Ignition, no spark problem help!

[Stan Disbrow]

Hi,

On the scope, I also added a connection to a timing light. So, by using that on number one cyl, and triggering the scope with that signal, I can look at all the firing pulses on the coil wire. That way, I see them all in firing order and can see by the waveforms how each is acting and so find the one (or more than one) which is having issues.

Handy, that.

Actually, this is pretty much the same as those fancy engine analyzers, only a lot smaller and cheaper.

Stan

[PatPax]

Hi Stan,

"Also, you do have this hooked up positive ground, right? If it is negative ground there will be a weaker spark from the coil than with it positive ground."

How do I get a positive ground?

I have a wire from the switch to the positive side of the coil ,then the negative side of the coil goes to the points as this is how it was wired when I purchased it this year. So that is how I put it back when replacing the points ect. So is this hooked up wrong?

I do have 12 volts from positive side of coil & 12 volts to points when open.

My manual does not show how to hook up the coil wires

[jtrichard]

A few things have screwed up this post/question.... IT was not said till about half way through the post its a 2010 SO it is 12V NOT 6V .... being a 2010 it should not have a ILBD (separate switches on a 2010)..... CHECK the battery and see witch cable is hooked to the FRAME if its the + then it is POS ground still if it is pos ground then the coil is hooked-up backwards..... (this is for 6V but the hook up is the same for 12V) http://www.forabodiesonly.com/mopar/att ... 1326673816 .... another thing is that if as said you have 12V to the coil then you need either a coil with a built in resistor OR a standard coil with an external resistor ( i would use an external resistor and add a HOT start system ) THE original switch has a resistor on the back of the switch so if hooked up right you would only have 6V to the coil so I have to assume that since you have 12V to the coil that you have an universal ING. switch

[Stan Disbrow]

Hi,

12v systems are negative ground. 6v systems are positive ground. All along, I have been talking about a 6v positive ground machine. This includes the way the starters are engaged via a pull rod to a manual switch.

The polarity of the ground is which battery terminal is hooked to the machine itself.

Most coils in 12v machines are actually 6v coils. They have a ballast resistor between the power feed, as in ignition switch, and the coil input. This drops the voltage at the coil from 12v to 6v. If this is not present there is a very good chance of burning out the coil primary winding.

The 'hot start' mentioned is where one runs a wire from the start terminal of the key ignition switch to the coil input. So, 12v hits the coil when the starter is engaged. And only while it is engaged. This actually puts about 9 volts onto the coil since the starter load pulls the battery voltage down. That produces a hotter spark than normal, which helps starting. The 9v is not applied long enough to damage the coil. Once the key is released, the coil is fed via the run terminal of the key switch and the resistor is back dropping the 12v to 6v for the coil.

Stan

[jtrichard]

HI STAN I know you are not use to these "new" fancy four cylinder machines LOL ....But the 2010s were originally 12V positive ground.... and the "hot start" wire would have to come off of the "R" terminal (DELCO STARTER) on the starter solenoid IF it was ran off of the start terminal on the starter switch the back feed/voltage (for lack of better term) from the coil would keep the start solenoid engaged

[Stan Disbrow]

Hi,

12v pos gnd? I will stick that away for later. I knew some early 50s cars and trucks were 12v pos gnd until someone figured out having the electron source as the common mitigated the electrolysis corrosion issue. That had not been much of an issue at 6v but became much worse at 12v.

The new generation 10 series is something I have no experience with. I jumped from the 2-cyl to the 3-cyl 20 series. As in the 820, 1020, 1520 and 2020 wheel tractors and the JD350 crawler (which is kin to the 1520) which are totally different than the 1010 and 2010.

For some reason, I was thinking the OP had a 2-cyl when his sig line says it is a 2010. Even if that had clicked, I would still have had the polarity backwards.

And, I left out a critical part in my Hot Start description. The danged Diode. There has to be a Diode to prevent backflow of the coil feed power to the starter solenoid when hooked to the Start terminal of the Ign switch!

Or, as you say, use a terminal on the starter which is there to provide switched power for that purpose.

I think I shall shut up now and let the 2010 guys take over....

Stan

[PatPax]

OK I have cleaned points, checked open points with volt meter & get 12 volts with switch on. Still no spark.

Stan, I read many of your post, you are so knowledgeable! I copy & print them & put them in my owners manual in the appropriate chapter. I also have jrichard, Tigerhaze, Lavoy & others in my owners manual, what a fantastic web site.

[Stan Disbrow]

Hi,

I said I was gonna shut up, but this part works on anything with coils, points and plugs....

Next step is to hook a spark plug onto the coil lead. I usually stick a spare plug wire into the coil and lay the test plug anywhere handy on the engine with the gap such I can see a spark.

Then, with the cap off and the points open, I switch on the ignition and use a screwdriver tip to jump across the points. That makes a magnetic field inside the coil. Then, I pull the screwdriver off and there should be a spark at the test plug.

So, this will test the coil. If it works, then you need check it again with the starter cranking. This will check for some fault with voltage drop under starter load. If it still sparks, then we can move onto rotor, cap and timing issues.

If not, then we have to ensure power is present at the points when cranking and then point gap if it is and it won't spark.

I have seen where key ignition switches have issues with power to the points when over in the crank side yet be fine in the run position....

Stan

[jtrichard]

HI STAN I was thinking a Diode would stop the back feed ..... You have tons of knowledge i don't have .... I know spark issues can be a bitch I was not familiar with the test that you just posted have to keep it in mind for future reference... I have a 310 case wheel with gas and it did not have a resistor on it and it would fry points in short order ,started and ran great though lol i put an external resistor on it and points seem to last much longer now hummmm go figure

[Tigerhaze]

I am flattered that I mentioned with the others here, but in reality I am good at finding relevant posts by the experts here and bringing them back to discussions!

I can second Stan's observation about ignition switches and related wiring causing a no spark situation-I had a similar no spark issue on my 8N tractor and tracked it down to an intermittently operating ignition switch and a faulty isolation grommet on the distributor housing for the coil to points wire. My 8N had been converted to 12V negative ground and I had used a "12V" coil so those were not an issue.

It is true that 2010 crawlers were built as 12V positive ground, but it seems like every 2010 I have been around was converted to negative ground when they also lost their generators for alternators

[Paul Buhler]

I'll second PatPax's comments about this being a great site. I've learned a great deal here over the years and it's so refreshing to read civil, helpful discussions. Happy Holidays.

[Stan Disbrow]

Hi,

When I realized I had been a dummy there - talking about specifics for the wrong model - I was going to edit them. But, then I thought (I know, Dangerous) I would leave them. The title of the thread is not specific to any given machine, so someone with a no-spark issue will find it easily. And, at the rate we're going the information will soon cover any spark system there is out there!

I will now add the 'why' for the condenser. Which, in electronic terms, is known as a capacitor.

The pulsed nature of the ignition means we are actually talking about alternating current. Direct current is converted to AC by the action of the points. The coil is a step-up transformer. And, transformers are an AC-only component.

One item to always consider is that in an AC circuit, a coil shifts the energy in one direction, and a capacitor shifts it in the opposite direction. So the condenser is there to bring balance the force. Better than Anakin Skywalker did, anyway.

If there is no balancing, as in no condenser, then the backfeed voltage from the actual spark will cause another spark - across the points. That, then pits them quickly.

But for testing, one can disconnect the condenser and be OK. Sometimes the condenser isn't right in some way and can make for a weak spark.

One thing about a weak spark is it may spark out in the air and not under compression. But, one can tell by how fat the zap looks with a test plug.

Stan

[PatPax]

Will someone please explain in simple terms what is a "positive ground"

And how to properly hook up the coil, as I think the previous owner had it wired opposite as shown in the manual. It ran that way for the 8 months I have owned it. BUT now no spark.

[gregjo1948]

Attach the positive post on your battery to the frame of the machine.

[Paul Buhler]

Will someone please explain in simple terms what is a "positive ground"

Edited: in a positive ground system, the positive side of the battery is attached to the frame, and the negative side to your starter. The current goes through its usual circle opposite that of a negative ground. The system will have a generator, not an alternator.