Jump to content


Photo
- - - - -

Cutting out randomly


  • Please log in to reply
24 replies to this topic

#1 JakeWard

JakeWard

    Hall Monitor

  • Members
  • PipPipPip
  • 96 posts
  • Location:Chico, Ca
  • Cars:Want a 2 door 510... and I'm scouring the net for the right one

Posted 28 January 2017 - 01:24 PM

So first it's a 72 521 with a stock L16 32/36 and original distributor.

Driving along just fine then it'll fall on it's face like it has no spark, let out a backfire, I pull over, and it keeps idling. Soon as I try to drive away, it does the same thing over and over.

Anyone have something like this happen? I can't seem to replicate it on demand just inconveniently in traffic.

#2 flatcat19

flatcat19

    Back in Black

  • Senior Member
  • PipPipPipPipPipPipPipPipPipPip
  • 20,475 posts
  • Location:Tri-Cities, WA/PDX
  • Cars:Smaller. Better. Slower. Lower.

Posted 28 January 2017 - 01:53 PM

Since it's backfiring, you have fuel.


Suck, squish, bang, blow.

You can't hang if your nuts haven't dropped...it's physics


#3 sebpv

sebpv

    Senior Member

  • Senior Member
  • PipPipPipPip
  • 790 posts
  • Location:Chicoutimi, Quebec, Canada
  • Cars:1973 Datsun 620 M/T std cab

Posted 28 January 2017 - 02:52 PM

check you spark plugs maybe. Check the gap and the current state
Blame my french side if you don't understand

https://www.flickr.c.../113076263@N04/

#4 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 71,821 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 28 January 2017 - 03:36 PM


 

So first it's a 72 521 with a stock L16 32/36 and original distributor.

Driving along just fine then it'll fall on it's face like it has no spark, let out a backfire, I pull over, and it keeps idling. Soon as I try to drive away, it does the same thing over and over.

Anyone have something like this happen? I can't seem to replicate it on demand just inconveniently in traffic.

 
Backfire out the exhaust?????????
Well you can get the same thing by turning the ignition off and then on again. The engine keeps turning pushing unburned gas and air into the exhaust. When spark is resumed all the gas in the pipe explodes. This tells me that you have an interruption of your ignition spark... could be badly worn points, any loose wire on the primary side of the coil or to the points. Start by checking every wire connection. A loose connection is hard to find, engine and driving vibration opens and closes the connection. Idle the engine and wiggle the wires.
 
Backfire out the carburetor?????????
This is almost always caused by an overly lean mixture. Remove the spark plugs and look at them. Lean mixtures will over heat the plugs and clean them, the porcelain will be very light in color or even extremely white . A proper mixture will be a tan color and a rich mixture will be very dark and even sooty black. Lean conditions can be from too small a jet or something clogging the jet.
Posted Image

#5 DanielC

DanielC

    Senior Member

  • Senior Member
  • PipPipPipPipPip
  • 4,727 posts
  • Location:West Linn,Or

Posted 28 January 2017 - 03:43 PM

There is no filter on the fuel pick up pipe in the gas tank.  Crud in the tank can collect around the pick up pipe, and clog it.  When you slow down, or let the engine idle, there is not an much demand for fuel, and the crud can drift away from the pick up pipe.  A quick check of this problem is to blow air back through the fuel line toward the gas tank, and see if the problem goes away temporary.



#6 JakeWard

JakeWard

    Hall Monitor

  • Members
  • PipPipPip
  • 96 posts
  • Location:Chico, Ca
  • Cars:Want a 2 door 510... and I'm scouring the net for the right one

Posted 28 January 2017 - 05:14 PM

I just swapped the fuel filter because it was cheap and had a bit of junk in it.

There's a bit of fraying on one of the braided dealios inside the distributor. Related? I don't know

https://flic.kr/p/R4qmdh

#7 kelowg

kelowg

    Hall Monitor

  • Senior Member
  • PipPipPipPip
  • 1,041 posts
  • Location:modesto ca
  • Cars:70 521

Posted 28 January 2017 - 06:59 PM

Well it sure as hell cant help. Clogged line/pickup and or loose connections most likely



#8 tr8er

tr8er

    Datsun Mechanic

  • Senior Member
  • PipPipPipPipPip
  • 7,310 posts
  • Location:Hawaii
  • Cars:'71 PL510; 01 Frontier 4X4

Posted 28 January 2017 - 07:10 PM

Backfire out the carburetor?????????
This is almost always caused by an overly lean mixture. Remove the spark plugs and look at them. Lean mixtures will over heat the plugs and clean them, the porcelain will be very light in color or even extremely white . A proper mixture will be a tan color and a rich mixture will be very dark and even sooty black. Lean conditions can be from too small a jet or something clogging the jet.


My guess

#9 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 71,821 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 28 January 2017 - 07:15 PM

So Jake... backfire out the exhaust or the carb???? Help us narrow this down some.


Posted Image

#10 JakeWard

JakeWard

    Hall Monitor

  • Members
  • PipPipPip
  • 96 posts
  • Location:Chico, Ca
  • Cars:Want a 2 door 510... and I'm scouring the net for the right one

Posted 28 January 2017 - 10:19 PM

Backfiring out the exhaust.

#11 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 71,821 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 28 January 2017 - 10:23 PM

Then look at the primary side wiring of the distributor including the points, coil and ballast resistor. Make sure the distributor is securely grounded to the engine. Are the points in good condition and gaped about 0.022"?


Posted Image

#12 Jersey

Jersey

    Member

  • Senior Member
  • PipPipPipPip
  • 550 posts
  • Cars:1979 Datsun King Cab, 1972 Cadillac Coupe deVille, 1968 Lincoln Continental...

Posted 28 January 2017 - 10:37 PM

I drove one of my 620s to the dump one day and it ran awesome. The next day I go to start it and nothing! It would turn over: But would not fire. It took me a while to figure it out, it was the wire inside the distributor that ran to the 2nd set of points, it had a very small nick in it and was grounding out against the inside of the distributor. I replaced it and it fired right up and ran great.
Jersey

#13 JakeWard

JakeWard

    Hall Monitor

  • Members
  • PipPipPip
  • 96 posts
  • Location:Chico, Ca
  • Cars:Want a 2 door 510... and I'm scouring the net for the right one

Posted 29 January 2017 - 06:46 AM

Not to throw more parts at a problem, I have an incoming matchbox dizzy lined up from a trade but it's used and may not work (seems unlikely)

I need to check the gap, and replace that frayed wire on the inside of the cap.

#14 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 71,821 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 29 January 2017 - 07:07 AM

Yes, start with the obvious (possible) causes first.

 

Occam's razor...... the simplest explanation is usually the right one.


Posted Image

#15 JakeWard

JakeWard

    Hall Monitor

  • Members
  • PipPipPip
  • 96 posts
  • Location:Chico, Ca
  • Cars:Want a 2 door 510... and I'm scouring the net for the right one

Posted 31 January 2017 - 02:27 PM

So I was going to ask what to call that part, but randomly stumbled on it.

Which ignition condenser is which? Or are they interchangeable?

There's a JA500 and a JA503

#16 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 71,821 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 31 January 2017 - 07:51 PM

I would imagine they are all pretty much the same. The condenser (also called a capacitor) reduces point arc when they open.


Posted Image

#17 JakeWard

JakeWard

    Hall Monitor

  • Members
  • PipPipPip
  • 96 posts
  • Location:Chico, Ca
  • Cars:Want a 2 door 510... and I'm scouring the net for the right one

Posted 03 February 2017 - 06:29 PM

Ended up with a matchbox dizzy in a trade.

Tossing it on tomorrow if it's not dumping rain.

#18 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 71,821 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 03 February 2017 - 06:39 PM

In Cali.... it's only rain.

 

You can run your stock coil IF you keep your ballast resistor. This will only convert to a pointless ignition.

 

If you want the full effect of higher voltage you will need a one ohm 12 volt coil. Any '78 and up coil will do for this. If you try to use your points coil for this the matchbox will draw too much power through it and over heat and burn it up. A points coil is only able to handle less than 8 volts. This is why there is a ballast to drop the voltage.


Posted Image

#19 JakeWard

JakeWard

    Hall Monitor

  • Members
  • PipPipPip
  • 96 posts
  • Location:Chico, Ca
  • Cars:Want a 2 door 510... and I'm scouring the net for the right one

Posted 03 February 2017 - 07:04 PM

So just snag a duralast coil from Autozone? Or is the junkyard Nissan OEM better?

#20 datzenmike

datzenmike

    KING RAT

  • User Administrator
  • 71,821 posts
  • Location:Vancouver Island
  • Cars:'74 710 sedan, '76 710. prevoius... '78 620, '71 521, '68 510 new '76 B-210

Posted 03 February 2017 - 07:09 PM

Can't go wrong with a Nissan coil. They were designed for this. (likely cheaper too) ALWAYS trust the stock parts above any other when possible.


Posted Image