Need help with a MOPAR starting issue
Discussion
My brother-in law has a 1973 dodge charger 400ci that refuses to start. He has possibly found that the primary coil winding isnt sending a signal to the secondary coil winding. The whole wiring loom has been checked and all is showing continuity throughout (inc at the bulkhead connectors) and the ignition switch isnt showing any problems. The ballast resistor,voltage regulator,ecu,coil,ign pickup and rotor arm have all been changed and there is still nothing.
Come on someone,please give us some help with this as even the auto electrician who spent 4 hours on it yesterday is racking his brains......there has to be a p.h'er who may know what is causing this misery (its booked in to go to battlesbridge american show and we dont wanna go in his ruddy mini).
Come on someone,please give us some help with this as even the auto electrician who spent 4 hours on it yesterday is racking his brains......there has to be a p.h'er who may know what is causing this misery (its booked in to go to battlesbridge american show and we dont wanna go in his ruddy mini).
I'll admit I don't like ballast resistor systems but starting from square one, does it spark? Pop a lead onto a known good spark plug and crank the engine over (helps to do this in the near dark).
If it is, is it sparking at the right time? I've twice got things 180 degrees out when changing engines and it is easier done than one might think.
Are you absolutely certain there is fuel? I've attended a broken down relative who assured me there was fuel - and having checked the previous two items and found all ok, I went into disbelieve mode and sure enough, he'd run out of petrol.
Lastly, what was the last thing he did to the car? If it's anything to do with fuel or electrics, get very suspicious about it!
If it is, is it sparking at the right time? I've twice got things 180 degrees out when changing engines and it is easier done than one might think.
Are you absolutely certain there is fuel? I've attended a broken down relative who assured me there was fuel - and having checked the previous two items and found all ok, I went into disbelieve mode and sure enough, he'd run out of petrol.
Lastly, what was the last thing he did to the car? If it's anything to do with fuel or electrics, get very suspicious about it!
OK, fuel, sparks compression. Got those and it will run.
Sparks. Take the coil out, put it on the bench - wire it up, with an HT lead & a plug. Cut the circuit (like a set of points) - if no spark, your new coil is toast as well. If spark, your coil is good. Points or electronic? Either way, crank it, and if you get lots of sparks, the circuit is working. May be sparking at the wrong time, but all the electrics are good. At this point, you've got to think about timing. Is the HT cap on back to front - usually not possible, but with aftermarket caps it might be. Put a timing strobe on it and turn it over - do the marks roughly line up. Even if the timing is wildly wrong, it will usually cough. If all that comes up OK - you've got sparks.
Fuel. Take the feed to the carb off. Ignition on. Are you covered in fuel? If yes, you have pressure, don't celebrate with a quick cig. If no, suspect fuel pump. After cranking - pull a plug, Is it a bit wet and smelling of petrol? If no, suspect carb - are the floats free, is something blocked? If yes, then you have petrol.
With petrol and sparks, you have one thing left, compression and timing. He hasn't changed the cam or something daft?
Alternatively, sell it to me as "spares and repairs". £500 seems reasonable! :-)
Sparks. Take the coil out, put it on the bench - wire it up, with an HT lead & a plug. Cut the circuit (like a set of points) - if no spark, your new coil is toast as well. If spark, your coil is good. Points or electronic? Either way, crank it, and if you get lots of sparks, the circuit is working. May be sparking at the wrong time, but all the electrics are good. At this point, you've got to think about timing. Is the HT cap on back to front - usually not possible, but with aftermarket caps it might be. Put a timing strobe on it and turn it over - do the marks roughly line up. Even if the timing is wildly wrong, it will usually cough. If all that comes up OK - you've got sparks.
Fuel. Take the feed to the carb off. Ignition on. Are you covered in fuel? If yes, you have pressure, don't celebrate with a quick cig. If no, suspect fuel pump. After cranking - pull a plug, Is it a bit wet and smelling of petrol? If no, suspect carb - are the floats free, is something blocked? If yes, then you have petrol.
With petrol and sparks, you have one thing left, compression and timing. He hasn't changed the cam or something daft?
Alternatively, sell it to me as "spares and repairs". £500 seems reasonable! :-)
Fuel - yep,loads coming thru the 4 barrel.
Ignition is the dodge electronic system.
Spark - no......and that is what is confusing.the car was running ok (300bhp at wheels on the dyno) but it had been running a bit rough for a few days (intermittantly) and now refuses to even try and start. The coil,ballast,pick up,ecu,rotor arm,etc have all been replaced since but to no avail. When it turned over it gave a single weak spark and then nothing until you stopped cranking and then it gave a residual spark (which it isnt even doing now).
Ignition is the dodge electronic system.
Spark - no......and that is what is confusing.the car was running ok (300bhp at wheels on the dyno) but it had been running a bit rough for a few days (intermittantly) and now refuses to even try and start. The coil,ballast,pick up,ecu,rotor arm,etc have all been replaced since but to no avail. When it turned over it gave a single weak spark and then nothing until you stopped cranking and then it gave a residual spark (which it isnt even doing now).
Providing the wiring is sound, this is almost certainly an ignition control box issue. The quality of ignition control boxes (even original and well-known performance brands) is exceedingly variable. A Mopar specialist will be able to test this, but the usual way is to substitute a known good one.
But one important point first: the ignition control box and the alternator regulator MUST be earthed correctly (from the outer case). This has been the cause of many (sometimes intermittent) problems.
Once you've got it fixed OP, come back and tell us what the problem was.
But one important point first: the ignition control box and the alternator regulator MUST be earthed correctly (from the outer case). This has been the cause of many (sometimes intermittent) problems.
Once you've got it fixed OP, come back and tell us what the problem was.
I know nothing about the "dodge electronic ignition system" - but at a guess this is either not sensing engine rotation or it is fubared. If your coil produces a nice fat spark when you manually fire it, it is not being fired - the magnetic field depends on a nice clean break, and if it is not getting that, then you get weak/no sparks.
Ign on and the coil +ve should be 9v it is fed by a blue wire from the ballast., Cranking the coil should see 12v min (battery volts) this is supplied by a brown wire which defeats the ballast, no way will it start without 12v at the coil. to check, I think on a '73 the ballast should have a blue wire to the supply side with 12v, a blue on the ballasted side with 9v and on the same side a brown with 12v on crank.
Quick and dirty check is just jump a wire from the battery +ve to coil +ve and crank it up. if it fires up that's your problem, don't leave it running long as it will boil the coil.
Edit to add, when you crank I think the blue wire drops it's power until you release the key which is why you get a solitary spark when you let go, power comes back for a moment as the engine stops rotating
Quick and dirty check is just jump a wire from the battery +ve to coil +ve and crank it up. if it fires up that's your problem, don't leave it running long as it will boil the coil.
Edit to add, when you crank I think the blue wire drops it's power until you release the key which is why you get a solitary spark when you let go, power comes back for a moment as the engine stops rotating
Edited by Athlon on Thursday 12th May 22:28
http://bertram31.com/newbb/viewtopic.php?f=2&t...
https://mopar 440 1973 ignition module&hl=en-GB&prmd=sivn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiq7Zjfn9XMAhWIJ8AKHeRkDZQQ_AUICCgC&biw=601&bih=914#imgrc=vqLPwdNCWVv6eM:
https://mopar 440 1973 ignition module&hl=en-GB&prmd=sivn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiq7Zjfn9XMAhWIJ8AKHeRkDZQQ_AUICCgC&biw=601&bih=914#imgrc=vqLPwdNCWVv6eM:
Edited by sun.and.rain on Thursday 12th May 23:17
And one more.
http://www.classicwinnebagos.com/forum/index.php?t...
Good luck!
Edit - I've just scrolled down through this link and THIS is the one to check out,, very detailed troubleshooting.
http://www.classicwinnebagos.com/forum/index.php?t...
Good luck!
Edit - I've just scrolled down through this link and THIS is the one to check out,, very detailed troubleshooting.
Edited by sun.and.rain on Thursday 12th May 23:28
He has been working on the car all day. Checked and re-checked and nothing. He has now resigned to the fact that the car wont be going to battlesbridge this sunday BUT he has a guy going round to have a full look-over it next week who is an ex-u.s race car mechanic so hopefully he may find out whats wrong with it. There is a possibility that the original ecu was faulty and that the brand new ecu is also faulty.....wont know now until the guy has checked it all out (he has all the old school testing gear,all we had was a multimeter).
Heres to hope!!
Heres to hope!!
is there a capacitor (condenser in old money) in the dizzy, or is that function achieved with the ECU?
You haven't mentioned one so I suspect not...
...but if there is check/replace that too.
Had a weak spark in the dim and distant that took ages to diagnose till we found a broken wire into the capacitor,
regards,
Jet
You haven't mentioned one so I suspect not...
...but if there is check/replace that too.
Had a weak spark in the dim and distant that took ages to diagnose till we found a broken wire into the capacitor,
regards,
Jet
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