LONG-TERM BUT INTERMITTENT FIRING (?) PROBLEM ON CLIPPER

POSTED THIS PREVIOUSLY IN ERROR ON BIG BLOCK INJECTION SECTION - SO COPIED OVER

HARD TO DESCRIBE BUT SOUNDS LIKE ENGINE MISFIRES, STUTTERS, WITH KANGAROO JUMPS IN LOW GEAR/LOW SPEEDS PARTICULARLY.

WHAT ITS NOT:
NOT FUELTANK/CORROSION ISSUE - HAD THAT - FITTED NEW TANK 1-2 YRS AGO AND FUEL FILTER IS CLEAR.

WHAT'S BEEN REPLACED:
PLUGS / HT LEADS / DISTRIB CAP & ROTOR ARM/ COIL. (THERMOSTAT AS WELL REF APPARENT LINK TO TEMPERATURE/HEATING DIFFERENCE - MENTIONED BELOW).

WHAT MADE A DIFFERENCE:
DC & ROTOR ARM MADE AMAZING CHANGE - BACK TO NORMAL, BUT AFTER 2 WEEKS ALL STARTED AGAIN, THAT'S WHEN I CHANGED COIL AND ANOTHER NEW DC AND ARM - HIS TIME NO CHANGE.

WHAT'S KNOWN:
CAR IS A 1991 H CLIPPER WITH WEBER CONVERSION CARB AND HAS BEEN RUN DAILY BY ME FOR LAST 9 YRS, SERVICED TWICE A YEAR AND CURRENT AT 140,000 MLS.

THIS HAS BEEN GOING ON FOR NEARLY A YEAR SO NOTHING IS ACTUALLY BREAKING DOWN, AND IT STILL DRIVES DAILY. NO PATTERN TO WHEN PROBLEM COMES OR GOES. APPARENT ON MOST JOURNEYS SOMETIMES AT BEGINNING (COLD), MIDDLE OR END (WARMED UP), AT ALL SPEEDS AND SOMETIMES FOR PART OF OR WHOLE JOURNEY. SOMETIMES I GET 2 DAYS WITH NOTHING AND SOMETIMES 2 DAYS OF CONSTANT SPLUTTERING, JUMPING. SEEMS TO MATCH WITH SLIGHT DROP IN WATER TEMP AND SLIGHT LOSS OF HEAT. THERMOSTAT CHANGED AND SYSTEM FLUSHED AND NEW COOLANT IN.

RECOGNISED VW SPECIALIST IS 'STUMPED' MAINLY DUE TO THE INTERMITTANT FEATURE OF IT. USUALLY RUNS FINE WHEN I PUT IT IN.

I'M NOT A MECHANIC AND DON'T PERSONALLY WORK ON CAR EXCEPT MINOR REPLACEMENTS ABOVE. ….. HELLPPP !!!!
  :dontknow:   .

ONE REPLY SUGGESTED IGNITION AMPLIFIER WHICH I HAVE NOW REPLACED - BUT NO CHANGE !!

Stop shouting !!!

My bet would be a sticking valve or just a lot of coke

WHAT ITS NOT:
NOT FUELTANK/CORROSION ISSUE - HAD THAT - FITTED NEW TANK 1-2 YRS AGO AND FUEL FILTER IS CLEAR.

But did you change the fuel/Vapour separator when you did this, located at front of rocker cover, did you do timing?
Also with cold weather depending if your going on motorways, mositure will creep up the cold intake part of air filter on the big blcok carb engines due to  the cold air feed being near the grill, i have covered behind the grill just for this time of year as when moisture mixes with petrol and air, it will lose power and start blowing black smoke from exhaust.
Simply sit and let engine warm for approx 5 minutes and you can set off again.
If you have a weber the signs of moisture getting in you can clearly see droplets on the body of the carb, this will need the grill covering so to stop it getting up the air intake of air filter box.
Try the above but also check the timing and make sure the carb gets a emissions test done at your local garage as it maybe out and running rich
Pete

timing.
and faulty vac advance.

Was I shouting ….. sorry !  but its been over 9 months of frustration.

Very grateful for all the suggestions which due to my mechanical ignorance I can't answer directly other than to say the car is garaged every night, serviced twice a year and goes to the garage for everything.

However, a recommended car spark is giving it a look for the first time on Tues and I'll pass on the suggestions.

Will update for the benefit for any future 'sufferers' !

cheers,

wpa

Condensor, Points or if it doesnt have those the TCI module?

Is there crap in the tank? Just because it was fixed before doesnt mean that a tanker hasn't dumped a big chunk of rust in the petrol station….

If its had overheating troubles, has it warped the head, head gasket gone? etc…

Could even be a blocked water pipe effecting the choke, something like that.

are you sure that it's not just running lean? this will cause misfiring.

Possibly no-one will be interested but, just incase, the 'saga' continues…

Auto Electrician spent some time looking/checking but similarly 'stumped'  :dontknow: and, as a result, thinks its more likely fuel-related and suggested checking fuel lines to/from tank and tank pick-up, and, if still no joy suggested new fuel pump. This is the plan for next week. If that fixes it I'll be eating my proverbial 'bunnet' !  ops:

In the meantime, despite getting a few days of trouble free driving again - which happens from time to time with no apparent explanation (eg same daily journey and driving conditions) it came back with a vengence and, for the first time in nine months, lots of smoke !

If i end up doin' myself in, there will be at least a record of the reason !

Fuel lines checked both ways, tank pick up and all is clear. Nevertheless, new fuel pump and filter fitted anyway - so if that all rules out the fuel theory looks like its back to electrical (distributor ?).

Recent smoke turned out to be unconnected (according to specialist/engineer who inspected it). Head gasket blown on No 1 and that has now been sorted with head re-build and skim.

Anyone know a good automotive exorcist ?   :twisted: