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Discussion Starter · #1 ·
Hi Folks, hope everyone is doing great.
I have some trouble regarding my pathfinder 2000 LE 3.3L ( has 105k Miles on it).


The car started driving heavy, does not have a lot of power, feels like it’s less responsive to throttle, started to have bad MPG, and also started to over heat when stationary or moving under pressuere. Things I have done so far:

  • identified a leak on air intake hose ( between filter and throttle body) and replaced the hose
  • replaced the spark plugs, wires and distributor. Adjust timing to 15BTDC according to the procedure.
  • checked the TPS and MAF sensor signals and they are all good.
  • cleaned throttle body with throttle body cleaner
  • Checked for vacuum leak and have not identified anything obvious
  • No error codes on ECM


None of these have helped. I have a ThinkDiag OBD reader and tried to diagnose more, something seems off. So, the obd reader shows me time advance degree on cylinder 1. On good idle it's 15 degrees ( i also checked with timing light and followed the procedure to set timing correctly ). But as I rev the engine I expcted the timing to steadily increase, however that does not really happen, instead it drops, then jumps back up to 40 when the rpm is way too high.

It's driving me nuts, the car does not have much power, is not much responsive and now it overheats when you pressure it a bit. I appreciate any help!
 

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NF Mod/Nissan Master Tech
2006 Pathfinder LE, 2003 Frontier SVE
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10,473 Posts
A lot of drivability problems occur on these engines due to bad distributors. I can't say that it is definitely your problem, but something to keep in mind. If you can find one in a junkyard for cheap, it might be worth getting it to swap out and see if it fixes the problem. Other things I would look at would include checking the distributor cap and rotor and ignition wires, checking fuel pressure and exhaust back pressure, or possibly a mechanical issue, such as the timing belt jumping a tooth or a head gasket failure. Speaking of timing belt, they are due at 105,000 miles or 7-years, whichever comes first. Has it been changed or changed recently?
 

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Discussion Starter · #3 ·
Thanks a lot! Yeah, I replaced the entire distributor assembly ( cap, rotor, coil) but it did not change much. The timing belt had been changed like 30k ago, 12 years ago. So, the car is over due for timing belt!
i have not checked the fuel/exhaust back pressure, I will check that.
i have not found any sign for mechanical issues, no leak from valve cover gaskets either.
 

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NF Mod/Nissan Master Tech
2006 Pathfinder LE, 2003 Frontier SVE
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Thanks a lot! Yeah, I replaced the entire distributor assembly ( cap, rotor, coil) but it did not change much. The timing belt had been changed like 30k ago, 12 years ago. So, the car is over due for timing belt!
i have not checked the fuel/exhaust back pressure, I will check that.
i have not found any sign for mechanical issues, no leak from valve cover gaskets either.
I said head gasket...not valve cover gasket. The only thing that valve cover leaks will do is make a big mess and potentially cause a fire if it leaks on the exhaust manifold!
 

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Discussion Starter · #5 ·
I said head gasket...not valve cover gasket. The only thing that valve cover leaks will do is make a big mess and potentially cause a fire if it leaks on the exhaust manifold!
Makes sense, I can check the cylinder compression! Thanks for the tip.
 

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Discussion Starter · #6 ·
I said head gasket...not valve cover gasket. The only thing that valve cover leaks will do is make a big mess and potentially cause a fire if it leaks on the exhaust manifold!
Checked compression on a warm engine with throttle open, all cylinders have around 120-140 psi, except cylinder #4, that one has around 60psi!
 

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NF Mod/Nissan Master Tech
2006 Pathfinder LE, 2003 Frontier SVE
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Checked compression on a warm engine with throttle open, all cylinders have around 120-140 psi, except cylinder #4, that one has around 60psi!
Compression should be close to 173 PSI. Minimum spec is 128 PSI. It's best to have a charger on the battery when doing a compression test to make sure the cranking RPM doesn't get too low. Obviously, #4 is a big problem! Try adding a tablespoon of oil to the cylinder and see if the compression comes up to spec. If it does, you may want to try doing the same to the other 5. If not, you have a dead cylinder. A cylinder leakdown test could show where the compression is going; you would need to put the engine on top dead center #4 cylinder to test that specific cylinder. If you have an air line that'll connect to your compression gauge's hose, you could pump air into the cylinder while at top dead center #4 and see listen to where the air goes; remove the radiator cap first. If air bubbles come up through the coolant, the head gasket is bad. If you hear it coming up through the valve cover with the oil cap off, it's going past the piston rings or piston (if there's a hole in it). If you hear it coming out the exhaust pipe or the throttle body, it's getting past the exhaust valve or intake valve, respectively.
 

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Discussion Starter · #8 ·
Compression should be close to 173 PSI. Minimum spec is 128 PSI. It's best to have a charger on the battery when doing a compression test to make sure the cranking RPM doesn't get too low. Obviously, #4 is a big problem! Try adding a tablespoon of oil to the cylinder and see if the compression comes up to spec. If it does, you may want to try doing the same to the other 5. If not, you have a dead cylinder. A cylinder leakdown test could show where the compression is going; you would need to put the engine on top dead center #4 cylinder to test that specific cylinder. If you have an air line that'll connect to your compression gauge's hose, you could pump air into the cylinder while at top dead center #4 and see listen to where the air goes; remove the radiator cap first. If air bubbles come up through the coolant, the head gasket is bad. If you hear it coming up through the valve cover with the oil cap off, it's going past the piston rings or piston (if there's a hole in it). If you hear it coming out the exhaust pipe or the throttle body, it's getting past the exhaust valve or intake valve, respectively.
Thanks again for super detailed instructions. I will perform the soak test and will update you, but I don't think I will go any further after that, as I really don't want to pull an engine or do major work here, the car is old and is not worth spending on it, so probably will just sell it for cheap mentioning the issue of course.


I forgot to mention that I performed a test to detect combustion gas in coolant and the test result was negative. I am still really wondering as why the car overheats. Another question, is any hack solutions here that does not require major work?
 

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NF Mod/Nissan Master Tech
2006 Pathfinder LE, 2003 Frontier SVE
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10,473 Posts
Maybe you have a restrictive radiator that is causing the overheat? I would normally say have it flow tested, but last time I priced new radiators on Rockauto they were dirt cheap and it would make more sense to a get a new one that pay for testing the old one.
 
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