Intermittant knocking

S

SoCalMJ

NAXJA Forum User

Location

Downey, CA

• Aug 25, 2005

• #1

I have an '89 MJ with a 4.0 and AT. It seems like every second or third time I start it the engine knocks or the valves are ticking like all get out. It sounds bad. If I stop and restart it usually it will go away. Could this be the CPS or a stuck lifter?

 

J

jeepsrock

NAXJA Forum User

Location

LA California

• Aug 25, 2005

• #2

Well before you think of it being a mechanical problem which it can very be, i would take a look at some sensors.

Mainly the knock sensor and o2 sensor which could cause intermittant knocking, by running the engine to lean or rich. Also try switching gas companies.

Pete

 

Only In A Jeep XJ

NAXJA Forum User

Location

Greenville, Texas

• Aug 25, 2005

• #3

Old jeeps like that have weak lifters my 87 xj does it all the time.

 

S

SoCalMJ

NAXJA Forum User

Location

Downey, CA

• Aug 31, 2005

• #4

I've noticed it often runs smooth at initial start up, then starts knocking as it warms up. I will look into the sensors.

Since I'm a total newbie, how do I tell if they're out of whack?

 

L

L92XJ

NAXJA Forum User

Location

Orlando, Florida

• Nov 2, 2005

• #5

my 92 does the occasionally does the same thing. (Knocks and misses like it lost cyclinder) but the problem goes away if turn the engine off and restart.

Anybody know what causes this?

 

L

L92XJ

NAXJA Forum User

Location

Orlando, Florida

• Nov 3, 2005

• #6

would an intermittant injector cause this?