Car cranks but wants to start when i release the key but wont run

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Jake1974dart

Jake1974dart

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maybe you guys can help me with this headache. Right now i have a small block 408 1974 dart and i am having trouble with start up. I have an electronic ignition with the orange box and the msd blaster ss coil with a recurved stock distributor. I have already replaced the box, original coil, ballast resistor, and ignition switch in the column. I dont know what else could be causing this situation. Any suggestions will be a big help.
-Jake
 
Check for voltage at the ballast resistor. Key on and then Key in start position.

sounds like it drops when you let go of the key?

Could also be ignition if you are not start/running , Have you checked for spark at the plugs as well?

Bruce
 
kybatman said:
Check for voltage at the ballast resistor. Key on and then Key in start position.

sounds like it drops when you let go of the key?

Could also be ignition if you are not start/running , Have you checked for spark at the plugs as well?

Bruce
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I I’ll check for voltage at the ballast do you guys know what it should be reading and the motor has spark because sometimes i can get it to run when I release the key
 
Also the ignition switch in run.

Sounds like it cranks fine.
 
My bet is ignition switch. No power in start.

Easy way to check is jumper from battery plus to coil plus and then crank. If it starts then it is not ignition system, it is ballast, or wiring or switch
 
Stop changing parts and get the manual and check for the correct voltages at start and run. You only complicate it and get confused!
 
Hold it in the start position and see if it will crank and start up. It won't hurt it for a couple seconds. If it does, put a ballast resistor on it.
 
How about some more info as well! Does it have a stock harness, any mods ETC!

Your avatar would lead us to believe a 74.
 
1969383S said:
How about some more info as well! Does it have a stock harness, any mods ETC!

Your avatar would lead us to believe a 74.
Click to expand...
It is a 74 dart I just had to change the engine wire harness because the other on smoked it self the new one is from a 73 dart with a slant 6 car so I had to modify the harness to the v8 style. I am going to check the voltage tonight do you guys know what it should be reading ?
 
Jake1974dart said:
maybe you guys can help me with this headache. Right now i have a small block 408 1974 dart and i am having trouble with start up. I have an electronic ignition with the orange box and the msd blaster ss coil with a recurved stock distributor. I have already replaced the box, original coil, ballast resistor, and ignition switch in the column. I dont know what else could be causing this situation. Any suggestions will be a big help.
-Jake
Click to expand...
Fought the same battle with the exact same symptoms. I changed everything just like you have. I deduced the only thing left, after checking and making sure that I had 100% good grounds, was the electronic ignition wiring harness. Ordered one and installed it, problem solved. Don't know if that is your issue, but this sounds very familiar. Haha
After inspecting the old ECU connector, it looked to me like the socket for pin number 2, the wire that actually sends the signal to the negative side of the coil, was pretty sloppy and wallered out. As was pin 4 and 5 the wires to distributor.
And I can't logically tell you why that would have anything to do with the no start scenario in crank but start in run. I'm just saying don't forget the wiring, cuz it's 40 to 50 years old unless you already have a new wiring harness. In that case, never mind. LOL
 
moparmandan said:
Fought the same battle with the exact same symptoms. I changed everything just like you have. I deduced the only thing left, after checking and making sure that I had 100% good grounds, was the electronic ignition wiring harness. Ordered one and installed it, problem solved. Don't know if that is your issue, but this sounds very familiar. Haha
After inspecting the old ECU connector, it looked to me like the socket for pin number 2, the wire that actually sends the signal to the negative side of the coil, was pretty sloppy and wallered out. As was pin 4 and 5 Common wires to distributor.
And I can't logically tell you why that would have anything to do with the no start scenario in crank but start in run. I'm just saying don't forget the wiring, cuz it's 40 to 50 years old unless you already have a new wiring harness. In that case, never mind. LOL
Click to expand...
Honestly that might be something worth checking! This is the plug that goes to the ignition box right ? Where did you get the new harness from ?
 
Jake1974dart said:
I I’ll check for voltage at the ballast do you guys know what it should be reading and the motor has spark because sometimes i can get it to run when I release the key
Click to expand...
This is what I'm talking about. Won't start in crank. If you're quick, it will start and run (with the key in the Run position) if the motor is still turning fast enough. Correct?
 
Jake1974dart said:
Honestly that might be something worth checking! This is the plug that goes to the ignition box right ? Where did you get the new harness from ?
Click to expand...
Yep.
That was a couple years ago. Pretty sure I just found it on eBay. Or someplace like year one.
 
moparmandan said:
This is what I'm talking about. Won't start in crank. If you're quick, it will start and run (with the key in the Run position) if the motor is still turning fast enough. Correct?
Click to expand...
Exactly my problem! So I’ll check the bulk head for the ignition switch if it’s loose then I’ll have to order a new one look at year one
 
Frustrating ain't it? That one kicked my *** for a while.
Yes, make sure the brown and dark blue wire coming out of the bulkhead are in good shape. Remove the factory vinyl bundling tape and have a good look. They both have a welded splice that can be problematic. Also make sure you have a good ground to the ECU. Most people suggest running an extra ground wire to one of the case screws.
 
toolmanmike said:
And why would that change?
Click to expand...

I don’t know why it would change but it takes two minutes to check it.

I had a problem with a no start and the car acted like it was flooded when hot. Cold it was ok. It was the reluctor gap. New dizzy it was. Same as op stated it wanted to start when you let go of the key.
 
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moparmandan said:
Frustrating ain't it? That one kicked my *** for a while.
Yes, make sure the brown and dark blue wire coming out of the bulkhead are in good shape. Remove the factory vinyl bundling tape and have a good look. They both have a welded splice that can be problematic. Also make sure you have a good ground to the ECU. Most people suggest running an extra ground wire to one of the case screws.
Click to expand...
Thank you very much and it is very frustrating lol been kicking my *** for the last couple months
 
Ok so I have gone and check my wire harness and found a couple things but i have questions too. I have not check the voltage because I don’t have a multimeter to do the reading. Would the voltage regulator have anything to do with the start up ?

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