Adam Posted July 12, 2010 Share Posted July 12, 2010 So my Pathfinder's been running well lately, except when the humidity is really high. If it's raining, it's even worse. It doesn't have much power before 2.5k rpm, runs rough, past 3k or so it's fine, but even maintaining speed is causing popping out the exhaust, it'll backfire a lot when it's humid as well, as if, for some reason, it's deciding it needs to run super rich when it's humid out... Any ideas? A run-down of the latest work since I'm sure not everyone saw my other thread... Timing belt is new, spark plugs, wires, rotor, throttle body was cleaned, fuel rail and fuel injectors replaced, air filter is new, maf sensor was cleaned, O2 sensor and cat replaced, exhaust leaks fixed. I just passed over 200k this morning too... I'm also only averaging 13-14mpg... I haven't replaced the distributor cap yet, but I'm considering swapping the distributor next, I'm not sure if it's working properly or not, could the crank angle sensor cause issues like this? No codes from the ECU either, everything is normal. Link to comment Share on other sites More sharing options...
Tungsten Posted July 13, 2010 Share Posted July 13, 2010 (edited) Your problem is caused by the poor grounding to the ECU and MAF sensor. The problem is fixed by adding a sub harness to the MAF sensor, which adds a new ground path. You should check out my MAF wiring thread here... http://www.nissanpathfinders.net/forum/index.php?showtopic=26778 This post here is the answer to the problem: http://www.nissanpathfinders.net/forum/index.php?showtopic=26778&view=findpost&p=505236 The way I see it is that the sub harness not only adds a ground to the MAF sensor, it also adds a new ground to the ECU. I think the problem here is that the ECU has a poor ground connection through the body to the battery which causes a voltage drop and this sub harness actually fixes that. Run the ground wire directly to the negative terminal on the battery for best results. Edited July 13, 2010 by Tungsten Link to comment Share on other sites More sharing options...
Adam Posted July 13, 2010 Author Share Posted July 13, 2010 Your problem is caused by the poor grounding to the ECU and MAF sensor. The problem is fixed by adding a sub harness to the MAF sensor, which adds a new ground path. You should check out my MAF wiring thread here... http://www.nissanpathfinders.net/forum/index.php?showtopic=26778 This post here is the answer to the problem: http://www.nissanpathfinders.net/forum/index.php?showtopic=26778&view=findpost&p=505236 The way I see it is that the sub harness not only adds a ground to the MAF sensor, it also adds a new ground to the ECU. I think the problem here is that the ECU has a poor ground connection through the body to the battery which causes a voltage drop and this sub harness actually fixes that. Run the ground wire directly to the negative terminal on the battery for best results. That is awesome! I searched for weather, didn't think to try humidity. Thanks for the links, I'm gonna pull the Pathfinder around back and try this right now! Link to comment Share on other sites More sharing options...
Adam Posted July 13, 2010 Author Share Posted July 13, 2010 Alright, so I added the extra ground, and it made a difference in off the line power immediately, but I've still got the miss from 2-2.5k, feels like a rather random miss, not predictable at all... It's not humid enough for the humidity issue, the rains from the hurricane seem to be gone... We'll see what happens when I swap the distributor... if anything, it'll be one more thing narrowed out, and cheap from the boneyard... Link to comment Share on other sites More sharing options...
RJSquirrel Posted July 13, 2010 Share Posted July 13, 2010 try a new cap first. If you do change the distributor, make sure the timing is properly set. Good luck. Link to comment Share on other sites More sharing options...
Adam Posted July 13, 2010 Author Share Posted July 13, 2010 try a new cap first. If you do change the distributor, make sure the timing is properly set. Good luck. I got pretty good with setting the timing with how many times I've taken the distributor out Link to comment Share on other sites More sharing options...
Adam Posted July 13, 2010 Author Share Posted July 13, 2010 This morning it's idling rougher, I have to hold my foot on the gas or it'll just about die, dips around 500-600rpm if I'm not giving it a little gas... I'm going to snag the MAF sensor and TPS sensor from the junkyard today while I get the distributor... I'm also likely going to verify my timing belt install this weekend. Link to comment Share on other sites More sharing options...
Adam Posted July 13, 2010 Author Share Posted July 13, 2010 Got a new distributor cap, as the junkyard Pathfinder is gone now... Didn't change anything. I'm going to check my timing belt this weekend, make sure I did it just right, and I'm going to also redo all the rewiring I did with solder instead of crimp connectors. Link to comment Share on other sites More sharing options...
Adam Posted July 14, 2010 Author Share Posted July 14, 2010 Got some sprinkles and high humidity this morning(around 90%), and the Pathfinder is definitely handling the rain better. It's pretty much a night and day difference. Thanks! Link to comment Share on other sites More sharing options...
Tungsten Posted July 14, 2010 Share Posted July 14, 2010 so what was the problem? care to share? lol Link to comment Share on other sites More sharing options...
Adam Posted July 14, 2010 Author Share Posted July 14, 2010 The maf ground wire fixed most of the weather problem. I still have random misfires, but they were never weather related. Link to comment Share on other sites More sharing options...
Recommended Posts
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 accountSign in
Already have an account? Sign in here.
Sign In Now