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Discussion Starter #1
I'm having issues with my truck running rich, I'm unsure if it's constant or only when warming up, it sure has quite the fumy/fuely smell to the exhaust, even after sitting for 15 minutes warming up, it still has quite the misty and foggy exhaust. It doesn't burn oil or coolant. After driving on the highway a bit, it stops smoking and the smell really dies down. I have quite a vibraty idle at 550-650 rpm, from what I read, many say this is normal. Truck seems to run great with a lot of power.

I posted a little while go about this, but didn't get a lot of help, thats okay, but I'm wondering if it could be a fowled plug or something, I was told that my P0420 code meaning bank1 catalytic converter failure was not my cause of the engine running rich but was CAUSED because of my truck is running rich and I need to identify why it's running rich.

Having this P0420, I will have nissan change out my catalytic converters. I could understand that having a bad catalytic converter wouldn't make the truck run rich, many run their trucks with no o2 sensors even plugged in without issues, just have to deal with the ECM constantly throwing a code.

I cleaned the MAF up real nice, looks good. Checked my vacuum hoses and they seem fine, all my fuel lines and coolant lines look fantastic... I'm lost guys!

thanks
 

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The 550-650 shake is normal, just have your idle bumped to 725-750 and that will fix the issue.

I think your best way to check for a fouled plug is to pull the first or second plug on the drivers side since the passenger side is covered by the intake manifold.

I would venture to say that since its cold in Utah, your getting the normal rich mixture during warm-up and that may be coating your cats a bit so it requires the increased rpm on the hwy to clean them out.

Side Note: I wonder if there could be some kind of issue with your injectors? Could they be semi-stuck in the open position? How have your mpg been doing?
 

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Discussion Starter #3 (Edited)
thanks for the quick reply! ..

Yeah, it'd be a great idea to bump up the idle, that stock tune idle is so low.

First off, my MPG has been pretty alright. On the highway I'm a little under 19, could get better if I didn't drive 80 everywhere I go, City is around 15/16, Combined is like 17.5ish. To me, that seems pretty good. But I know for sure that my real fumy strong fuel smell exhaust is not normal, none of my friends' newer trucks do this on cold startup/ever and nor does my rodeo... yeah the rodeo will have a little smokey/white exhaust for a minute or two in the morning start, but goes away quickly and has no odor.

Okay, do I pull the ignition coil off or unplug the cable going to the ignition coil?.. Which is better on the ECM ?

I guess it could be possible that I may have a leaky injector... should I run injector cleaning through my tank? .. I've got a can of seafoam in my garage but I'm a bit scared to run that through my frontier, is it safe to run it through my tank?
 

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if you had a fouled plug you would most likely have a misfire code too. and if your truck was running too rich to the point that the ecu could not correct it then you would also have a code from one of the farther forward o2 sensors. with one of your cats no longer working properly you will get a very fuelly smell since the unburnt fuel is not getting burned up in the cat. this will also cause a very misty and foggy exhaust, once i took the cats off my z the exhaust became very misty and foggy even on mornings i didnt' think it was cool enough to do so. have you gotten under your truck and knocked on the cats at all to see if there are any rattles, with this being your only code and with your symptoms a cat is your most likely culprit here. with out the smell the next most likely problem is a bad sensor itself, possible damaged wires. if you have a scan tool or an oscilloscope check to make sure that the o2 sensor has a pretty steady waveform, if it fluctuates alot then the sensor is likely the problem. if it really was running rich beyond the ability for the ecu to adjust it back to normal then you would have a code from one of your pre cat sensors.
 

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I would remove the negative battery cable. Then disconnect the coil. Then remove the coil. Then remove the plug and inspect. There are some nice pics online of fouled plugs and what caused them.

The seafoam isn't a bad idea but if you run it thru the vacuum line, you may need to change your plugs sooner then later. If you put some in the gas tank, then it should be fine, just follow the correct concentration or else it will smoke a bit. It may also be better to just run a tank of high test with a lot of detergents thru it (possibly Shell, they run a lot of commercials).

Side Note: An 05 with 28k, was it wrecked at one point? I am just wondering how long it sat with crappy fuel in it and if it caused any gunk build-up in the fuel rails. I only think this since my sisters old Kia had a mis-fire issue where there was fuel gel/gunk buildup in the fuel rail and the last injector was fubared. It just happened that the blcokage prevented the fuel from entering the cylinder but the gunk could have worked its way into the injector and kept it in the open positon.
 

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Pix of the plugs?
 

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Just a little side note. I get the same "rich-gas smell" on each startup in the morning. It goes away after a minute or two .. even if its bitterly cold out. I been thinkin' it was pretty normal for this truck .. and not much of an issue. Glad to hear other people have the same ..


d-mo
 

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i have the same issue as of the last couple days. my truck has 83k on it and as far as i know stock plugs etc. just curious if maybe driving in town only and not really getting up in th RPMs might cause this? i have been doing that for about a week but before that did a 1600km trip. the cats on my work truck (dodge 5500) can get so clogged from idling that the truck will cut power, the remedy is a good highway drive to heat them up and clean them out
 

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pretty sure its just a cold start warm up thing , happend to me over the winter
i was thinking the same thing (plugs)it got warmer and it went away
 

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any fix for this? my truck still smells rich, its been doing it all summer on basically every cold start up. MPG seem to be suffering a bit as well. no codes and goes away after its well warmed up. 89k miles now
 

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any fix for this? my truck still smells rich, its been doing it all summer on basically every cold start up. MPG seem to be suffering a bit as well. no codes and goes away after its well warmed up. 89k miles now
Disconnect the battery for at least 10 minutes, clean your cable and battery posts, this should set your ECM to a default mode. See if there is any improvement.
 
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