1982 Ford F-150 Distributor Popping

Tiny
BFREE
  • MEMBER
  • 1982 FORD F-150
  • 5.8L
  • V8
  • 4WD
  • AUTOMATIC
  • 92,000 MILES
The truck began to run rough and misfire. I set the timing with a light at 12* BTDC which made the engine run much smoother but the distributor is popping. It is loud and is not a rhythmic sound. I have checked the firing order of the plug wires and it was good. Spark plugs look good. I disconnected each plug wire from the distributor individually while engine was running to check if all cylinders were getting spark. Each cylinder was getting a spark since the rpms decreased with each wire disconnection. I replaced the distributor with a new one since it was original but the distributor is still popping. What is causing this popping (or misfire) from the distributor? Could it be faulty plug wires?
Friday, June 20th, 2014 AT 11:33 AM

12 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Mght be a burnt valve and or a broken pushrod check compression
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Saturday, June 21st, 2014 AT 6:10 AM
Tiny
CJ MEDEVAC II
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  • 222 POSTS
LAST TIME YOU DID A "FULL TUNE UP" ?

IN OTHER WORDS, HAVE YOU REPLACED ALL OF THE "EXPENDABLE PARTS" AS PER MAINTENANCE SCHEDULE "MILES" OR "TIME PERIODS"?

NEED HELP WITH THAT? SEE MY ANSWER, IN THIS LINK!

https://www.2carpros.com/questions/2007-ford-taurus-tune-up

NOW THAT YOU HAVE IT ALL 100% AS IT SHOULD BE - (MAYBE THE PROBLEM IS FIXED!)

IF NOT, WE NOW HAVE A FRESH START (STUPID VARIABLES ARE NOW OUT OF THE EQUATION!) MAYBE YOU HAVE MADE THINGS WORSE WITH YOUR TINKERING (BEFORE) MAYBE YOU DID THE TIMING PROCEDURE WRONG, MAYBE IT'S SOME CARB ADJUSTING. MAYBE WE HAVE A VACUUM LEAK? EVEN STUPID STUFF LIKE YOUR BUDDY SWAPPED 2 PLUG WIRES WRONG WHEN YOU WENT TO GET THAT COOL SWEET TEA FOR THE BOTH OF YOU-UNS!

ALL IN ALL, LET'S GET THE "PREVENTATIVE MAINTENANCE" CAUGHT UP (NOT JUST A PATCH JOB)

RETURN TO THIS THREAD, AND WE WILL WALK YOU THRU TROUBLESHOOTING. IT IS SO MUCH EZer WHEN YOUR EQUATION AIN'T CLUTTERED WITH THINGS THAT SHOULD ALREADY BE A "GIVEN"

I HAVE TWO JEEPS A '46 AND A '77 THE '77 IS CARBURETED AND HAS A FORD IGNITION SYSTEM, I HAVE MANY HOMEMADE PICS AND UNDERSTAND MIGHT NEAR EVERYTHING THAT COULD GO WRONG (TINKERED WITH WIRING MIGHT MAKE THINGS MORE DIFFICULT)

I'LL ATTEMPT TO HELP YOU ALL I CAN, AS LONG AS YOU HANG WITH ME AND PERFORM THE TESTING AND PROCEDURES. SOME OF THE CJ 5 AND CJ 7 QUESTIONS I'VE HELPED ARE OVER 100 RESPONSES LONG. SO, IF YOU HAVE THE TIME AND TOOLS, THE OTHER FELLERS MAY NOT GET YOUR MONEY.

KEEP ME POSTED AS TO WHEN YOU ARE GOOD TO GO WITH THE "PM" OR IF YOU NEED ADDITIONAL ASSISTANCE

A PLAIN JANE TIMING LIGHT- A TACH/ DWELL METER- A VOLTMETER- AND MAYBE EVEN A VACUUM GAUGE MAY BE NEEDED (STUFF LIKE IN MY 1st PIC)

THE MEDIC

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Saturday, June 21st, 2014 AT 9:50 PM
Tiny
BFREE
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  • 5 POSTS
I have replaced the distributor, rotor, plug wires and spark plugs without a change in the symptoms. After listening more closely, I discovered the popping was actually coming from the carburetor. I took it off last night and noticed that the gas I poured out of the bowls was brown. I'm assuming I have a lot of deposits in the carb from a dirty gas tank that was on the truck when I began working on it. I have since replaced the tank with a clean one. I'm planning to take the carb apart tonight and clean it out.
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Monday, June 23rd, 2014 AT 11:10 AM
Tiny
HMAC300
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  • 48,601 POSTS
Popping through a carb usually is an exhaust valvenot opening and the compression is trying to escape. Pull your valve cover on the cylinder that doesn't drop rpm as much as others.
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Monday, June 23rd, 2014 AT 12:02 PM
Tiny
BFREE
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Once I find the stuck valve, how do I get it moving again?
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Monday, June 23rd, 2014 AT 1:07 PM
Tiny
HMAC300
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  • 48,601 POSTS
It may not be a stuck valve it cold be a bad cam lobe/pushrod etc. You won't know until you see it. If it is stuck then spray penetrating oil on it and let it sti for a day then give it a light tap with ahammer. If it moves fine if not and really stuck then the head has to come off and go from there.
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Monday, June 23rd, 2014 AT 1:09 PM
Tiny
CJ MEDEVAC II
  • MEMBER
  • 222 POSTS
BACK TO MY ORIGINAL STUFF

IS IT TIMED CORRECTLY?

MEANING

DID YOU HAVE THE DWELL/ TACH HOOKED UP AND WERE AT THE CORRECT IDLE SPEED DURING THE PROCEDURE?

DID YOU REMOVE AND "PLUG OFF" THE VACUUM ADVANCE VACUUM LINE FROM THE DISTRIBUTOR DURING THE TIMING PROCEDURE? (RECONNECTED AFTER YOU ARE DONE)

MANY FOLKS HAVE NO CLUE THAT THIS IS CRITICAL-OTHERWISE YOUR TIMING WILL BE OFF- MAYBE A LOT!

THEN WE HAVE THE POSSIBLE "SLIPPED" HARMONIC BALANCER-IT DOES HAPPEN AND SHOULD BE CONSIDERED- (MOSTLY MEANING, ALL WAS TIMED RIGHT, EVEN SLIPPED, BUT NOW WHEN YOU CHECKED IT AGAIN, YOUR MARKS HAVE MOVED [MYSTERIOUSLY] SO YOU RE-TIME IT [UNKNOWINGLY] WRONG---I DISCUSS IT IN THIS POST A LITTLE MORE IN DEPTH

https://www.2carpros.com/questions/1971-pontiac-lemans-engine-running-problem-load-problem

EVER THOUGHT OF "TWEAKING" THE OLE CARB IDLE JETS USING MR. DWELL/ TACH TO PEAK THEM OUT? BEFORE YOU TEAR IT DOWN?

FROM TIME TO TIME I DO THIS ON MY JEEPS-MOSTLY AT SEASON CHANGES TO GET OUT THE FUMPF-FUM-FUMPF-FUMPF THAT YOU HEAR AT THE EXHAUST WHEN YOUR "MIX" IS SLIGHTLY OFF

HAVE YOU 'SPLORED THE VACUUM LEAK POSSIBILITY?

THE MEDIC
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Monday, June 23rd, 2014 AT 3:52 PM
Tiny
BFREE
  • MEMBER
  • 5 POSTS
I put a piece of paper on the exhaust tip and found that the drivers side exhaust flutters the paper. I then checked the vacuum on cylinders 5-8 by taking the plug wire off each one. Cylinders 5, 7 & 8 did not change vacuum. When I compress the valve spring the valve stem moves up & down by hand. I sprayed each stem with PB Blaster. I'm assuming I can rule out a stuck valve. Where do I go from here? Let it sit 24 hrs and see if it loosens up? Also, the vacuum is only about 17 and it's sweeping back and forth, not steady.
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Tuesday, July 1st, 2014 AT 8:38 PM
Tiny
HMAC300
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  • 48,601 POSTS
Short out each cylinder until the popping stops then check that cylinder like a valve or acam problem your lower vacuum leads to a valve type problem you should have done that first. Then pull the valve cover an dlook and see if valves go up and down if it does then check compression in that cylinder then all of them.
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Wednesday, July 2nd, 2014 AT 6:03 AM
Tiny
CJ MEDEVAC II
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SEE THE LINK IN "MY 1ST RESPONSE" IN THIS POST, THIS MAY HELP WITH THE VAC GAUGE DIAGNOSIS

https://www.2carpros.com/questions/2010-all-other-cars-how-to-change-gears-for-fuel

THE FUFF-FUFF AT THE EXHAUST SOUNDS LIKE A MIX SCREW

THE POPPING AT THE CARB SOUNDS LIKE TIMING

'SURE YOU DON'T HAVE 2 PLUG WIRES CROSSED?

DO YOU HAVE A PAL THAT MIGHT GO OVER IT TOO? MAYBE YOU ARE SORTA TUNNEL VISIONED IN YOUR WORK, ANOTHER OPINION MIGHT CATCH THE ERROR

KEEP US POSTED ON PROGRESS

THE MEDIC
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Wednesday, July 2nd, 2014 AT 8:05 PM
Tiny
BFREE
  • MEMBER
  • 5 POSTS
I watched the valves on the driver side and they all moved freely at idle. I'll recheck my plug wires again to make sure it's correct. My carb is a Holley 4160. (I prefer a Edelbrock 1405 but It came with the Holley) I'll recheck the air/fuel screws with a vacuum gauge. My timing was set using a light with the vacuum line disconnected from the distributor at 12* BTDC. That's supposed to be the factory setting. Could it be I need to advance the timing? I'll also check for vacuum leaks. I think you're right, I'm getting tunnel vision.
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+1
Thursday, July 3rd, 2014 AT 9:54 AM
Tiny
CJ MEDEVAC II
  • MEMBER
  • 222 POSTS
ONCE UPON A TIME ON A PREVIOUS CJ 5, I FOUND THAT MY 'STRIBUTOR WAS MAKING A SCRATCHING NOISE

STILL TURNED, BUT WITH THE TOP OFF YOU COULD SEE A SLIGHT WOBBLE

THE REPLACEMENT DID THE SAME THING

I PULLED IT AND LOOKED AT THE OIL PUMP SLOT

LOOKED FINE

I PLAYED WITH IT WITH A LONG SCREWDRIVER

I FOUND HALF OF IT TO BE BROKE LOOSE (THE EAR)

I GRABBED IT WITH A MAGNET

UPON REPLACING THE OIL PUMP I FOUND THAT THE BROKEN CHUNK HAD SCORED UP THE HOLE IN THE BLOCK PRETTY SEVERELY

I RAN IT ANYWAY, THE DIST SHAFT SEEMED TO STAY CENTERED UP, BESIDES THAT, I WAS ALREADY SLOWLY BUILDING ANOTHER 258 6CYL FOR IT. IT WAS STILL OK FOR ABOUT 6 MONTHS OF EVERYDAY DRIVING

THE MEDIC
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Thursday, July 3rd, 2014 AT 8:14 PM

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