# Rough idle and running rich.



## kd7skx (Jul 10, 2010)

Hi all, 

New hear and having some issues with a 97 Pickup I just bought. It is the 2.4l with a 5 speed.

It isnt running rough, but at idle it isnt smooth, it rattles the truck a bit. Also it smells like it is a little rich.

Plugs look good, wires are newish, and I am going to check timing. I cleaned the MAF as well.

I am getting a code that says P0175 System too Rich (Bank 2).

Any ideas. thanks

Other than that what do you guys think.


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## kd7skx (Jul 10, 2010)

Ok, the timing is fine, 10 degree's.

Forgot to add I am getting about 16 mpg as well. Thought these little pickups did better than that.


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## nissan4x4.27 (Jul 8, 2009)

i was told on mine which is a 97 hb 2.4 4x4 5 speed i would get no more then 14 mpg but only thing i could tell u is to mess with ur air fuel mixture screw cause mine was to lean but mine wouldnt run on its own and everyone will tell u check for vacuum leaks but seems to never be my problem but if i figure mine out i will let u know


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## kd7skx (Jul 10, 2010)

Well got an update, for those following along.

I went ahead and seafoamed it, man I didnt relize that it would smoke that much. But it seems to smooth some things out in the engine a little bit.

Also I changed out the cap, rotor, and spark plugs. The plugs looked absolutely horrendous. They were wet, very black and had some soot on a couple of them. I am guessing it burns some oil along with these plugs have not been changed in a very very long time. Also seemed to help with smoothing out the engine a bit.

Now for another possible problem. I think I might need to change the timing chain. It is rattling like non-other. I thought the rattle was from loose heat shielding but upon further inspection today under the hood it is coming from inside the engine in the area of the timing chain. Never heard an engine do this before, also never owned a nissan, so I am think chain after reading over other post on the topic.

If you guys got any input let me know. So the search continues.

Thanks

Brian


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## dentedsub (Oct 23, 2007)

was there no stored codes (mode 1)? cause i bet its the o2 sensor or theres something wrong with injectors. if theres no codes for any sensors maybe just try some fuel injector cleaner.


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## kd7skx (Jul 10, 2010)

No codes for the o2 sensor, but was think about replacing them later on just to see. I put some cleaner in the gas tank today so hopefully it will clear things up.


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## kd7skx (Jul 10, 2010)

Another update. Just noticed this when I got home tonight. When i came to a stop tonight the truck will surge rmp's at idle, surge's from 700 to 1000. Any way I will try to track this down as well. Thanks

Brian


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## sup_mario (Jun 30, 2010)

What do running rich means? Sorry, i really don't know.


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## kd7skx (Jul 10, 2010)

Means it is getting more fuel that the engine needs, the exhaust smells really heavily of fuel.


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## dvdswanson (Nov 6, 2005)

the truck has OBDII system so it will store codes if there were any. check the charcoal canister and lines to it. its above the spare tire under the bed.


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## kd7skx (Jul 10, 2010)

kd7skx said:


> I am getting a code that says P0175 System too Rich (Bank 2).


From above. Thanks


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## BBDirtbiking (Mar 6, 2009)

kd7skx said:


> Another update. Just noticed this when I got home tonight. When i came to a stop tonight the truck will surge rmp's at idle, surge's from 700 to 1000. Any way I will try to track this down as well. Thanks
> 
> Brian


My truck has been doing this as well, it is a 1987 HB 4x4 with the v6 motor and 5 speed transmission. It was getting really bad and then it got better when I changed the idle speed and moved the distributor cap a couple degrees, but it is starting to act up again, very inconsistent times to... 

I looked for vacuum leaks and none, so I do not know what is going on here. Hopefully someone can help our problem here. I also notice, on my oil gauge that when my truck surges it will go from a good idle, around 16 when warm, to like 6, then catches itself and shoots it up for around 25, then back down to low pressure... very strange, also seems to do it more when running in reverse, which doesn't make sense... didn't do it today though. Going to get some injector cleaner though and run it through my tank since I need to fuel up... sub gauge is at 1/16 -.- Lol.


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## GeoBMX4Life (Mar 25, 2010)

*PCV valve, or valve cover gaskets.*



BBDirtbiking said:


> My truck has been doing this as well, it is a 1987 HB 4x4 with the v6 motor and 5 speed transmission. It was getting really bad and then it got better when I changed the idle speed and moved the distributor cap a couple degrees, but it is starting to act up again, very inconsistent times to...
> 
> I looked for vacuum leaks and none, so I do not know what is going on here. Hopefully someone can help our problem here. I also notice, on my oil gauge that when my truck surges it will go from a good idle, around 16 when warm, to like 6, then catches itself and shoots it up for around 25, then back down to low pressure... very strange, also seems to do it more when running in reverse, which doesn't make sense... didn't do it today though. Going to get some injector cleaner though and run it through my tank since I need to fuel up... sub gauge is at 1/16 -.- Lol.


 With that type of oil pressure surge, you could check your valve cover gaskets, or you pcv valve, air getting in thru your gaskets will cause the pressure to fluctuate....PCV may be in need of replacing.


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## BBDirtbiking (Mar 6, 2009)

GeoBMX4Life said:


> With that type of oil pressure surge, you could check your valve cover gaskets, or you pcv valve, air getting in thru your gaskets will cause the pressure to fluctuate....PCV may be in need of replacing.


It is more of a surge of my oil pressure related to idle, like when my truck is just idling (note: Doesn't happen always, seems to be better after adjusting idle and distributor cap) I give it a little bit of throttle and it gets up all right, but when it drops back down it drops low, then it catches itself, at the point where it is lowest the oil pressure would be the lowest. After it catches itself, it shoots over my normal idle speed, then drops back down low, and same thing happens... Some times it does this quite a lot and frequently, which is what is confusing, if it did it all the time I wouldn't be as confused. If I have time I will check the PCV valve tomorrow, thinking about it now, that could be the culprit although I always did oil changes well before recommended mileage... I will have to check it out, thanks for that suggestion.


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## kd7skx (Jul 10, 2010)

So I bought a code reader and ran the code again. It is p-0171 now instead of p-0174 earlier.


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## GeoBMX4Life (Mar 25, 2010)

*Not familiar with p-0171*



kd7skx said:


> So I bought a code reader and ran the code again. It is p-0171 now instead of p-0174 earlier.


 Not familiar with this code, and my Haynes doesn't list it either...anyone else know this one?


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## kd7skx (Jul 10, 2010)

Pulled this off of a OBD2 web site,

Technical Description

System Too Lean (Bank 1)

What does that mean?

Basically this means that an oxygen sensor in bank 1 detected a lean condition (too much oxygen in the exhaust).


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## kd7skx (Jul 10, 2010)

Well I thought it was gone after cleaning the mass airflow senor with electronics cleaner a couple days ago, but error code P0171 is back and the mileage still aint getting any better. i went out and got a small propane bottle to check for vacuum leaks, still couldn't find any. So I am at a loss now. Any further ideas would be appreciated.

Here is what I have done so far;
New: plugs, wires, cap, rotor, fuel filter
Fresh oil change
Seafoamed the engine thru the oil, gas and vacuum lines
Cleaned mass airflow sensor with Electro-Wash
Tried to detect leaks with propane, wish I had a smoke machine to really know.

Any ideas would be appreciated. Thanks

Brian


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## GeoBMX4Life (Mar 25, 2010)

The code maybe coming from a broken wire too, maybe check the continuity from the MAF and the TPS to the ECU...I'm running out of ideas as well.


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## kd7skx (Jul 10, 2010)

After much googleing I think am going to get a new MAF. Seems like this is a fairly common error code and at least the bad mileage has been cleared up in a majority of cases by replacing the maf. Found one on ebay for $84, not too bad. Will update you when I get it.


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## kd7skx (Jul 10, 2010)

Update,

Word to the wise, do not buy a generic MAF sensor. I went thru two of them before getting a genuine nissan one, and got my money back. The generic ones, off of ebay any way, caused my truck to run horribly. Just installed the genuine Hitachi Nissan senor and the check engine light immediately went out and the truck is idling smoother now. We will see what the mileage will do here in a week or two. But my guess it will greatly improve.


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## zanegrey (Dec 5, 2005)

an 84 dollar maf sounds like a generic one to me..

fyi i carry used but good maf sensors...


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## kd7skx (Jul 10, 2010)

Yes they were the ones for $84. Found ones for a little bit more that were brand new Hitachi that is now installed on my truck and running much better.


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## kd7skx (Jul 10, 2010)

Errrrrrrr, 

So all that time and money now down the tube. The MAF didnt fix it. So back to the drawing board. Maybe a o2 sensor, temp sensor too maybe? I am at a loss at this point.

The check engine light came back on needless to say and the same dang error, p0171. I keep trying to find a dang vacuum leak but never can. That is why I thought MAF, but that didnt fix it. So on to a new plan.

If any one has any other ideas I am up for anything at this point. Just want the dang thing to run like it should.


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## zanegrey (Dec 5, 2005)

do a compression check ...


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## kd7skx (Jul 10, 2010)

I have been reading on several web sites that there is something called long term fuel trim and that it can be reset. How do I reset this? Basically it resets the ECU back to learning mode after you change out major components from what I understand.


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## kd7skx (Jul 10, 2010)

Well I pulled the O2 sensor today to replace it and I was set back by what I say. The sensor I pulled out was definitely bad looking. But it is one I have never seen before. It did not have a cap, it almost looked like just a large spark plug. The center was a metal rod surrounded by ceramic. The ceramic was almost all but gone and cracked and the the senor part didnt look much better. So hopefully this time I fixed it. One could only hope.

Here is the image of the sensor, I cant get it to post here for some reason from flikr.


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## minitrkingking (May 10, 2009)

Can't wait to find out if this helps. My truck does the drop in idle just the same sometimes, everything I have done to it have improved it but the drop is still there. Haven't done the o2 sensor yet.


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## kd7skx (Jul 10, 2010)

kd7skx said:


> I have been reading on several web sites that there is something called long term fuel trim and that it can be reset. How do I reset this? Basically it resets the ECU back to learning mode after you change out major components from what I understand.


Ok so I got this reset. I got a consult adapter off of ebay and some software called Tecu off another forum. Seemed to help after changing out the O2 sensor. I haven't driven it much since changing out the O2 sensor, but it doesn't seem to be going thru the gas as much. I will put a full tank thru it when I get back from vacation next week. Hopefully I will be in the mid 20's for mileage after doing all of this now.


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## CMax03 (Jan 17, 2009)

water temp sensor/wiring......


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## kd7skx (Jul 10, 2010)

CMax03 said:


> water temp sensor/wiring......


do you mean to check it out? I have not looked at it yet.

I guess I should add since replacing my O2 sensor I have not had the check engine light come back on for a week now. Before it would come on in less than a day of driving.


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## CMax03 (Jan 17, 2009)

yeah check it out......


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## kd7skx (Jul 10, 2010)

Well it finaly looks like my problems have been solved. Ran the truck now for two weeks with no check engine light coming back on. My milage has bumped up, I hit 180 miles on half a tank where I was only seeing 100 miles at half before. I will give you guys the final mpg when i fill it up, nice to say that I wount have to fill up probably till the end of next week. Finaly some relief from these gas prices, better mpg. Looks like replacing the O2 sensor solved it.

Thanks for all the help you guys gave me.

Brian


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## kd7skx (Jul 10, 2010)

Well the verdict is in. I gained 100 miles to a tank at 22.79mpg. That is town driving as well. I am taking a road trip in October, we will see what she does after 14 hours of straight driving.

Thanks again for all the help guys.

Brian


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## Pinina (May 13, 2009)

my truck varies from 24 - 18 mpg. it smells stong also in the exhaust.
i wonder if mine is going bad?


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