2001 Qx4 Hard Start, Intermittent Start, Electrical or fuel issue [SOLVED - fuel damper]

[Tallent89]

Hey guys,

I've seen multiple threads pertaining to Pathfinders and even some Qx4s of my year on hard starting issues, yet I have not found an answer that has fixed my issue.

I've had my Qx4 for 4 months now; started having intermittent starting issues a couple months in, it will crank, turn over, but no start on the first try. It started to happen about once a week and now since its been colder (could have nothing to do with it) its everyday at least once a day. Depending on how long I let it sit, it will start right away throughout the day or go back to the same issue and take a couple/few tries to fire up. It does not stall or die or have varying idling issues. I took it to the Nissan dealership twice with two weeks apart and the issue occurred for them at first and they couldn’t find anything wrong with it and say it'll turn over fine for them throughout the day! I need help
I assume after driving it around for the day it has been activating the issue since Nissan can't figure it out having the SUV for a total of 5 days!

The fuel pump is working every time I engage, the old FPR had gas coming out of the vacuum line and since replacing I have had no issue with it. I do hear sometimes different clicking patterns from the Throttle body position sensor when turning on or off the vehicle but I'm tired of throwing parts with no resolve.

Please find below everything I have done so far:
New Spark Plugs
Cleaned Injection coils
Replace air filters
Replaced Fuel pressure regulator (recommended by dealer)
Replaced Fuel Filter
Cleaned MAF
Fuel injection Cleaners (recommended by dealer)

[Tallent89]

One more thing, I have noticed a slight coolant leak, cannot pin point where from yet and not sure if its related.

[Rockwood]

"Depending on how long I let it sit, it will start right away throughout the day or go back to the same issue and take a couple/few tries to fire up."

It might help to explain this a little more - is it hard to start after sitting overnight? How long does it sit before you seem to have the problem reappear?

[Tallent89]

"Depending on how long I let it sit, it will start right away throughout the day or go back to the same issue and take a couple/few tries to fire up."

It might help to explain this a little more - is it hard to start after sitting overnight? How long does it sit before you seem to have the problem reappear?

It could be over night or just a couple hours where it wont start, It just depends on how it feels. After changing the FPR and Fuel filter it did work solid for about 4 days before it started everyday again.

[EdBwoy]

Agreed with Rockwood as above.

Have you attempted to scan it for codes, even if the check engine light is not on?
I ask this because to some extent it sounds like a camshaft/ crankshaft signal pickup issue. The sensors sometimes do fail intermittently but it might be something as simple as cleaning the sensors.

Then depending on the answer on how long it sits before acting different, it also sounds like an idle air relearning issue (a procedure which requires relearning the throttle closed position first - you mentioned noticing varying sounds from the butterfly valve, which might be the norm btw)

Edit: I see your response on the time. Does it seem to matter whether the engine is warm or not?

[850pathfinder]

i had this exact same issue last week with my 03 pathfinder that i rebuilt. New fuel pump cause i thought the check valve was bad and that worked for 3-4 days then started to take 4-7 seconds to fire up again. Replaced the fuel pressure reg and fuel dampner and it hasnt done it since. when i removed the vacuum lines no fuel was coming out of the reg or dampner but there was a strong fuel smell in both vacuum lines. we will see if that fixes it. If not ill remove the manifold and injector rail and see if i have a leaky injector. my LTFT are around -5.5% which would also be explained by leaky injectors.

[Tallent89]

Have you attempted to scan it for codes, even if the check engine light is not on?
I ask this because to some extent it sounds like a camshaft/ crankshaft signal pickup issue. The sensors sometimes do fail intermittently but it might be something as simple as cleaning the sensors.

Then depending on the answer on how long it sits before acting different, it also sounds like an idle air relearning issue (a procedure which requires relearning the throttle closed position first - you mentioned noticing varying sounds from the butterfly valve, which might be the norm btw)

Edit: I see your response on the time. Does it seem to matter whether the engine is warm or not?

I have not attempted scan codes yet but I will over the next couple days, thank you.

This morning, however, it started just fine with it being about 50 'F overnight and sitting for roughly 12 hours, then once I left work being around the same temp. I had the same issue -couple cranks til start.

I will get back to you once I check for codes and clean whatever sensors I am able to.

Thank you for your opinion

[Tallent89]

I will look into the damper though, I read some relative topics on it but nothing substantial.

[Wrierblock20]

Could be a leaky injector, I had hard starts plus P0300 multi so far I changed dizzy fuel filter plugs wires and royal purple max injector cleaner, now I have just P0302 cyl 2 misfire but since all the parts above a much quicker start only issue now is if I let it sit after a warm shutdown for 5min then start it up it misfires cyl #2 after 2-3 min of driving it goes away Also cold starts no misfire I think the fuel injector leaks then I have to burn the extra fuel to get it to go away just a FYI all my problems started with hard start then just got worse flashing CEL and stumble upon acceleration. Much better now but I know leaky injector is possibility going to pull the plenum off this Tuesday since I already tried changing injector number 2 without removing plenum and its not possible T.T

[Tallent89]

Agreed with Rockwood as above.

Have you attempted to scan it for codes, even if the check engine light is not on?
I ask this because to some extent it sounds like a camshaft/ crankshaft signal pickup issue. The sensors sometimes do fail intermittently but it might be something as simple as cleaning the sensors.

Then depending on the answer on how long it sits before acting different, it also sounds like an idle air relearning issue (a procedure which requires relearning the throttle closed position first - you mentioned noticing varying sounds from the butterfly valve, which might be the norm btw)

Edit: I see your response on the time. Does it seem to matter whether the engine is warm or not?

I checked for codes today and autozone found nothing.
I’m going to re check my coil injectors, FPD, and then attempt the camshaft sensors (too hard w/ having basic tools :/ )
Other than that, I’m out of options that cost minimal funds.

Thank you guys and once I find this problem out, I will share with all Nissan/Infiniti owners haha

[Tallent89]

I changed the Damper today and so far every start has been great.. Let's give it a week and see then!

[Tallent89]

Over one week in and the Damper seems to be the root of the cause! Every start is still great