1987 4.2 Jeep pinging

You may have excessive carbon build up which will cause the ping. It may be an octane ping as well. Try using some premium fuel to see if it goes away.
By the way, the kncok sensor is on the block. The sensor you are referring to is intake air temp sensor.

Roy

Re set ignition timing to correct settings and try the premium fule as mentioned in last post.

The kind of cleaning you need cannot be done by additives. It has to be done at a shop by a pro. It is a great service.

Roy

I WAS NOT SURE WHAT YOU HAD FOR A DISTRIBUTOR

I LOOKED HERE

http://www.autozone.com/autozone/parts/Cardone-Reman-Distributor/1987-Jeep-Wrangler-4WD/_/N-iibqeZ93xku?itemIdentifier=768895_0_0_

YOU HAVE, WHAT I "NOW" HAVE IN MY '77

MAYBE YOUR DISTRIBUTOR IS SCREWING UP

MAYBE THE MECHANICAL ADVANCE IS NOT WORKING, POSSIBLE BROKEN SPRING

IT COULD ALSO BE THAT THE VACUUM ADVANCE AIN'T-A-WORKIN'

BOTH OF THESE CAN EZily CHECKED W/ A TIMING LIGHT (NEVER EVEN LOOKING INTO THE BOTTOM OF THE DISTRIBUTOR...LESS YOU JUST WANT TO)

DO YOU KNOW HOW TO USE THE LIGHT TO TEST 'EM, OR DO YOU NEED SOME GUIDANCE?

THE MEDIC

INFO ON THE VEHICLE SUPER-SECEDES ANY OTHER INFO YOU FIND

IS THIS ACTUAL "PINGING" YOU ARE HEARING, OR IS IT ROCKER ARM/ PUSH ROD RATTLE OR TAPPING YOU ARE EXPERIENCING?

THE MEDIC

DO YOU KNOW HOW TO CHECK YOUR 2 ADVANCES WITH A TIMING LIGHT---TO SEE IF THEY WORK AS THEY SHOULD?

IF NO, I CAN TALK YOU THRU IT, YOU NEED A DWELL/ TACH METER AND TIMING LIGHT....I SORTA GO OUT OF MY WAY TO TRY TO HELP ANOTHER JEEP....1 EXAMPLE BELOW OF HOW FAR (THIS IS NOT YOUR FIX)

https://www.2carpros.com/questions/1980-jeep-cj7-timingtuning-problem-with-a

THE MEDIC

DWELL IS SORTA "A GIVEN" ON ELECTRONIC IGNITION, NO NEED TO TEST

I DO NOT KNOW IF YOU HAVE A MANUAL OR AUTO TRANNY--SO I CANNOT GIVE YOU YOUR IDLE OR TIMING SPECS

WHAT I MEAN AS FAR AS TESTING IS TO DISCONNECT AND PLUG VACUUM ADVANCE HOSE TO DISTRIBUTOR. PIC 1 (DISREGARD THE WRENCH AND TAPE MEASURE)

SET TIMING LIGHT ON ZERO--LEAVE IT THERE FOREVER---NOW IT IS NOT CONFUSING TO USE--IT'S JUST LIKE A REG TIMING LIGHT

JUST SHOWING YOU "0" ON MY SCALE (NOT MY TIMING) MY TIMING IS ABOUT "9 DEGREES" IN 2nd PIC. JUST SO HAPPENS PIC 2 IS COMPRESSION STROKE, AND #1 IS AT TDC (1 MORE 360 REVOLUTION, IT WOULD BE ON ZERO AGAIN, BUT ON THE EXHAUST STROKE, THAT WOULD NOT BE TDC)

I KEEP MY IDLE SET AT 700 RPM. IF IT CHANGES WHEN MOVING THE DISTRIBUTOR--I GET IT BACK TO 700 RPM W/ THE IDLE SPEED SCREW

WATCH TIMING MARKS---THIS SHOULD BE PERFECTLY SET WHERE I WANT MINE SET TOTHAT IS, EVERY TIME MY TIMING LIGHT FLASHES I SEE "PIC 3", 9 DEGREES BTDC.

YOURS WOULD BE WHATEVER IT IS SUPPOSED TO BE. IF NOT TURN DISTRIBUTOR TO GET IT THERE.I HAVE SPECS, JUST NOT ENOUGH OF YOUR INFO. HOOD STICKERS TAKE DOMINANCE OVER BOOKS

NOW THAT'S HOW TO TIME IT

TO TEST MECHANICAL ADVANCE, WATCH TIMING LIGHT, AND THROTTLE ENGINE UP SLOW---THE TIMING MARKS SHOULD ADVANCE FURTHER BACK FROM YOUR MARKS. IF SO, IT DOES WORK. IF NOT A SPRING ON THE WEIGHTS MAY BE BROKE, OR SOMETHING IS PREVENTING THE MOVEMENT, LIKE DIRT

THERE'S SEVERAL WAYS TO TEST THE VACUUM ADVANCE, I LIKE HOOKING THE HOSE BACK ON THE DISTRIBUTOR, THEN TAKE THE OTHER END OF THE HOSE AND SORTA TEMPORARILY HOOK IT TO A MANIFOLD VACUUM PORT---THIS WILL IMMEDIATELY ADVANCE THE DISTRIBUTOR MAYBE 10 DEGREES--- YOU CAN SEE THIS ALSO WILL MOVE THE TIMING MARKS BACK FROM WHERE YOU HAVE THE TIMING SET, IF YOU WATCH THEM IN THE LIGHT (A BUDDY PLUGGING AND UNPLUGGING THE LINE MIGHT LET YOU SEE IT BETTER. IF IT MOVES THE VACUUM ADVANCE WORKS. HOOK EVERYTHING BACK AS IT GOES

IS THE ARM IN PIC 4 (RED ARROW) IS MOVING, WHEN THROTTLED, MOST LIKELY VACUUM ADVANCE IS WORKING RIGHT. WITHOUT USING A TIMING LIGHT. IF IT DOES NOT MOVE, THE DIAPHRAGM THAT MOVES THE ARM MAY BE BAD, OR DEBRIS, ETC, WILL NOT ALLOW IT TO MOVE

THE REASON I THREW THIS IN, I HAVE SEEN TOO MANY PEOPLE USE AN ADJUSTABLE TIMING LIGHT INCORRECTLY (IT DOES HAVE ADVANTAGES, ONCE YOU DO KNOW HOW TO USE IT) ZERO IS BEST FOR TEACHING, OR USE A REGULAR LIGHT.

MAYBE IT'S THAT SIMPLE THAT YOU JUST SET THE MARKS WRONG.

SORRY I'M NOT THE BEST 'SPLAINER!

THE MEDIC