Baller FLeboeuf Posted February 23, 2019 Baller Share Posted February 23, 2019 This might sound silly but how are the spark plugs? The plug wires? The plug wires could need a change. Link to comment Share on other sites More sharing options...
Baller DanE Posted February 23, 2019 Baller Share Posted February 23, 2019 @Wish What did I tell you about running around in circles unless you check fuel pressure. Always start there. Low compression? Not likely if it runs good every now and then. A quick check for ya, sometimes the diaphragm in the fuel pressure valve starts leaking slightly, pull the vacuum hose off with engine running, if there is even the slightest drop of fuel coming out of the pipe where the hose sat you need to change fuel pressure valve. (that's where you attach the vacuum pump when testing fuel pressure anyway) Link to comment Share on other sites More sharing options...
Baller Orlando76 Posted February 23, 2019 Baller Share Posted February 23, 2019 You really have to verify fuel pressure at all rpm ranges while in gear, not just revving in neutral. Anti siphon valve is something that hasn’t been mentioned yet. But without verifying fuel pressure we don’t know to point in the electrical direction or fuel direction. Link to comment Share on other sites More sharing options...
Baller DanE Posted February 23, 2019 Baller Share Posted February 23, 2019 @Orlando76 Is correct, and I might add a fuel pressure reading while the symtomes occur is critical when determining which way to proceed with troubleshooting. Link to comment Share on other sites More sharing options...
Baller_ Wish Posted February 23, 2019 Author Baller_ Share Posted February 23, 2019 What are the in range readings supposed to be? Link to comment Share on other sites More sharing options...
Baller Orlando76 Posted February 23, 2019 Baller Share Posted February 23, 2019 It’s in the manual, I posted the link at beginning of thread. I think the manual said 39psi which seems low IMO but I guess the manual is correct. I don’t know how much it can deviate. FWIW I had a 200 Yamaha HPDI outboard. Book called for 56, if i punched it hard to plane out it’d stumble flat on its face if fuel got to 48psi. Link to comment Share on other sites More sharing options...
Baller_ Wish Posted February 23, 2019 Author Baller_ Share Posted February 23, 2019 Found a few resources that match up. 39psi is normal with a range from 35-45. Below 30 ..bad, above 60..bad. Link to comment Share on other sites More sharing options...
Baller DanE Posted February 23, 2019 Baller Share Posted February 23, 2019 And to properly check function of fuel pressure valve you should connect a vacuum pump to the vacuum pipe on the valve, lower rhe pressure with the pump and watch the fuel pressure drop by the same amount. But really what you need to check regarding that vacuum port is to pull the vacuum hose and make sure no fuel is leaking through the diaphragm. It does happen and will make the engine bog down intermittently when the small squirts of fuel finds its way to the intake manifold. Link to comment Share on other sites More sharing options...
Baller jhughes Posted February 23, 2019 Baller Share Posted February 23, 2019 For something so intermittent it seems electrical. Have you ruled out the kill switch by the throttle? I've also heard of the coil/TFI Module going bad on those over time. Link to comment Share on other sites More sharing options...
Baller_ Wish Posted February 23, 2019 Author Baller_ Share Posted February 23, 2019 Kill switch replaces last year. I've heard coil several times now. Doing fuel pressure test now. 37lbs key to on possision. No leaks. Link to comment Share on other sites More sharing options...
Baller DanE Posted February 23, 2019 Baller Share Posted February 23, 2019 @Wish Are you able to check fuel pressure while under way? You need to get a reading when the sputter occurs, if bad pressure is the cause you will never discover it when the engine is running ok. Fyi there are possible electrical malfunctions that can cause fuel pressure drops intermittently . For instance a bad fuel pump relay. Link to comment Share on other sites More sharing options...
Baller mfjaegersr Posted February 23, 2019 Baller Share Posted February 23, 2019 I'll second what @DanE said about the relays; you'd be about due if you haven't replaced it (them) yet. There's a second one, identical, for the .....ignition/ECM?...They're about $10-15 a piece; easy to swap in/out to test. If not the ultimate culprit this time, they're good to have on hand or simply install anyway once you've found root cause. Link to comment Share on other sites More sharing options...
Baller_ Wish Posted February 23, 2019 Author Baller_ Share Posted February 23, 2019 Test 1: So fuel pressure holds at a solid 37 in all possible conditions. After running the boat for 20mn we let it sit with fuel guage on it. Leak down was 1 psi over 20mn. 20mn later Test 2: ran it through its paces. Fuel pressure again solid 37psi in all conditions including during the misses. It did do the same miss. What we noticed this time is the miss is at 2000-2500rpms and once past that, at least today anyway, no miss. Link to comment Share on other sites More sharing options...
Baller Orlando76 Posted February 23, 2019 Baller Share Posted February 23, 2019 Well Wish you have an electrical issue. Link to comment Share on other sites More sharing options...
Baller DanE Posted February 23, 2019 Baller Share Posted February 23, 2019 That's some important information you got out of that test. Worst thing is it seems to come and go and as long as it's running ok it will be impossible to find anything wrong. If you haven't already I would change both relays just to be sure ( you're going to have to sooner or later anyway). If the problem persist you have some electrical troubleshooting ahead. Link to comment Share on other sites More sharing options...
Baller_ Rednucleus Posted February 23, 2019 Baller_ Share Posted February 23, 2019 Am I correct the miss occurs only after motor is well warmed up - so what electrical ignition components do not like heat. If it was my 93 Chevy it would be the ICM every time (on my 3rd one). Does your boat have one & has it been changed? Link to comment Share on other sites More sharing options...
Baller Orlando76 Posted February 23, 2019 Baller Share Posted February 23, 2019 To clarify, this is a new cap and rotor that you replaced AFTER the miss occurred? Coil Oil pressure switch EEC relay MAPP sensor We had a similar problem with the Excal I ski, turned out MAPP sensor. But as stated, caps and coil tend to act different when they’re warm. Link to comment Share on other sites More sharing options...
Baller DanE Posted February 23, 2019 Baller Share Posted February 23, 2019 MAP sensor is crucial, not that common but the years on this engine makes anything possible. Link to comment Share on other sites More sharing options...
Baller Orlando76 Posted February 23, 2019 Baller Share Posted February 23, 2019 Given the rpms that it gives out makes one think it could be something that makes it go to limp mode. Since it’s only an 83 second fix, bypass the kill switch to rule it out. Link to comment Share on other sites More sharing options...
Baller_ Wish Posted February 23, 2019 Author Baller_ Share Posted February 23, 2019 Rotor and cap are new since problem began as a way to correct it. Test #3 after 3 hours of boat sitting. Ran flawless for 15mn running up and down rpm range. Test #4 15'mn later after boat sitting. Same thing. Sputter at 2000-2500. Could not detect a miss above 2500. But the consistency of this problem is uncanny. Thinkn temp related causing some sort of ignition issue. What I have no idea. MAP and coil?? Link to comment Share on other sites More sharing options...
Baller jimski Posted February 24, 2019 Baller Share Posted February 24, 2019 Time to trade it in Link to comment Share on other sites More sharing options...
Baller DanE Posted February 24, 2019 Baller Share Posted February 24, 2019 Check the vacuum hose to MAP sensor. If it was solely a ignition failure (no spark intermittently) you should have some muffler explosions going on. Link to comment Share on other sites More sharing options...
Baller ToddA Posted February 24, 2019 Baller Share Posted February 24, 2019 We have a 99 SNOB with the GT-40, and I am following this very closely in the case we have anything similar happen. Anyone able to show us where the MAP sensor is located? Link to comment Share on other sites More sharing options...
Baller_ Wish Posted February 24, 2019 Author Baller_ Share Posted February 24, 2019 the arrow points to the plug that's plugged into the Ecoil. Next to this is the Map sensor with a vacuume tube (arrow to that) and a wire harnes. That is mounted with 2 bolts. Super easy too look either part up on line and get a good picture of the part via SkiDim.com Link to comment Share on other sites More sharing options...
Baller ToddA Posted February 24, 2019 Baller Share Posted February 24, 2019 @Wish Thanks!! Link to comment Share on other sites More sharing options...
spicoli Posted February 25, 2019 Share Posted February 25, 2019 If your tachometer is going bad it will make it miss Link to comment Share on other sites More sharing options...
Baller TEL Posted February 28, 2019 Baller Share Posted February 28, 2019 Wish, did you find what the problem was? Link to comment Share on other sites More sharing options...
Baller_ Wish Posted March 1, 2019 Author Baller_ Share Posted March 1, 2019 Infortunaley no. ? Hard to work on during the week. My neighbor has a GT40 so I'm gonna swap the Exoil and if that's not it swap the MAP sensor. Any suggestions still welcome. Had someone mention the entire distributer but that's a very expensive part not to have isolated as the cause. Link to comment Share on other sites More sharing options...
Baller rockdog Posted March 1, 2019 Baller Share Posted March 1, 2019 @Wish I haven't read everything here, but just this past month my ski partner had a similar issue on his Ex330. He thought bad fuel, I thought electrical from the start so we pulled all the Iridium plugs and replaced with standard plugs - problem gone immediately. If you haven't done plugs for a few years then it's the first thing I'd do anyway.. I think that's what it is. Link to comment Share on other sites More sharing options...
Baller_ Wish Posted March 1, 2019 Author Baller_ Share Posted March 1, 2019 Hmmmm I put in Iridium plugs 3yrs ago. That's interesting. I did pull them today and they all looked really good. Even my ski partner thought they looked good. But they are prob 300-400 hours old. Link to comment Share on other sites More sharing options...
Baller rockdog Posted March 1, 2019 Baller Share Posted March 1, 2019 yep get em done mate, easy fix hopefully for you and certainly worth the try. Link to comment Share on other sites More sharing options...
Baller jhughes Posted March 1, 2019 Baller Share Posted March 1, 2019 I've had the same set of Autolites in for the past 13 years and probably ~500 hours. Every time I pull the plugs they look fantastic. Cap and rotor are the same age. Tuned it up in 2006 when I got the boat. No need for anything fancy (iridium) or over maintenance in this engine, it's a basic 351W. FCC filter maybe every 5 years, I may have done it 3x total. Heck, I'll buy one of the one-year-old cap and rotors from the over-maintainers. Link to comment Share on other sites More sharing options...
Baller_ MISkier Posted March 1, 2019 Baller_ Share Posted March 1, 2019 I still say to run the boat, heat it up good, and do a compression check. The worst slalom equipment I own is between my ears. Link to comment Share on other sites More sharing options...
Baller_ Wish Posted March 1, 2019 Author Baller_ Share Posted March 1, 2019 @MISkier with low compression, wouldn't I be experiencing performance issues?? I have to say, so far every time we take it out for the first outing of the day, it is crazy impressive what torque it has and its performance overall. Would loss in compression cause a miss? Link to comment Share on other sites More sharing options...
Baller Orlando76 Posted March 1, 2019 Baller Share Posted March 1, 2019 I don’t think loss of compression is the issue, especially since it’s intermittent. But a $20 gauge and 10 minutes can rule out compression fault. Link to comment Share on other sites More sharing options...
Baller mfjaegersr Posted March 1, 2019 Baller Share Posted March 1, 2019 @Wish Did you try new relays? Perhaps you could borrow one/both from your buddy’s boat? Link to comment Share on other sites More sharing options...
Baller_ Wish Posted March 1, 2019 Author Baller_ Share Posted March 1, 2019 Swapping those is a good idea as well. Just have not seen my neighbor yet. Hopefully Sat. Link to comment Share on other sites More sharing options...
Baller_ Wish Posted March 2, 2019 Author Baller_ Share Posted March 2, 2019 @rockdog unfortunately for me, plugs were not the answer. Ran great first set/outing as usual with new plugs. 15 minutes after sitting the same miss/sputter on the second outing. ? Gave my neighbor the heads up on possibly swapping some parts. Hopefully he gets back to me and we can give that a go tomorrow. This is nuts. Link to comment Share on other sites More sharing options...
Baller Zman Posted March 3, 2019 Baller Share Posted March 3, 2019 I'm leaning towards one of those sensors. Gets warm and begins acting erratic. Link to comment Share on other sites More sharing options...
Baller_ Wish Posted March 3, 2019 Author Baller_ Share Posted March 3, 2019 @Zman ya, I keep coming back do the MAP sensor and Ecoil. Not sure what other sensors it could be that would induce a miss but only during a second outing. Link to comment Share on other sites More sharing options...
Baller DanE Posted March 3, 2019 Baller Share Posted March 3, 2019 @Wish I would not completely rule out the temp sensor either (temp sensor for the fuel injection system). A long shot yes, but it's difficult to come up with good advice when the sputter is not experienced first hand. Link to comment Share on other sites More sharing options...
Baller DanE Posted March 3, 2019 Baller Share Posted March 3, 2019 There should be an intake air temp sensor also that works the same way. Is the sputter occuring during a constant load or when accelerating? If it is during hammering the throttle the TPS (throttle position sensor) comes in to play. Link to comment Share on other sites More sharing options...
Baller rockdog Posted March 3, 2019 Baller Share Posted March 3, 2019 Dang it @wish, I hope you sort it out soon. Link to comment Share on other sites More sharing options...
Baller JAS Posted March 3, 2019 Baller Share Posted March 3, 2019 I have a GT -40 and also best friend who is marine mechanic. My suggestion is to have someone come to the lake and see first-hand what’s going on. If you buy unneccesary parts you could be chasing your tail all season. We read some posts on Planet Nautique about problem I was having. His opinion was that most were written by well meaning folk that knew about as much as I did. If problem is past the obvious get professional help. Plus they have the tools Link to comment Share on other sites More sharing options...
Baller aupatking Posted March 4, 2019 Baller Share Posted March 4, 2019 @Wish , thank you for having this issue at such a good time. B) Mine started the day after I saw your first post. I have the Excalibur 330 but they share the Fuell Controll Cell. Mine was sputtering pretty bad, even at startup. I was fairly certain it was simply water in the fuel but, after I drained the FCC and poured it into a clear bottle & let it settle, it really had no water there. I went ahead and pumped all fuel out and replaced the fuel filter. Put it back in the water with marine fuel treated with Sta-bil. She turned over several times and finally fired up nicely. Just to check though, I opened the clamshell, because I had primed the FCC & I was thinking it should have fired up sooner with a prime. That electric pass-through power for the high pressure fuel pump was bubbling fuel through the top. I ordered a new pass through. When I went to replace it, the red wire connector was barely connected at all. That may have been the problem the whole time. Once replaced, it runs perfect again. It’s beyond me how a connection in a closed environment becomes loose, but that seems to be the cause of my issue. Link to comment Share on other sites More sharing options...
Baller_ Wish Posted March 4, 2019 Author Baller_ Share Posted March 4, 2019 @aupatking glad u got yours sorted out. Bad gas was my first thought and did the same as you but unfortunately that's not it. I did take a 6 pass ski set today. Ran flawless. Driver said the boat felt oddly stronger. A good thing. But no chance at a second set for anyone. Still misses on the second set out. Still chasing my tail I know but most if not all of what I've done so far falls under general maintenance. Neighbors GT40 is actually being worked on. Stater and alternator so could not swap stuff. Coil is cheap enough to give that a go. Did some reading on coils overheating-ish when let's say a car is at idle for long periods of time in a traffic jam on a hot day causing intermittent missing until the engine was allowed to cool by not running. Sounded very similar in away. So far the only thing I've done that I regret is the plugs. Everything else was do for replacement anyway which may be why the driver said it feels stronger. I am making the strong assumption that the Ecoil is just a general auto part and nothing more even though it's on a boat. Link to comment Share on other sites More sharing options...
Baller DaveD Posted March 4, 2019 Baller Share Posted March 4, 2019 Isn't this the point where @eleeski tells you the boat is shot and to send it to him for proper disposal? Link to comment Share on other sites More sharing options...
Baller eleeski Posted March 4, 2019 Baller Share Posted March 4, 2019 The boat is shot. Send it to me for proper disposal. The USD team is looking for a boat. Eric Link to comment Share on other sites More sharing options...
Baller_ Wish Posted March 4, 2019 Author Baller_ Share Posted March 4, 2019 Eric, my guess is it would take you about 20mn to figure out what's wrong and it would make the best USD boat. I need your skills or you as my neighbor....on second thought ? Link to comment Share on other sites More sharing options...
Baller elr Posted March 5, 2019 Baller Share Posted March 5, 2019 @Wish - this thread may help: http://www.correctcraftfan.com/forum/forum_posts.asp?TID=27323&title=gt40-intermittent-rough-running Long story short -- solved!!! This would be a very tough issue to identify unless you're super with electrical diagrams and know what you're doing. Short answer: corrosion in the fuel injector harness caused the injectors to OHM out, making them shut down. Injector harness was testing at 30 OHM, should be no more than 12 OHM. Mechanic cleaned harness and replaced corroded connectors inside the harness. Boat works great! Of course, this took a long time to track down, mechanic swapped the ECM, distributor assembly, cleaned injectors, etc, etc so after 3+ days of labor charges, it's finally fixed, just a huge punch in the wallet. Glad to have it back, and hope this will help anyone in future. Link to comment Share on other sites More sharing options...
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