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Author Topic: No start. I think I figured it out. Just need confirmation.  (Read 1081 times)

Sketchysk8er

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2009 EFI C5. I turn the key, hit the switch and press the button. Turns but wont start. When I hit the switch I don't hear the fuel pump do its 3 second prime before I try to start it. I can however hear the relay click in the fuse box. So I unhooked the connector at the fuel pump and put a volt meter on it and got 12v. So is it safe to say that my fuel pump took a poop at 2k miles and I need to spend $300 on a new one? :(  is there any other things I should try?

Arizoni

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Re: No start. I think I figured it out. Just need confirmation.
« Reply #1 on: July 05, 2012, 05:14:07 AM »
Assuming your 2 year warranty is gone you could try appealing to Kevin's good nature and desire to obtain defective hardware so he can help the Indians improve their product?

Maybe that's a pipe dream but IMO a fuel pump should last longer than 2 years.
I know of many FI cars with over 10 years on them like my Miata and their fuel pump is still working fine.
Jim
2011 G5 Deluxe
1999 Miata 10th Anniversary

Kevin Mahoney

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Re: No start. I think I figured it out. Just need confirmation.
« Reply #2 on: July 05, 2012, 08:02:48 AM »
You cannot assume that it is the fuel pump by this sort of testing. Don't go there. It is a bad assumption and will lead to throwing parts at a problem with no clear diagnosis. While possible, fuel pumps do not fail much. They are most prone to failure if you run with the low fuel light on routinely. The pump uses petrol in the tank to cool itself. The definitive test is to remove the petrol hose at the throttle body and run a pressure test. The correct values are found in the shop manual. There is a LOT of pressure from the pump so this test is not for the faint of heart. Also you cannot be stupid and be smoking a cigarette, have a hot engine etc.
The fuel pump is expensive (be thankful it is not the catalytic converter) so you do not want to misdiagnose the problem.

Sketchysk8er

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Re: No start. I think I figured it out. Just need confirmation.
« Reply #3 on: July 05, 2012, 09:51:30 PM »
I will run the pressure test. Just wondering tho, wouldn't the pump at least make a noise even if it were not giving full pressure or does it  work like...zero flow (say maybe a clogged injector) means fuel backed up all the way to the pump and wont allow it to turn? (thus no noise) This is my first bike and Im still learning so sorry if Im asking dumb questions.

Arizoni

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Re: No start. I think I figured it out. Just need confirmation.
« Reply #4 on: July 06, 2012, 01:07:15 AM »
I'm under the impression that the pump runs when the computer tells it to run.

When I first turn on the ignition key I can hear a 'wheeeeeeeeeee' that lasts about 3 seconds.
I always thought that this was the pump pressurizing the supply line.

If I use my kick starter to turn the engine over with the ignition key on I can hear a short 'whee' from the fuel tank.
I believe this is the pump operating to replace the squirt of fuel that was injected while the engine was turning.

I'll admit I may be wrong because the Service Manual says the pump is controlled by the computer but it has a high pressure bypass valve in it which returns fuel that is in excess to the fuel tank.

In any case, the Service Manual says the pump output pressure should be 294Kpa which my computer link says is equal to 42.64 psi.

IMO, if your fuel pump is receiving a full 12 volts of power at its connector that says the fuel pump relay under your side cover is working and the fuel pump should be running but as Kevin says, test it.

Be careful with the fuel pump outlet.  As one of our members found, its plastic and easy to break.
Jim
2011 G5 Deluxe
1999 Miata 10th Anniversary

Kevin Mahoney

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Re: No start. I think I figured it out. Just need confirmation.
« Reply #5 on: July 06, 2012, 03:47:20 PM »
No need to overthink this. You will have about 10 minutes into the project and you will know for certain if it is the pump or not.

jartist

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Re: No start. I think I figured it out. Just need confirmation.
« Reply #6 on: July 08, 2012, 03:07:02 PM »
With the key on try tapping it gently so as not to break the connector with the handle of a screw driver or something similar.  I don't mean any disrespect but I'm guessing that if the pump doesn't make any noise when you turn the key the pressure is going to be low so what will testing the fuel pressure do?

Kevin Mahoney

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Re: No start. I think I figured it out. Just need confirmation.
« Reply #7 on: July 08, 2012, 04:03:45 PM »
Why would you want to replace a $300 fuel pump without performing a 10 minute test? It may be a fuel pump but throwing parts at a problem is only expensive. Most problems are simple to diagnose definitively which can save you a lot of frustration and money. I have been doing this a long long time and every time I go down that road I get bushwhacked by either the obvious or the simple.

jartist

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Re: No start. I think I figured it out. Just need confirmation.
« Reply #8 on: July 08, 2012, 04:24:08 PM »
It may be a fuel pump but throwing parts at a problem is only expensive... ...Most problems are simple to diagnose definitively which can save you a lot of frustration and money.
I definitely agree with that! I've learned that one on my cars over the years. ::) Beware the red herrings!

Knowing what diagnostic checks for what symptoms and what it tells you is what separates the bad mechanics from the technical geniuses.