Engine Dies around 1/2 tank of gas - Help Needed

Well done.   You'll continue to be amazed at how well the 351W HO runs on "old school" systems.

JQ

Update - Switched the PORTEC out today and hooked up (I helped someone who actually knew what they were doing) the PCM RETRO KIT. After much advice and several discussions regarding cutting wires, timing, timing curve and a lot more stuff I know nothing about I made the choice to to with that unit. Mainly because it is OEM, I can get support if I need it and it is a "known entity" That being said thanks for all for advice and problem solving you guys provided. This is an awesome community. Now the good part -

Boat Ran Like a CHAMP!!! It hasn't run this good since I bought it. I just didn't realize how bad it was running. It sounds like a sewing machine under there now. Starts up quick, temp stays good (Used to say it was running hot - PROTEC?) IT screams out of the hole and the acceleration is awesome.

The install was pretty painless - Note: The person who helped me also builds drag cars for a hobbie. Start to finish was less than three hours and it took about 15 seconds to set the timing and we were done.

Issues - The only issue we had was the cover (Where PROTEC used to be - covers ballister, 50 amp etc...) didn't want to go over the wires and fuses and stuff. Slight mod and good to go. I can post some pics but they are pretty uneventful. Looks like a normal engine..

Thanks for all the help guys!!!!!

desertskier wrote: Swapping to the DUI is a good idea but if you want to try something while your waiting for parts. Locate the 12.5 amp breaker on the aft of the engine near the coil pack. Turn on the key and measure the voltage. It should be close to battery voltage, 12-14Vdc. If it's lower than say about 10Vdc it may be that the Protec unit is not getting sufficient operating voltage and intermittently going into limp mode. I had this problem a long time ago and was able to fix it with some wiring changes. My Protec is still working at 1500hours

Thanks. I will check that out this evening.

It can't.

I wouldn't bother with a new harness unless you need a new harness. The protec has extra sensors/switches but will not harm anything to leave them be. Neither harness will give you the exact wire/connector needed for the DUI. It is easy to add/modify in either case.

Bri892001 wrote: 91NaughtyQ wrote: Bri8g2001 - Does that harness allow me to skip cutting any wires when installing the DUI? ... Thanks. Orlando76 wrote: The DUI doesn't use a wire harness. It only requires a hot and a neutral. Jonny Quest wrote: ...And, NO, the harness on skidim is not designed for the DUI /HEI unit, but rather for an external coil & distributor unit (like the Mallory). JQ Everyone is correct (including me). Yes, that wiring harness would allow you to skip cutting wires. Yes, the DUI only requires a hot and a neutral. But, you still need: *to get a positive (red) feed to the dash *a switched (purple) feed from the dash (key) to the ignition *ground (black) to the dash *distributor signal (grey?) to the tachometer *oil pressure sender signal to the dash *water temp sender signal to the dash *alternator output to the battery *ignition voltage to the alternator for the exciter line if you have such an alternator *trouble light alarm signal to the dash (works of oil and temp switches) Did I miss anything? I'm not sure, there's a lot of wires Yes, correct, this harness is not specifically for the DUI. It is closer to the correct one for an electronic distributor and coil (non ballasted) setup. But, it provides an ignition source for the dizzy, and takes care of all the functions I mentioned above.

Hmmmm...When I swapped out my ProTech AND my Throttle-body Fuel injection, I yanked everything off that had to do with ProTech and the TBI. I took all the ProTech wiring and associated breakers off. Gone. I did keep the sensors in place -- just removed the wiring.

As I recall, there was no need to re-wire a bunch of systems that were related to the ProTech. Here is what I did:

- positive (red) feed to the dash - This comes in from the main wire harness into the 50 amp breaker and starter switch / solenoid

- ground (black) to the dash - This comes in from the main wire harness and I ran a new wire to the block and joined to the existing ground wires.

- distributor signal (grey?) to the tachometer - This comes in from the main wire harness and I ran a new wire to the DUI tach terminal. You are correct, it is a gray wire.

- oil pressure sender signal to the dash - Is not affected by the ProTech wiring harness and connects directly to the main wire harness. (Oil Pressure sensor for ProTech was left in place, but wire was disconnected)

- water temp sender signal to the dash - Is not affected by the ProTech wiring harness and connects directly to the main wire harness. (Water temperature sensor for ProTech was left in place, but wire was disconnected)

- alternator output to the battery - Is not affected by the ProTech wiring harness and connects through the 50 amp breaker and then to the main wire harness.

- ignition voltage connects to the main wire harness.

- trouble light alarm signal to the dash (works of oil and temp switches) - This alarm no longer functions.

CC even put the unused positive and negative wires for the electric choke in the wire bundle. All I had to do has hook 'em up.

The DUI positive input is wired directly to the "I" terminal on the starter solenoid / switch. I used 12 gauge wire with an in-line fuse.

I've slept since then, so some of the details are a little fuzzy...     I can double-check when I get back to the garage.

JQ

It's a simple 3 wire hook up. No other wiring changes needed to keep all the functionality you mention above. If it were my money, I'd skip the wiring harness. The wiring portion of the swap is pretty simple and straight forward.

Thanks Johnny quest. Appreciate all of the help.!!!

JPASS - So with no distributor I would have it sitting on TDC for number 1. It should look similar to the pics. Got it. After that then install the DUI and advance or retard to get it to 12 degrees BTDC at idle and it should also be 34 degrees BTDC at 3k RPM. When that is achieved tighten up recheck and if all is good I am set?

91NaughtyQ wrote: JPASS - Sounds great. I think I am going to order the live wires with the DUI. I do have one question as to the timing. With the DUI it is my understanding that I want to set the timing at 700 RPM on the DUI and that should do it. Please take a look at this pic and help me understand what that should be and where I initially set it before I crank that motor. Super newby to the timing stuff so I am asking a ton of questions..

Timing should be 12 degrees at idle and about 34 degrees at 3K RPM. You may have to make some slight adjustments, but that should get you close.

Notice the position of the cap in the pics in the install thread. If you're at TDC on cylinder one and install the new DUI, yours should be similarly positioned like the ones in the thread. If it's way off, you may want to double check things.

JPASS - FYI

I printed out your instructions and have been reading up on the process. Thanks for posting.

While you're waiting for your parts to arrive, I'd go check the wiring harness at the coil pack and trigger plug at the current dizzy.

Read the wiring portion of the instructions and confirm your hot, signal, and ground wires. If you have questions, post pics. That will help us help you.

I would get some dielectric grease for your new wires. If you need to make your own, don't worry, it's way simple.

Maybe pick up some wire organizers too.

The DUI doesn't use a wire harness. It only requires a hot and a neutral.

Does anyone know if the wiring harness on skidim makes it "plug and play"?

If in stock I will not worry about the color. Tried to take the boat out again today (I know it is a roll of the dice) and it died again after a bit. Odering DUI tommorrow.

I'd recommend that while you are installing the DUI, and adding new plug wires you put in a fresh set of plugs. Be sure to gap them per the DUI instructions. You will need a timing light to do the job. You can buy one or borrow one. If you lived closer to Washington I'd come help you. I found the DUI job to be a lot of fun and relatively easy to do. Follow the instructions in that link precisely and you'll have no problems. I actually printed them out and had them right there by my side.

It takes some time to get your DUI. I think it took about two weeks for my order to arrive. At the time they were backed up and they build and test every unit. It is high-quality stuff. My engine fires and runs with some real gusto now. I think you'll find this to be a good choice.

At the end of the job be sure post a photo and add your name to the list of guys who have done the DUI swap in the DUI instruction thread.