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engine wont turn off

2K views 6 replies 4 participants last post by  JeepHammer 
#1 ·
since i installed my new DUI distributor the engine wont shut off when i turn the key off. I have it on a relay exactly the way the instructions say. Anyone know whats wrong?
 
#2 ·
My first guess would be the relay is stuck. Try testing with a volt meter and see if it's putting voltage out with the key off. If it's not is the relay wired correctly? If both those check out see how long it runs with the key off as there may be some residual charge that isn't dissipating.
 
#3 · (Edited)
Since you didn't post the instructions or link to the instructions, we have NO IDEA how you have things wired.

If you didn't install a power relay to feed the HEI, then it's not putting out at it's full potential anyway.
That's probably a blessing, when they do put out at full coil potential, they usually just arc away inside the cap like crazy anyway...

Close your plug gap up to about 0.045" and you will avoid a TON of problems in the long run!
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My first guess would be the relay is stuck. Try testing with a volt meter and see if it's putting voltage out with the key off. If it's not is the relay wired correctly? If both those check out see how long it runs with the key off as there may be some residual charge that isn't dissipating.
Nope, only about 1 chance out of 1,000 that he has a power relay in the circuit and if it's DUI's instructions, I know he doesn't have a relay in the circuit.

Chances are he's converted over to a Delco SI alternator and didn't tell us about it!

Run On with a Delco SI alternator is just another one of those 100 or so Problems with DUI and the other HEI clone makers don't tell you...

You will have to install a diode in your alternator wiring to get your distributor to shut off.
Once started charging, the alternator is back-feeding your ignition circuit.

There is an easy way to get it stopped and I'll post it when I find the pictures...

Diode, Radio Shack p/n 276-1144, small crimp connectors from Radio Shack also.
Plug/Pig Tail available at any of the auto parts stores.




This arrangement takes the place of the resistor wire, so you can just add the diode, or fully replace the resistor wire entirely like the picture shows.
 
#4 ·
If its not what JeepHammer said to check then my money is on this....if you are running an electric fan disconnect the + wire to that fan and start the Jeep...then turn it off...I bet it shuts right down. Or your blower motor for your a/c - heater is back feeding the realy the 12 volts and causing run on. A dc motor self generates power as it rotates. All you need to do is put a diode inline with the + feeding your fan if this is the problem. If there is a better way to correct this please correct me Jeep Hammer.
 
#5 ·
Finding a common diode on the consumer market to handle fan currents can be a real pain!...
Isolating your fan feed from the ignition circuit would solve the problem.
Run your fan off an accessory circuit so it's disconnected from power when you turn the key off, just like the ignition circuit is.

Another way would be to use a power relay that is diode protected...
That will keep the fan source separated from the ignition switch or accessory wiring.
 
#7 ·
If you used the old coil wire, you need to install the diode as shown in my first post.
It's a quirk of Jeep and Chevy wiring that you need to use a diode when adding a power relay.

Grounding to the engine block is fine, as long as the engine has a good ground, which isn't always the case.
 
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