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As far as I'm aware it does, the second gen I did this on didn't tell me and I'm not experiencing anything since I did this in December with the fresh motor.
 

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Discussion Starter #22
Thanks Cricki, I will let you know if that solves the problem or not. I sure hope it does. That sensor is a tough one to get to with that oil cooler in front of it. I appreciate your help a lot.
 

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Even if it doesn't fix it, it one of those things that help as the "sensitive knock sensor" was a known issue.
 

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Discussion Starter #24
I just had a thought, since I just rebuilt this engine the rings haven't had time to seat in yet. Since they aren't seated, that will cause more blowby. That extra blowby will increase the amount of extra air introduced into the intake via the PCV valve. I was wondering if that would be enough to trigger the ECM into a lean condition after it warms up.

I have a catch can on the PCV to catch any oil that might get blown by. Not that that has anything to do with anything. I do know there is considerable blowby as I can feel it when the oil cap is removed. If I remove the oil cap completely it will blow oil out, it is that strong.
 

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As long as the pcv is routed correctly after the maf, it is all a sealed system. There is a thread about proper routing depending on engine setup. Double check that because it can get complicated.

As far as the oil cap off, Ive seen many motors that vary with amount of apparent blowby. Thats hard to measure. I only know to gauge that by the amount of oil burning.

Ive seen O2's that have to be dealer part only..
 

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Discussion Starter #26
When I installed the catch can. I just basically replaced the hose that was already there with the catch can in that line. The PCV valve hose wasn't before the MAF but after so none of the blowby goes by the MAF, it goes straight into the intake, at least on this engine.

I will have to wait and see how much if any oli is burned later, I have about 120 miles on the engine now.

A funny thing happened a few times today, the battery light flashed on for a second then went off, later it did it a couple more times. Any suggestions, maybe a loose wire?
 

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Discussion Starter #27
I made a smoke machine to check for intake leaks yesterday and checked for leaks. As far as I can see there are no leaks in the intake. I am going to use my shop vac and hook the exhaust side of the vac to my tail pipe, then use soapy water to see if there is a leak in the exhaust system. Using the smoke machine will not work very well on the exhaust IMHO. I could be wrong but the way I have to hook the machine up is a lot of trouble. I still haven't turned the knock sensor around but that is in the works also, it just won't stop raining long enough to get things done around here.
 

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Discussion Starter #28
Well I got out there today and I hooked the exhaust side of the shop vac to the exhaust pipe, sprayed the exhaust manifold with soapy water and bingo, there is the problem for the P2A00 code, leaking manifold in two places and both on the #1 side. The cat I put on just before I rebuilt the engine so I can't return it.

Is there a way to by pass the 02 sensors other than spacers. The fans are so close to the bottom 02 sensors now I am afraid the will cut the wires, no way will a spacer fit on there. If I were to totally seal all the holes in a 02 sensor and reinstall it, would that work? I can't afford another converter, this car is a money pit already.
 

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Weld the holes.

Also how did you do it? I am also chasing a vac leak but have a hard time to find it. Which smoker did you use and how did you hook up the shopvac?


Sent from my iPhone using Tapatalk
 

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They sell angled o2 spacers but that's not going to do anything in your situation, I'd weld the holes/ leaks as well.
 

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Discussion Starter #31
MoltenNismo there isn't any hole to weld, the flange on the exhaust manifold that bolts up to he head is not flat, it is bent. If there was a perfect straight edge laid on the exhaust manifold flange that bolts to the head, the ends of the flange turn up or away from the straight edge. There is where the leaks are, the exhaust leak is what is causing the code P2A00. I used my shop vac to pressurize the exhaust system. I put the hose from the shop vac into the tail pipe and taped it there. I took the hose from the shop vac sucking side and put it on the blowing side. I didn't use the smoke machine on the exhaust.

I used the smoke machine I made to see if there was a leak in the intake and there was none. I used a very small 12 volt compressor to blow the smoke into the intake. I stretched a rubber glove over the hose that the MAF is in so no smoke would come out there. I clamped the hose from the smoke machine into the hose from the intake to the PCV valve and plugged the line that was on the PCV valve.

I used baby oil for the smoke on a tightly wrapped cotton rag. In the video in the link I post below, I would go with the taller one as the smaller one does get hot after while but man does it put out the smoke.

Cricki, I am not sure there is even enough room for an angled adapter on the lower 02 sensor. I contacted the seller of the catalytic converter as it has a 3 year warranty on it, I hope they will honor their warranty, if not I will try to find a machine shop who will mill it flat. That flange is every bit of 3/8 inch thick.

 

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Discussion Starter #32
I forgot the photos of the exhaust manifold flange that bolts to the head, you can see the bubbles where the leak is.
Leak 1.jpg
Leak 2.jpg
 

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Discussion Starter #34
Did you replace the manifold gasket when you rebuilt it?


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Yes, there was a steel gasket in the gasket set, it still leaked with that one so I bought another gasket that was metal with a fiber, I installed both gaskets hoping that would take care of it but it didn't.

I contacted the place I bought the catalytic converter from and they are going to replace it. It had a 3 year warranty and it has been on the car since August or September of 2019.

I have done a lot of reading about 02 sensors trying to understand exactly how they work. In doing so I found with a closed loop system even a slight manifold leak can really mess the fuel trim up big time. So now I know what has been causing the car to stumble and lose some power after the engine warms up to operating temps.

The 02 sensors don't work until they hit 600 degrees and then is when they oscillate between 0.1 and 0.9 volts. If they go lower or higher the CEL will come on and the fuel trim will be off and produce a lean or rich mode, or limp mode.
 

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That leak is ridiculous and makes me what re examine my 2A00 but I would have to get the flange milled... or have a shop swap flange. Race header for reference.
 

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Discussion Starter #36 (Edited)
Cricki, I am convinced the exhaust leak is my problem for the stumbling and loss of some power going up hill. I read where one fellow performed an experiment with his headers. He purposely did different things to see what would happen with exhaust leaks. He slightly loosened the bolts so it would leak at the gasket and same results as when he drilled small holes in his headers. (I thought that was a real waste but that was him.)

The way the 02 sensors work is: there are small holes in the 02 sensor where the wires go into it. Those small holes are so outside 02 can enter the sensors. There are holes in the tip of the sensor in the exhaust path that let unburned 02 enter the tip of the sensor. Oxygen from the outside is moving inside the sensor at the small holes at the wires and oxygen is moving in the exhaust part of the sensor. This 02 of different amounts and combined with heat produce a slight electrical current. This is simplified, but it is complicated because of the materials that make up the 02 sensor.

The sensor does not work until it hits 600 degrees. There is a wire on the 02 sensor that is connected to an internal heater to speed up the heating so the sensor will work faster combined with the heat from the exhaust. Once it hits 600 degrees, if there is more unburned oxygen in the exhaust that isn't burned, than is supposed too, it will cause the 02 sensor to produce a higher or lower electrical current which will trigger the CEL. And it will send a signal to the ECM that the system is in need of less or more gas due to the ratio of too much unburned 02 in the exhaust. The sensor oscillates under normal conditions (after it hits 600 degrees) between 0.1 and 0.9 volts, if the 02 ratio is where it is supposed to be.

If there is an exhaust leak that is even ever so slight, extra 02 is introduced into the exhaust system and the 02 sensor with pick that up and there goes the code P2A00. A bad sensor will kick that code out also.

Had the people not taken my catalytic converter back, I was going to take the converter to a machine shop and have them mill the flange flat. That flange on mine is every bit of 3/8 inch thick so trying to straighten it by tightening the bolts on the head more will not work, it could mess the head up. The only other option for me would be a dummy sensor that would fool the ECM with the correct current to shut out the code. There is not enough room to put even an angled spacer on the downstream sensor on my car, the wires are about 1/4-3/8 inch away from the fans as it is now.

The idiot who put this mixed up junk of an engine in this car should have it back and him deal with all this junk. It is a good engine now and when I ever get it straightened out it should last a good while. I am really close to having all the bugs worked out.
 

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I'm curious to know if you ever got it figured out. I'm currently dealing with a p0420 code but my cat is gutted so I'm trying to figure out if I maybe have a leak somewhere.
 

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Discussion Starter #38
I'm curious to know if you ever got it figured out. I'm currently dealing with a p0420 code but my cat is gutted so I'm trying to figure out if I maybe have a leak somewhere.
A leak isn't your problem, your catalytic converter gutted is your problem. All you can do with a gutted cat is space the down stream 02 sensors or buy dummy sensors that will fool the ECM. The bent flange on my upstream cat is causing an exhaust leak that is causing my P2A00 code. The converters are good on my car it is the bent flange on the upstream converter that is my problem.
 

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Discussion Starter #39
Latest on my catalytic converter: The first converter I bought had a bent or warped flange that bolts to the head. I returned that one and they sent me another one but it was worse than the first one. I contacted them and they issued me a store credit at my request instead of a refund. I ordered a different brand name converter and this one also costs more. I checked the flange and while it wasn't perfect it was by far much better than the other two. I installed it and have driven 152 miles and so far no codes or CIL. I will continue to drive and and hope it doesn't spit a code. I will let you know later what is going on.

The car still has a slight stumbling problem and slight loss of power when it warms up and usually this stumbling is when going up hill. I can let the car sit for an hour and it is fine again until it warms up. I may replace the injectors to see if that might help. At this point all I can do is throw parts at it to see what is the problem. I have so many new parts now, a few more won't matter.
 

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I've had your issue before with the stumbling/loss of power when warmed to operating temp. I replaced fuel pump/injectors in the same line of reasoning that you're having and for nothing. Eventually this problem turned into car shutting off at idle at operating temp and other weird bogging/idle issues. Turned out to be my MAF. The weird thing is it never threw a code or anything that indicated it was the MAF or anything related. Try cleaning yours and see if it helps.
 
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