve covers and it's like $220... Why do I need new valve covers, what, they can't sell just the gasket set... Damn...
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