what is engine knocking mean

Asked by Jul 05, 2013 at 08:37 PM about the 2006 Nissan Altima 2.5 S

Question type: Maintenance & Repair

engine knocking when stopping and turning car off

5 Answers

When stopping...keeps running is a phenomenon called "dieseling" which means that the combustion chamber is running hot and the fuel supply isn't being shut-off when the key is turned off~ might be a stuck relay...see what the trouble codes tell us~

1 of 1 people found this helpful.

I kind of puzzled your complaint and instantly thought "detonation", which is real bad and usually occurs when you've got an out-of-position distributor OR the engine was put together wrong~....but thankfully is just dieseling~....whew.

26,575

Just to supplement what the Judge said....From Wikipedia : Knocking (also called knock, detonation, spark knock, pinging or pinking) in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder starts off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front. The fuel-air charge is meant to be ignited by the spark plug only, and at a precise time in the piston's stroke cycle. Knock occurs when the peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. The shock wave creates the characteristic metallic "pinging" sound, and cylinder pressure increases dramatically. Effects of engine knocking range from inconsequential to completely destructive. Detonation can be prevented by any or all of the following techniques: the use of a fuel with high octane rating, which increases the combustion temperature of the fuel and reduces the proclivity to detonate; enriching the air-fuel ratio which alters the chemical reactions during combustion, reduces the combustion temperature and increases the margin above detonation; reducing peak cylinder pressure by decreasing the engine revolutions (e.g., shifting to a higher gear, there is also evidence that knock occurs more easily at high rpm than low regardless of other factors); decreasing the manifold pressure by reducing the throttle opening, boost pressure or reducing the load on the engine.

4 of 4 people found this helpful.
255

There's a recall by Nissan to fix this very problem. It has to do with the Engine Control Valve. Call your Nissan Dealer for details, and they will set you up.

4 of 4 people found this helpful.

@ Robert- yeah they'll set you up alright. To get robbed

Your Answer

Altima

Looking for a Used Altima in your area?

CarGurus has 74,663 nationwide Altima listings starting at $1,500.

ZIP:

Nissan Altima Experts

  • #1
    Tom Demyan
    Reputation
    2,130
  • #2
    putolile
    Reputation
    730
  • #3
    Cassie Sapphire
    Reputation
    690
View All

Related Models For Sale

Used Nissan Maxima
284 Great Deals out of 23,060 listings starting at $899
Used Honda Accord
1,033 Great Deals out of 60,523 listings starting at $999
Used Toyota Camry
1,045 Great Deals out of 68,981 listings starting at $295
Used Honda Civic
800 Great Deals out of 72,083 listings starting at $1,400
Used Nissan Sentra
519 Great Deals out of 48,306 listings starting at $1,595
Used Toyota Corolla
872 Great Deals out of 56,853 listings starting at $1,099
Used Hyundai Sonata
718 Great Deals out of 49,081 listings starting at $790
Used Chevrolet Malibu
1,073 Great Deals out of 72,017 listings starting at $1,896
Used Ford Fusion
987 Great Deals out of 71,084 listings starting at $1,200
Used Kia Optima
476 Great Deals out of 28,958 listings starting at $2,450
Used Dodge Charger
416 Great Deals out of 27,419 listings starting at $2,495
Used Chevrolet Impala
480 Great Deals out of 33,615 listings starting at $777
Used Hyundai Elantra
477 Great Deals out of 41,022 listings starting at $1,995

Used Cars For Sale

2017 Nissan Altima 2.5 S For Sale
11 Great Deals out of 13,707 listings starting at $12,942
2016 Nissan Altima 2.5 S For Sale
54 Great Deals out of 3,080 listings starting at $10,626
2015 Nissan Altima 2.5 S For Sale
115 Great Deals out of 4,534 listings starting at $7,455
2014 Nissan Altima 2.5 S For Sale
99 Great Deals out of 2,432 listings starting at $3,900
2013 Nissan Altima 2.5 S For Sale
32 Great Deals out of 1,170 listings starting at $3,200

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.