1997 Ski Nautique Ford 351PCM Won't Start

[Peter6000]

I got both of the testers today. I did the spark test and got it to jump about 3/4 of the way. I did the fuel pressure test and it held at about 35 psi. What do I do now? The engine should run in theory but it is not running. One thing to add is that when I go to start it for the first time it kinda starts for about a second but after that it doesn't try to go.

Spark is good, so you get to much or not enough fuel.
It's stops injecting fuel if you throttle goes above 70% while cranking, start for like 10 sec than slowly move the throttle to 100% while cranking.
If it starts you injecting to much fuel.
If not take the spark plugs out if the dry it's not enoth fuel.
Report and we go from there.
Could be a sensor the gt40 only has a few all can be tested with a multimeter.
Look at the first few pages of the pro boss service manual and test them all.
Only the map sensor is a bit tricky it puts out frequency you need a multimeter that can measure Hz.
Getting to the cables can be tricky I have a break our box but if you don't, carfully puch a needle through the cable and tape it up later.
If you Google / Ebay ford gt-40 ecu breakout box you can see what I'm talking about. I got a used one for $50 years back from ebay.

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[97nautique*]

The boat started and ran after I cranked her at 50-100% throttle for about 7-10 secs. It died after that but with some perseverance it ran great at idle. So where do I go from here, is it an adjustment screw for fuel? Like I said in an earlier post, the new plugs that were in for about an hour were darker on the starboard side.

[Peter6000]

The boat started and ran after I cranked her at 50-100% throttle for about 7-10 secs. It died after that but with some perseverance it ran great at idle. So where do I go from here, is it an adjustment screw for fuel? Like I said in an earlier post, the new plugs that were in for about an hour were darker on the starboard side.

Not sure why one side would be darker, however looks like it's injecting to much fuel.
How long did the fuel pressure stay above 30 psi when the ignition in on but fuel pump is off?
If it stays up for at lest 5 min you fuel injectors don't seam to leak.
In that case it could be a sensor.
Test these first, ECT, ACT, throttle position.
If all OK test MAP.
Considering the salt water also check the connectors and clean them with electrical contact cleaner. Include the ecu.
If you unsure on how to test the sensors let me know and I tape a video tomorrow have to work on my engine anyway.
If OK check idle air control valve take it off look inside and turn ignition on it should pull open and move smothly.
If the channel look dirty clean them.
You can also test it by disconnecting it and start the engine but you have to give it a little gas to stay alive.
IAC valve is mounted on the throttle body.




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[97nautique*]

The pressure stayed up for over 10 mins. I have the original owners manual which says how to do them I think, but a vid would be very helpful.

[Peter6000]

The pressure stayed up for over 10 mins. I have the original owners manual which says how to do them I think, but a vid would be very helpful.

You need the pro boss service manual the pdf is here under manuals.

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[Peter6000]

You need the pro boss service manual the pdf is here under manuals.

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I make a video tomorrow

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[97nautique*]

Ok, Thanks!

[Peter6000]

here is the YouTube video hope it helps

https://youtu.be/hFmI-_B9IVs

Peter

[97nautique*]

Just watched it. Thank you for it, will use today and I'll get back here with a reply.

[97nautique*]

So my voltmeter has ohms, but there are like 5 setting that range from 200-200k I think. Either way I don't know which setting to use when I get into the sensors. The limp sensor and ECT look to be new. The boat is starting with throttle at 60% consistently, the manual even says this has to be done at startup. If I run into any problems I will get the right voltmeter and do the tests, but from here I'm gonna leave it. Thanks to everyone with the help again.

[Peter6000]

So my voltmeter has ohms, but there are like 5 setting that range from 200-200k I think. Either way I don't know which setting to use when I get into the sensors. The limp sensor and ECT look to be new. The boat is starting with throttle at 60% consistently, the manual even says this has to be done at startup. If I run into any problems I will get the right voltmeter and do the tests, but from here I'm gonna leave it. Thanks to everyone with the help again.

Start from the high setting like 10k if you have for more precision switch down.


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[Peter6000]

Start from the high setting like 10k if you have for more precision switch down.


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So just to confirm this you start with 60% throttle and than it runs normal?

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[97nautique*]

If I put 60% and start its fires right up and then I bring it to idle. I just went for a slalom run on it about 1hr ago and it got on plane perfectly and towed fine right at 31mph. There are no sputters or coughs when it runs. Like I said, if something does go wrong with it, I'll revert to your video and fix it. And my voltmeter goes in order 2000K, 200K, 20K, 2000, 200. Are you saying the the voltmeter should be used at 2000k for more precise reading? Also, does the negative lead go into the COM jack as pictured in your video?

[Peter6000]

You don't have to buy a new multi-meter here is how you work the settings for resistance (ohm).
As you can see your over all range goes from 0 to 2000k (2000000) and you only have 3 or 4 digits in the display.
If you know the resistance you want to measure select the setting just above the value
example: You want to test a 15 k ohm resistor you need to set it to 20K
if you want to test a switch that's closed the resistance would be less the 1 ohm you set it to 200
If you don't know the resistance of the test object at all, start with the highest (2000k) and switch down until you see a open in the display
then go one back.
The 60% throttle startup is not normal it should start with the throttle in idle position.
Peter

[97nautique*]

Ok I see what you're saying now. Does the negative lead go into the COM jack or the other jack? I will do these tests today if I have time then.