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

[DesertEscape]

I'm stuck trying to get my 1994 Ski Nautique with the 351 Windsor, Pro-Tec ignition and EFI (4 throttle body injectors) running for the 2nd time. It started on the first attempt last week after I put the engine back together having rebuilt the top end Before my first start attempt, I set the timing to 10 degrees BTDC using a timing light and cranking the engine over with the starter with the fuel pumps unplugged. When the engine started on the first attempt, I was thrilled! I ran it for about 5-10 minutes making sure the 160 degree thermostat I installed was working correctly. The timing was right at 18 Degrees BTDC at 700 rpm which was right in line with the factory specs. Some friends of mine who were present during the first start convinced me to retard the timing back to 12 degrees BTDC at idle which I did and the engine seemed to run a little better at idle and during acceleration under no load conditions on the driveway using a "fake lake" water cooling. When I attempted to start the engine the next day, I couldn't get it started after 10-12 attempts. I let it sit for three days and today set the initial timing back to 10 degrees with starter cranking thinking that the the retarded timing was hurting my ability to start.....So now it's set right at factory conditions and exactly where I had it set before my first engine start and I still can't get it to start....I could really use some fresh ideas on troubleshooting at this point as I'm baffled!

A little more background detail on the boat and engine. I bought it from a brother who hadn't used it in 9 years in Indiana where it was stored in a warehouse. After towing it to Arizona last fall, I took it out in November for a lake test and it ran pretty rough (at idle and during initial acceleration) but cruised nicely on the lake. After doing some compression and leak down tests, I decided to pull the heads and have them machined. The piston bores looked really good on inspection with no visible wear so I decided to leave them alone and just focus on the heads. The machine shop said the valves were holding vacuum fine and didn't need machining so they just installed new valve seals, freeze plugs, and machined the decks. I installed new head gaskets, intake manifold gaskets, exhaust manifold gaskets, and all new cooling hoses.

When I attempt to start it, the engine acts like it want's to fire but just will not start. On some of my attempts, it's backfiring and couple of times started to race up but did not stay running.

Any and all advice would be appreciated!

Hoping to get it on the water later this week

[NautiqueJeff]

Without seeing it, my first guess would be that the Pro-Tec ignition is failing. I am surprised yours worked at all as old as it is. Most of those have failed by now.

Here's the kit needed for conversion:
https://nautiqueparts.com/electronic...pcm-rk107025a/

[DesertEscape]

I realize the Pro-Tec systems are failure prone but it seems unlikely to me that the engine would run one day and not the next. Before my engine start attempt today, I removed the spark plugs and cranked the engine with the starter motor and tested each spark plug wire with my timing light and all 8 seem to fire consistently. I placed a spark plug in the spark plug boot and attached a ground wire between the electrode ground and my engine ground. Based on this simple test, I convinced myself the ignition system was working ok. I'm leaning toward fuel delivery and specifically excess fuel based on back firing. How would I test the fuel delivery injectors to determine if my fuel delivery schedule is consistent with starting conditions?

Thanks

[jpwhit]

Back firing is typically an indication of the ignition is firing at the wrong time, not excess fuel. Excess fuel typically floods the engine and suppresses firing at all because the plugs get too wet with fuel.

[Jonny Quest]

Check your PM

[s_kelley2000]

Is it possible that anything changed with the firing order between the first start up and the next day? Or was all of the spark testing done after the no-start issue cropped up?

[DesertEscape]

"Indy" is back from the dead and breathing again! It's a little (ok a lot) embarrassing to admit but the dead man's kill switch lanyard was disconnected and I didn't notice it. One of must have pulled it by accident getting in or out of the boat.

What is weird is that the engine actually runs worse after warming up than it does right after firing up. I wish I knew more about how the EMS system works on this Pro-Tec/ Pro Boss EFI motor! I know on my 1995 Isuzu Trooper which has a similar control system with similar sensors, it has an "open loop" control during start up and then switches to "closed loop" following warm up.....so it feels like maybe something is happening in the closed loop control on the EMS which tells me I may have a sensor issue or something on fuel delivery. Does anyone know if there is a better control schematic/wiring diagram available for this motor? The "Engine Wiring Diagram 351 Ford Pro=Tec" that's in my engine manual doesn't exactly match my ECM and, of course. Any suggestions on "tuning"/troubleshooting

[Scooter G]

Good find, I think the kill switch has gotten all of us at one time or another.
From everything I've read, not expert in this arena, but I would go back to Jeff's Pro-Tec comment...

[Scooter G]

Good find, I think the kill switch has gotten all of us at one time or another.
From everything I've read, not expert in this arena, but I would go back to Jeff's Pro-Tec comment...

[SilentSeven]

What is weird is that the engine actually runs worse after warming up than it does right after firing up. I wish I knew more about how the EMS system works on this Pro-Tec/ Pro Boss EFI motor! I know on my 1995 Isuzu Trooper which has a similar control system with similar sensors, it has an "open loop" control during start up and then switches to "closed loop" following warm up.....so it feels like maybe something is happening in the closed loop control on the EMS which tells me I may have a sensor issue or something on fuel delivery. Does anyone know if there is a better control schematic/wiring diagram available for this motor? The "Engine Wiring Diagram 351 Ford Pro=Tec" that's in my engine manual doesn't exactly match my ECM and, of course. Any suggestions on "tuning"/troubleshooting

Not a protec guy by any means but a few observations.

'Open loop' and 'closed loop' typically refer to engine with exhaust O2 sensor(s). The O2 sensors feed the ECU which will then trim the fuel settings based on the sensor reading. Open loop is typically during the startup cycle when the engine runs rich by design and you don't want the ECU to trim the fuel. Closed loop is when the O2 sensor input are used by the ECU to trim fuel and timing, is the normal run state for the engine and engages at some point during warmup. None of this applies to your engine as this engine does not have an O2 sensor.

If your engine runs worse after warmup, inspect the circuit that feeds the ECU run temps. If that sensor circuit is not telling the ECU to move to the warm run cycle, the engine can run poorly. Typically the cold run cycle is ended by either a dedicated engine temp sensor or the coolant temp sensor. Suggest you try ID the sender, make sure there's no corrosion, verify the wiring is connected and the sender outputs are in range.

Maybe someone else can help you with a Protec specific manual....

[DesertEscape]

SilentSeven, I appreciate the explanation on how the ECMs work on my vintage Nautique. With a lack of documentation out there, It's really a black box as to what's really inside the ECM and how the control circuit works. I wonder if there were service manuals and instructions given to dealers who worked on these systems?

Latest update with a couple of fun pictures:

My automotive technician neighbor came over last week and we did some troubleshooting together on the 351 Windsor with the ProTec ignition. We're both pretty convinced one of the coil packs is going bad on the ProTec module. When we moved our timing light from one cylinder to another, we couldn't get the light to trigger on the number 3 cylinder and the number 5 cylinder seems to be triggering erratically. The coil pack is firing but just seems weak. We thought about swapping the two coil packs on the module to see if the problem follows the swap but the torx screw heads on the coil packs felt like they were going to strip out and I didn't want to loose the engine totally as we had lake trips planned on Thursday, Friday and Saturday The engine is still idling rough but runs decent at cruising speeds but is not as smooth as it should be!

When my son arrived from out of town, we customized an 8 foot long bimini we picked up on Amazon to mount on the boat by shortening the poles. This is probably the best upgrade we've done on the boat so far! It was around 100F at the lakes and the shade was primo with this new bimini. We had to slant the mounting location of the rear struts forward to allow for more swing of the wakeboard rope on the pylon which worked out well.

We enjoyed the time on the lake but I will say I was a little nervous on 3-4 occasions on our third day of boating when the engine stalled while idling. Fortunately, we were always able to start the engine in neutral, throttle up, and keep it running. I believe it's running too rich at idle and low power conditions with the poor Pro-Tec ignition condition and building up unburned fuel in the number 3 (and possible number 5 cylinder)

I did have a wild idea about an interim fix for the ProTec. My neighbor and I were pretty confident that the PCM ProTec ignition coil packs were actually parts from an automotive application and packaged as part of ProTec by PCM. After doing a bunch of online sluthing owever, we couldn't find any match of an automotive "Wasted Spark" coil pack that matches the form factor of the PCM ProTec quad packs. We reached the conclusion that PCM must have had these coil packs specially made for them which is shocking given the relatively low production volume of boats compared to automobiles.

Here's the wild idea: What if we were to remove the existing ProTec coil packs from the control module and attach external quad coil packs from an automotive application (both Chevy and Ford made quad coil packs) and make the electrical connections with spade connectors and wiring? It seems like it would work and wouldn't cost much money. My assumption is that the problem is in the coil pack itself and not in the ECM module. I also understand that the PCM ProTec coil packs are no longer available for sale. I'm still planning on retiring the ProTec ignition system but I actually like the idea of maintaining the fault monitoring of the ECM for low oil pressure and high engine temperature with the factory ECM and don't want to loose that functionality. Has anyone tried this before?

My go forward plans for the boat:

1. Replace the ProTec ignition with a DUI marine distributor. Maybe try the automotive coil pack hack as an interim while waiting for new Distributor parts.
2. Install a Fresh Air Exhaust system.
3. Locate and install a pylon extension pole so we improve wake boarding and wake surfing options.

I welcome any feedback!

Mark

[NautiqueJeff]

I would be extremely careful putting non-marine parts in your engine box. There is a reason PCM had their own coil packs made. Just do the conversion the right way and be done with it. It is safe, and most people who do it say their boat runs better than it ever has after the conversion is done. See my link above.

[DesertEscape]

Appreciate the feedback Jeff. I don't want to do anything that will compromise occupant safety. After installing the PCM ProTec conversion kit, will the engine projection features for low oil pressure and over temperature be preserved as well? I'm assuming this kit only affects the ignition system. I currently have the EFI/ throttle body fuel injectors on this boat that would not be impacted by the conversion.

Thanks,

Mark

[NautiqueJeff]

That should all be preserved.

[DesertEscape]

Jeff, Is this connector schematic and operational description you've shared contained in some kind of ProTec manual that is available to boat owners? I've not come across anything this detailed in a PCM engine owners manual.

I'm 99% confident (I always hold out 1% just in case there's something I didn't think of) that the ProTec ignition module is bad on at least one quad pack so I'll be doing a conversion and taking out the ProTec module and pick up sensor. It would be nice to have an overall schematic of the "as is" ProTec system that's accurate.

Thanks for your help!