Re: Electrical Gurus Needed - UPDATE
[Re: stumpy]
#1326049
11/14/12 09:46 PM
11/14/12 09:46 PM
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Joined: Jul 2007
Posts: 1,526 North Carolina
cjskotni
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Quote:
Are you using relays on the fans etc?
Yes I am using relays for each of the fans and the A/C as well.
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Re: Electrical Gurus Needed - UPDATE
[Re: stumpy]
#1326051
11/15/12 12:58 AM
11/15/12 12:58 AM
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Joined: Aug 2003
Posts: 2,470 Answering the call of the wild
ThermoQuad
top fuel
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top fuel
Joined: Aug 2003
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Answering the call of the wild
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Let's try some troubleshooting instead of mud slinging. If your ignition switch is from 1973 we are all wasting out time here as this is classic symptoms of a bad ign switch. OK???? Voltage tests should be done when the car is running. When the car is running there should be 13.8-14.4 volts across the battery terminals and 7-9 volts at the coil. Period. Pick a ballast resistor that puts the coil voltage at 9 volts. If you want to get technical E=IR E being volts I the current & R the resistance As soon as the car dies measure the voltage at the coil. 7 volts or more is what i would expect to see. Next unplug the distributor pick up and put the leads across the terminals going to the dist. Crank the engine and meter should be changing state-ie going from OL [over limit] to a reading in ohms...Pick up is working if meter is changing state, the number is not important. There should be several grounds from the body to the engine including one from the control box to the engine. Post a pic of your grounds and control box set up
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Re: Electrical Gurus Needed - UPDATE
[Re: ThermoQuad]
#1326052
11/15/12 08:35 AM
11/15/12 08:35 AM
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Joined: Jul 2007
Posts: 1,526 North Carolina
cjskotni
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Quote:
Let's try some troubleshooting instead of mud slinging.
If your ignition switch is from 1973 we are all wasting out time here as this is classic symptoms of a bad ign switch. OK????
Voltage tests should be done when the car is running.
When the car is running there should be 13.8-14.4 volts across the battery terminals and 7-9 volts at the coil. Period.
Pick a ballast resistor that puts the coil voltage at 9 volts.
The previous ignition switch was about 6 years old and I just replaced it with a brand new one. Voltage drop across the switch is ~0.2V.
With the motor running with fans off, voltage is near 15V and with fans on, drops to around 14.2-14.4V or so. This translates to a volatge on the ignition side of the ballast of ~13.8-14V.
I think you are correct when you say the issue is the ballast. The ballast is only leaving 4.2V on the hi side of the coil once the fans are on. When you put the car in gear and the idle drops to ~700 RPM, the coil voltage starts falling below 4V and thats when the idle starts dying.
I have two ballasts on order with lower resistances. I will measure them when they arrive and fill everyone in on how they work!
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Re: Electrical Gurus Needed - UPDATE
[Re: cjskotni]
#1326053
11/15/12 10:39 AM
11/15/12 10:39 AM
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Joined: Jan 2003
Posts: 4,664 Newfoundland
mopar_man
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Ok first post on this problem . Problem: engine dies after 15 mins. or so Problem: haven't isolated the whats causing this. Here's what I would do to isolate harness and ign. system . Disconnect wires from + side of coil. Run two wires from battery to + terminal on coil . one wire with an in line ballast resistor . start car and remove solid wire so you don't cook the coil if the engine still dies, you have very little wireing and parts to look at ........ I would unhook your alt. just for the test . Now if the engine still dies , your down to coil, ecm , dist and carb/fuel . see what happens .
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Re: Electrical Gurus Needed - UPDATE
[Re: mopar_man]
#1326054
11/15/12 02:34 PM
11/15/12 02:34 PM
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Joined: Jul 2007
Posts: 1,526 North Carolina
cjskotni
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Quote:
Ok first post on this problem .
Problem: engine dies after 15 mins. or so Problem: haven't isolated the whats causing this.
Here's what I would do to isolate harness and ign. system . Disconnect wires from + side of coil. Run two wires from battery to + terminal on coil . one wire with an in line ballast resistor . start car and remove solid wire so you don't cook the coil if the engine still dies, you have very little wireing and parts to look at ........ I would unhook your alt. just for the test .
Now if the engine still dies , your down to coil, ecm , dist and carb/fuel . see what happens .
I am thinking we **may** have found the issue when I saw that when the coil voltagge drops below ~4V the idle becomes rough and begins to lower which drops the voltage more and death spirals the motor.
With the fans on and in park the idle is about 800 RPM which keeps the coil voltage at 4.2V which is enough to keep her alive. Once I get below around 750, the alternator isn't keeping enougg voltage which begins this process.
I troubleshot the wiring and I am seeing voltage drop of almost 10V on the OEM ballast I have which is too much for my Blaster coil apparently.
I am guessing with the everything cooled off, I am right on the verge of too weak of a spark but the heat from the motor running may have pushed it over the edge raising resistance in the ballast/wiring.
Not sure why I ran OK before but this started about two months ago. Maybe I was just marginal the entire time and I just stepped over the edge?
I am hoping my theory here is correct as I have about troubleshot the hell outta this ignition system!
If this doesn't work, I will be trying your test along with others...
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Re: Electrical Gurus Needed - UPDATE
[Re: cjskotni]
#1326055
11/15/12 07:23 PM
11/15/12 07:23 PM
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Joined: Dec 2005
Posts: 151 ontario
70plumrt
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I had a Ram that would die after 20 mins. When I'd take it to the mechanic it would work fine. The next day same thing! After the third time he drove it till it stalled on him and wouldn't restart. Turned out the fuel pump was over heating! Funny thing was a different mechanic thought it needed a whole new full exhaust system!
1969 Charger
1968 Charger R/T
1972 RR TB3 340/4 spd
2002 Ram
1998 Durango
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Re: Electrical Gurus Needed - UPDATE
[Re: coronetville]
#1326056
11/16/12 01:41 AM
11/16/12 01:41 AM
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Joined: Sep 2003
Posts: 1,688 Marlboro, NY, USA
Rick_Ehrenberg
top fuel
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Joined: Sep 2003
Posts: 1,688
Marlboro, NY, USA
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Quote:
...If you upgraded with a 100 amp alt you have to upgrade alt. wiring
Amen to that! This is a meltdown waiting to happen.
Rick
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Re: Electrical Gurus Needed - UPDATE
[Re: Rick_Ehrenberg]
#1326057
11/16/12 11:42 AM
11/16/12 11:42 AM
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Joined: Jul 2007
Posts: 1,526 North Carolina
cjskotni
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Quote:
Quote:
...If you upgraded with a 100 amp alt you have to upgrade alt. wiring
Amen to that! This is a meltdown waiting to happen.
Rick
I respectfully disagree! The way I have my fans wired, it is no more likely to "meltdown" than a factory setup.
I take the fan relay feeds directly from the alt stud so while the car is running, no fan current goes through the bulkhead/ammeter charging circuit! The only point where the 20 amp draw of the fans would go through the entire charge circuit is when it fulls from battery (car off). I doubt that a couple of seconds of 20 amp draw when the car is off would burn up the OEM wires which are all brand new in my case. :-)
Also a common misconecption is that a hi output alternator will push those extra amps through the charging circuit. The car/battery will only "take" what it needs (ohm's law). The only difference is that the hi output alternator will be able to "hold" a higher voltage given a lower resistance (more load/accessories ON) than the OEM 60 amp unit.
The issues where people are burning up their cars with hi-output units is where they tap into 12V power from the starter relay or battery terminal whitch DOES pull the extra current for those extra accessories (fuel pump/fans/etc) through the entire engine/dash harness while the car runs.
It also doesn't help if you have 40+ yr old wires and they are dirty and corroded....not to mention the factory didn't build much margin into the charging circuit as we all know.
Not a bad idea to upgrade the wiring but not necessary if wired/maintained correctly.
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Re: Electrical Gurus Needed - UPDATE
[Re: cjskotni]
#1326058
11/16/12 03:37 PM
11/16/12 03:37 PM
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Joined: Jan 2003
Posts: 5,912 Athens, Greece
Pyper70
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Sounds like your fusible link is overloading with driving time and it blows out and shuts your car down. After a while the Fusible link "resets" and you are back on your way until you shut down again right? Are you sure the new Fusible Link is of equal or greater value since you claim to have a new harness. I removed my fusible link from my systems when I upgraded to MSD and a larger alternator. I ran the PowerMaster 120a Single wire straight to the batter with a 6 GA. cable. remove your ballast resistor as that is designed to use a lower voltage coil, not needed with a Blaster coil or MP coil. All those cables from the ballast resistor get fused together I think with a wire nut. I put an inline fuse where the fusible link would be and put on a 25a fuse...then a 35a...then a 40a...thats with everything on....the heater, the stereo system, the headlights, the everything..I ended up replacing the 40a fuse with a 40a reset breaker from a 737 cockpit (my friend worked at SAGE Air...) big red button on the firewall...looked clean...people never knew what it was. Never blew another fusible link.
One other thing to check is the Starter relay...it supplies your cabin with all the necessary power...if it heats up from a bad ground or a leak in the circuitry...you will blow the fusible as well..
And finally, the only other time my Charger has slow blown a fuse was when the wiring for the power seat ended up getting grounded to the floorpan because the shielding came off the cable..I was driving to Vegas at 3am...stopped for gas 3 hours out...and she wouldn't let me leave the gas station until I dragged her to an electrical shop by tow truck and he found the broken wire under the carpet.
Family owned 1969 Charger R/T DualQuad 440/727/GVO/3.55s
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Re: Electrical Gurus Needed - UPDATE
[Re: Pyper70]
#1326059
11/16/12 03:50 PM
11/16/12 03:50 PM
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Joined: Jan 2003
Posts: 3,905 Minnesota
3twos
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Minnesota
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I think 2 ohms is way too much. Also I seem to remeber the blaster 2 coil should use a .8 ohms resistor?
Last edited by 3twos; 11/16/12 03:54 PM.
Al & Sheila
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Re: Electrical Gurus Needed - UPDATE
[Re: 3twos]
#1326060
11/16/12 04:33 PM
11/16/12 04:33 PM
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Joined: Jan 2003
Posts: 5,449 So Cal
Sinitro
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So Cal
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Quote:
I think 2 ohms is way too much. Also I seem to remeber the blaster 2 coil should use a .8 ohms resistor?
According to the Mopar Performance catalog.. When using a Blaster coil, the correct ballast resistor value is 0.25 Ohms which is Mopar #P2444641.
Just my $0.02..
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Re: Electrical Gurus Needed - UPDATE
[Re: stumpy]
#1326062
11/16/12 05:56 PM
11/16/12 05:56 PM
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Joined: Jul 2007
Posts: 1,526 North Carolina
cjskotni
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Quote:
When a fusible link blows it's gone. There is no reset to it just like a regular fuse.
It's not the fusible link or a break in the charging circuit. With the ammeter, it will die when I have a neatral charging situation (niether charge or discharge).
I am pretty sure its a low volatge condition on my coil from the OEM ballast.
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Re: Electrical Gurus Needed ***Progress Finally***
[Re: 3twos]
#1326064
11/17/12 01:34 PM
11/17/12 01:34 PM
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Joined: Jul 2007
Posts: 1,526 North Carolina
cjskotni
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Guys, Well I purchased the MSD .08ohm ballast that is what their documents suggest to use with the Blaster coil. Now I get between 7.5V to 8.5V on the coil! I cranked her up and ran for 25 minutes or so, no shutting off. I don't know if I will have the chance to take her for a spin this weekend and I am a little gun-shy now of being stranded for the 4th time with this issue! Idle still drops about 20 RPM when the fans kick on at idle but I would imagine that's normal as the alternator is now putting up some resistance on the belts with the new 20 amp load. However I idled in gear with fans for 6 or 7 minutes and idle held steady around 700-720RPMs. An interesting note is that whatever I seem to set the curb idle to out of gear (750-850+ RPMs) does not seem to make much difference to what the engine settles at in-gear (always 700-720 RPMs). I do see a difference in how fast the car moves at idle when I let the brake go but that's it. Is that normal? I don't want to set my curb idle to any more than 850RPM but I was wondering if that might help keep the in-gear idle a bit higher to keep this problem at bay....apparently not. Oh and by the way, thanks for everyone's input here so far! It is nice to see people taking the time to help a fellow hobbyist here I will keep posted if the issue rears its ugly head again.
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Re: Electrical Gurus Needed ***Progress Finally***
[Re: cjskotni]
#1326066
11/18/12 11:01 AM
11/18/12 11:01 AM
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Joined: Jul 2007
Posts: 1,526 North Carolina
cjskotni
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Ok guys, Another update here. I decided last night to check the fuel filter and sure enough it was significantly gunked with debris. I assumed this was ok becuase I cleaned it out when I had the car dyno'ed in August and I have had very little run time since then. I think this may be part of the issue for sure. I know somebody here said to check the carb for fuel so on that suggestion! Seems a little bit different from normal fuel filter issues where it just clogs and that's the end of it, no/poor running until it's fixed...not run for 15-25 minutes then die... I will try to test and let you know how it goes!
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