Engine Repair - Intermittent No Start

Intermittent No Start

Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=51597
Printed Date: November-21-2024 at 10:44pm

Topic: Intermittent No Start

Posted By: modularman
Subject: Intermittent No Start
Date Posted: May-31-2024 at 1:03pm

Hello Everyone. This is a great post. Lot's of great info on here. I have a question. I have a 1995 SN GT40 Pro Boss with a weird issue. When I recently bougt the boat, it would have an extended crank when cold, but once it started all was good. Once it was warm, it ran and started well. Then the other day I took it to the lake and it all of a sudden had a weird crank, start immediately, run for one second then shut off issue. It would do this over and over. This probem cropped up simply by towing it to the lake (so I am assuming the vibration/bouncing on the trailer made something electronic unhappy). I have replaced the ignition switch, bypassed the lanyard switch, replaced both relays, swapped the ECU for a known good one, checked engine grounds, verified battery voltage, voltage at the ignition switch, and voltage at pin 30 of the fuel pump relay lead. All test good. My boat does not have the 50 amp fuse in the battery box, fyi. As I have been going through the testing procedures over the past few weeks, I have noticed different symptoms. Sometimes I have intermittent power to the fuel pump relay, other times its dead. The new relays I bought have a power light on top of them. With the key on, engine off. the relay for the ECU has a strong consistent 12v signal. The relay that controls the fuel pump and spark will flicker and as it is flickering, you can hear the fuel pumps intermittently priming and the coil firing inside the distributor. Then after it does this intermittent routine, it will loose power and all is dead again. When the fuel pump relay is flickering, it will start, run poorly with an uneven idle, and then shut itself off. On a few occassions while cranking, I have noticed the engine will fight the starter briefly giving the cranking event a brief stall, then will start cranking again normally, like an engine that has the ignition timimng off. This is leading me to belief that I might have a PIP issue, if the sensor is feeding the computer bad data as to where the engine is running or not. Any ideas? Anyone else have this ame issue? I would think that since I have a good consistent 12 source at pin 30 with KOEO with the relay removed, and also have a good consistent 12v signal to pin 87(or whichever one gets power from the relay - i can't remember), then the inline diode to the starter solenoid should be good, right? Let me know what y'all think. Thanks in advance for any input you might have

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ModularMan
Bay Area Boat Fanatic

Replies:

Posted By: KENO
Date Posted: May-31-2024 at 2:04pm

I'd probably read the thread in the link as a next step

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=47911" rel="nofollow - link

And if you're thinking about the PIP, you either take the distributor out and disassemble it to replace the PIP or get a whole replacement distributor with a cast iron gear or reuse your gear that you have now making sure it's located on the shaft properly because the aftermarket gears and the Ford gears usually have different locations for the pins and redrilling would be necessary once the gear is located properly

A distributor for a 94 f-150 with a 351 with a cast iron gear will work. Cheap at places like Rock Auto , Amazon, Ebay local parts store, etc and numerous people around here have used them. Do your homework with a search here on CCF. The cap has a vent that you'd need to seal with RTV so it doesn't do any venting for marine use to minimize chances of an explosion in the case of a gas leak

you could look at this link too, more better pictures, boneflier obviously had an easier time posting pictures on planetnautique

http://www.planetnautique.com/vb5/forum/nautique-topics/maintenance-technical-discussion/591096-1997-gt40-suddenly-quits-intermittently" rel="nofollow - link

PS..............The relay for the fuel pumps doesn't have anything to do with making a spark, the ECM takes care of that through it's relay.

Another PS, I see you did the old cut and paste double barrel shotgun approach from your post in the thread that was linked up above from planetnautique. Wink

Have you put power directly to the fuel pumps, bypassing the relay, and tried starting the engine since in your other post here on CCF a couple weeks ago you mentioned that you couldn't make the pumps run with the STO connection but they would run with power supplied, but I don't see any mention of trying to start it at that point? It'll help narrow down your problem.

If it runs good like that, then your PIP/distributor isn't the problem.

modularman wrote:

Hello to lewy2001. You seem quite knowledgeable about the Ford EEC IV diagnostics. I am hoping you can help me with my boat. I am new to boat ownership. Recently picked up a 1995 SN GT40 Pro Boss. The boat is incredibly clean. It was very well maintained prior to my ownership. That having been said, I noticed after getting the boat home it would have an extended crank condition. After about one minute of cranking it would fire up and run well. When trying to restart after running it a both, it would fire right up. Once it cooled back down, it would go back to an extended crank. Without getting any time to diagnose the extended crank, I took it to the lake for a quick shakedown, and once in the water, it cranked and fired immediately (faster than it ever started before cold) but would stall after 1-2 seconds of running. It kept doing this at the lake. So back on the trailer and back home. Played with ignition switch (which looked new) and it fell apart while removing it. Figured that was it. Threw a new switch in it and no change. Noticed at this point, fuel pumps don’t prime but will pump when directly jumped to 12v source (could not get the pumps to activate through the STO diag port). After reading your post, I checked my battery box for a fuse (no fuse present), battery cables clean and tight, lanyard attached and appearing to work. I tested for power at both of the plugs that power the relays next to the ECU and found power only at terminal 30. No power at the other terminals no matter if key was on or off. I’m assuming this is the issue since I’m supposed to have power to terminal 86? Seems odd that the running concern changed after simply towing it to the lake. I’m assuming the vibration on the trailer has caused the running concern to change? Let me know what you think. Thank you in advance for any help you can provide.