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Fuel pumps do not prime and yet engine runs fine.

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Georges f View Drop Down
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    Posted: November-16-2021 at 3:25pm
Fuel pumps do not prime and yet engine runs fine.

Hello
We have air nautique 210 gt40 5.8 2002 for three years . we love this boat and this engine
I noticed that the fuel pumps do not prime anymore, and yet the engine starts well.
what orders gas pumps to prime ?
let me explain.
this summer, we replaced the hydraulic valve lifters. everything went well. before the first start in order to make the break-in, the pumps have primed, I was able to bleed the high pressure fuel circuit.
since then, the boat has gone out three times on the river and the fuel pumps have always primed . nothing to report. it's time to get interesting.
after these three satisfactory outputs, I decided to replace the alternator, battery and harness because I added two speaker tower and it pulled too much on the battery.
I ordered the Parts on nautiqueparts
and I replaced them with great care.
I also replaced the electrical sheath which runs on the rocker cover on the starboard side because it was melted in some places. after that, I couldn't try the boat and the sound system on the water because it was wintering time. I am about to winterize in my yard and therefore start the engine one last time. I switch on the ignition, and no priming the gas pumps !! I crank the engine and it starts up fine as usual.

since then I have been trying to find out why the pumps no longer prime. I tried a lot of things that I read on this forum, I retraced my steps, I replaced the two relays: fuel pumps and EEC , i also replaced the starter solenoid.
I specify that I buy all the parts on nautiqueparts
when I enter the unlock code on the pad and validate by pressing the start key, at this precise moment the pad lights up and I do not hear the fuel pumps, I do not hear the two small relays . I press the start button a second time, and the engine starts well.
Has anyone had the same problem?
Could someone tell me what causes both fuel pumps to engage for four seconds when the unlock contact is made?
thanks in advance
Georges
P.S excuse the errors in writing ...
we are in France. thank you Google Translate
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MrMcD View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: November-17-2021 at 2:00am
If there is not pressure at the fuel rail the injectors will not spray fuel and you will not be able to start the engine.  If your system should not prime till you turn the key to the start position.  The fact that it does start each time tells you this is happening on time.   
Are you saying the pumps do not keep running after you turn the key on, and then run for 2-3 seconds before shut off?   I am not sure exactly what part on the engine shuts off the fuel pumps after priming should the engine not start.  Probably programmed into the engine control computer.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mpost Quote  Post ReplyReply Direct Link To This Post Posted: November-17-2021 at 9:29am

Found this in the GT40 owners manual. From your description it sounds like the fuel pump relay is not being turned on my the ECM when the key is in the on postions. But your boat has the keyless start pad so it may be the issue here. I also included a link to the GT40 wiring harness for reference. 
Maybe someone else can chime in on the relay input, but it looks to me like the same signal should power the FP relay for priming and for running. 



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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-17-2021 at 3:01pm
Hello MrMcD
Thank you for your help. I really appreciate.
I also thought about a problem on the computer !!!
Normally on the first use of the day, I validate the unlock code on the Pad and the pumps prime for 3 or 4 seconds.
Then I press the start button and the engine cranks up great, and it runs great.
It can run for several hours if I wish. Until I decide to stop it. So the fuel pumps as well as the pump relay works.
Here is my concern: on the first use of the day, I validate the unlock code on the pad, and the pumps do not prime for 3 or 4 seconds. Then I press the start button and the engine cranks up great and runs great, until I decide to stop it.
Why are they not starting like they used to?
No matter how much I look, I can't find it ..
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-17-2021 at 3:48pm
Hello Mpost
Thanks for your help, it's really nice !!

I will study the text from the owner's manuals that you sent me.
I also thought there was a problem with the pad. I will change it as a precaution, but it costs 600 € in France. It's a bit pricey and I would have liked to be sure this was the failing part.
Thanks for the electrical diagram, I have already found it on this forum and I have already studied it a lot. The threads and colors really match.
I have no oxidized or cut wire and the 2 main earth wires on the port and starboard rear of the engine are ok.
I have read on this forum that the computer is grounding a wire from the fuel pump relay in order for them to operate. Maybe to prime for 3 or 4 seconds, the computer will ground another wire so they will work.
Difficult to confirm.
I am looking at the various electrical diagrams in my possession, and I do not understand what orders to prime!
Is it an electronic or an electrical issue?
Cordially
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: November-17-2021 at 4:02pm
If the engine starts quickly with no excessive cranking it sounds like you do have pressure delivered on time?  You are correct the pumps should activate first.   Not sure why yours do not but obviously when you hit start they are activating or you would not be able to start the engine.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-17-2021 at 4:32pm
This is exactly what I think.
I have the same conclusion as you about gas pumps.
I'm looking, I'm looking..
cordially.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: November-17-2021 at 5:54pm
I just realized you are in France, wow, a long ways afar working on a Nautique.  Good for you.  I hope the answer shows up soon.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: November-17-2021 at 6:30pm
If you look at the diagram(s), the power always has to get through the ECM relay and the fuel pump relay and the pumps be grounded by the ECM whether the keypad is depressed once to validate the unlock code or pressed again to start the engine. It's the same ground point and relays in either case.

When you press once to "unlock", power comes from the keypad and the pumps will run for roughly 2 or 3 seconds and then turn off because the PIP signal from the distributor is telling the ECM that the engine isn't running and the ECM takes away the ground for the pumps so they stop.

When you press the button again, the power to the pumps is still supplied from the keypad but it also gets fed power from the start relay/solenoid until you let go of the button and then it's fed only from the keypad but since the PIP signal tells the ECM that the engine is running the ECM maintains the ground closed and the pumps keep running supplying fuel to keep the engine running.

I think that's how it "should" work.Wink

I don't think that does anything to explain why yours is acting differently, but I think that I'd check the wiring at your start relay/solenoid to be sure that it matches the original wiring as a starting point.

It seems like the issue started after your harness and solenoid  changes.

Maybe like you're thinking it's the keypad, but that's a lot of money to throw at the problem unless you rule out everything else.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: November-17-2021 at 7:05pm
And if the engine starts and runs each and every time, maybe live with it?

If it is starting slowly due to the fuel pump not activating on time it needs to be fixed.

I just repaired the fuel pump in a Mercedes E350 with the PZEV fuel system, ultra low emissions fuel system.  That system does not activate the fuel pump until you turn the key to the full start position.   This is the first electric fuel pump car I have ever worked on with this system.   You can check the fuel pressure any time with key off and it is at zero, turn key on and it stays at zero, hit the start button and the fuel pressure is instantly 59 lbs.  Stop the engine and it again returns to zero pressure in a couple seconds.  It works but seems very odd to not have a return line in a high pressure fuel system.  In the PZEV system the fuel pump is actually welded closed inside the fuel tank?  Who thinks up this stuff.   Oh well, your boat is not the first engine to run without having the fuel cycle in advance.  I do think it might leave you prone to Vapor lock on a hot summer start but no more so than the Mercedes and it seems to work fine.  Mercedes was paid by the state of California to sell the PZEV ultra low emissions cars.  Having zero pressure in the system is supposed to reduce vapor escaping into our air.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-18-2021 at 12:37pm
Thank you MrMcD for your help.
Indeed I could live without the gas pumps that are priming. Especially since it starts quite well. Besides, this engine has always started well, I really love this engine.
As you said, it's not the first engine that starts without priming.
I will keep thinking about the problem, and when I have had enough I may decide to change the ECM.
Thanks again.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-18-2021 at 1:30pm
Hello Keno thank you for your help.
Your explanations are clear and understandable.
I replaced the starter solenoid by looking at the photo I made before taking it apart, and drew a quick little drawing.
I may have been wrong.
I will draw a drawing to explain how I connected the starter solenoid
Maybe someone on this forum can confirm.
I spotted and tested the different wires around the two relays, and nothing to report! I also spotted the purple wire coming from the solenoid and going to the EEC relay, and nothing to report. I tested the two small diodes with anti-feedback which come from the solenoid, nothing to report they work. The usefulness of these two diodes puzzles me, I do not understand.
They are connected to the solenoid. One on I, and the other on the big terminal with the starter relay.

OK..That's it, my skull is starting to smoke 😂😂

I will take the time this weekend to do some tests around the Pad and its power supply.
Thank you again Keno ..
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-18-2021 at 2:37pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-18-2021 at 2:43pm
diagrame solénoïde
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-18-2021 at 2:44pm
Here's how I hooked up the new starter solenoid.
Am I wrong?
Thanks in advance.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: November-18-2021 at 6:36pm
Your drawing looks right to me

You can compare the wiring to the diagram on page MT16 of the manual in the link below.


It doesn't match the drawing in the Planet Nautique link earlier, but you know what you had from a picture and duplicated it, so I'd stick with what you have.

The diodes prevent backfeeding

The top one in your diagram in the purple wire from the large lug prevents the ignition wiring from backfeeding the starter mounted solenoid which would keep the starter engaged all the time while the engine was running.

The bottom one I think in a really tough to follow, hard to explain flowpath,  does the same thing (lets the starter disengage).

It seems like you're covering things pretty thoroughly in your troubleshooting so you'll eventually find something Wink

I also think that like MrMcD said, keep using it since it starts good and runs good.

Logically when you go thru Run to Start  with a key switch, you barely spend any time in Run before the key is in Start (in other words, you don't hesitate for a couple of seconds in Run, before then taking the key to Start, you just turn the key to start in one smooth motion) With your keypad holding the button down instead of quickly releasing it, does the same thing I think. ( I have nothing with a keypad so i could be screwed up on this, but I did start somebody else's more than once)

That would mean the fuel pressure is coming from the pumps with the key in Run for a very small fraction of a second before the key is in Start supplying power to the pumps, then when you release the key or in your case, let go of the button when the engine starts, the pumps are supplied from the purple ignition wire associated with the key or keypad being in Run.

PS my skull is smoking too, wondering what caused your change Wink
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: November-18-2021 at 10:45pm
Listen to Ken, he understands the electrical pretty dang well.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-19-2021 at 2:01pm
Hello MrMcD
Thank you for your advice and thank you for sharing your experience with your Mercedes. It’s very relevant. !! Ultimately I'm not going to make myself sick with the priming which lasts 2 seconds and only once at the start of the day.
if I find so much better…. otherwise 🧐 we will see ..🤷‍♂️
Thanks again.
Really nice this forum ..👍
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-19-2021 at 2:04pm
Hello Keno
Thank you for your answer..
Thanks for the link, it's really interesting and I didn't have it yet.
I'm going to check the solenoid connection again, but like you said, I have the picture of the connection before disassembly, and my little diagram.
After explanations, I better understand the use of the two small anti-return diodes.
Indeed it is clearer that way. It will allow me to go further in my research.
I understand the Run / Start context well, it's clear and it seems to work very well for a lot of people. And it works well for my engine too.

I would like to orient myself towards the Pad and the 8 Pin connector on the starboard rear of the engine. Make tests with the purple wire which goes to the solenoid and which comes from the Pad, and the red wire which returns from the neutral switch.
However it is quite cold right now (32 ° F), and my barn is not heated. I am not very motivated. ☹️
I will study the new diagrams in my possession and I will continue my research on the boat when the motivation returns 😂😂
Many thanks to you Keno and thanks to everyone else.
If I have anything new, of course I'll share it on this post.
Best regards.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-19-2021 at 2:12pm
Air nautique 2002
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-19-2021 at 2:16pm
Air nautique
Here is our boat.
It's not very young anymore, but we love him.
Cordially
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: November-19-2021 at 2:59pm
I think that is so cool that you have a Nautique in France, are there many others?  Great looking boat.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Georges f Quote  Post ReplyReply Direct Link To This Post Posted: November-19-2021 at 3:20pm
Yes that's super cool. She is a good quality boat and she has aged very well.
There are a lot of Nautique in France, but also master Craft and Malibu. However, a Nautique is the class 👍😂
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