It won't start. My turn!

Hmm...just my luck! I wire in a kill switch, and now it won't start! The only thing I changed in the engine compartment is that the alternator charge wire no longer goes to the power box but now goes straight to the battery

It has gas, electric pump is running fine, accelerator pumps squirt fuel like normal, I have 11.9 volts at the coil and the orange box...did my coil or orange box freakishly go out the first time I tried to start it after rewiring the battery to have a kill switch?

Engine cranks like normal

Without a helper to turn the key while I check for spark, how can I test the coil or box? I left the key in the on position and unplugged the distributor to jump the wires thinking it would trigger the box to fire the coil, and had the main wire from coil to distributor unplugged and close to a ground to see if it would spark and there was nothing.

I noticed that my coil negative terminal was also reading 11.9 volts...that can't be right, can it?

With the key off, the coil had zero resistance accross it, so that's ok, right?

Where so I go from here?

Vehicle is a 98 Dakota with a carb'd big block, orange box ignition, and an mad blaster coil, no ballast resistor. It's got 3 years and 3500 miles with this set-up and worked fine 4 days ago, I know the orange boxes are known to go out on this set-up, did mine decide to go out right when I changed the main battery run to include a kill switch?

Posted By: RapidRobert

Re: It won't start. My turn! - 06/27/09 12:27 AM

Quote:

ok I tried that and the only sparks I got was from the coil negative terminal, nothing from the main lead to the distributor...bad coil?

It would appear that the secondary side has went open but to confirm before you buy another one put an ohmmeter across the center terminal and either of the pri terminals(on K ohms scale depending on your meter type) & see if you have continuity & if so how much.

Posted By: aarcuda

Re: It won't start. My turn! - 06/27/09 12:28 AM

If you have an open across coil pos and neg, the coils shot. But it can't be open if you measured voltage off the neg term to batt gnd

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 12:34 AM

Quote:

If you have an open across coil pos and neg, the coils shot. But it can't be open if you measured voltage off the neg term to batt gnd

when I measured voltage between coil negative and battery ground, with key on, it was still hooked up to the ignition box and tach sending wire. any chance of "back feed" from the tach or ignition box creating that voltage there?

there was zero resistance from positive to negative on the coil (which is closed, right?) I think that was with the key off too...I can check again when I get home.

Posted By: aarcuda

Re: It won't start. My turn! - 06/27/09 12:37 AM

Btw, the coil should fire the plug when you remove the gnd from the neg side. It's the collapsing field that fires the plug.

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 12:39 AM

ok. instead of tapping the ground then, I'll hold it grounded, and lift to see if it fires the coil then.

if it's supposed to be grounded EXCEPT when the coil fires...then why did my negative terminal have voltage on it? if it's grounded, shouldn't it read zero volts, and then read volts when the ground is removed, and thus firing the coil?

Posted By: aarcuda

Re: It won't start. My turn! - 06/27/09 12:40 AM

Disconnect the tach and try it. Tach can cause no starts if they go bad

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 12:45 AM

man, I really hope it's not the tach! a coil is much cheaper!

I'll try that in the morning, thanks!

Posted By: aarcuda

Re: It won't start. My turn! - 06/27/09 12:47 AM

The coil is a. Coil. Power on pos goes thru coil and show on the neg terminal. That creates a field when neg is grounded. Remove the gnd and field collapses and jumps to secondary out to plugs ( spark)

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 12:51 AM

Quote:

The coil is a. Coil. Power on pos goes thru coil and show on the neg terminal. That creates a field when neg is grounded. Remove the gnd and field collapses and jumps to secondary out to plugs ( spark)

ok. I always wondered how the volage going in circles around the middle would create a charge...that makes sense though.

so if the coil is grounded, and then the ground is removed, it SHOULD fire, right? and if it doesn't then it's most likely someting broken in the coil?

I'll try that before hooking the ignition box back up to it and cranking away again to see if ti was the tach or not.

Posted By: aarcuda

Re: It won't start. My turn! - 06/27/09 01:23 AM

yup, a ballast resister is needed. you probably smoked the coil.

http://www.msdpower.com/download/8202.pdf

but you did just install a master kill switch. how is it wired? the timing seems very suspicious.

EDIT
I found this: http://www.blowbyracing.com/msdblastercoil.html

says the primary resistance is 0.440 ohms which is pretty darn low.

lets look closer at the kill switch.

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 01:43 AM

Quote:

yup, a ballast resister is needed. you probably smoked the coil.

http://www.msdpower.com/download/8202.pdf

but you did just install aa master kill switch. how is it wired. the timing seems very suspicious

I don't think so, they even say that their MSD6 or 7 system delivers 12V to the coil, and that a seperate 12V signal is not needed when using and MSD box, and they said it needs a .8ohm resistor if used on a stock POINTS style ignition...mine is a stock ELECTRONIC style ignition...didn't think a resitor was needed, and like I said, 3 years, 3500 miles...

if it did need a resistor, then yea, I guess I cooked it, but kind of funny that it happened just now!

I don't think the kill switch had anything to do with it...just bad timing. I did move the battery all the way to the back, which added about 10 feet to the main positive battery cable by the time I sent it through the switch...but I still had 11.9V at the coil with the key on and not running, I don't THINK my problem is a voltage drop issue...the volt meter in the dash drops to about 9 or 10 volts while cranking the engine...don't know what it dropped to before, never paid attetion, cause it always started!

the other change was to take the main charge from the alternator to the power distribution box on the driver side inner fender (which then sent it back to the battery, and/or powered everything else on the truck) and sent it back to the battery side of the kill switch. nothing else was changed, and it seems to be working just fine, like I said, it cranks at normal speed, shows 11.9V at the coil, ignition box, etc...

Posted By: aarcuda

Re: It won't start. My turn! - 06/27/09 01:48 AM

i edited my response after finding the primary resistance of that coil IS so low.

Posted By: aarcuda

Re: It won't start. My turn! - 06/27/09 01:54 AM

Quote:

Quote:

yup, a ballast resister is needed. you probably smoked the coil.

http://www.msdpower.com/download/8202.pdf

but you did just install aa master kill switch. how is it wired. the timing seems very suspicious

I don't think so, they even say that their MSD6 or 7 system delivers 12V to the coil, and that a seperate 12V signal is not needed when using and MSD box, and they said it needs a .8ohm resistor if used on a stock POINTS style ignition...mine is a stock ELECTRONIC style ignition...didn't think a resitor was needed, and like I said, 3 years, 3500 miles...

if it did need a resistor, then yea, I guess I cooked it, but kind of funny that it happened just now!

I don't think the kill switch had anything to do with it...just bad timing. I did move the battery all the way to the back, which added about 10 feet to the main positive battery cable by the time I sent it through the switch...but I still had 11.9V at the coil with the key on and not running, I don't THINK my problem is a voltage drop issue...the volt meter in the dash drops to about 9 or 10 volts while cranking the engine...don't know what it dropped to before, never paid attetion, cause it always started!

the other change was to take the main charge from the alternator to the power distribution box on the driver side inner fender (which then sent it back to the battery, and/or powered everything else on the truck) and sent it back to the battery side of the kill switch. nothing else was changed, and it seems to be working just fine, like I said, it cranks at normal speed, shows 11.9V at the coil, ignition box, etc...

if the MSD is a capacitive discharge system (which I think it is), the coil gets fired BY THE BOX. both the + and - coil powers comes from the box and not from the ignition feed +12 v) and thats why a ballast resister isnt needed.

But when you use a stock box, the stock (or orange box) only sends the groun d signal to the coil so you need (i believe) a ballast resistor whe nusing the orange box or points

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 01:55 AM

Yea I saw that. I'll have to see if Ican duplicate the .440 ohms, or if it truely is zero. zero would indicate an internal short in my opinion. I might have had the sensitivity set too high on the voltmeter when it registered a zero.

Posted By: aarcuda

Re: It won't start. My turn! - 06/27/09 02:05 AM

Quote:

Yea I saw that. I'll have to see if Ican duplicate the .440 ohms, or if it truely is zero. zero would indicate an internal short in my opinion. I might have had the sensitivity set too high on the voltmeter when it registered a zero.

too high a setting would show 0. but after further checking, the MDS 6 and 7 are CD ignitions. thats why they dont need a ballast. im pretty sure you need ballast resistor with the orange box (look at figure 2 in the instructions- it says so)

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 02:11 AM

all the more reason to finally get off my butt, solder the red and blue wires back together on the used MSD6AL I bought, and get it onto the truck.

...but, I think I'll fix this problem first, before I throw a questionable, used ignition box on there too!

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 05:19 AM

when set to the most sensitive setting, my volt meter reads .5 all by itself. Hmm...must be cheap wires or poor calibration

Accross the coil it read 1ohm, minus the .5 of the meter itself, it's coil resistance at .5 I'll say that's in spec with .44!

When I grounded the coil with the key on, and then "broke ground" I did get a very faint spark out of the coil...but it wasn't as big as the spark I got from the ground wire as I removed it from the ground

I'll try starting it tomorrow (when it's not 1am and ok to make noise again!) with the tach unhooked to see if the tach was the problem or not

Posted By: 1_WILD_RT

Re: It won't start. My turn! - 06/27/09 05:51 AM

Where the coil for the Cuda?? FWIW I haven't seen a report on the test light results...

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 04:41 PM

Quote:

Where the coil for the Cuda?? FWIW I haven't seen a report on the test light results...

I tore the cuda apart 4 years ago, and have since moved 2 and a half times...it's in a box somewhere. My garage is a pile of boxes, car parts, garage equipment and the cuda...by the end of this summer, I should have my 30x40 shop built, and I can finally spread that stuff out and unpack it!

Both the coil and orange box have power in "run" and in "start". I thought maybe I had a bad ground since the battery is now 6 feet further from the engine, and the ground cable is in a new spot, do I used a jumper to ground the box straight to the neg battery post, still no start. Resistance accross the coil is .5 ohms, but shows an open from the positive terminal to the coil wire..,Is this normal? Or should it be .5 like the terminals?

After seeing how weak the spark was last night by grounding the coil and making it fire, I think it's a weak coil...finally burnt out from not running a ballast maybe? Just freak timing!

I think I'm ready to replace it and see what happens, unless I can check something else? (I guess I could get a helping hand and have someone crank the engine while checking the coil spark that way yet too)

Posted By: 1_WILD_RT

Re: It won't start. My turn! - 06/27/09 04:59 PM

FWIW if you hook up a test light to the negative side of the coil (the side oppasite the 12v hookup) the light should pulse when you crank the engine, typically you can watch the light while cranking the engine with the key so you don't have to track down any help... If it doesn't pulse there won't be a spark... If it does pulse & theres no spark put a coil on it...

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 10:09 PM

test light results!

no dice.

wired up the test light to the coil positive, and the coil negative, with the key on, it should light up, right? it doesn't

it doesn't flash while cranking either. tach wire is pulled way out of the way too, so no interferance from that.

I DID have the orange box from the cuda, it was still on the firewall...but hasn't run in 4 years. same results. no light.

so...2 bad boxes?

bad ground to box? I thought I tested that too, by putting a jumper from the case of the box straight to the negative battery terminal, I attached it at the screw that holds it to the inner fender, which touches bare unpainted metal on the box, and I attached it to the blue annodized thing on the front, and it wouldn't start when I tried that.

with a helper (the wife reluctantly gave me about 45 seconds of her time

), I had it all hooked up and pulled a plug, had her crank, and no sparks.

oh yea...I succumbed...brand new coil while she was doing this

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 10:11 PM

Quote:

FWIW if you hook up a test light to the negative side of the coil (the side oppasite the 12v hookup) the light should pulse when you crank the engine, typically you can watch the light while cranking the engine with the key so you don't have to track down any help... If it doesn't pulse there won't be a spark... If it does pulse & theres no spark put a coil on it...

just re-read this...how do I hook up the test light?

coil installed as normal, put the positive of the light to the negative of the coil, and ground the light to the frame? or unhook the coil and put the light in place of the coil?

Posted By: 1_WILD_RT

Re: It won't start. My turn! - 06/27/09 10:13 PM

Test light, ground the clamp, hook the probe up to coil negative post...Leave the coil hooked up.. Wish I was closer..

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 10:45 PM

Quote:

Test light, ground the clamp, hook the probe up to coil negative post...Leave the coil hooked up.. Wish I was closer..

ok...but the test light was the last thing I tried.

I was so sure it was the coil, so that was what I did first.

that didn't work, so I had my wife crank with a spark plug pulled, looking for spark. it's either so weak it can't be seen, or not there.

changed the orange box, with the old one from the cuda that worked when I pulled it apart 4 years ago, and still no spark at the spark plug. and I had a jumper from the strap of the plug straight to the battery to ensure good ground there as well...

I'll give the light a shot, but...at this point, I don't know what could be the problem.

the gap at reluctor? ...the magnet and star wheel inside the distributor...is very tight, I didn't measure it but it looks like it's less than the thickness of a sheet of notebook paper.

I don't get it!

if I get a few minutes after dinner, I'll re-try the test light with the coil hooked up properly.

Posted By: aarcuda

Re: It won't start. My turn! - 06/27/09 10:56 PM

The spark plug needs to be grounded to fire. No resistance between coil hi voltage (secondary side) and either the + or- side is not good. The schematic in that link I posted shows a connection ( it will be much higher than the primary resistance)

Posted By: aarcuda

Re: It won't start. My turn! - 06/27/09 11:03 PM

Secondary resistance should be 3100 ohms (3.1k ohms)

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 11:07 PM

I'm laughing right now.

problem found, problem fixed, engine started, and my new kill switch works like it should and shuts down everything.

the problem was the coil negative wire to the orange box...was brittle and broke...but the heat shrink tubing was holding the connector onto the end of the wire...I found this as I was doing the test light the RIGHT way...light didn't flash at all...steady on.

I went to pull the plug on the box to swap the box to the other one, as now I don't know which one is which...and I slipped, and tugged on the wire enough to pull it out of the heat shrink...I thought "hmm...I bet that's been my problem the whole time.

grabbed another connector, stripped the end of the wire, crimped it on, tossed it on the coil, and the darn thing fired right up!

I guess I'll test the other orange box so I know if it's still good or not, then put the oil coil on to see if it is still good...as it probably is, and take the new coild back...that's $42 the wife will be happy I didn't spend!

I guess next time, I know to ohm out the wires too, not just the components!

Thanks for the help guys...guess I didn't need it!

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 11:11 PM

and if you read above, I said why I suspected the coil...I knocked it while trying to remove a stuck bolt on the alternator, so I could swap out the alternator charge wires...apparently that "knock" against the coil is the one that broke the copper wires at the soldered and heat shrunk connection

Posted By: aarcuda

Re: It won't start. My turn! - 06/27/09 11:11 PM

But now you know so much more about coils and how ign systems work

Posted By: 70Cuda383

Re: It won't start. My turn! - 06/27/09 11:14 PM

Quote:

But now you know so much more about coils and how ign systems work

true! I had a rough idea of how coils worked...coil of wires, creates a magnetic field...capable of creating much higher voltages than the input voltage...I did have an electrical engineering course at the Academy!

I suppose I learned more on how to troubleshoot an automotive electronic ignition system.