GT40 crank, no start, crank again and it fires |
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2001Sunsport
Groupie Joined: October-07-2015 Location: MI Status: Offline Points: 86 |
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Posted: January-30-2018 at 5:25pm |
Trying to gather info before the boat comes out of storage. Found a number of threads with no start issues, but this boat always ends up starting.
1995 Supra Comp TS6M with the tubular intake GT40 and no FCC. Many times when attempting to start the boat, it will crank and not fire. Try a second time and it's about 50/50 on starting. Try a third and it always starts. Once started it will run great all day. Shut it off and same starting issue appears. Things to check from other threads: - Fuel rail pressure - every time I've checked was when the issue had already presented itself, and then it started on the next crank. No good data at this point, will have to check again during the first start attempt. - Replace relays - Check/clean electrical connectors on engine harness - Check ignition switch connections Any other thoughts? |
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Dreaming
Platinum Member Joined: May-21-2010 Location: Tacoma, WA Status: Offline Points: 1870 |
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Hi Andrew, it sounds to me like your Anti siphon valve might have a leak, or that you are getting air in your fuel system. I would try cleaning the antisiphon, checking to make sure that your tank vent is clear, and replacing the fuel filter. to me it sounds like your pumps are working, but it takes a couple of tries to fill the fuel rail. I may be totally off base, but they would be easy tune up items to eliminate before you dive into bigger and better things.
Thanks for the post on Protec, Glad my old gear had a useful afterlife it would be great to have an option for using TBI for anyone who hasn't replaced the system yet. |
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2001Sunsport
Groupie Joined: October-07-2015 Location: MI Status: Offline Points: 86 |
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Thanks for the advice!!
It took a while to get around to testing things out, but definitely wanted to share my findings. I probably would have been in more of a hurry if my Protec system had been failing.
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2001Sunsport
Groupie Joined: October-07-2015 Location: MI Status: Offline Points: 86 |
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Replaced both relays just because they were cheap. Didn't change anything, but figured I'd start there.
Dreamings theory was pretty close. Put a fuel pressure gauge on the rail and turned the key to run, didn't move but heard both pumps. Tried again, 5psi, then 15, again, 30 once more and got 40. Ordered a low pressure pump from summit. Carter P4389, it's a marine pump. Old pump was a Carter 152-875. Pumps are identical on the outside. $55 plus the ride. Key on, first turn to run and rail pressure was 40psi! Think I found the issue. Low pressure pump was getting weak but could be coaxed into working. Thanks for the help! |
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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That's the pump,sure beats the 200+ the others want
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3600 |
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Nice work!
I have used a fuel pressure gauge with a 4 foot connecting hose to help diagnose fuel issues on fuel injected engines with intermittent issues. Hook it up and route the hose so you can run the engine and see the gauge. Makes it easy to seen what your pressure is in many situations. |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4945 |
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Once you confirm that the LPP fixed everything, I 'll post this one up on the GT-40 diagnosis thread and spreadsheet.
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wetskier2000
Senior Member Joined: September-07-2005 Location: New Hampshire Status: Offline Points: 367 |
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Which one is the low pressure pump on an FCC equipped GT-40? The one beside the FCC, external to the FCC?
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Current: 1997 Nautique
Previous: 1987 Nautique 1964 American Skier |
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gun-driver
Grand Poobah Joined: July-18-2008 Location: Pittsburgh, Pa Status: Offline Points: 4112 |
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2001Sunsport
Groupie Joined: October-07-2015 Location: MI Status: Offline Points: 86 |
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Just a heads up, I have a 1995 with no FCC. People more knowledgeable than I can confirm if FCC equipped boats use a different low pressure pump.
Hopefully the weather will improve here and I can report back if the boat is 100% fixed shortly. |
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gun-driver
Grand Poobah Joined: July-18-2008 Location: Pittsburgh, Pa Status: Offline Points: 4112 |
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They aren’t that knowledgeable then. Same low pressure pump, different high pressure pump. https://www.skidim.com/Electrical/products/1057/ |
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2001Sunsport
Groupie Joined: October-07-2015 Location: MI Status: Offline Points: 86 |
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No go on the LPP fixing the issue. Debating doing the HPP or waiting until the fall to pull the fuel tank. Can't get to the anti-siphon without pulling the tank on my Supra Comp.
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2001Sunsport
Groupie Joined: October-07-2015 Location: MI Status: Offline Points: 86 |
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So the latest symptoms are still the need to make the fuel pump prime 3-4 times before it starts, but also sometimes when launching a skier it feels like it falls on its face and other times it will rip their arms off.
I'm leaning toward replacing the high pressure pump shortly, but wanted to ask if anyone thought a anti-siphon could cause the power differences in addition to the starting trouble. |
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gun-driver
Grand Poobah Joined: July-18-2008 Location: Pittsburgh, Pa Status: Offline Points: 4112 |
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Sounds like your high pressure is on its way out, if it was the anti siphon I would think it starve for fuel when full throttle also
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2001Sunsport
Groupie Joined: October-07-2015 Location: MI Status: Offline Points: 86 |
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New high pressure pump showing up today...fingers crossed. I'll update with results.
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gun-driver
Grand Poobah Joined: July-18-2008 Location: Pittsburgh, Pa Status: Offline Points: 4112 |
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I’m guessing you went with this one, and are plugging the crossover line.
https://www.summitracing.com/parts/crt-p61171 |
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2001Sunsport
Groupie Joined: October-07-2015 Location: MI Status: Offline Points: 86 |
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Yes sir, and one of these adapters. https://www.summitracing.com/parts/fra-491956 Saw some older posts on here that said it seemed to work well. |
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2001Sunsport
Groupie Joined: October-07-2015 Location: MI Status: Offline Points: 86 |
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New high pressure pump seems to have solved the issue. Had one rough start after a hot soak, but boat has been running great and has all its power back. Gives a nice consistent pull every time now!
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3600 |
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Every once in a while, maybe once in 25 starts my factory stock GT40 will fail to start promptly. With these engines there should be no cranking, just turn the key and they fire.
When mine does not fire immediately as it should I quickly turn the key to the off position then back to the run position and wait till I hear the fuel pumps pressurize before turning to start. Has worked each time for my boat. I think sometimes I rush to start before it has fuel pressure causing this condition. |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4945 |
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I'll log the high pressure pump as the fix in the GT-40 diagnostic thread.
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