Jump to content
metalmonkey47

NO SPARK on '76 620

Recommended Posts

Haven't even had it for 6 hours yet :(

 

Truck is a '76 620 with L20B and points dizzy

 

I have no spark from the coil. We started it up, and it ran rough with little power. Eventually got to running about perfect other then an occasional stumble.

 

 

Got it running to take around the block and get some pictures for the other thread, and started having severe missfires, loss of power, and eventually it stalled and has no spark at the coil.

 

 

I know little about L20B and even less about points ignitions (although this isn't a dizzy related problem.)

 

 

The battery is a 4 month old yellow top Optima. Currently charging for some more troubleshooting :(

 

 

 

Where do i start?

Share this post


Link to post

Sounds like coil or dizzy, sometimes you cant feal alot of shaft play without removing it, but you probly know about shaft play, does it have a balast resister intaked? Some time they go bad, then the condencer goes out then the points burn up.

Fusable linkes look good?

Did you check the wheel bearings? Unrelated but important none the less lol

Share this post


Link to post

Did the battery go dead? My first guess woulf be Alternator is bad and now not enough juice in the Battery to create the spark.

 

You said the battery is charging now, so I am assuming it is dead.

Share this post


Link to post

Dizzy is out of the question. Theres no spark at the coil, so the problems there or back.

 

I tested all the fuses with a multi meter and they're all good.

 

By ballast resistor, do you mean the piece here located below IGN coil? Cuz that mofo kinda got hot I noticed...

 

IMAG0861.jpg

Share this post


Link to post

Sounds like coil or dizzy, sometimes you cant feal alot of shaft play without removing it, but you probly know about shaft play, does it have a balast resister intaked? Some time they go bad, then the condencer goes out then the points burn up.

Fusable linkes look good?

Did you check the wheel bearings? Unrelated but important none the less lol

 

^^^ Second condensor ,,, before replacing ,,, simply use a multi-meter to check power supply to the coil ,,, then same with the ballast resistor ,,,

 

condensor's work or they don't ,,, not in between ,,, they go bad off the shelf or just randomly when they wish ,,, consumable item ,,, run a stock coil not performance until problem figured out ,,,

 

good luck :)

Share this post


Link to post

Did the battery go dead? My first guess woulf be Alternator is bad and now not enough juice in the Battery to create the spark.

 

You said the battery is charging now, so I am assuming it is dead.

 

Well, it's dead now lol. We were trying to get it to run, so we ran it low. Didn't die, but I put it on the charger anyways.

 

 

That was a thought, but it ran fine all the way home, and ran fine up to this point.

 

 

 

 

 

It hesitated to run at first, but we idled it up and it decided to start running right.

Share this post


Link to post

Dizzy is out of the question. Theres no spark at the coil, so the problems there or back.

 

I tested all the fuses with a multi meter and they're all good.

 

By ballast resistor, do you mean the piece here located below IGN coil? Cuz that mofo kinda got hot I noticed...

 

IMAG0861.jpg

 

Correct MM47 ,,, That is the Ballast Resistor ,,, :) ,,, test it across the contact point studs with a multimeter to give you an idea wether to see if it works or not :D ( crude fast test yes )

 

Your wires look a bit corroded/tough shape ,,, remember electricity travels on the outside of the copperwire ,,, and insulation can be weathered/penetrated over time ,,, ;)

 

Your coil should never be "kinda hot" ,,, a touch warm is possibly ok ,,, my last :"performance" coil got FAIRLY hot and I had a lot of problems with starting/runability for 1 or 2 days until I replaced it with a "stock" coil ,,,

Share this post


Link to post

If you find correct voltage to a component and it does not operate, the component is defective :D

Share this post


Link to post

First --- > Test power coming to the coil from the main harness ,,, then trace back through main harness if no power coming to the coil from main harness ,,, or if power coming from main harness ,,,, go forward towards other ignition components/coil/resistors/wires ,,, at least how I would test since you said coil not discharging :)

 

Check all your grounds bud ! clean em !!! rubbing alcohol can clean fast or vingar and q-tip/sandpaper ,,, :)

Share this post


Link to post

Alright guys, cleaned up connections and I'm gonna see what the meter tells me....

 

 

Hopefully It's nothng much more then that...

 

 

 

BRB with results!!

Share this post


Link to post

You seemed to rule out distributor to fast..........the distributor MAKES the coil work .

 

If your points are burned or your condenser is bad the coil wont fire no matter how much voltage you have..and that goes for a L20b or a briggs and stratton lawn mower..

 

File the points ,and make sure there is voltage to them .....

 

without coil saturation the coil can`t build up enough voltage to fire.

Share this post


Link to post

Word!

 

The points may be closed and not opening. Coil and ballast will get warm with key on.

Share this post


Link to post

Agreed BannanaSammich ,,, Points and Condensor are one of the first things you will be replacing for a tune-up or troubleshoot ,,, that's how I learned a bit ago :) ,,, Feeler-Gauge should be good enough for points gap setting , but dwell meter should be used for preciseness ( I have always used a feeler gauge :lol: )

 

Resistor is testing some voltage ,,, obviously power coming from main harness ! ,,, cool moving on ,,,

 

Points Condensor = $10 ? maybe ? out of pocket :D

Share this post


Link to post

Alright, here's some more info and my current finds:

 

 

All grounds are clean, and all connections are clean. Points were replaced about 2 weeks ago? It ran afterwards. Had a missfire, but was probably more fuel related then anything. Gap and all was set and confirmed.

 

 

Everyone is all out of stock on a condenser for the truck. Does it have to be vehicle specific? Or can I use any generic?

Share this post


Link to post

i think you can use a GM one also. Forget points and gaps, go matchbox :D

Share this post


Link to post

I should have noted all the components i spoke of i burnt out....... With my "after market" ing. switch, i was putting power to the ballast resistir you pic shows all the time, rookie move i know.

Share this post


Link to post

Alright, here's some more info and my current finds:

 

 

All grounds are clean, and all connections are clean. Points were replaced about 2 weeks ago? It ran afterwards. Had a missfire, but was probably more fuel related then anything. Gap and all was set and confirmed.

 

 

Everyone is all out of stock on a condenser for the truck. Does it have to be vehicle specific? Or can I use any generic?

 

Good Stuff !

 

DSince it's external ,,, I would try one from a 70-73 zcar if that is not out of stock/same one,,, the fuck is it gonna hurt ya know ? :D ,,, if you don't have a 90-degree phillips head bit and need one to possibly get to the condensor ( like on my zcar ) ,,, just unbolt/pull the distributor out replace it (buy distributor base gasket to !) ,,, only one way it can go back in :)

 

Carry a spare condensor/points set with you on trips ;)

Share this post


Link to post

Alright, here's some more info and my current finds:

 

 

All grounds are clean, and all connections are clean. Points were replaced about 2 weeks ago? It ran afterwards. Had a missfire, but was probably more fuel related then anything. Gap and all was set and confirmed.

 

 

Everyone is all out of stock on a condenser for the truck. Does it have to be vehicle specific? Or can I use any generic?

 

Disconnect the condenser... you can run without it just to try and get it going. Replace later.

 

Pull the cap off and crank.... see if the points are opening and closing. This wouldn't be the first time someone forgot to tighten the points plate down and the gap closed up.

Share this post


Link to post

I'm getting an electronic dizzy in a few days, just don't have it as an option just yet :(

 

 

Won't run without condenser hooked up. It's raining now, so I'm not gonna play with the dizzy.

 

 

 

 

 

 

Kinda curious if it's points related.... reporting back as soon as it stops pooring!

Share this post


Link to post

 

Won't run without condenser hooked up. It's raining now, so I'm not gonna play with the dizzy.

 

 

It absolutely will run without the condenser connected. All the condenser does is reduce arcing when the points open. It simply prolongs the life of the points.

Share this post


Link to post

Man this isnt hard at all.

This is DIZZY related proplem!!! Esp in POINT vehicles. Rarely does a coil or ballast resisitor go bad. Esp the stock spec ones. Unless soembody swapped them out with mismatchset.

 

Does it spark or not at the end of the wire comming out of coil????????

If NOT ck the point gap. gap it. Is the condensor wire isolated correctly?????? make sure that screw dont ground out the points inside.

If condensor was replaced try the old one again also. I though the l20condensore were inside the dizzy cap.BAD Condensor will run at idle what I have seen but fatster you go the more it will cut out!!

 

 

Ballast should not get HOT unless there was a real low ohm coil installed. Like a EI coil.

 

Depending on the ballast resisitor ohm value you could read about 6 volts.

 

also best to know if your alternator was charging while this was running.before all this happened. But I will assume it was good as a bad alternator will slowly kill off the battery and not start.

 

 

I bet this is just a bad points gap(.020 should be good)

Coil looks stock and theballast looks stock also.

 

 

if point gap doesn fix it maybe the coil but I think if you ohm out the points when they open between ground or case of the dizzy to the putput lug(where the wire would hook to). points open read open on meter points close the meter will read Zero ohms.

Share this post


Link to post

Turned it over and it started. It ran like absolute SHIT and any throttle made it struggle and eventually stall. it won't start again.

 

 

I have spark intermittent. point gap is correct and I do have spark in the dizzy.

 

 

The wire from coil to dizzy has NO spark (until two seconds ago, but doesn't anymore) I'm gonna pull the points and re-inspect... if needed I'll go get new ones.

 

Sorry for the ignorance. I haven't dealt with points ignition's in about two years, and even then I was a total noobie at it.

 

Video on the way...

Edited by metalmonkey47

Share this post


Link to post

Sounds like condenser to me. Remember my intermittent issues? New points, cap, rotor, coil, ballast resistor, plug wires, and plugs and it still ran badly. As soon as the condenser went in, all was fixed.

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.