'03 Launch SSV Spitting/coughing after 1 hour

Hi all,

I have an issue that started after being on the lake for several hours.

Boat: 2003 Supra Launch SSV 350 TBI (5.7L Vortec)

It consistently follows the same pattern:

1) Go on lake for around 1 hour, everything runs great, can go WOT without problems even with a wakeboarder.
2) After 1 hour (hot engine), engine will pop/spit after pulling a wakeboarder or going under some type of load. When it begins spitting, it will continue to do so every few seconds until the boat is throttled back to idle.
3) If we try to go again, it only takes 2 minutes to start acting up again. Once it is acting up, don't need to pull anyone to start having problems. Any speed over 8 mph will do it.
4) If we wait for 20 minutes with the engine off, it seems to reset/cool down or and take 10 minutes to start acting up again (not confirmed).
5) Will occur at any speed over 8 mph once it starts. Has never occurred under this speed.

Have performed the following steps and diagnosis.

- New distributor cap and rotor
- New spark plugs and wires
- Have now been through 3 new half tanks of fuel. (Note: It started the 2nd weekend since being in the garage during winter. The first was a 2 day camping trip with no problems and running hard all day both days).
- New fuel/water separator. No water inside in the old one.
- Mechanic ran it for 45 minutes hooked up to computer couldn't replicate or see issues. Seems to need full ballast bags/towing wakeboarder to be initiated. Saw a bad cap on a wire and figured that was it. Still had problems afterwards.
- Checked fuel line connections and hoses
- Checked all fluids
- Checked gas cap

Next steps:

- Throttle Position Sensor from this thread (https://forum.supraboats.com/archive...p/t-17067.html) where the person had the exact same issue
- Run external fuel tank (difficult because I have to replicate an issue that takes 1 hour to test)
- Pull fuel tank and lines and inspect inside
- Compression test

Any input would be appreciated. Thanks!

Fuel pressure under load.

Sounds like a clogged filter. I do not see fuel filter on your list of replacements.

The fuel/water separator is the fuel filter unless I am mistaken?

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Originally Posted by CornRickey

Fuel pressure under load.

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Diagnosis recommendations? I can think of inspecting fuel tank/lines internally, external fuel tank, fuel pressure monitoring, and/or replacing fuel pump.

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Originally Posted by tbs156

The fuel/water separator is the fuel filter unless I am mistaken?

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Nope. 2 different things. The fuel filter is frequently tucked up forward, almost under the floor boards.

Check the fuel pressure when the engine is under load. If pressure drops out of spec then change the filter, same issue after then consider the high pressure fuel pump.

My 03 didn't come with a seperator

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Originally Posted by CornRickey

My 03 didn't come with a seperator

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My fuel water separator was located on the aft side of the engine on the port side. It says "fuel/water seperator" WIX #33225. I'll go hunting for a fuel filter. Where is yours located?

Update:

Followed all fuel lines. Only one fuel water separator. On the new one I installed it is printed "fuel water separator/filter".

Ran hand along both lines from tank to to throttle body and fuel pump. After running hand along lines it stank of gasoline. This doesn't seem normal to me. I think the lines and the connections should be replaced.

Installed new Throttle Position Sensor this morning as well.

I noticed when pressure is put on fuel tank, air is released through the gas cap, I assume this is the fuel vent acting as normal. I'm very curious how the air designed to escape through gas cap, because I can not for the life of me see where it would come out.

Next steps: Inspect pickup tube and vent ports. Probably replace fuel lines and connections.

Any ideas how to check fuel tank for gunk, etc? How would you go about cleaning it out if so?

Hot days only? Could be vapor lock. When you're not in motion are you venting the engine compartment?


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It's fuel injected.

The inside of the cap says "vented" or something like that so I would assume that is normal. I would check the fuel pressure under running conditions prior to change out components. Things can get really confusing on symptoms when you start swapping parts.

[QUOTE=Zkdk3000;129765]Hot days only? Could be vapor lock. When you're not in motion are you venting the engine compartment?

The boat restarts with ease every time, and the coughing/spitting doesn't kill the engine. From what I understand, that sounds unlikely to be vapor lock. It runs great under 2000 rpm.

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Originally Posted by CornRickey

The inside of the cap says "vented" or something like that so I would assume that is normal. I would check the fuel pressure under running conditions prior to change out components. Things can get really confusing on symptoms when you start swapping parts.

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Ok, maybe I'll do that tonight. I haven't done it before, but I'm guessing you buy a fuel pressure gauge and hook it up somewhere between the pump and the throttle body?

Another update. The return fuel line had two micro sized holes from the hose bubbling at two points that were leaking small amounts of gas. Hence why my hand got gas on it while tracing the lines. Replacing both the sender and return lines. I don't see how this would create any of the issues I have been having, so I'm not really considering that as the problem. Thankful nothing bad has happened with leaking fuel! :???:

Install the gauge in the Schrader valve on the fuel rail on the port side. If it is tbi you'll have to do some research. With your floor up I would confirm the one way check valve it's functioning properly. It is mounted to the return line between the hose and the tank fitting. It screws into the 90 degree brass fitting on the tank and has a barbed end for the return hose.

Could possibly be the ignition control module? If it gets too hot it will not function properly. But you replaced the distributor, maybe you also replaced the ignition control module sitting in the distributor?

Got an update! Could use some help on these final steps.

Talking to a mechanic buddy and he recommended unplugging the tan wire w/blue stripe. It's some type of temperature sender that could be cutting fuel. Well, turns out it was already unplugged, or there are two of them. We found one already unplugged on the bow/starboard side of the engine. Didn't get a chance to find where it might plug back in to, will look tonight.

However, we saw another tan wire sticking off the aft of the engine in the center at the top, turns out that goes to the temp gauge in some way. WELL! Unplugging that wire, bam boat ran like a dream, no coughing, sputtering nothing for several minutes straight. During this time of good operations the temp gauge stayed at "0" (makes sense). We have now concluded something is electronically cutting fuel to the engine above 2000 rpm (after being warm for 30 min). I'm not sure if this is considered 'limp mode'. But it is all adding up.

Didn't want to risk overheating the engine by unplugging temp gauge for too long, so for now its plugged back in. But now, wondering what diagnosis this is? Something appears to be sending a false signal to the boat that it is overheating or something. The temp gauge itself seems to work ok and boat runs at 160 on the dot throughout the "bad" operations.

Some semi-unrelate side notes:

Going to double check impeller because it has been 2 years anyways this weekend.

Also, we replaced the fuel lines intake/return and the throttle position sensor at the same time. The boat ran terribly at idle and super rich (gas pooling behind the boat). We had installed a new fuel pickup tube, cut that at an angle at the bottom, retightened connections, filled lines with gas before plugging them back in, and put the old TPS back in. One of those things fixed that issue, but certainly made me nervous!

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Originally Posted by roosm

Could possibly be the ignition control module? If it gets too hot it will not function properly. But you replaced the distributor, maybe you also replaced the ignition control module sitting in the distributor?

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Did not replace the ignition control module, only the cap and rotor.

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Originally Posted by tbs156

Did not replace the ignition control module, only the cap and rotor.

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Mine died, more suddenly than yours. If memory serves me right. First time the engine did some coughing and then died, once cooled down it started up, quickly died and remained dead.
I read a bit on the issue and found that the IGM can break from corrosion or heat and that it can start working erratically before it fails. In my case I got no spark.
The idea is basically that the IGM will get a pulse from the magnet on the rotor every time the rotor lines up to fire on a cylinder. This will tell the ECM to operate the Igniction Coil.

Might be a long shot, but you could possibly try to remove the IGM. Clean it from old heatsink-paste and corrossion, apply new heatsink-paste and re-mount it. If the issue is that it gets hot new heat sink paste might keep it cool enough.
Less corrosion on the ground point would also develop less heat. I am pretty sure mine died from corroded ground points since they looked bad.

I am however no expert on the matter, more talking from personal experience and what I have read elsewhere.
One thing that is for sure is that mine ran better after the new IGM. With old EGM I would always do crank-crank-crank-fire. Never an issue starting, but it just took a few revolutions. After the new ignition module it fired probably 10-times as fast. It was basically instantaneously from turning the key.

Another update,

Unfortunately, it isn't related to the tan wire going to the temperature gauge. Pulled it and still had issues. Took 1.5 hours to for the issue to start happening today. Finally got it to start by running perfect pass at 22 mph for 10 minutes straight. Once it starts it happens between 30 seconds - 2 minutes into driving above 2000 rpm.

Still pretty sure it isn't perfect pass related, because it will occur with or without it engaged.

Still wondering if this is limp mode. It doesn't seem to match, because it will run in minute spurts above 2000 RPM. It just doesn't like to do it a lot. My dealer said if limp mode it would be 1200 RPM and a buzzer. Haven't heard the buzzer sound yet.

When the issue happens, the engine misses for a couple seconds, then pops a couple times. Maybe like miniature quiet fire crackers going off. Never kills the engine, and goes away after pulling back below 2000 RPM. It seems as though it would keep doing it, unless you pull back below 2000 RPM.

I put the new TPS back on, and it caused rough idling operations again. It did not have the coughing issue during this time, but didn't leave it on longer than 5 minutes.

Probably put on a fuel pressure gauge on it next.

Current questions I've been pondering to myself:

1) Is this limp mode or not?

2) Does anyone know if the engine stores codes for mechanics to read later? The other option is run it on the river near the shop, when the issue comes up, call up the shop and have them send someone down with the computer to observe.

3) Maybe the transmission oil cooler? Leaving the engine off for 10 minutes at a time seems to help. And it always takes an hour on the lake for the issue to come up.

I have a 2001 Supra Launch SSV, should be identical (actually the engine is from a 2002 Supra Launch SSV but that is a long story).
I also have the 350 TBI.

Once my oil cooler, that has a strainer in it, got clogged with sea weed and we over heated. That put the boat into limp mode.
There was no buzzer (should there be??). What happened to us was that you could idle just fine, you hit full throttle to get wakeboarder up, the boat would go full for 1 or 2 seconds, then it would act almost like it does if you have ever ran it out of gas. No coughing or anything, more like someone pulled the throttle back to idle speed. Then it would just run 1200 rpm or something like that. It wouldn't actually die like it does when out of gas, but until reaching about 1200 rpm it acted the same.

Yours sound different. Might be different as well. Mine was definitely caused by an overheat (or almost over heat)...

The engine should store codes and you would be able to read them yourself with a LED-light and a paper clip if you wanted to.
http://www.offshoreonly.com/forums/do-yourself-boating-budget/103342-make-marine-efi-code-tool-less-than-$1-00-a.html

My bet would still be ICM or Ignition Coil itself as they can fail intermittently when hot. Bad thing for you is that this is not so easy to check when it is just acting up, not completely failed. I could easily determine that I did not get spark at all when my ICM failed.
I know this is a 4.3 litre carb, but it is a Thunderbolt IV...
http://www.marineengine.com/boat-for...hr-of-run-time

Issue seems very close to your issue, resolution seems to have been ignition coil.

Good Luck!
Mike

My first thought when I read your post was 'it's overheating and going into limp mode'. I still would bet that is what's happening. I have an '03 Launch SSV too, and similar things have happened to me over the years. I think your boat is just barely overtemping, and bouncing off of limp mode. Boats mostly overheat for three reasons: 1. Impeller is bad, 2. Sticks/debris lodged in transmission cooler, 3. thermostat failed closed. I'd be looking at the impeller and trans cooler for sure. I think you're pumping water but not quite enough water. You'll suck crap right into the trans cooler if you get in shallow, mucky water.

The other thing that could be happening is the ECT is failing and giving an occassional 'too hot' signal to the computer. I believe there is a test for the ECT involving measuring the resistance with the sensor in boiling water. Or you could just replace, I think they're only like $35. I'm not positive, but I think the temp sensor for the dash gauge is different than the one on top of the engine for the computer. Or maybe they are just out of calibration with each other.

If the issue is not pumping enough water, also check the water hoses. If one of them has a soft spot, it may be collapsing under the negative pressure when the engine is trying to suck in lots of water. Who looks at that long water hose that runs under the engine from the transmission cooler to the water pump? Kinda gets forgotten cuz under the engine and it's usually fine.

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Originally Posted by tretter7

My first thought when I read your post was 'it's overheating and going into limp mode'. I still would bet that is what's happening. I have an '03 Launch SSV too, and similar things have happened to me over the years. I think your boat is just barely overtemping, and bouncing off of limp mode. Boats mostly overheat for three reasons: 1. Impeller is bad, 2. Sticks/debris lodged in transmission cooler, 3. thermostat failed closed. I'd be looking at the impeller and trans cooler for sure. I think you're pumping water but not quite enough water. You'll suck crap right into the trans cooler if you get in shallow, mucky water.

The other thing that could be happening is the ECT is failing and giving an occassional 'too hot' signal to the computer. I believe there is a test for the ECT involving measuring the resistance with the sensor in boiling water. Or you could just replace, I think they're only like $35. I'm not positive, but I think the temp sensor for the dash gauge is different than the one on top of the engine for the computer. Or maybe they are just out of calibration with each other.

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When yours went into limp mode, did it make popping sounds after 2k RPM? My dealer said it would be 1200 RPM and there would be a buzzer. Other people online said it would be more akin to running out of gas.

Update, going to water test tomorrow.

New steps taken:

1) Replace ignition coil (cheap and easy)
2) Clean transmission oil cooler, not really clogged or anything. I just inspected each end. Not sure if there was more to inspect? Found a neat little 2" twig inside one end.
3) Did DIY engine code reader (thanks roosm for the link!). Got codes 14 (Engine coolant temperature (ECT) sensor -voltage high/low) and 22 (Throttle position (TP) sensor -voltage low). Both things I have worked on and unplugged at some point. I reset the codes so I'll see if either pops up again.
4) Replaced impeller, old one was in excellent condition.

Fuel pressure gauge is on order and will arrive Friday. If none of this worked and there are no codes, I'll run it again on the fuel pressure gauge to see if there is a possible fuel delivery issue.

Wish me luck! Oh yeah, while I've been working on this there is short in my wake plate because it has gone through two fuses in the last week and my bilge switch is working intermittently so it too needs to be replaced. Yay! Haha

Quote:

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Originally Posted by tbs156

Update, going to water test tomorrow.

New steps taken:

1) Replace ignition coil (cheap and easy)
2) Clean transmission oil cooler, not really clogged or anything. I just inspected each end. Not sure if there was more to inspect? Found a neat little 2" twig inside one end.
3) Did DIY engine code reader (thanks roosm for the link!). Got codes 14 (Engine coolant temperature (ECT) sensor -voltage high/low) and 22 (Throttle position (TP) sensor -voltage low). Both things I have worked on and unplugged at some point. I reset the codes so I'll see if either pops up again.
4) Replaced impeller, old one was in excellent condition.

Fuel pressure gauge is on order and will arrive Friday. If none of this worked and there are no codes, I'll run it again on the fuel pressure gauge to see if there is a possible fuel delivery issue.

Wish me luck! Oh yeah, while I've been working on this there is short in my wake plate because it has gone through two fuses in the last week and my bilge switch is working intermittently so it too needs to be replaced. Yay! Haha

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Can you share the link to the DIY code reader? I'm not hitting the right WOT max rpm and have done a similar rabbit chase to try to address it. Thanks in advance. -Zack

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Originally Posted by zajata

Can you share the link to the DIY code reader? I'm not hitting the right WOT max rpm and have done a similar rabbit chase to try to address it. Thanks in advance. -Zack

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The link is in my post a couple of posts up.

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Originally Posted by roosm

The link is in my post a couple of posts up.

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Thanks. Saw it after I responded. That's an incredibly clever solution to pulling the codes!

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Did replacing the ignition coil fix the problem?

So had to update. I FUCKING FIXED IT. What a long summer last year chasing this issue. Had to run it 3 times this summer just to confirm I actually ACTUALLY fixed it.

It was the IGNITION COIL. Big thanks to roosm. I guess it must overheat after an hour of use.

So here is a final list of things I replaced/addressed trying to track down this issue. Got a lot of 'long term' maintenance items knocked out cuz of this issue. Should add, I don't think the boat threw any codes this entire time that weren't my own doing by unplugging wires, etc. I don't think it was ever going in to limp mode.

1) Spark plugs
2) Plug wires
3) Distributor Cap
4) Throttle Position Sensor (left old one in, because new one cause it to run extremely rich/rough)
5) Fuel Filter
6) Both Fuel Lines (found a leaky line which made this entire endeavor worth it)
7) Impeller
8 ) Transmission Cooler Inspect/Clear
9) Fuel pick up tube
10) Ignition Coil

On another note. I was losing power and getting symptoms of running out of gas this past weekend despite having a half tank. I had felt minor symptoms over the past month, but chalked it up to prop wash. Then on the trailer it wouldn't even start and the fuel pump wasn't priming or making noise. I replaced the fuel pump ($400 part!) and it still didn't make noise. No 12v to the pump wires either. I traced the power lines to some in line fuses, and bam one was shot. Plugged a new one in and it ran perfectly tonight. A full 30 psi from the fuel rail. I think the fuel pump died and threw a fuse on the way out.

Oh yeah and that short on the wake plate was because the wires running from the steering column to the stern were rubbing on the sharp edge of the aftermarket radio and grounded them out.

What a trip these boats can be. Hoping I can make it the rest of the summer without another issue!

I have a 2005 24SSV.

It was doing exactly as you described. Coughing and Spitting after almost exactly 1 hour of running. You could set your watch by it.

I found your thread and replaced the ignition coil 2 weekends ago.

I am declaring it fixed since I have had 2 perfect running weekends.

Thanks a bunch to ALL.

Just another data point. I found this thread as I was experiencing very similar symptoms. The only difference was that mine did not go away once the engine cooled down. Ran fine for an hour or so and then bam, no power over a certain RPM. Took a chance and replaced the coil as I was able to find one near the lake I am at and it worked. After removing the old one I noticed it had been blown out the side but on the bottom where it was not visible.

Anyway, thanks for sharing your solution and it saved me a ton of time and money.

Dave

So as it turns out, the coil really appears to be bad, but it did not completely fix the issue. I still have a cold high idle with surging and I think misses as it vibrates more than usual. I just got my code scanner so going to see if that turns up anything. Rotor, cap, plugs, impeller, and egr all changed this spring, but honestly, I had the high and surging idle for a couple years. Exhaust manifolds were off getting freeze plugs redone, so took advantage of the easy access. I will update with any codes I find.

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Originally Posted by Sluggo

So as it turns out, the coil really appears to be bad, but it did not completely fix the issue. I still have a cold high idle with surging and I think misses as it vibrates more than usual. I just got my code scanner so going to see if that turns up anything. Rotor, cap, plugs, impeller, and egr all changed this spring, but honestly, I had the high and surging idle for a couple years. Exhaust manifolds were off getting freeze plugs redone, so took advantage of the easy access. I will update with any codes I find.

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You might want to check your IAC. That will definitely cause high idle and surging. I disconnected mine doing some routine maintenance and forgot to plugsit back in. It would not idle down. As soon as I saw it was unplugged, I reconnected it and went back to normal idle. The ECM goes into a high idle if the IAC is not sending a signal. Your scanner will give you a lot of got info. I bought the one from Rinda. $500. Bucks, but worth every penny.

Thanks @secondsupra2004, that had crossed my mind as well but wanted to get codes, if any, before buying parts.

I was able to get my scanner and it did show codes 22 and 34. Low voltage on both TPS and MAP. I picked up a MAP from Advance Auto today and TPS sould be here tomorrow. Plan to replace both, clear codes, and see what happens. Fingers crossed as we head out Friday morning to Lake Norris for a HB Trip out of Beach Island Marina.