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Discussion Starter #1
My fuel pump runs for up to 1 1/2 minutes to pressure up before the car will start
after sitting overnite. Shorter than that after sitting less time, but never only a couple of seconds.
I've been searching for this problem here in the forums for hours and don't see anything like it so please don't flame me.
New fuel filter, clean maf, 32psi at the rail while idling.
What is it?
Thanks!
 

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sounds like the fuel pump relay may be sticking.....bust out the multimeter and check to see if voltage is present going to the fuel pump, and if there is, is the relay sending voltage because it has stuck, or because the EEC is the one energizing the relay
 

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Discussion Starter #4
sounds like the fuel pump relay may be sticking.....bust out the multimeter and check to see if voltage is present going to the fuel pump, and if there is, is the relay sending voltage because it has stuck, or because the EEC is the one energizing the relay
Thanks I'll try that...
 

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Discussion Starter #5 (Edited)
To clarify, do you mean it runs for 1.5 minutes continuously or that it takes 1.5 minutes to build up the proper pressure in the fuel rail?
It pumps continuously for that minute or so before it will start. Once the pump stops it will start right up, so I am assuming it's still building pressure. It sometimes makes a sqealing sound just before it stops pumping.
I haven't checked the pressure at the rail while it's pumping.
 

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I think, if the car won't start before the minute is over, that you have either a dying pump, or a failing fuel pressure regulator. The regulator is cheaper and easier to fix.
 

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Well, there is no pressure sensor on the fuel rail, so the PCM doesn't command the pump to run until there is a specified pressure. If it is running for that long, I would say you CCRM (constant control relay module) which houses your fuel pump relay among other things might be bad. To be sure you would need to test with a multimeter to see, like guitar maestro alluded to, if the PCM is energizing the relay or if it is stuck. If it is stuck, I have a working one if you need it.
 

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Discussion Starter #9
Well, there is no pressure sensor on the fuel rail, so the PCM doesn't command the pump to run until there is a specified pressure. If it is running for that long, I would say you CCRM (constant control relay module) which houses your fuel pump relay among other things might be bad. To be sure you would need to test with a multimeter to see, like guitar maestro alluded to, if the PCM is energizing the relay or if it is stuck. If it is stuck, I have a working one if you need it.
Not sure I follow Chris. The PCM doesn't command the pump to run until there is a request for pressure? A sticking relay would delay that request?
Thanks!
Dean
 

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The PCM energizes the fuel pump relay under 2 conditions. 1) The key is turned to ON/RUN and the engine isn't running. 2) The key is turned to ON/RUN and the engine is running. Under condition 1, it is only supposed to run for about 2-3 seconds, just enough to prime the system to start the car. Under condition 2, it should run non-stop. What I was saying is that there is no feedback to the computer regarding how much pressure is at the fuel rail, so the PCM doesn't "know" when the pressure is built up enough. That means that if the fuel pump is running for so long when you just turn the key ON and the engine isn't running, either the fuel pump relay is sticking, or the PCM is commanding it for too long which means there is something wrong with the PCM. That's why you need a multimeter to test to see if the relay is stuck or if the PCM is really commanded it to run for that long.
 

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Discussion Starter #11
Makes more sense now. I'll check those out before I go pulling the tank.
Wasn't looking forward to that job!
Thanks for clearing that up for me Chris.
I'll keep you posted on the results.

Dean
 

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Discussion Starter #12
Probably not a bad fuel pump

After listening closer I am hearing the fuel pump turn on in the final couple of seconds of the 2 minutes of the wait for pressure.
The fan runs the whole time and diguises the pump noise.
I'll try replacing the fuel pump relay under the hood first.
If that doesn't do it I'll switch the PCM with my other car.
 

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I wish you had said the fan was running. That narrows it down. This is the same issue I have seen on several 96/97 cars. There are three wires that go to the DPFE sensor at the back of the engine. These wires tend to melt and when they short out, the symptoms you describe occur.
 

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Discussion Starter #14
Wires

Thanks again Chris.
I haven't placed a fuel pump order yet... so I'll check wires first.
It is now making a gurgling sound from the back presumably fuel trying to make it's way to the front.

Dean
 
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