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colinnwn last won the day on December 27 2018

colinnwn had the most liked content!

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About colinnwn

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    NPORA Fulltime Resident
  • Birthday 10/01/1976

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Previous Fields

  • Your Pathfinder Info
    AC 3" Lift
  • Place of Residence
    Dallas, TX
  • Mechanical Skill Level
    Standalone Tool Chest Mechanic
  • Your Age
  • What do you consider yourself?
    Rarely Go Off-Road
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  • Year

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  • Gender
  • Location
    dallas, tx
  • Country
    United States
  • Interests
    Skydiving, SCUBA diving

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  1. I'll check the grounds. But I don't think the battery is having any trouble handling the fan. Even when the old alternator wasn't charging the car for the first minute or two, the battery was able to start and run the car with the voltage remaining around 12.5. This is approximately the same voltage that the battery bug captures as the lowest voltage during an engine start (which it assumes by watching for significant voltage swings. I think the alternator is just trying to replace the used charge too fast and the IACV motor can't keep up with the increased demand. This is the same reason that ECUs command increased idle air at the same time they turn on the AC at idle, or sense high power steering pressure. I think I've even heard some cars do it that have factory electric radiator fans.
  2. I'll disconnect the coolant line. The alternator is keeping up with the fan. It only bogs down the engine for 1 or 2 seconds each time the fan starts, until the IACV has a chance to add enough air to bring the idle speed back up to 750 and stable. In fact I think the fresh alternator is able to keep up too well, and that is why it is able to pull down the idle speed momentarily. The old alternator was probably letting the voltage sag during the fan start, because the regulator was tired and unstable and couldn't energize the alternator sufficiently. I'll do more research on capacitors. I've replaced several of them on HVAC equipment. I understand they can be dangerous to people if not discharged, and equipment if miswired. I've just never designed my own circuit. It sounds like they won't blow themselves up if you connect them directly to a voltage source that is under their rated voltage. They just charge to the supply voltage and stop. For example at first I didn't understand why people suggested putting a bulb in the negative line. Then I realized it was because if you didn't, the capacitor would try to recharge as fast as the current draw it was supplying, and there would be little net change in the inrush current, the whole point of the capacitor. The bulb slows the recharge rate of the capacitor. I saw some formulas for how to calculate the right capacitor size. I figured I should do that. But I also figured that the power required of a 12 volt 18 amp radiator fan would be less than or equal to the compressor rating of a 9000 btu air conditioner rated for a 120 volt 15 amp circuit, so that capacitor should be good or slightly overrated.
  3. Just to play around with options, I do have a 88-108 mfd 250 vac HVAC start capacitor laying around. I've never wired up my own capacitor circuit. But from doing some research, it looks like AC capacitors should work fine with DC. I could wire one side of the capacitor through a bulb like a 194 to the negative battery terminal to control the recharge rate. Then off the other capacitor terminal run one wire to the positive battery terminal, and another wire to the fan controller positive input. I'm not sure I will do this, as I don't quite trust myself to not let the magic smoke out. Sent from my SM-N950U using Tapatalk
  4. Interesting on the coolant bypass. You think it is unlikely to cause problems by bypassing? What specifically about the fuse do you think is a bad idea? Just another potential failure point? I sorta have the same concern about the coolant bypass. But if others have done it successfully, then I guess it is worth doing. If I ran into icing in the valve, I should be able to get it underway with some careful manipulation of the throttle pedal if it dawns on me what is going on. Sent from my SM-N950U using Tapatalk
  5. The alternator was disassembled and tested by an alternator shop before I put it in a couple of weeks ago. I asked him to check the brushes and test diode ripple specifically, because I was hoping to not do another alt swap on this vehicle. It is a generic Malaysian 13900 I got at a junkyard but the guy said it looked new or freshly rebuilt inside. Until more out of place symptoms appear, I have no other reason to believe anything is wrong with this alternator. Sent from my SM-N950U using Tapatalk
  6. I can watch the voltage pretty much constantly on my Scan Gauge, and I have a "Battery Bug" that monitors voltage constantly including during starts, and the voltage is within normal range. The battery bug says I have 70% battery life (not battery charge). I would trust that testing in-situ more than the crappy battery load testing equipment at most auto stores. So I'm fairly certain it is fine. I did some research and found this on the relearn process https://www.nissanhelp.com/diy/pathfinder/projects/2001_2002_nissan_pathfinder_idle_air_volume_learning.php Based on that, I don't have the pre-condition to need an idle volume relearn. The shop I took it to for the valve cover replacement has a stellar reputation. It is idling so smoothly now, I wouldn't be surprised if they actually did the relearn. If I didn't have an electric fan, this wouldn't even be happening. It's the surge of electric power demanded by the fan startup, potentially exacerbated by my rebuilt alternator that can supply more power to the battery to replace it, at the expense of the engine power surge. It is also possible my IACV motor is getting marginal or clogged. But it is very strange this occurred suddenly and exactly after a shop visit, where everything else related to engine idling smoothness improved so drastically at the same time. I was vaguely aware that if the IACV ingested coolant as it aged and died, that it could burn out your ECU. So I had been wondering about replacing it proactively. It is a little expensive to do that. The cost is similar to an ECU repair if it did fry it, the only downside would be waiting on the turnaround of the ECU repair or trying to do it myself. When the weather is better I will probably remove and inspect the IACV. I also found this thread where someone recommends putting a 1-5 amp fuse (I assume it would need to be a fast-blow fuse) inline with the IACV and it might prevent it from frying your ECU if your IACV ever does go out. https://forums.nicoclub.com/idle-air-control-valve-iacv-replacement-diy-for-2001-pathfinder-t607957-30.html?sid=ad4c250f17e7c09848e838cf13fa93b7
  7. The battery is good as best I can tell. It is approx 2 year old Optima and starts the truck fine. It has been abused because my old alternator overcharged it to 19 volts, and then the replacement alternator was obviously undercharged it for several months until I realized what was going on. But at no point did it ever fail to start the car, or drag the starter significantly. I haven't done the IACV relearn or clean the IACV. I was hesitant to do that since this problem is only related to starting the radiator fan, and otherwise the idle is very solid and stable. But I guess I will try that. I'll research the process to do the IACV relearn. Do you know if it requires the NISSAN CONSULT?
  8. I got the valve cover gaskets redone on my Pathy. It is running even smoother than it has in years. I assume that is because they found and replaced some more vacuum hoses that were brittle and leaking. A side effect has been that when my electric radiator fan kicks on, the engine idle RPM drops by about 250, and seems like it is stumbling for a second until the IACV can catch back up. It never did this before. But I imagine that is because there were enough air leaks the IACV didn't need to do much, and the ECU just fed the engine a bit more fuel. It is fine to leave as is. But its one of those things I'd like to improve if I could. The first thing I thought is if I could tap into either the signal from the air conditioner or the power steering pressure sensor that signals the engine to idle up right as the fan is turning on, that would help. Has anyone done this? I'm going to get out the FSM wiring manual and look through it. As I was writing this, I thought maybe an easier solution would be to just put the radiator fan controller inline with a capacitor, like they do with high power amps. Maybe that would smooth out the initial surge current enough to give the IACV valve more time to recover.
  9. My Pathy threw a P0420 yesterday. I found that means the bank 1 front catalytic converter is operating below expected threshold. It determines this by comparing the switching frequency of the front o2 sensor to the back o2 sensor, and if the back o2 sensor is switching approximately less than twice as fast as the front one, it throws the code. Among the top causes, the first 2 are a defective cat, or a defective upstream o2 sensor. I was wondering if there was a consensus on which was more likely to fix it, the o2 sensor or the cat? For anyone who has had to replace the front cat, have you had success with one of the much cheaper RockAuto direct replacement cats? Was it very difficult to replace yourself? I have air tools. But I don't have a lift and don't want to have to go cutting into anything or welding. If it isn't a drop in replacement I should probably leave to an exhaust shop. I cleared the code, and in the last 4 trips it hasn't come back yet. I haven't tried resetting all the ECU trims yet, if that is even possible without a NISSAN CONSULT. But I want to be ready to go with a plan of action for when it comes back. Thanks.
  10. colinnwn

    2002 R50 Pathy lift questions

    Lots of information in these threads http://www.nissanpathfinders.net/forum/forum/67-r50-faq39s-amp-pinned-topics/ I did a 2 inch spring lift from here 12 years ago https://www.4x4parts.com/c-1044800-nissan-suspension.html Here is my write-up of it http://colinnwn.blogspot.com/search/label/pathfinder I also put on manual locking hubs, so I could stop unnecessary wear on the front driveshaft. I've had zero trouble with it, besides riding harsh, in those 12 years and 100,000 additional miles. I'm at 260,000 miles today.
  11. colinnwn

    Cleaned MAF sensor tripped code

    The common causes are vacuum leak or IACV malfunction. Though I guess if your MAF was really dirty and now it's clean it could cause greatly changed signal. I'd look over everything I removed or touched very carefully to see if I didn't tighten something or broke something, then do the idle speed relearn procedure. Sent from my SM-N950U using Tapatalk
  12. colinnwn

    Oil mileage?

    I change my oil every 10,000 miles with generic full synthetic oil 5-30, and a Purolator PurOne or Mobil 1 oil filter. I'm at 260,000 miles and have a slight valve tick for a second or two at first morning start, but other than some oil leaks, the engine seems great. For a couple years I did 10k filter changes and 20k oil changes. But as the engine got older, I decided that was a bit long. Sent from my SM-N950U using Tapatalk
  13. colinnwn

    Front suspension clunk....

    How hard were putting in the sway bar links and bushings? Do you need a shop press or torch? Sent from my SM-N950U using Tapatalk
  14. colinnwn

    P1140 code

    I'm confused, nowhere on Google have I found where this is associated to a knock sensor for Nissan Pathfinders. https://www.google.com/search?ie=UTF-8&client=ms-android-hms-tmobile-us&source=android-browser&q=nissan+pathfinder+p1140 These are the manufacturer specific codes that vary, so it could be a knock sensor on other vehicles. I've been moving the camshaft sensors between banks and the error code has followed the bum camshaft sensor. Now with a second new camshaft sensor the error code has completely gone away. On my vehicle at least it doesn't seem to have anything to do with the knock sensor. Sent from my SM-N950U using Tapatalk
  15. colinnwn

    P1140 code

    So when I put in the new sensor, on the 2nd drive I got a P1135, which is basically the same code and same likely causes as P1145. From reading it seems the ECU doesn't set these codes until the 2nd drive with this fault. I couldn't imagine a faulty new sensor but before doing something harder or more expensive, I swapped the new and working old sensors. This time the code followed the new sensor P1110, which is the same code as P1140. I bought another sensor, this time a Standard Motor Products PC458, that cost $50. Now I've driven twice and no code. I guess the $15 was a false economy. Sent from my SM-N950U using Tapatalk

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