Hi Guys

I came home yesterday after completion of 750KMS Xmas journey in all around my b310 did not have any issue before i start the journey i replaced the alternator external regulator too .
but noticed there is sudden miss after putting a gear and acceleration at once, but it is just for a second then after car pulls as usual but i am keen to know what causes that ?
i drove it around 50-80 KMPH range and sometimes with ac and all the way it gave me around 13-14 KMPL

thanks
regards
sumith

Congratulations on your road trip.

Normally this is caused by a lean spot in the carburetor. You will need to narrow down the cause.

Often the cause is the accelerator pump not putting out the full shot of gasoline. You can test this very easily by doing the "Accelerator Pump Test" outlined in Carburetor Adjustment.

Fuel economy of 14 km/l is very good if you did a lot of stop-and-go driving or going up and down hills. On a level road B310 can get around 16 km/l at 100 kph.

That's a bit high l per km but you were in mountain country you said with ac so it's borderline.

As for the mis, probably needs a retune with new alt etc. did it happen only once or all the time now?

Points gap may need readjustment or carby bit of a retune.

Hi Guys

Thanks for replies, it happen all the time but no harm just for an second thereafter car is like a wild bull pulling nicely,
do you guys recommend a carburetor cleaning and reassemble or just an re tune up ?
will there be a big change in fuel economy since i am running my carb without Anti-dieseling valve ?

thanks
regards
sumith

Anti-diesel valve has nothing to do with fuel economy. Its purpose it to more quickly cut the fuel flow after you turn the engine off.

Never recommend a carburetor cleaning for this type of problem. Instead simple tests are recommended.

Basic no-parts-replaced Tune-up is always recommended. It only costs labor and you can do it yourself.

A miss upon acceleration can be Lean Carb, but usually it's one of two issues.

Bad Capacitor
Too Close Clearance on Intake Valves.

If it's worse when cold, the Intake Valve adj is most likely.

Rusty Wrench

Good advice Rusty Wrench.

Valve clearance is part of a Tune-up, so that's part of the basic foundation. Always check those things.

The condensor is only used on points-based distributors, and there is no good way to test at home (?). You can swap a known good one or just try a new condensor -- they are supposed to be replaced every 12,000 miles anyways. The is another reason why we recommend going Electronic Ignition -- it is vastly more reliable. Many Datsun units are over 30 years old now and have never stopped working.