'03 Launch SSV Spitting/coughing after 1 hour

[tbs156]

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.

[roosm]

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

[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.

[scottschmitt]

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.

[tbs156]

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.

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.

[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

[zajata]

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

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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[roosm]

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.

[zajata]

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

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

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[hlewis12]

Did replacing the ignition coil fix the problem?