Few Stupid Questions
Few Stupid Questions
I hope this one doesnt display irreversible sign of stupidity, but being around cars my whole life I still cant get the exhaust down. How many catalysts are in the 03 max exhaust and whats a catback? Also, from what I understand that a catalyst only reduces smog when engine is cold, once its warm it doesnt really need a cat. Also, the catman Y-Pipe, does it have a catalyst on it?
I'm looking at a possibility that my catalyst is bad and pushes exhaust back into the engine and I'm looking for a cheapest way to fix it (since a catalyst contains precious metals I dont think its a cheap Idea to look for it at my local dealer).
My car also seem to vibrate on idle, and when accelerating it kinda does it in stages, not smooth. As if I have a bad sparkplug or a coil. Is the exhaust (catalyst) a possible culprit?
And whining... It sounds like a power steering pump on an old Ford. It whines according to idle, the more rpms the more intense the whine. I deducted that its cause is most likely the grounding of the engine (it was swapped and thats when the whine started) because my power steering pump seems fine. How do I ground the engine, any thoughts?
I'm looking at a possibility that my catalyst is bad and pushes exhaust back into the engine and I'm looking for a cheapest way to fix it (since a catalyst contains precious metals I dont think its a cheap Idea to look for it at my local dealer).
My car also seem to vibrate on idle, and when accelerating it kinda does it in stages, not smooth. As if I have a bad sparkplug or a coil. Is the exhaust (catalyst) a possible culprit?
And whining... It sounds like a power steering pump on an old Ford. It whines according to idle, the more rpms the more intense the whine. I deducted that its cause is most likely the grounding of the engine (it was swapped and thats when the whine started) because my power steering pump seems fine. How do I ground the engine, any thoughts?
You have 3 cat's one for each bank and one after the y-pipe. The cattman y does not have any cat, nor does the stock y-pipe.
You throwing any codes???
About the whining, I don't know how a bad ground would cause that. You check the belts themselves?
You throwing any codes???
About the whining, I don't know how a bad ground would cause that. You check the belts themselves?
No codes. The belts will probably have to get replaced so I can pinpoint it, unless there is a way to test the belts? Visually, they seem fine. No cracks... OEM Nissan belts... But for the cats, where are the other 2 located. They are not in the headers, are they?
Yeah, in the 5.5 gen, the precats are bolted right on to the bottom of the headers.
Junior Member
Joined: Jan 2009
Posts: 39
From: Miami, Fl
the catback exhaust would be connected to your catlythic (sp) converter so you wouldn't need to do any modifications just use some WD40 on the bolts about 20 minutes before you try to unscrew if not it will be very difficult, also if you remove and of the cats on your car you will throw a check engine light so its better to maybe get high flow ones if you want i have a magna flow for the bottom cat but still have the factory ones that are part of the exhaust manifold (headers)
I hope this one doesnt display irreversible sign of stupidity, but being around cars my whole life I still cant get the exhaust down. How many catalysts are in the 03 max exhaust and whats a catback? Also, from what I understand that a catalyst only reduces smog when engine is cold, once its warm it doesnt really need a cat. Also, the catman Y-Pipe, does it have a catalyst on it?
I'm looking at a possibility that my catalyst is bad and pushes exhaust back into the engine and I'm looking for a cheapest way to fix it (since a catalyst contains precious metals I dont think its a cheap Idea to look for it at my local dealer).
My car also seem to vibrate on idle, and when accelerating it kinda does it in stages, not smooth. As if I have a bad sparkplug or a coil. Is the exhaust (catalyst) a possible culprit?
I'm looking at a possibility that my catalyst is bad and pushes exhaust back into the engine and I'm looking for a cheapest way to fix it (since a catalyst contains precious metals I dont think its a cheap Idea to look for it at my local dealer).
My car also seem to vibrate on idle, and when accelerating it kinda does it in stages, not smooth. As if I have a bad sparkplug or a coil. Is the exhaust (catalyst) a possible culprit?
Second, when you say your "catalyst is bad", I think you simply mean it is old and plugged. Essentially, the interior of a cat is a porous ceramic or metal component with hundreds of little holes/tubes, the surface of which is coated with precious metals (the catalyst). This serves to increase the surface area, enabling more pollutants to be converted into harmless gases. Over time, surface build-up decreases the size of the holes, increasing the back-pressure in the exhaust (between the exhaust valve and cat). The solution for this is one of the following: replace the cat - I recommend a high-flow cat (HFC) -, gut the existing cat (basically remove, destroy the inside and reinstall), or use a test-pipe (i.e. put a pipe in place of the cat). All of these will improve engine performance and could lead to a drop in fuel consumption.
Third, just for review, the exhaust components (in order from cylinder to tailpipe): header (also called exhaust manifold; one per cylinder bank) with or without pre-cats, y-pipe, main cat, b-pipe (or resonator), piping (over axle), muffler. Each is a separate piece bolted to the next so that, when an individual piece fails, it can be removed and replaced. The last three components are usually considered a "cat-back exhaust [system]".
If you want to test whether the cat is causing the poor idle quality, remove the cat and run it without to see if the idle improves...
Hope this clears up your understanding.
the catback exhaust would be connected to your catlythic (sp) converter so you wouldn't need to do any modifications just use some WD40 on the bolts about 20 minutes before you try to unscrew if not it will be very difficult, also if you remove and of the cats on your car you will throw a check engine light so its better to maybe get high flow ones if you want i have a magna flow for the bottom cat but still have the factory ones that are part of the exhaust manifold (headers)
Since you asked, I'll attempt to clear up your understanding of modern exhaust emission hardware + function. First, an engine never really "needs" a catalytic converter (cat) - it can run just fine with nothing behind it (i.e. no obstruction to the flow). Emissions controls were added in the 70s to reduce smog-forming emissions. Modern three-way cats (three pollutants: NOx, HC and CO) are included in all exhaust systems, sometime including "pre-cats" as on the Maxima. A cat is simply a area that "enables" conversion reactions in the exhaust gases due to the catalyst-coated surface. The cat (i.e. reactions in the cat) only starts to function once it reaches a certain temperature. Under cold start-up conditions, the cat does not function for the first 10 seconds (semi-WAG) of operation, thus pre-cats, positioned very near to the cylinders and hence heat up very quickly, help to reduce emissions on cold start-up. Also, an important note: for proper function of the cat, the engine must hold the lambda value at or very near 1.0 (air-fuel ratio near the stoichiometric value). If it is either too rich or too lean, the cat does not function correctly.
Second, when you say your "catalyst is bad", I think you simply mean it is old and plugged. Essentially, the interior of a cat is a porous ceramic or metal component with hundreds of little holes/tubes, the surface of which is coated with precious metals (the catalyst). This serves to increase the surface area, enabling more pollutants to be converted into harmless gases. Over time, surface build-up decreases the size of the holes, increasing the back-pressure in the exhaust (between the exhaust valve and cat). The solution for this is one of the following: replace the cat - I recommend a high-flow cat (HFC) -, gut the existing cat (basically remove, destroy the inside and reinstall), or use a test-pipe (i.e. put a pipe in place of the cat). All of these will improve engine performance and could lead to a drop in fuel consumption.
Third, just for review, the exhaust components (in order from cylinder to tailpipe): header (also called exhaust manifold; one per cylinder bank) with or without pre-cats, y-pipe, main cat, b-pipe (or resonator), piping (over axle), muffler. Each is a separate piece bolted to the next so that, when an individual piece fails, it can be removed and replaced. The last three components are usually considered a "cat-back exhaust [system]".
If you want to test whether the cat is causing the poor idle quality, remove the cat and run it without to see if the idle improves...
Hope this clears up your understanding.
Second, when you say your "catalyst is bad", I think you simply mean it is old and plugged. Essentially, the interior of a cat is a porous ceramic or metal component with hundreds of little holes/tubes, the surface of which is coated with precious metals (the catalyst). This serves to increase the surface area, enabling more pollutants to be converted into harmless gases. Over time, surface build-up decreases the size of the holes, increasing the back-pressure in the exhaust (between the exhaust valve and cat). The solution for this is one of the following: replace the cat - I recommend a high-flow cat (HFC) -, gut the existing cat (basically remove, destroy the inside and reinstall), or use a test-pipe (i.e. put a pipe in place of the cat). All of these will improve engine performance and could lead to a drop in fuel consumption.
Third, just for review, the exhaust components (in order from cylinder to tailpipe): header (also called exhaust manifold; one per cylinder bank) with or without pre-cats, y-pipe, main cat, b-pipe (or resonator), piping (over axle), muffler. Each is a separate piece bolted to the next so that, when an individual piece fails, it can be removed and replaced. The last three components are usually considered a "cat-back exhaust [system]".
If you want to test whether the cat is causing the poor idle quality, remove the cat and run it without to see if the idle improves...
Hope this clears up your understanding.
@ OP
How long you had the car?
Auto or manual?
Have your coils ever been changed?
The whine, can you tell where (what side) it is coming from?
Member
Joined: Dec 2010
Posts: 225
another good way to detemine if your cat is bad without unbolting it is to take out your precat 02 sensor(befor the catalytic converter) and see if it runs any better. it will allow enough of your exhaust fumes to exit befor it hits the cat ( it might sound funny... your car i mean lol) but it would sound even worse if you ran it with the cat unbolted to so.... up to you.... if the exhaust is old and rusty i wouldnt recommend unbolting the cat incase you break one of the bolts then your buying yourself a tap and dye set and spending hours snugged under the car extracting the bolt that broke! i learned this from experience!!!!!
a cat back exhaust: an exhaust system that begins after the cat.
are you sure you ps pump is good?
ground from batt to frame, from the bellhousing... one of those should work.
a cat back exhaust: an exhaust system that begins after the cat.
are you sure you ps pump is good?
ground from batt to frame, from the bellhousing... one of those should work.
Last edited by getflushed; Jan 15, 2011 at 05:45 PM.
its an auto and the coils came with the salvaged engine. Since it was swapped I've had the 'shakes' The whine seems to be coming from the power steering side but power steering looks fine, the fluids dont smell burnt and again, came about after the swap. Had the car for 1.5 yrs
Since you asked, I'll attempt to clear up your understanding of modern exhaust emission hardware + function. First, an engine never really "needs" a catalytic converter (cat) - it can run just fine with nothing behind it (i.e. no obstruction to the flow). Emissions controls were added in the 70s to reduce smog-forming emissions. Modern three-way cats (three pollutants: NOx, HC and CO) are included in all exhaust systems, sometime including "pre-cats" as on the Maxima. A cat is simply a area that "enables" conversion reactions in the exhaust gases due to the catalyst-coated surface. The cat (i.e. reactions in the cat) only starts to function once it reaches a certain temperature. Under cold start-up conditions, the cat does not function for the first 10 seconds (semi-WAG) of operation, thus pre-cats, positioned very near to the cylinders and hence heat up very quickly, help to reduce emissions on cold start-up. Also, an important note: for proper function of the cat, the engine must hold the lambda value at or very near 1.0 (air-fuel ratio near the stoichiometric value). If it is either too rich or too lean, the cat does not function correctly.
Second, when you say your "catalyst is bad", I think you simply mean it is old and plugged. Essentially, the interior of a cat is a porous ceramic or metal component with hundreds of little holes/tubes, the surface of which is coated with precious metals (the catalyst). This serves to increase the surface area, enabling more pollutants to be converted into harmless gases. Over time, surface build-up decreases the size of the holes, increasing the back-pressure in the exhaust (between the exhaust valve and cat). The solution for this is one of the following: replace the cat - I recommend a high-flow cat (HFC) -, gut the existing cat (basically remove, destroy the inside and reinstall), or use a test-pipe (i.e. put a pipe in place of the cat). All of these will improve engine performance and could lead to a drop in fuel consumption.
Third, just for review, the exhaust components (in order from cylinder to tailpipe): header (also called exhaust manifold; one per cylinder bank) with or without pre-cats, y-pipe, main cat, b-pipe (or resonator), piping (over axle), muffler. Each is a separate piece bolted to the next so that, when an individual piece fails, it can be removed and replaced. The last three components are usually considered a "cat-back exhaust [system]".
If you want to test whether the cat is causing the poor idle quality, remove the cat and run it without to see if the idle improves...
Hope this clears up your understanding.
Second, when you say your "catalyst is bad", I think you simply mean it is old and plugged. Essentially, the interior of a cat is a porous ceramic or metal component with hundreds of little holes/tubes, the surface of which is coated with precious metals (the catalyst). This serves to increase the surface area, enabling more pollutants to be converted into harmless gases. Over time, surface build-up decreases the size of the holes, increasing the back-pressure in the exhaust (between the exhaust valve and cat). The solution for this is one of the following: replace the cat - I recommend a high-flow cat (HFC) -, gut the existing cat (basically remove, destroy the inside and reinstall), or use a test-pipe (i.e. put a pipe in place of the cat). All of these will improve engine performance and could lead to a drop in fuel consumption.
Third, just for review, the exhaust components (in order from cylinder to tailpipe): header (also called exhaust manifold; one per cylinder bank) with or without pre-cats, y-pipe, main cat, b-pipe (or resonator), piping (over axle), muffler. Each is a separate piece bolted to the next so that, when an individual piece fails, it can be removed and replaced. The last three components are usually considered a "cat-back exhaust [system]".
If you want to test whether the cat is causing the poor idle quality, remove the cat and run it without to see if the idle improves...
Hope this clears up your understanding.
Oh, and one more, knock on wood, no SES lights as of yet. Once, after the swap-the CPSensor.
And again, thanks for your time
another good way to detemine if your cat is bad without unbolting it is to take out your precat 02 sensor(befor the catalytic converter) and see if it runs any better. it will allow enough of your exhaust fumes to exit befor it hits the cat ( it might sound funny... your car i mean lol) but it would sound even worse if you ran it with the cat unbolted to so.... up to you.... if the exhaust is old and rusty i wouldnt recommend unbolting the cat incase you break one of the bolts then your buying yourself a tap and dye set and spending hours snugged under the car extracting the bolt that broke! i learned this from experience!!!!!
a cat back exhaust: an exhaust system that begins after the cat.
are you sure you ps pump is good?
ground from batt to frame, from the bellhousing... one of those should work.
a cat back exhaust: an exhaust system that begins after the cat.
are you sure you ps pump is good?
ground from batt to frame, from the bellhousing... one of those should work.
I'm gonna spend all day tomorrow being a grease monkey that I am (if weather permits) and hopefully will have some things solved (changing some suspension parts too)
Hey zhuleek, I have an 02 6MT SE. I have the same whining you're describing. It started up a couple weeks ago for me when it started getting cold. It's not as loud now but I can still tell. The only thing I did to it before it happened was make a couple of grounding wires, one for battery negative to chassis and engine block to chassis. Other than that I did nothing different and heard the whining. It's louder as the rev's are higher, but if I'm moving at above of 20 mph, road noise and stuff make it so I can't hear it. I also have the shaking at idle and some rattling which I think is the cats. My car has 120k on it. I didnt suspect grounding at first since I don't know why that could cause the whining, and the shaking, I suspect is due to bad mounts.
I still don't know why grounding could cause that whining noise, but that's the only thing i did. I changed my serpentine belt since someone thought it was a seized pulley and after checking, noticed the belt had cracks, but it didn't really make a difference. I'll let you know if i figure anything out though, but for the time being, seems like we have some similar problems.
I still don't know why grounding could cause that whining noise, but that's the only thing i did. I changed my serpentine belt since someone thought it was a seized pulley and after checking, noticed the belt had cracks, but it didn't really make a difference. I'll let you know if i figure anything out though, but for the time being, seems like we have some similar problems.
So its possible that both things are related? If we have two same symptoms one of which is caused by bad grounding, maybe the shakes will go away once we get rid of the whining. Logically, I can not explain how the 2 problems can be caused by the same thing but I would suggest using some sand paper on the terminals where you grounded your engine. I was gonna do it this sunday but didnt get to it (I changed front pads/rotors-thank you autozone for your 2yr warranty, did sway bar bushings-energy suspension is awesome and other minor things). Also, what was the reason you grounded your engine?
I don't really think they're related. I had the shaking way before the whining. I did sand down the places where I grounded my engine. The reason I did it was to see if it would make a difference, because of all the good things I read about grounding kits. I had some spare wire left over so I just made my own kit and put it on.
Then its possible that it is the clogged cats/headers. So did you undo the grounding? And if you did, from what I understand, it still whines? Of, and curious, did the grounding kit of any advantage? I heard mixed thoughts on that
Also, check this out. its on grounding and how the ECU and imroper grounding can effect idle...
http://www.350zmotoring.com/forums/d...g-kit-diy.html
http://www.350zmotoring.com/forums/d...g-kit-diy.html
It could be, but I don't have a CEL on. I might have one once in a blue moon but it shuts off by the end of the day. I haven't had time to go undo the grounding kit since it's been cold and I've started up classes again since break's over for me. As far as any noticeable advantages, I felt like the car started easier, and I had a problem where one of my dome lights would turn off randomly when I turn it on. It hasn't happened since then.
As far as RPM's go, when i'm idling, it doesn't fluctuate. If it does, I can't tell by watching the needle. Because of this and no CEL, I'm assuming that my problem for shaky idle could be the engine mounts.
As far as RPM's go, when i'm idling, it doesn't fluctuate. If it does, I can't tell by watching the needle. Because of this and no CEL, I'm assuming that my problem for shaky idle could be the engine mounts.
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