Engine won't start again after a successful first attempt-advice?

[mpost]

The manual that Jeff got the picture came from is here
GT-40 Service Manual.pdf

[SilentSeven]

DesertEscape - regarding a coil hack for the pro-tec model....if any hack was possible, it would have been discovered by now. This is not a new problem, it's caused lots of pain, isn't exactly cheap to resolve which means that just about every possible alternative has been explored. I'm with Jeff - just replace it and move on. "Buy once, cry once".

Just think about enjoyable your boat will be when it runs great and you don't have to worry about getting back to the dock!

Here's what the kit includes. Board discount code PND10 will save you 10%.

https://nautiqueparts.com/electronic...pcm-rk107026a/

[DesertEscape]

Thanks mpost for the GT-40 Service Manual and SilentSeven for the suggestions. this is exactly what I was looking for!

I'll be replacing the ProTec ignition system as suggested but I want to keep the electronic fuel injection for the time being and not put a carb in just yet, Step #1. If the ECM that controls the EFI fails in the future, I can take /Step #2 and go with a carb setup. I'm hoping that the lower power electronics needed for the EFI control will give it more longevity but we will see how that goes

[DesertEscape]

Upon closer examination, it does look like this GT-40 Service manual is for the next generation EFI system that has individual multiport injectors whereas my boat uses the 4 injector pod/throttle body injection system but it will be very helpful and is infinitely better than the engine owner's manual.
Thanks

[Tom_H]

You'll have to go on CCfan to find it, but about the only way to keep the TBI is to step down the distributor square wave signal from 12V to 4V. I just swapped out my protec/tbi a few days ago for a DUI and a Quick Fuel M600. The boat runs really well comparatively, and I'd recommend just going that route. If you want any of my protec take-offs, you're welcome to them, but I think you're just kicking the can. If you go back to a carb, you will lose the limp/slow mode protections that fed into the ECM, but your dash gauges (temp and oil pressure) will still work fine (as they're fed from different senders that the switches that fed the ECM). It's possible to wire those switches into an audible alarm or an ignition cutoff though.

BTW, one sure sign of the Protec failure is if you have epoxy leaking out of the coil module (down the mount plate, and likely onto the bell-housing/transmission - and is likely why your screws were difficult as it gets on the threads and semi-hardens). Once you see that, it's pretty much done. With a timing light, mine was all over the map on spark and very erratic on each cylinder.

[Tom_H]

Also, the wiring diagram for the Protec is attached (ignition side). This doesn't show the ECM/TBI wiring though (ignition side harness only). You can reuse this harness to connect the DUI by cutting off certain wires at the EMS plug and connecting them, and then connecting the applicable ones at the Trigger plug connector to the DUI (basically just 12V and tach signal). Look up a thread on ccfan by Jpass for Protec Ignition Swap which will have all the details for what wires to connect.

[DesertEscape]

Tom_H, Thanks for the info on your ProTec experience and upgrade. I received my DUI electronic ignition earlier this week and finally got time to install it today. I used the JPASS instructions which were pretty straight forward using the wires from the ProTec distributor pick up device. When I pulled off the ProTec coil pack/electronic module, my unit was also leaking epoxy out the case. I also had very eratic firing based on timing light strobe patterns. I haven't fired up the engine as I was under the impression that I could keep my Throttle Body Injector (TBI) fuel control system and use the new integrated distributor/ignition system. Your comment that I will need to modify the "distributor square wave from 12 Volt to 4 volts" tells me that my new DUI ignition system puts out a 12 volt square wave on the "Tach" terminal which must be different than what the ProTec system was doing. Are you saying that the primary ECM that controls the Throttle Body Injector fuel controls want's to see a 4 volt square wave vs (and I'm making an assumption here) a 12 volt square wave that the DUI will put out?

Thanks for your help! I'm looking forward to getting this boat back on the water with a reliable ignition system!

Mark

[Tom_H]

DesertEscape From what I understand, the trigger unit was sending a 4V square wave signal, whereas the tach output on the DUI is a 12V. For the ECM to be able to recognize the signal and fire the injectors accordingly, it needed to be stepped down to a 4V. This is the thread I was referring to on CCFan https://www.correctcraftfan.com/foru...h-a-dui-system

For me, it wasn't worth the effort to try and keep the injection, as the injectors and many of the sensors associated with it are either obsolete or very hard to come by (i.e. knock sensor), so kind of figured I'd be down the carb road eventually. If you want any extra parts, hit me up. Cover shipping and maybe a few bucks for beer, and they're yours (throttle body w/injectors/IAC/TPS/fuel pressure regulator, entire FI wire harness, low/high pressure pumps (which were both new in the past couple years), ECM, MAP/ambient pressure sensors, etc.). I didn't plan on pulling the water temp switch, oil pressure switch, or knock sensor out, but I can pull the knock if needed. The other two are pretty readily available yet.

[DesertEscape]

Tom_H

Thanks so much for the reply and links to the correct craft fan threads on modifying the DUI signal to be compatible with the EFI ECM. This is very helpful and will allow me to finish the installation! It's good to know someone else has added a DUI distributor and was able to keep the PCM factory EFI system. I will send you a PM on your offer to take the extra Pro-Tec hardware which is very generous.

Mark

[DesertEscape]

I just wanted to follow up with a successful report on my 1994 Ski Nautique with the PCM 5.8 HO engine with throttle body fuel injection. Thanks to this forum and the folks on the Correct Craft Fan forum, the boat is running good! A big Shout Out to Johnny Quest, Tom_H , JPass, SilentSeven and MikeWolf (and others I might have missed) for helping me get this boat running like it should! The ProTec ignition has been pulled out and replaced with a DUI (Davis Unified Ignition Marine version ) ignition module/distributor and still uses the factory throttle body fuel injection system. The key step for making this work was creating a voltage divider circuit shown in the schematic below and the photo of the homemade module I made using a terminal block to mount the resisters to providing a more stable mounting scheme for this new tach signal voltage reduction "module". I used 1 watt resistors that are connected to the terminal block that should have plenty of power capacity. I calculated that the resistors are consuming less than 0.1 watts each. The voltage divider circuit should be reducing the 0-12 volt square wave tach signal coming from the new distributor to slightly less than 0-4 volts for the fuel injector controller circuit. I wired everything up initially using wire nuts and the engine started on the first crank using my "fake lake" hose cooling. After running it for 15 or 20 minutes to make sure everything looked good, I connected all the wires more permanently.

I took the boat out late last week with a buddy and we put it through the paces in about an hour without any issues that we could tell. It idles nicely and comes up to full throttle nicely. My hope is take the boat out later this week for a full load test.

Several on the forum have advised me to pull the electronic fuel injection out of the boat and replace it with a carb since the EFI parts are no longer available, which I may end up doing eventually, but I really wanted to take a big half step in that direction first since the EFI still seems to work ok and my throttle body injectors are working well for the time being.

Hopefully the EFI control module and components will stay alive for awhile!

Mark

[SilentSeven]

Interesting. Thanks for the followup....I'm always amazed at the workarounds that people have created.