No spark to plugs...OK to distributor...

[kgrantkey]

Yes, I know, this should be as simple as pie. I pull the plug wire off and have no spark at the sparkplugs. I pull the coil wile off the distributor and have spark.

 

Couldn't be simpler huh? It's a dizzy so i replace the cap, no fix. I replace the rotor button, still no fix.

 

This is not a daily driver and it's too hot outside to do much until evenings. I will update this when i correct the problem. It just seems like the simplest problem you could have....fire to the distributor but not to the plugs....

 

 

I really thought replacing the rotor button would fix this.

 

 

__ L20B in 78 620 converted to dizzy years ago. Usually starts by just barely bumping it over.--

[Skib]

well lets look at the order of things

 

 

coil > coil wire > dizzy points or matchbox > rotor > cap > plug wires > plugs

 

 

you get spark up to the dizzy and you replaced the cap and rotor so we can start crossing a few things off

 

coil > coil wire > dizzy points or matchbox > rotor > cap > plug wires > plugs

 

now were just down to a few things, is your dizzy at matchbox or does it have points?

if its points they could be burned out or you need a new set of plug wires.

[DanielC]

Put the engine at 10 degrees BTDC. Pull the distributer cap off, and mark on the side of the distributer where the rotor is pointed. Put the cap back on. Does the mark you made line up with a spark plug wire tower?

[banzai510(hainz)]

try new plugs

[kgrantkey]

try new plugs

 

 

OK, here is my thought process. When i pull the coil wire from the top of the distributor, place it near the frame/ground and turn the starter it sparks.

 

I reconnect the wire to the top of the distributor and check the spark at the end of any plug wire i get no spark.

 

This commonly means a bad rotor button or cap. I have a matchbox dizzy on the truck.

 

 

 

I think i caused this while trying to connect ign battery to my choke. I have an ongoing problem with choke relay/external VR, and changed the carburetor to one that doesnt pump as much gas when you press the accelerator. With the old carb i could pump a few times and squirt enough gas that the choke didnt have to work to start the truck.

 

Everything is back to normal now.

 

It is possible the rotor is not perfectly lined with a terminal in the cap. I think this may be why the book says make this your #1 spark terminal on the cap but not sure.

 

The thing is, none of that changed from great spark at plugs to none at all.

 

I may swap the coil in case the spark is weak due to that. Like i said it's too hot at the moment to do much, but I'll look further into it tonight at let everyone know what it was.

 

It still could be the cap as the one i put on (1 of 3 i got) was laying around for some reason. It seemed like a good cap but with extremely high voltage a crack or anything will cause the spark to go to the easiest way to ground.

[ggzilla]

It could be the new choke wire. To test that, temporarily disconnect the wire.

 

Or the plug wires could be bad, and not passing the spark. Usually this only happens to one wire.

 

Maybe there is a crack or short trace in the cap, diverting the coil spark. Remove the cap and inspect the inside surface carefully. Sometimes washing it with soap & water helps. You almost never need to buy a new cap, they last 40 years (though for some reason people keep buying new ones).

[banzai510(hainz)]

GGZILLA,You almost never need to buy a new cap, they last 40 years (though for some reason people keep buying new ones).

 

Tell me about it I use the same BlueStreak ones FOREVER.

 

 

Unless your not telling us soemthing like you swap out the dizzy and it went 180deg off you might be looking for spark on the wrong wire.

 

The choke relay is a big deal. usauly it wear down a batter on the 510s. I dont kknwo truck as this does soemthing when doing a IR alternator. So I assume you already moddd the connector with jumper wires.

 

If nothing was changed put a phillips head in the plug wire and put it near ground/metal and it should spark to ground. then your wire is good. then maybe all the plugs are fouled?

[kgrantkey]

GGZILLA,You almost never need to buy a new cap, they last 40 years (though for some reason people keep buying new ones).

 

Tell me about it I use the same BlueStreak ones FOREVER.

 

 

Unless your not telling us soemthing like you swap out the dizzy and it went 180deg off you might be looking for spark on the wrong wire.

 

The choke relay is a big deal. usauly it wear down a batter on the 510s. I dont kknwo truck as this does soemthing when doing a IR alternator. So I assume you already moddd the connector with jumper wires.

 

If nothing was changed put a phillips head in the plug wire and put it near ground/metal and it should spark to ground. then your wire is good. then maybe all the plugs are fouled?

 

I have disconnected the wire i hooked to the carb choke. Like i said everything is back to original. Same carb as before, all wires like they were.

 

It's strange. It not off 180 or anything and if it had you still should get fire at the end of a plug wire, just at the wrong time.

 

I have an aftermarket coil. It cant be 100% bad or I'd get no spark out of the end of the coil wire.

 

The way i test for spark is placing the wire with a screwdriver in it near a good ground, close enough for the spark to jump across. This is 1st grade stuff for testing for spark. It's just not the usual easy quick fix.

 

I don't think it will be very difficult to fix once i go at it with an hour or two to really make a few more tests.

 

Just thought it curious. That's why i said i'd repost what i find.

 

The next test will be to remove all plug wires from the cap except the one i look for spark from. Move it around to each terminal. If you got spark going in, it's gotta go somewhere.

 

I think i'll also check the resistance between the coil wire input of the cap to ground. If that were to show a short to ground that'd be something.....well it's about 90% and getting cooler so i'll check it more thoroughly in a few hrs.

 

Thanks for all the advice. This truck usually starts up before you can snap your fingers.

[ggzilla]

THat's how I would test it. carry on.

[kgrantkey]

THat's how I would test it. carry on.

 

Tonight it was easier to see the spark. Looked weak from the coil. Plugged coil wire back into distributor cap with only 1 plug wire attached and no matter how close i got to ground it still wasn't getting any spark.

 

I decided it had to be the coil.

 

Replaced my Accel 8140 High performance 42000 volt coil, with old coil that needs external resistor that was laying around. Just hooked it up reconnected my plug wires and she fired right up.

 

I should have recognized the weak spark to begin with but oh well. I didn't add an external resistor so I'll try to locate a coil with the right impedance amongst all my junk or just wire in the resistor.

 

The accel had a primary resistance of 1.4 ohm. Secondary 9.2K ohms. I may need to recheck the specs on whatever coil i choose to use, but the accel lasted a long time.

 

Anybody know the impedance required for a coil on a l20b with matchbox dizzy that don't require a resistor...off the top of your head?

 

hmmm i'll do some checking.

[DanielC]

My opinion, you will be better off with a stock coil of just about any kind, rather than a coil painted to look really nice in a auto accessories store. The kind of store that has lots of spoilers and fart cannon muffler tips.

[banzai510(hainz)]

MSD Blaster 2 works with the matcbobox and not ballast. its a .7 ohm coil thats can handle the 12volts.

or a 79 620/200sx Japan made coil(no bling).

 

Persoanlly the matcbox with the low inpedance coil has alot better spark but its alot more current running thru the key switch but never heard of any real proplems.

I always run the stock point coil( about 1.6 ohm) and the ballat of about 1.6 ohms

 

I have a Accell Supercoil and I run 2 ballast resisitors as the SuperCol is .7 ohms and it comes with a .85 ohm resisitor and I use the stock 1.6 ohm which more or less come out close to stock total resisitance.

 

As for this:

The way i test for spark is placing the wire with a screwdriver in it near a good ground, close enough for the spark to jump across. This is 1st grade stuff for testing for spark. It's just not the usual easy quick fix.

 

Believe me people wont tell you what they did. Just say it dont run no more and find out they swapped out half the stuff from different datsuns. Put different coil in not matching resisitance and wonder why it dont run but when the oil lady drove it it worked for 25 years before the new Bling col goes in.

Som of Accell Super Stock point coils are now made in China. CANT go wrong with the made in Japan stuff!stock

[DanielC]

Banzi510 said this.

"Can go wrong with the made in Japan stuff!stock "

I am pretty sure he forgot the "'t" in the word "Can"

[kgrantkey]

Banzi510 said this.

"Can go wrong with the made in Japan stuff!stock "

I am pretty sure he forgot the "'t" in the word "Can"

 

 

The coil i found laying around came from one of my 620s i'm pretty sure. It has "use with external resistor" printed on it.

 

I think I'll run it just like the accell and see how it does. I've prolly got a few others somewhere.

 

Oh, come to think of it i know i got a coil off a 80 something 200sx.

 

I found a couple alternators that are internally regulated. 1 is from the 200sx the other i think is from a honda or maybe a saturn. My VR drains the battery, or could be my choke....gives me something to do this weekend.

 

;) :D ;)

[kgrantkey]

Here is the carb i want to put back on. It needs a choke cause it don't spurt gas like my stock carb, but it will deliver more gas than the stock. Came off a 2300 cc Toyota. Using the hi-rise as an adapter.

 

You can see the pretty yellow coil that went bad too.

 

 

[banzai510(hainz)]

going by this recent photo you have a Acell super stock coil. This is a point coil and you need a ballast with it as its not made to run a straight 12volts.Only on START there is a bypass wire that will be at the +sde coil.Thats the only time it will get 12 or try to keep 12 as the battery is loaded down by the starter taking up alot of current.

I cant see if the ballast is hooked up or not in the photo. No ballast a point coil will get hot and burn out.(when I dont know but it will)

 

If you red Uncle LauLau's thread on his matchbox dizzy install.

 

B on match box will go to the +side of ballast reisitor

C - side coil

 

 

i got a coil off a 80 something 200sx:

if you have this you dont need the balssast and can run stright of batt voltage as made to take the high current

[datzenmike]

You can see the pretty yellow coil that went bad too.

 

Yellow bling coils are like hot g/f. Look great in the light but what counts is how well they work in the dark.

[ggzilla]

My matchbox high energy coil is 30 years old now, still working.

[datzenmike]

Shiny bright fishing lures catch more fishermen than fish.

[banzai510(hainz)]

Shiny bright fishing lures catch more fishermen than fish.

 

 

I know they catch me too!

 

 

what kind of carb is that?

[KENTURTLES671]

Yes, I know, this should be as simple as pie. I pull the plug wire off and have no spark at the sparkplugs. I pull the coil wile off the distributor and have spark.

 

Couldn't be simpler huh? It's a dizzy so i replace the cap, no fix. I replace the rotor button, still no fix.

 

This is not a daily driver and it's too hot outside to do much until evenings. I will update this when i correct the problem. It just seems like the simplest problem you could have....fire to the distributor but not to the plugs....

 

 

I really thought replacing the rotor button would fix this.

 

 

__ L20B in 78 620 converted to dizzy years ago. Usually starts by just barely bumping it over.--

http://www.youtube.com/watch?v=r1-XZoDr6GE

[kgrantkey]

Shiny bright fishing lures catch more fishermen than fish.

 

 

I know they catch me too!

 

 

what kind of carb is that?

 

 

Holley 64-9232 - or Asian 2brl that came off a 84 Toyota 4Runner with 2.4 L4

 

 

 

I like the carb. It made a difference in the idle (smoother) and especially WOT. When my choke stopped working i put my Hitachi back on because it pumps more gas to crank a cold engine with the Electric choke broke.