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Discussion Starter · #1 ·
So when I purchased this car for my Son it had a knock upon startup
I've always assumed it could be bearings or the timing chain tensioner most likely
One day it died on my Son & now it's only firing on 3 cylinders, cylinder 4 doesn't fire
I've replaced plugs, coils, injectors cam & crank sensors & intake manifold gasket
I brought a used ecm that did nothing & couldn't even be flashed I was told
I have a new timing chain kit as well as rod & main bearings which I don't think is the issue but the price wasn't too bad so I bit the bullet
I forget the codes that came up bc it's been a few months but they all revolved around the work I did
I'll get her back this weekend to mess with it once again but I really think my chain jumped or so
Any input would be greatly appreciated & if there are any Nissan Tech's in South Jersey please hit me up lol
Car only has 83,000 miles
2004 Nissan Sentra 2.5S
Thanks All
 

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Discussion Starter · #4 ·
Ok so I just did the compression test & the numbers were all low but all around the same
110-110-105-110
I did the noid test but only on cylinders 1 & 4
1 lit up & 4 did not
Also plug 4 is clean while the other 3 show carbon so where do I go next lol
I'm glad this was super easy these two jobs
 

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I’m pretty sure the compression should be about 170 psi according to the service manual. I would try adding about a tablespoon of oil to each cylinder then do the compression test again.
If the pressure increases after you add oil then you may have worn cylinder rings.
If the pressure stays about the same then you may have bad valve seals.
Worn cylinder rings would require a rebuild to fix (sounds like you’re preparing for that?), but valve seals can be replaced in the chassis if you have the right tools for it. JWT has an in-chassis valve compressor that works with QR25’s.
 

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If number 4 is not getting power or ground, you have to fix that circuit.

yeah I was gonna say the 2.5S had the 1.8 body but with a qr25. A car of legend for sure.
 
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Discussion Starter · #10 ·
I’m pretty sure the compression should be about 170 psi according to the service manual. I would try adding about a tablespoon of oil to each cylinder then do the compression test again.
If the pressure increases after you add oil then you may have worn cylinder rings.
If the pressure stays about the same then you may have bad valve seals.
Worn cylinder rings would require a rebuild to fix (sounds like you’re preparing for that?), but valve seals can be replaced in the chassis if you have the right tools for it. JWT has an in-chassis valve compressor that works with QR25’s.
Thanks konkey00
 

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Discussion Starter · #12 ·
So since having this car at that shop since 5/6, I finally got a call back that it is the timing chain tensioner that went bad (duh) & also my #4 injector is not firing lol
He basically had to repeat to me a few months later what I initially told him?
If I have to get an ECU flashed for my ride that's cool so long as my timing has been replaced?
Who knows, maybe getting it back in timing will also get the ECU to recognize everything is synched correctly
I've come to the realization that absolutely no one wants to work on the 2.5 Nissan motors & always come up with excuses as to why it's something else
Gee Wiz!?!
 

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Its cuz you pretty much have to pull the motor for that kind of job on this car. Also very expensive.

Be wary about #4. It is possible to have one cylinder that loses compression from a non flat valve from timing chain jump if it was right on the threshold. But you can usually hear if the injector is working or not. I assume they did that diag correctly
 

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Discussion Starter · #14 ·
Its cuz you pretty much have to pull the motor for that kind of job on this car. Also very expensive.

Be wary about #4. It is possible to have one cylinder that loses compression from a non flat valve from timing chain jump if it was right on the threshold. But you can usually hear if the injector is working or not. I assume they did that diag correctly
I'm hoping to get the car back later this week as I've heard nothing else for about 3 weeks now.
Hopefully I can get it to the next Guy that may actually want to make some money & finally at least replace the chain & all so I can see where to go next
Thanks Sus Spec
 

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Discussion Starter · #17 ·
Ok, I finally got my ride back. Still isn't running right but I'm going to take care of her.
New issue she has now is no power to the fuel pump relay, the other wires are getting juice just not this one. Black/yellow wire by my left foot & starter signal fuse isn't lighting up either.
Can the fuel pump be going bad or might it be something else?
At crankup since she doesn't start the pump is not hissing but after a few cranks you can here where it hisses afterwards
Again thanks for your time & knowledge Everyone
 

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Maybe the relay is dead??? or a power form of a relay?

You check the boxes in the engine bay yet?
 

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Ok, I finally got my ride back. Still isn't running right but I'm going to take care of her.
New issue she has now is no power to the fuel pump relay, the other wires are getting juice just not this one. Black/yellow wire by my left foot & starter signal fuse isn't lighting up either.
Can the fuel pump be going bad or might it be something else?
At crankup since she doesn't start the pump is not hissing but after a few cranks you can here where it hisses afterwards
Again thanks for your time & knowledge Everyone
Factory compression for the QR25DE in the 2.5L is 181psi. You are well below the service limit for that engine, it's toast.
 
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