Hot wire for D.U.I. distributor -where to connect?
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Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=49280
Printed Date: November-21-2024 at 10:49pm
Topic: Hot wire for D.U.I. distributor -where to connect?
Posted By: uncle-buck
Subject: Hot wire for D.U.I. distributor -where to connect?
Date Posted: September-26-2020 at 4:26am
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Ordered a DUI distributor, but am not sure where to connect a hot wire to power it. Boat is a 1990 Ski Nautique with PCM Ford 351W. I know it needs to be connected to a terminal that's only hot when the key is in the ON position. Would that be the wired end of the (bypassed) ballast resistor or does someone have a better idea? Thanks |
Replies:
Posted By: SNobsessed
Date Posted: September-26-2020 at 6:07am
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I would use the original ignition 12V wire ( I think it is purple, feeds the ballast resistor) unless you think there is someting wrong with it, like corrosion.
------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: uncle-buck
Date Posted: September-26-2020 at 6:32am
| The manufacturer recommends a separate hot wire. |
Posted By: SNobsessed
Date Posted: September-26-2020 at 6:41am
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Separate from what? Won't the purple wire only be feeding distributor & choke? Should be able to handle that.
------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: 8122pbrainard
Date Posted: September-26-2020 at 6:49am
I agree but the only way to use a seperate wire is to add a relay. Here's a wiring suggestion from DUI.  ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
SNobsessed wrote:Posted By: uncle-buck
Date Posted: September-26-2020 at 6:50am
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With all due respect, I'm asking how to run a new hot wire from a switched 12 volt source to the distributor. BTW, I like your tagline. There are few things better than a nice cold beer on a hot day. |
Posted By: GottaSki
Date Posted: September-26-2020 at 6:53am
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I use a relay to power the choke and the alternator energize. This frees up the purple wire to juice only the msd energize and the relay You could do something similar and not have to run another wire from dash ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: uncle-buck
Date Posted: September-26-2020 at 6:58am
Thanks. How can I get more info. on your setup? I don't know much about relays or wiring. |
Posted By: GottaSki
Date Posted: September-26-2020 at 7:00am
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Don't relay the ignition because during cranking the voltage drop won't permit the relay to apply power to ignition and it will sometimes fire only when you stop cranking , if you are lucky ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: GottaSki
Date Posted: September-26-2020 at 7:06am
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If electricity isn't your bag, I can understand I'm not able to draw something out for a while, but your added relay is switching in 12v constant at the engine to the choke and alt. A little plastic hella 20A is all it takes ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: uncle-buck
Date Posted: September-26-2020 at 7:11am
No hurry. The DUI distributor isn't scheduled for delivery until mid-October. Thanks
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Posted By: 8122pbrainard
Date Posted: September-26-2020 at 7:14am
"Typical 12V automotive relays have a "pull in" voltage around 8V and a drop out voltage somewhat lower." If there's less than 8 volts during cranking then I'd say there are other problems with the electrical. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: GottaSki
Date Posted: September-26-2020 at 7:19am
Real world conditions say someday a labored start occurs and the relay won't see enough voltage to close then one trying to start with the ignition off. I stand by ignition must not be relayed ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: 8122pbrainard
Date Posted: September-26-2020 at 7:25am
Tom, Don't get me wrong as I agree with your recommendation. I'm just saying if there is less than 8 volts then there are othet problems. Here's the same directly from Bosch: "The pull in voltage is the minimum voltage required for the relay coil to pull the contacts (30 and 87 on the Bosch relay) together. The pull in voltage is about 8 volts for a typical Bosch relay."
------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: KENO
Date Posted: September-27-2020 at 5:23am
I think you meant to say a terminal that's hot in the ON and START position otherwise it isn't gonna start very good  You could probably do a search and see how many people have used a relay to power their DUI, then you could wire it like SNObsessed said Hook the tach wire in the harness to the DUI tach wire and hook the coil supply in the harness (it's 12 gauge wire) to the power wire for the DUI with the resistor bypassed or like you asked above, the wired end of the (bypassed) ballast resistor works just fine if you want to do a separate wire. If you want maximum voltage to the distributor when cranking the engine a short bypass wire from the "I" terminal on your starter solenoid(relay) to the power wire will provide that voltage while cranking and when the key goes back to ON the "I" terminal has no power (in your 90 SN with a carburetor and distributor) and the alternator is now working and putting out 14 volts or so and the distributor is happily making sparks.. I've done them with and without the bypass and the bypass is a little extra insurance to give the best voltage when cranking. If you want a little drawing or picture, let me know.
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Posted By: KENO
Date Posted: September-27-2020 at 5:39am
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If you really want to cut down on voltage drop while starting the engine, get yourself a PMGR starter. Smaller, lighter, turns the engine over faster and doesn't draw nearly the current that the earlier Ford starters do. Maybe you have one, but I didn't see that in your list of replaced parts in the "drive me to drinking" thread. A good starter and part number would be Arco 70200 for your normal rotation engine.
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Posted By: desertskier
Date Posted: September-28-2020 at 1:50pm
On my '92 I ran the positive wire for my DUI directly from the 50amp breaker on the engine through two relays. I used the old ignition wire as the relay control voltage. It comes directly from the ignition key and is also connected to the "I" terminal through the old fusible link exactly as came originally. I didn't add any new wires to the dash. Not sure if a '90 has the link or not although I doubt you need it. Ran it for the last two summers with zero problems. This was a Protec conversion so the wiring is a little different than a '90. The Protec system has two fault sensors which a '90 doesn't have. I wired the old over temp fault sensor to the second relay so the engine shuts off if it overheats. The third relay in the picture is just a spare. ------------- 92 SN - Owned since 93 99 Pro Air 89 SN - Went to live on a lake in Texas 75 Donzi 16 - Sold in 93 |
Posted By: KENO
Date Posted: September-28-2020 at 3:14pm
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50 amp breaker................ it's a distributor not a small welder
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Posted By: Riley
Date Posted: September-28-2020 at 3:29pm
| So, converting a PCM engine to a DUI and stacking the purple wire, the orange wire to the starter, and the wire to the DUI on one end of the no longer needed resistor is wrong as there might be too much voltage drop to the DUI? |
Posted By: KENO
Date Posted: September-28-2020 at 4:58pm
 I think you mean the purple wire, the green wire to the alternator excitation and the red to the choke all being from the same spot and you're wondering if there's too much voltage drop for the DUI distributor. Not on the DUI's I've wired, they've worked fine. You can put in the jumper from the "I" terminal to the coil wire for a little extra insurance that you get the max voltage to the coil when cranking the engine. |
Posted By: Riley
Date Posted: September-28-2020 at 6:00pm
| Wire colors are as I posted, but there is no choke wire. The orange wire to the starter is actually to the solenoid, so it must be to the I terminal. I added an hour meter to the stack, so hopefully it won't cause a problem. Guess I should put a meter on it while it's running. |
Posted By: KENO
Date Posted: September-28-2020 at 8:12pm
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DUI says their HEI draws 2 to 3 amps See the first FAQ in the link below
http://performancedistributors.com/faqs/" rel="nofollow - link |
Posted By: Jonny Quest
Date Posted: October-02-2020 at 1:04pm
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On my 1994, the PCM factory wiring used the starter switch solenoid “I” terminal as the ECM power feed for ProTec. This was a key on/start switched power source. When I removed ProTec, I used the “I” terminal for 12V power feed to the new dizzy. It worked very well for my DUI conversion. I did run a 20 amp in-line breaker...just for fun. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: KENO
Date Posted: October-02-2020 at 4:23pm
JQ This is like deja' vu all over again.............you're the only person in the world that had a solenoid with an "I" terminal that magically supplied power from internal to the solenoid when the key is in RUN It only gets powered from internally when the key is in START
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