Backfire in intake/air cleaner

JESY HASWELL

MEMBER
1993 NISSAN PATHFINDER
3.0L
V6
4WD
AUTOMATIC
194,000 MILES

So I recently bought this vehicle knowing it had issues but cannot for the life of me figure out what is causing it. When I give it gas it makes a loud almost fart/popping noise that comes out of the air filter. Same if I rev it but if I slowly rev it it doesn't pop until roughly little over 2,000 rpm's. What could cause it to be doing this? Any suggestions on what would do it and what to fix?

5 Replies

JDL

MECHANIC
16,098 POSTS

When I hear backfire I think spark timing and valve timing. How long since a tune-up? Here is link for backfiring:

https://www.2carpros.com/articles/engine-backfires-while-running.

Repair guides at top of page, check it out a lot of good information, different links. Spark timing, 15 degree btdc. As far as valve timing have to check timing belt. In the diagram you can see the alignment points for cam and crank. If you get a new belt, make sure the new belt has the proper shape teeth, evidently some belts have different shaped teeth and it makes a difference or there wouldn't be a service bulletin about it.
There could be other issues?

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Wednesday, February 27th, 2019 AT 9:47 AM

JESY HASWELL

MEMBER
3 POSTS

Timing belt was replaced ten thousand miles ago so still pretty new and done at a shop. Checked the spark plugs all are firing and in good condition. Still I played with the distributor to see if advancing or retarding it would fix the pop it didn't. I do not know if it is my MAS or a fuel pressure issue or a air fuel mixture problem.

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Wednesday, February 27th, 2019 AT 9:56 AM

JDL

MECHANIC
16,098 POSTS

Any applicable trouble codes that point to anything? Do you have good cylinder compression? Do you have proper fuel pressure? Without something to point in proper direction, it's hunt and peck for me. That backfiring caught my attention, so I wondered about valves and or fuel.

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Wednesday, February 27th, 2019 AT 10:32 AM

JESY HASWELL