Voltage for my pro-tec swap

It is mentioned in another post that the D.U.I. needs 10.5 V. I have checked every post on the relay and get NO more than 9.7. ( not a place i can use. It is hot all the time)
BATT key on 12.38, start 11.09
TOP RELAY POST key off or on 12.49. Start 9.7
RELAY POST to 12.5 breaker key on 11.5. Start 8.2
RELAY POST TO NUETRAL SWTCH key on 0. Start 7.8
P WIRE key on 11.5. Start 8.3

Is my relay OLD and draging the voltage down? Or the starter?

Once you get the starting voltage fixed you have a couple of choices for the DUI connection. Either use the wire at pin P which is the key switched voltage or wire in a relay. When I do this to my boat I am going to wire in a relay. Using a relay will provide the DUI with as close to battery voltage as possible. The input to the relay would be from the 50 Amp breaker or rewire the 12.5Amp breaker and use it in series with the voltage from the 50Amp. The wire from P would be the control line, the output would go to the DUI and then use one of the ground wires. If you want to go this route I can draw a diagram for you if this doesn't make sense. For the time being just keep following JPASS'es write up. The relay would be easy to add after you finish everything else.

Easy way to check is to remove the wire at the starter and run your test again. Most likely the starter though.

deleted: I was confused

When the starter is disconnected there is less current flowing and therefore less IR (current x resistance) voltage drop. I have never made these measurements but I think regardless of what the starter is doing you should still see the same voltage at the starter relay as the battery or very close.

BATT key on 12.38, start 11.09
TOP RELAY POST key off or on 12.49. Start 9.7
RELAY POST to 12.5 breaker key on 11.5. Start 8.2
RELAY POST TO NUETRAL SWTCH key on 0. Start 7.8
P WIRE key on 11.5. Start 8.3

Interesting. It looks like the voltage now at the P wire (10.1) is higher than what the input was at the top post (9.7) with the old relay. The voltage at the top relay post must have gone up also. Maybe just disconnecting and reconnecting the cables helped also. Looks like your getting close.

Took it to the rebuilder. Gonna be $75 to rebuild. Be ready tomorrow. He has also done the alt and the starter on my old porsche 914. Both are doing great.

Cool thing he actually confirmed that with the new relay i should get a voltage increase and i did get a slight increase thru the relay WITHOUT THE OLD STARTER CONNECTED.

Before I did the DUI I had installed a new relay and a rebuilt starter. Could be the reason I had no problems. My DUI upgrade ran like a champ all summer with no issues. It fires up with gusto every time.

I copied this statement from a DUI technical article on one of the Hot Rod websites.

"Contrary to what some will also say, low voltage, as in still using the resistor or a resistor wire, will not kill an HEI module,. It will make the overall spark weaker exponentially as volts are reduced. After a certain level of volt input lowering, the module will simply stop working from lack of volts, and the system will simply not idle. Once again, low volts will not harm an HEI module, it'll just stop malking spark when it gets to the point it can no longer run on what isn't there. Add volts, it will come back alive again."

So the good news is that if your ignition running voltage is on the low side you are only losing performance not damaging the DUI. I don't think that was the case with the Protec's.

You should probably add any DUI/Protec replacement specific info to the JPASS thread to keep in all in one thread. I doubt anyone will ever search for por-tec. But it's good to keep the side discussions out of his thread.

I know yours isn't running yet so I was asking KROUNDY. I am curious what voltage people are seeing either before or after they do the swap but you are first one to ever post any measurements. Thanks. Once the key is switched to the run position the voltage will come from the key switch/dash/ignition breaker switch so depending on how good your wiring is going to and from and through your dash you may see something less than 11.5. When the key is in the start position the voltage has a more direct path to the battery through the starting relay but that goes away when the key is switched to run. The "I" terminal on the starting relay supplements the key switch voltage to fire the ignition when the engine is starting. I have been looking through DUI info on the internet to try and find a minimum operating voltage but only found the statement that I posted above. The 10.5 starting voltage requirement came from the DUI manufactures website for your distributor but they don't specify a minimum running voltage but since it is a 12V system I would try and get as close to 12V as possible.

desertskier wrote: You should probably add any DUI/Protec replacement specific info to the JPASS thread to keep in all in one thread. I doubt anyone will ever search for por-tec. But it's good to keep the side discussions out of his thread.

I added a link from the ProTec Ignition Swap thread over to this one.

Thanks for the suggestion.

Sooo. A long time ago when my boat only had a few hundred hours on it I had intermittent ignition problems. The engine would hesitate and die under acceleration and sometimes would be hard to start. I could "cure" the problem temporarily by disconnecting, cleaning with alcohol and reconnecting the Protec and engine wiring harness connectors. So I did a little research and found the dash wiring problem which also caused gauge deflection when navigation lights are turned on etc.. although I never measured the voltage it must have been on the low side. After installing additional wires for positive and negative from the engine to the dash and a single wire from the ignition breaker switch to the key switch I have not had any Protec problems since. Engine has about 1500 hours currently. Therefore I believe that low voltage causes Protec problems and may contribute to overall failure of the unit. But I don't believe that all years of Protec boats have dash wiring problems. That's why I'm curious what voltage readings people are seeing. If the running voltage is close to battery voltage then you can follow JPASS'es write-up and it should work just fine. If you have low voltage then there are a few ways to fix it and none of them are very difficult. The starting voltage issue is something I had not thought of until reading the DUI website and is a separate issue from the running voltage. I originally posted the wiring instructions that JPASS used in his write up but as we learn more about the system I think it's worth making sure we are installing the DUI correctly and getting max performance. I think the best conditions to make the reading would be on the lake under load at high RPM but if it is good at idle in the driveway that is a good sign.

It looks like the fusible link is there to disconnect the ignition circuit from the starting circuit if a short occurs when the starter is engaged. If you connect your DUI wire to "I" instead of 26 you would need to either leave the connection at 41/42 on the breaker or connect them together and remove the breaker. I don't think I would remove the fusible link unless you replace it with a fuse. If you connect the DUI to "I" and leave the fusible link (or a fuse) and 41/42 connection then you have removed the fusible link from the starting circuit but you have added it to the running circuit. With the original wiring there is no current flowing through the fusible link when the key is in the run position only in the start position.

Correction - I did test the voltage when i was doing the installation. I remember this now. Forgive me as I'm fighting a cold and drugged up on cold meds.

I ran out to the garage just now and without the engine running I get 11.9 at the relay and 10.9 at the wire going into the DUI.

I have a lot more clearance than you on that t-stat hose. No issues there at all. Like JP, I thought this was a pretty simple install. Put it in and it worked great right out of the box.