2004 GTX 4-tec 155hp wakeboard changing spark plugs

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Walls89

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Hi all. Does this sound right? I changed the plugs and coolant sensor on my gtx. Started it and it stalled on two separate occasions. It has never stalled before. Usually idles around 2. Well, hooked it to the hose so I could take a little more time to throttle it. It started and stayed running this time. I let off the throttle and it idled. I noticed the idle speed jump from 2 to 3 and it stayed at 3. Is this because it has new plugs?

Could it have anything to do with the coolant sensor? Oh. And when I was taking the seat support off, I noticed the vent tube that was connected to the seat support was not connected to anything at the other end. Is this normal? I think so as it's just a vent. But very new to seadoos and wanted to make sure.

I got a p0116 error on this ski last week so I changed the coolant sensor. Hope it works and doesn't beep at me next time I take it out.
 
Did you take the caps off the new plugs? Could be a bad plug new out of the box, it wouldn't surprise me. Sounds like it's missing, so it would be a plug problem. Should idle around 1800 rpm.

Not likely the engine temp sensor you changed. You are referring to the one at the rear top by the large coolant line, correct?
 
Hi. Thanks!

I did unscrew the caps on the spark plugs and made sure the clicked down good and secure. They were all 3 brand new spark plugs. Do you think it's possible the computer just had to readjust to the new plugs and this is why it stalled at first. Then it ran without stalling but idled high.

And regarding the coolant sensor, it is the one right above the oil filter. When I took the old one off it started leaking coolant down on to the engine. I tried to get most of it off, but is it possible it got in something to cause the stalling at first and high idle speed?

I guess I shoulda drained the coolant before changing that sensor. Newbie. Ughh
 
Is there two coolant sensors? I'm concerned now because the sensor I put in looked a little different than the one I pulled out. The one I pulled out had a light blue connector and a more rounded type copper sensor that went into the engine. The one I bought on eBay had a black plastic connector and a more pointy type copper sensor that was inserted into the engine.

I thought it was just because it was an aftermarket part but would serve the same purpose. Had the same part number.
 
New spark plugs can be bad. If they are dropped by the person behind the counter, who would know? I have had new spark plugs on aircraft fail. The only way to be sure is to test on spark plug tester. If you have a laser temp, you can try to aim it at the exhaust manifold next to each cylinder. Coldest one wins.
 
I don't have a laser temp:(
It's not missing now. Just idling higher. Would that be a sign of a bad plug?
 
My cardinal rule for flying aircraft is to keep the ratio of takeoffs to landings at unity. Checking the spark gap dimensions on new plugs before installing them helps to maintain this ratio.

If you have a dead cylinder due to a misfiring spark plug, following a short test run of a few minutes the dead cylinder spark plug will be much cooler to touch than the others.
 
My cardinal rule for flying aircraft is to keep the ratio of takeoffs to landings at unity. I though walking away from the landing is the cardinal rule. :thumbsup:

If you have a dead cylinder due to a misfiring spark plug, following a short test run of a few minutes the dead cylinder spark plug will be much cooler to touch than the others.
. Using a crayon is also a nice trick. The least melted is your coldest.
 
Great tips guys! Thank you!
So I take it that a steady idle that is high (3000rpm) could spell a faulty plug?
 
I agree with ski-ddo, if you have a high idle spark plugs are not your problem. If you have not done so already get it back in the water and run the ski until it reaches normal operating temperature. Do you still have the high idle problem?

Not sure how much coolant you lost during the sensor change, but you should replace that amount in the coolant reservoir after the engine warms up and 'burps' itself. Be sure to have some on hand first time out and keep an eye on the level.
 
Gonna try to get it out tonight to test the sensor. Right after I installed the coolant sensor and new plugs here is what happened.

Without a hose I went to start it. It started then stalled. Tried again. Started then stalled again. Then, I wanted to give it some throttle so I hooked it up to the garden hose. That's when it started staying running without stalling. But as I was looking at the rpm I noticed it go from 2000 rpm to 3000rpm and stayed steady at 3000rpm until I shut it off.

I will see how it does tonight. Do the computers have to adjust to new plugs ever? Maybe the old plugs were really bad? Maybe when I test it tonight it will straighten out.

Oh, can I get coolant from Walmart? If so, what kind and brand? I have to pour it directly in the coolant tank right?
 
Lube the throttle cable. You might just have a little bit of a sticky cable. Dirt or debris could be keeping open. Or just an adjustment.
.
Make sure the throttle body is closing and operating correctly at the engine. Lubing the throttle body is on maintenance list.
 
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Great tips guys! Thank you!
So I take it that a steady idle that is high (3000rpm) could spell a faulty plug?

I would not anticipate this to be the case, at least not in my experience. My suspicion is something else is/was afoot.

I think if the original spark plugs were really bad, it would not have run smoothly and should run the same with the new plugs, assuming they are properly gaped and have not been damaged in some way.

Often when performing maintenance, it's best to do one thing at a time and test the ski before moving on to the next thing b/c sometimes problems can be inadvertently introduced.

Could be the temperature sensor is incorrect for the application and the computer is unhappy about this, it should measure approximately 2280 to 2736 ohms at 19 to 21°C (66 to 70°F)

Also, make sure to burp any air trapped in the cooling system as per the service manual instructions and top it off with the correct antifreeze mixture concentration before running the engine for an appreciable amount of time(more than a few minutes) running with a malfunctioning cooling system can cause overheating.

Are there any fault codes/warnings, is it running smoothly?

Edit: That is, it should run as well or better with the new plugs, not worse. If everything's okay with the plugs before and after changing them, the computer should not notice or readjust noticeably. If the plugs were bad before changing them, it would have been running roughly and now it would run better(smoother, b/c it's not missing).

If you did not check the plug gaps and confirm they are set correctly, I would suggest removing them and making sure the gaps are set correctly.
 
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By the way, it's not good to mix different antifreeze chemistries when adding to the existing coolant, make sure your coolant is the same type as specified by the service manual and that it's mixed in the correct ratio before adding it to the tank.
 
Thanks for all your great advice sportster!

I will definitely only change one thing at a time going forward.

Ok, so I get it on the water this evening. Press start. It hesitates and does not turn over. Pressed button again and it turned over but did not start. Released the start button, then next thing you know, it started turning over without me even having the start button pressed??? It finally stopped turning over. I then pressed start again and it finally started. Sounded rough, got chk engine error, retrieved a p0505 code but kept on going and within a minute of riding it ran as good as ever.

Topped out at 60 mph. Rode for about 30-40 mins. Shutting it off and restarting a few times in between. Firing right up every time. No beeps or codes at all.
P?
I'm not sure if this is good but topped out at 7500 rpms consistently at 60 mph. Is that good for 155 hp?

So I guess the sensor worked!!

But now new issue. The start button acting up. Any advice? And t
 
P0505 is the idle speed loss of control. Could be the idle air bypass electric valve is malfunctioning, or maybe it was resetting.

But, I wonder if your electric starter was running at this time and causing this loss of idle control?

If the starter solenoid is sticking, the starter motor can keep running or possibly begin running on it's own. So in this case I would replace the starter solenoid no question, b/c if it is sticking this will become an expensive repair, much more than a solenoid costs.

The other possibility I can think of, is one of the battery terminals may be slightly corroded/lose, but even so I think a new starter solenoid is money well spent to avoid possibility of an even more expensive repair, then go from there.

Strange, that you have these mysterious electrical issues, as if a ground wire or electrical connection somewhere is the root cause.

But regardless of anything else, first I recommend replacing the starter solenoid in case it's sticking b/c if it is, your starter and possibly starter bendix drive will be quickly eaten alive. Do this first, disconnect the battery until you can do this, then once this is out of the way the problems may even disappear altogether but don't be surprised if there isn't a corroded connector somewhere causing these mysterious issues.

Edit: Another thing, if your start button is sticking, this could also cause the starter motor running by accident/itself as well, but should not be the cause of an idle speed loss of control fault b/c once started the MPEM will not pull in the starter solenoid (assuming the starter solenoid isn't sticking and has it's own nefarious ideas).
 
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Thanks for all your great advice sportster!

I will definitely only change one thing at a time going forward.

Ok, so I get it on the water this evening. Press start. It hesitates and does not turn over. Pressed button again and it turned over but did not start. Released the start button, then next thing you know, it started turning over without me even having the start button pressed??? It finally stopped turning over. I then pressed start again and it finally started. Sounded rough, got chk engine error, retrieved a p0505 code but kept on going and within a minute of riding it ran as good as ever.

Topped out at 60 mph. Rode for about 30-40 mins. Shutting it off and restarting a few times in between. Firing right up every time. No beeps or codes at all.
P?
I'm not sure if this is good but topped out at 7500 rpms consistently at 60 mph. Is that good for 155 hp?

So I guess the sensor worked!!

But now new issue. The start button acting up. Any advice? And t

Yep 7500 RPM is good RPM. My 05 wake 155 turns 7400 to 7450 consistant.
 
Glad to hear 7400-7500 rpm is good! It will only top out at 60 MPH though. Is that typical for a 2004 GTX Wake 155 HP?

Sportster, I think it's possible with it resetting when the P0505 errror appeared. The error code did not come on again and all was good after the initial start.

I have always noticed a delay with the starter when you press the start button. I wonder if the batter is bad? I also read somebody say they removed the start button and one of the two wires connected to it was disconnected. Could this be it?

If it is a solenoid, any ballpark figure of how much they are and are they hard to install?

I hope its not the starter..ughhh. I know they are a pain to get to.
 
I think a new starter solenoid is cheap insurance against this symptom and potential starter damage IF it is actually sticking, and you'll find the price palatable.

That said, the start button switch on these isn't immune from corrosion and dirt/water getting inside them and sticking also but don't overlook a sticky starter solenoid either.

In addition to replacing the solenoid you may find the start switch could use cleaning or replacement, my guess is just cleaning, disassemble as best you can without ripping the entire boat apart and hose it out best you can using a can of light oil like WD-40 or something if it feels like it's binding inside, I don't know exactly what yours looks like but mine has a red cover over it that unscrews, I think, or maybe it just pops on.

The idle problem COULD be the electric starter motor was running at the same time as the engine? When this occurs the starter and drive gears (bendix) will likely be damaged if this keeps happening.

Also, you may have a battery cable loosening up or corroding somewhere, causing mysterious electrical faults. Inspect the ends closely and remove them to go over the connectors with a wire brush (such as brass or stainless bristles) to clean the oxidation, wipe them down using some dielectric grease (such as used for silicone spark plug connectors) and reattach.

It's possible your battery may have an issue as well, sometimes they can crank great one minute and not work at all the next, I find those small batteries are lucky to make it past a second season. So if there's any doubt about it's condition don't be too hesitant to replace it with a new one, money well spent if it's more than a couple seasons old.

Some people insist on replacing their starting battery every year but in my opinion this is unnecessary and sometimes a replacement battery is found to be junk from the beginning.
 
I'm definitely taking your advice and ordering the solenoid. On Amazon I'm seeing this part -- Parts Unlimited Starter Solenoid SL4000

And I'm also seeing this part on Amazon -- Starter Solenoid Relay Switch for SeaDoo 3D, GS, GSI, GSX, GTI, GTS, GTX, HX, LRV, RX, RXP, RXT, SP, SPI, SPX, SUV, XP, XP800, WAKE, Challenger, Explorer, Islandia, Speedster, Sportster, Utopia 278-001-802, 278-001-376, 278-000-513


I'm not sure what to get. They are definitely two different parts.

I have a 2004 GTX 4-tec Wakeboard edition 155 HP
 
Hmm...I'm reading that a bad solenoid will cause clicking when you press the start button. Mine is NOT clicking. It's just hesitating before it actually starts to turn over after you press the start button.

Then, as I said, last night....I wasn't even pressing the START button and it started turning over??
 
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