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Car won't start - No spark - No voltage at Coil #582456 01/14/10 06:09 PM 01/14/10 06:09 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Hi guys, This past weekend my 1970 Challenger finally pulled it's first "no start" on me (after 5+ trouble free years). I went to fire it up and it just cranked and cranked .. Checked for fuel and it was fine. Took off the distributor cap and verified the rotor was turning. Checked for spark at the distributor-to-coil wire - nothing. I then swapped out the ballast resistor to a brand new one I had - still no spark. Finally, I put a multimeter to the coil and checked for voltage with the key both in the "run" position and while cranking - zero voltage both ways. I know very little about electrical problems, so I'm not sure what to try next? Could the coil or ECU (Mopar Orange) box be bad? Or something earlier upstream like the ignition switch or bulkhead piece? If so, how to test these things? The car has started so reliably in the past that it surprised me something could have just gone dead without going flakey first, but I guess anything can happen.. Any tips on what to check next would be greatly appreciated! Thanks much!

Re: Car won't start - No spark - No voltage at Coil [Re: dg_dodge] #582457 01/14/10 06:12 PM 01/14/10 06:12 PM
Joined: Jun 2005 Posts: 4,041 michigan woods imfixinmopars426 master
imfixinmopars426 master Joined: Jun 2005 Posts: 4,041 michigan woods	first get a wiring diagram,then look at the bulkhead connection.burnt wiring,ballast resistor,fusable links near battery. it should be easy to find.

Re: Car won't start - No spark - No voltage at Coil [Re: imfixinmopars426] #582458 01/14/10 07:00 PM 01/14/10 07:00 PM
Joined: Jan 2003 Posts: 32,928 Grand Prairie,Texas stumpy I Win
stumpy I Win Joined: Jan 2003 Posts: 32,928 Grand Prairie,Texas	Try turning the key on and jumping the starter relay on the fender. If it starts then you probally have a bad feed wire from the bulkhead connector.

Re: Car won't start - No spark - No voltage at Coil [Re: stumpy] #582459 01/14/10 07:08 PM 01/14/10 07:08 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Thanks guys for the replies. I did try starting from the starter relay as well - with my remote starter switch -- but still no spark. Would any of the wires that go through the bulkhead affect only spark while still allowing the starter to crank ? I never quite understood that process.. Thanks!

Re: Car won't start - No spark - No voltage at Coil [Re: dg_dodge] #582460 01/14/10 07:25 PM 01/14/10 07:25 PM
Joined: Jan 2003 Posts: 104,346 Garden Grove, CA OzHemi Penguin-hating Ginger
OzHemi Penguin-hating Ginger Joined: Jan 2003 Posts: 104,346 Garden Grove, CA	Could be the ECU took a dump if you have no voltage to the coil out of the orange box. Are you getting voltage too it ? (or just swap the box out real quick if you have a spare around)

Re: Car won't start - No spark - No voltage at Coil [Re: OzHemi] #582461 01/14/10 07:37 PM 01/14/10 07:37 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Hi, I don't have an extra ECU to try out unfortunately. Is there a way to check the voltage going to the ECU? (I assume it's zero coming out of it since there is nothing at the coil??). Thanks!

Re: Car won't start - No spark - No voltage at Coil [Re: dg_dodge] #582462 01/14/10 07:44 PM 01/14/10 07:44 PM
Joined: Jan 2003 Posts: 104,346 Garden Grove, CA OzHemi Penguin-hating Ginger
OzHemi Penguin-hating Ginger Joined: Jan 2003 Posts: 104,346 Garden Grove, CA	You can check the ballast resistor to make sure you are getting voltage there first off. Then just work your way back to the bulkhead connector. But those orange boxes seem to just take a dump like that (could be distributor pickup, no voltage through the bulkhead connector,etc,etc.. but ECU is where I would look to first)

Re: Car won't start - No spark - No voltage at Coil [Re: OzHemi] #582463 01/14/10 07:55 PM 01/14/10 07:55 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Thanks much for the great diagram on that. I will test this out on Saturday when I get over to the car. To test voltage at the ballast resistor (2-pronged), does it make a difference which way I attach the positive and negative leads on the multimeter? I see that the resistors don't have +/- sides to them .. Thanks!

Re: Car won't start - No spark - No voltage at Coil [Re: OzHemi] #582464 01/14/10 07:59 PM 01/14/10 07:59 PM
Joined: Aug 2007 Posts: 6,095 Valencia, España NachoRT74 master
NachoRT74 master Joined: Aug 2007 Posts: 6,095 Valencia, España	take in mind the yellow and red wires ilustrated on this diagrams are slightly incorrect for pre 75/76 cars. First, yellow wire is really brown and doesn't come from starter relay, comes from ign switch Second, red wire going to coil is brown OR blue ( depending of year ) the yellow wire coming from starter relay is JUST CORRECT for laters cars where the starter relay provides the ballast bypass instead coming directly from ign switch. Is a very diff starter relay setup With a Charger born in Chrysler assembly plant in Valencia, Venezuela

Re: Car won't start - No spark - No voltage at Coil [Re: dg_dodge] #582465 01/14/10 08:06 PM 01/14/10 08:06 PM
Joined: Aug 2007 Posts: 6,095 Valencia, España NachoRT74 master
NachoRT74 master Joined: Aug 2007 Posts: 6,095 Valencia, España	Quote: To test voltage at the ballast resistor (2-pronged), does it make a difference which way I attach the positive and negative leads on the multimeter? I see that the resistors don't have +/- sides to them .. Thanks! Doesn't really matter if you have a digital tester since you have to check voltage keeping one of the meter leads with chassis ground/batt negative not prong with prong. If meter leads are turned around you simply will get negative reading, but still same numerical scale. Will matter if is an Analog Tester so check at batt ends which positissn on meter leeds will give you 12 volts reading at needle, and keep negative on that lead. Then positive lead to test wires. On blue wire you have to get 12 volts on RUN ign switch position. Brown wire must get 12 volts at START position. when ballast is plugged the opposite side you are getting 12 volts on both stances, will read 5 to 10 volts With a Charger born in Chrysler assembly plant in Valencia, Venezuela

Re: Car won't start - No spark - No voltage at Coil [Re: NachoRT74] #582466 01/14/10 08:48 PM 01/14/10 08:48 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Thanks very much for the info! If I want to test the wires coming from the bulkhead connector - would I just put the positive prong from the multimeter at the connector on the firewall and ground the negative prong? Or would I need to remove the harness at the bulkhead for this? Thanks!

Re: Car won't start - No spark - No voltage at Coil [Re: dg_dodge] #582467 01/14/10 08:51 PM 01/14/10 08:51 PM
Joined: Jan 2003 Posts: 104,346 Garden Grove, CA OzHemi Penguin-hating Ginger
OzHemi Penguin-hating Ginger Joined: Jan 2003 Posts: 104,346 Garden Grove, CA	You should be able to get your test lead into the end of the bulkhead without removing it.

Re: Car won't start - No spark - No voltage at Coil [Re: OzHemi] #582468 01/14/10 09:31 PM 01/14/10 09:31 PM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	most likely bad orange box. Check that it didnt lose it's ground. then take off the wire to the coil negative primary terminal and with a jumper wire with an alligator clip on each end, clip one end of the jumper to this coil (pri-) terminal and repeatedly touch the other end alligator clip to ground repeatedly like Morse Code & see if the large coil to dist secondary wire (the dist end) held 1/4" from ground sparks (Check with key "on" and key in "start") If it (large coil wire) sparks (in both positions) that only leaves the dist pickup (not likely) and the orange box (most likely). If it doesn't spark in both positions do Nachos voltage checks to find the open (check/clean the firewall bulkheads 1st) and take all (3) wires (2 small 1 large) off of the coil & w your multimeter see if the pri and sec sides of the coil have continuity. What coil and what ballast are you using? Last edited by RapidRobert; 01/14/10 09:33 PM. live every 24 hour block of time like it's your last day on earth

Re: Car won't start - No spark - No voltage at Coil [Re: RapidRobert] #582469 01/14/10 10:10 PM 01/14/10 10:10 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Thanks very much guys for the crash course in troubleshooting. This really helps! I'll try all this out on Sat. RapidRobert - My coil looks like it's a stock/oem type - black cylinder 12v. Ballast resistor is a typical looking 2-pronged ceramic one (sorry, don't have access to the car now to see what ohms it is - but I had a brand new ballast spare that I swapped in and it didn't spark with that one either). Also, I have two wires going to the negative side of the coil (and one to the positive). You said to remove the wire from the "coil negative primary terminal" - which of those two on the negative side might that be? If I need to detach the bulkhead connector at the firewall to inspect/clean it, does this piece just "snap" out or is there more to it? I've tried never to go near that thing for fear of breaking it.. Thanks again folks for all the tips! Thanks

Re: Car won't start - No spark - No voltage at Coil [Re: dg_dodge] #582470 01/14/10 10:21 PM 01/14/10 10:21 PM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	I was thinking if you have a high powered coil w a lower ohm ballast that they would be more likely to fail but from your descrip that's not the case here. Take ALL wires off of the coil(-) pri terminal to do the test (your 2nd wire is most likely a tach rpm sensing wire). The bulkheads: some have a wire bail like a master cyl cover & if so take it off or flip it over & you'll see the nubs on the ends of the black bulkhead that hold them on. Depress them inward & wiggle the connector off. live every 24 hour block of time like it's your last day on earth

Re: Car won't start - No spark - No voltage at Coil [Re: RapidRobert] #582471 01/14/10 10:48 PM 01/14/10 10:48 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Thanks again Robert! If I need to clean the back of the bulkhead connector unit, is regular electronic parts cleaner spray ok, or are these units too old for chemicals like that?

Re: Car won't start - No spark - No voltage at Coil [Re: dg_dodge] #582472 01/14/10 10:54 PM 01/14/10 10:54 PM
Joined: Apr 2009 Posts: 228 northeast texas S strokin73cuda enthusiast
strokin73cuda enthusiast S Joined: Apr 2009 Posts: 228 northeast texas	If your coil has no voltage to the pos. terminal by grounding your multimeter to a good ground not the neg. side of coil you will need to work your way from thier. Your car 70 challenger didn't come out with electronic and scince you said you weren't good at electronics I'm assuming you didn't wire it in. Make sure you have a good ground when you check the coil for voltage by testing the battery positive while using the same ground. 496 stroker,Indy srs , new best 6.87 @ 98 1.46 60'

Re: Car won't start - No spark - No voltage at Coil [Re: strokin73cuda] #582473 01/14/10 11:05 PM 01/14/10 11:05 PM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	Clean the terminals on the half you pull off w a small bristle brush and the firewall half terminals w an extra seperate male terminal or a small eyeglass screwdriver (be conservative, only need to scrape some fresh brass lines)not open them up any then yes hit it w your spray cleaner. live every 24 hour block of time like it's your last day on earth

Re: Car won't start - No spark - No voltage at Coil [Re: RapidRobert] #582474 01/14/10 11:18 PM 01/14/10 11:18 PM
Joined: Jul 2008 Posts: 157 California D dg_dodge OP member
dg_dodge OP member D Joined: Jul 2008 Posts: 157 California	Thanks very much all for the great tips. I've learned a bunch of great stuff!

Re: Car won't start - No spark - No voltage at Coil [Re: dg_dodge] #582475 01/14/10 11:23 PM 01/14/10 11:23 PM
Joined: Dec 2003 Posts: 5,314 Carstairs, Alberta, Canada dave571 master
dave571 master Joined: Dec 2003 Posts: 5,314 Carstairs, Alberta, Canada	Quote: Hi guys, This past weekend my 1970 Challenger finally pulled it's first "no start" on me (after 5+ trouble free years). I went to fire it up and it just cranked and cranked .. Checked for fuel and it was fine. Took off the distributor cap and verified the rotor was turning. Checked for spark at the distributor-to-coil wire - nothing. I then swapped out the ballast resistor to a brand new one I had - still no spark. Finally, I put a multimeter to the coil and checked for voltage with the key both in the "run" position and while cranking - zero voltage both ways. I know very little about electrical problems, so I'm not sure what to try next? Could the coil or ECU (Mopar Orange) box be bad? Or something earlier upstream like the ignition switch or bulkhead piece? If so, how to test these things? The car has started so reliably in the past that it surprised me something could have just gone dead without going flakey first, but I guess anything can happen.. Any tips on what to check next would be greatly appreciated! Thanks much! You are giving yourself too little credit. You have found there is no power at the coil. THAT is what is wrong. The coil needs power to operate. If you were using a trouble shooting chart the next step would be "repair circuit, and retest". Put the key in run, and physically follow the wire back from the coil using a test light (NOT a meter) checking at all the connectors until it lights up. As said, bulkhead is a common spot. I've seen the connector for the ignition switch burn up too. The reason I say not the meter, is the meter can be inaccurate in a situation like this, as it does not put load on the circuit. You can still have voltage, but not enough current capacity for anything to work. Can be great for making you chase your head up your... u know.

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