what is engine knocking mean

kingb1000
0

Asked by kingb1000 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

4 Answers

judge_roy
Not Active

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 out of 1 people think this is helpful.
judge_roy
Not Active

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.

Racer_X
12,955

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.

2 out of 2 people think this is helpful.
Robert Walsh
175

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.

3 out of 3 people think this is helpful.

Your Answer

Related Questions

Altima
Looking for a Used Altima in your area?
CarGurus has 73,102 nationwide Altima listings starting at $1,250.
ZIP:

Search Nissan Altima Questions

Nissan Altima Experts

#1 Tom Demyan
Tom Demyan
Reputation 580
#2 tenspeed
tenspeed
Reputation 340
#3 Cassie Sapphire
Cassie Sapphire
Reputation 160
View All

Related Models For Sale

Used Nissan Maxima"
688 Great Deals out of 20,044 listings starting at $595
Used Honda Accord"
1,278 Great Deals out of 78,767 listings starting at $1,000
Used Toyota Camry"
1,987 Great Deals out of 75,230 listings starting at $1,200
Used Honda Civic"
851 Great Deals out of 47,183 listings starting at $999
Used Nissan Sentra"
644 Great Deals out of 28,834 listings starting at $1,495
Used Toyota Corolla"
1,239 Great Deals out of 44,713 listings starting at $990
Used Hyundai Sonata"
1,076 Great Deals out of 48,202 listings starting at $1,400
Used Ford Fusion"
1,860 Great Deals out of 72,896 listings starting at $2,995
Used Chevrolet Malibu"
1,601 Great Deals out of 60,934 listings starting at $1,940
Used Kia Optima"
482 Great Deals out of 34,733 listings starting at $1,900
Used Volkswagen Jetta"
877 Great Deals out of 46,196 listings starting at $850
Used Mazda MAZDA6"
266 Great Deals out of 13,623 listings starting at $1,500
Used Nissan Murano"
461 Great Deals out of 16,496 listings starting at $3,995
Used Dodge Charger"
696 Great Deals out of 27,977 listings starting at $4,200

Used Cars For Sale

2014 Nissan Altima 2.5 S For Sale
129 Great Deals out of 7,985 listings starting at $14,988
2013 Nissan Altima 2.5 S For Sale
153 Great Deals out of 3,326 listings starting at $11,990
2012 Nissan Altima 2.5 S For Sale
95 Great Deals out of 2,702 listings starting at $10,987
2011 Nissan Altima 2.5 S For Sale
97 Great Deals out of 1,629 listings starting at $8,988