Bad fuel pump?

[toadjammer]

I need help to try and diagnose a problem. I have an '04 chevy malibu classic that has developed a warm start issue. It has popped up a couple of times, but seems to be getting worse. It is an intermitent fuel pump that doesn't always turn on with the initial key switch to start position. I have swapped relay thinking that may be a solution but that had no positive result. The thing about it is that I always thought that if a fuel pump started acting up that it just went bad. I can get it to kick on by trying to start it multiple times. The real issue is that this isn't a predictable problem, one trip it will have problems and the next it will be fine.
Thanks for any input .
Toad

[Mr.Nutcase]

fuel pressure? is this Direct Fuel injection, then you need Tech 2/Scanner tool to read pressure?

[toadjammer]

I can hear if the fuel pump kicks on or doesn't when the key switch is turned to the on position. I am thinking that the ecm or start curcuit is programed to turn on the fuel pump to pressurize before trying to start every time. This then leads to either something bieng wrong with the starting curcuit, a wire is damaged or the fuel pump is bad.

[bgott]

I haven't played with any of the newer ones, the old ones kicked the fuel pump on for two seconds to prime the system whenever you turned on the key.

[yellowbox]

next time it doesnt start , hit the gas rank with a soft , rubber mallet to see if it starts
these cars are known to go thru fuel pumps once they get past 60,000

[dipper]

could also be a bad ground, there is a wire from the sending unit that goes to the frame/body of the car.

[z28snksknr]

I don't know if it's the case with your car, but I know some vehicles that do not do the "prime for 2 seconds" thing. They only are an "on-demand" system. Some other systems only run the pump when the car is running.

I'm only bringing this up so that you verify that your pump should run EVERY time you turn your key to the on position.

Is it possible that you are getting vapor lock? I recall (perhaps incorrectly?) that the LS series engines and possibly the derivities of them do not have a return line from the engine since the fuel pumps are self-regulating, so it could be possible that fuel is vaporizing, increasing the pressure in the system so the pump doesn't run (and the car can't start on vapors)

[tcianci]

when you do finally get it to start when it's hot, does it stumble like it's flooded until it clears out? I had this problem on a Chevy V8 and it was the fuel pressure regulator.

[STClurker]

yellowbox
Re: Bad fuel pump?
next time it doesnt start , hit the gas rank with a soft , rubber mallet to see if it starts
these cars are known to go thru fuel pumps once they get past 60,000

^^^^^^^^^^^^^^^ seen that

tcianci
Re: Bad fuel pump?
when you do finally get it to start when it's hot, does it stumble like it's flooded until it clears out? I had this problem on a Chevy V8 and it was the fuel pressure regulator.

^^^^^^^^^^^^^^ been there with the wife's '98 malibu with the 3.1


sorry I don't know how to muli-quote

[MottsRods]

Toad, i just fixed my Yukon that was doing something similar. It would just turn over when trying to start. I checked fuel pressure at the engine,42psi...good. So I finally checked the output of the fuel pump and it should have been at 60psi....but it was at 22 thus the not starting.

[ironroad 9c1]

Change the pump and be done.

[toadjammer]

Originally Posted by ironroad 9c1

Change the pump and be done.

Tell you what you give me the $250 and I would be more than willing to trouble shoot by replacing parts.

MottsRods,
How could it be that you had that big of a differance between the two pressures? If the fuel pressure is 42 in the engine compartment the only way to achieve this is by the fuel pump creating said pressure.

Is it a possibility that a key switch could go bad and creat a problem like this?

The reason that I question the fuel pump is because if the key is cycled a few times you can hear the fuel pump kick on the car will proceed to start.

Can anyone verify that this is a model that has a continuos running fuel pump or that it should be kicking on for a couple of seconds every time the key switch is turned to the run position.
Thanks
Toad

[ironroad 9c1]

I told you what the problem is , but keep guessing.
Plus it you do it right , you can just buy a new pump for about 60 bucks and not have to needlessly replace the entire "Package" that gm so thoughtfully designed, I did on my wife's 2002 s10, I wasn't gonna pay 300 bucks for some plastic and to replace a sending unit there was nothing wrong with. I took it apart and just replaced the pump itself.
And all GM fuel pumps just come on for a few seconds to prime the line.

[MottsRods]

Dunno how it happens that way, but it did....and has been...but it's fixed now. New pump and runs like new.

[toadjammer]

MottsRods,
Thanks for the info.

Originally Posted by ironroad 9c1

I told you what the problem is , but keep guessing.
Plus it you do it right , you can just buy a new pump for about 60 bucks and not have to needlessly replace the entire "Package" that gm so thoughtfully designed, I did on my wife's 2002 s10, I wasn't gonna pay 300 bucks for some plastic and to replace a sending unit there was nothing wrong with. I took it apart and just replaced the pump itself.
And all GM fuel pumps just come on for a few seconds to prime the line.

So please enlighten us all to where we can pick up a $60 dollar fuel pump that is a direct replacement. I have no problem changing it. But at anything over $100 I want to be resonably sure that it is the culprit.

By the way did your wifes 2002 s10 just up and die or did it work intermitently?

[ironroad 9c1]

You seem like a smart guy...you figure it out.

[alamerang]

One question, does the "Security" light flash on the dash when this is happening? If so you have a problem with the pass key sensor or a bad key. Try using your spare transponder key to see if that makes it run better.

[toadjammer]

Originally Posted by ironroad 9c1

You seem like a smart guy...you figure it out.

What you can't support your earlier statements? Where you just blowing smoke? Come on if you have an obvious way of fixxing it and saving a couple hundred dollars why not share.

And answer my other question "By the way did your wifes 2002 s10 just up and die or did it work intermitently?"