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 Post subject: Fuel pump for startup
PostPosted: Wed May 17, 2006 5:06 pm 
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my car doesnt start until about 2 - 4 second starting cranks. It used to start right up, and the only thing i noticed that has changed is the fuel pump does not turn on anymore when the key is in the 'run' position while the engine is not running. I have a feeling it takes a long time for the car to build up fuel pressure, because after it has been running and shut off, it starts right up. Does anyone know the mechanism for the fuel pump starting?



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PostPosted: Fri May 19, 2006 8:49 am 
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There is a relay under the hood, at the front drivers side, by the horn. There are two relays on my car, one for fuel pump, one for horns. If the computer sees engine not running status, it may not run the fuel pump. Mine doesnt run every time I turn the key to ignition. Fuel pressure test is the only way to rule that possibility out, since the car DOES run.

Had a look at your mass airflow sensor lately? When mine was on the fritz, it took a lot longer to turn the car over and get an accurate air reading. Just a thought among many possibilities.



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PostPosted: Fri May 19, 2006 12:16 pm 
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When I first got my car, it would sometimes take a 2-4 second duration to start the engine. I was able to trace the problem to my starter. It was covered in oil from a leaking gasket on my engine. Once I replaced the gasket and installed a new starter, my problem was solved.

Hope this helps.



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PostPosted: Fri May 19, 2006 8:17 pm 
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MysterHK wrote:
When I first got my car, it would sometimes take a 2-4 second duration to start the engine. I was able to trace the problem to my starter. It was covered in oil from a leaking gasket on my engine. Once I replaced the gasket and installed a new starter, my problem was solved.

Hope this helps.


While that can be a problem, the electric starter in a car has no bearing on spark, fuel, or compression. If it were covered in oil, it would either turn over slow, or not at all. Since the starter works, and he is noticing that the pump isnt running, I would say that this possibility could be safely eliminated, assuming all the premsis are true.

The thing to do, IMO, is first check the simple stuff like grounds and relays if you are positive that the pump isnt running. You will need a diagram, and a multimeter. While I cant say it is for sure an electrical problem, if the pump isnt running, then that is the most logical starting point. Make sure you have found the cause before you just throw parts at it.

Hope this helps ya out,

Andrew



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PostPosted: Fri May 19, 2006 8:18 pm 
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88delta88 wrote:
Had a look at your mass airflow sensor lately? When mine was on the fritz, it took a lot longer to turn the car over and get an accurate air reading. Just a thought among many possibilities.


I think I may be wrong, but wouldnt a faulty MAF trigger a trouble code and a light?



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PostPosted: Fri May 19, 2006 9:18 pm 
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andrewk wrote:
........ Make sure you have found the cause before you just throw parts at it........

I'll drink to that.



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PostPosted: Fri May 19, 2006 11:48 pm 
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The MAF is fairly new (a couple of months old). I will check those relays and see what happens. The pump has to turn on at some point, so i would assume the relay is working. It only starts slowly when it is cold, not when warm.



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PostPosted: Sat May 20, 2006 3:31 am 
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andrewk wrote:
MysterHK wrote:
When I first got my car, it would sometimes take a 2-4 second duration to start the engine. I was able to trace the problem to my starter. It was covered in oil from a leaking gasket on my engine. Once I replaced the gasket and installed a new starter, my problem was solved.

Hope this helps.


While that can be a problem, the electric starter in a car has no bearing on spark, fuel, or compression. If it were covered in oil, it would either turn over slow, or not at all. Since the starter works, and he is noticing that the pump isnt running, I would say that this possibility could be safely eliminated, assuming all the premsis are true.

The thing to do, IMO, is first check the simple stuff like grounds and relays if you are positive that the pump isnt running. You will need a diagram, and a multimeter. While I cant say it is for sure an electrical problem, if the pump isnt running, then that is the most logical starting point. Make sure you have found the cause before you just throw parts at it.

Hope this helps ya out,

Andrew


Come to think of it Andrew, you're right. As a matter of fact, now that I recollect again, it was turning over slow and there were times when I had to turn the key to the "off" position again and then start the engine. My bust. I stand corrected.



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PostPosted: Sat May 20, 2006 3:25 pm 
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MysterHK wrote:
andrewk wrote:
MysterHK wrote:
When I first got my car, it would sometimes take a 2-4 second duration to start the engine. I was able to trace the problem to my starter. It was covered in oil from a leaking gasket on my engine. Once I replaced the gasket and installed a new starter, my problem was solved.

Hope this helps.


While that can be a problem, the electric starter in a car has no bearing on spark, fuel, or compression. If it were covered in oil, it would either turn over slow, or not at all. Since the starter works, and he is noticing that the pump isnt running, I would say that this possibility could be safely eliminated, assuming all the premsis are true.

The thing to do, IMO, is first check the simple stuff like grounds and relays if you are positive that the pump isnt running. You will need a diagram, and a multimeter. While I cant say it is for sure an electrical problem, if the pump isnt running, then that is the most logical starting point. Make sure you have found the cause before you just throw parts at it.

Hope this helps ya out,

Andrew


Come to think of it Andrew, you're right. As a matter of fact, now that I recollect again, it was turning over slow and there were times when I had to turn the key to the "off" position again and then start the engine. My bust. I stand corrected.


Nothing wrong with being "corrected", it happens to all of us. After all, that's why we are here!

Andrew



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PostPosted: Sat May 20, 2006 10:45 pm 
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Andrewk, my MAF never caused an error code, and if the sensor is just covered in dirt, it will just perform poorly, in my case anyways. The symptoms were poor throttle response and hard starting when warm. If there is a short, or the sensor packs it in, I am certain it would cause an error code.

But, from his response, the symptoms are hard cold starting, and his MAF is not very old. So, this can also be safely eliminated.



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PostPosted: Sat May 20, 2006 11:44 pm 
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88delta88 wrote:
Andrewk, my MAF never caused an error code, and if the sensor is just covered in dirt, it will just perform poorly, in my case anyways. The symptoms were poor throttle response and hard starting when warm. If there is a short, or the sensor packs it in, I am certain it would cause an error code.


Its interesting that the design of the MAF is such that it can "fail" without "failing". Then again, maybe the late 80's ECM technology wasnt capable of recognizing the lack of airflow over the MAF? I guess they don't call it R&D for nothing... Score one for "R" in this case :wink:

88Delta88 wrote:
But, from his response, the symptoms are hard cold starting, and his MAF is not very old. So, this can also be safely eliminated.


Indeed. How's it coming abbike18?

Andrew



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 Post subject:
PostPosted: Sun May 28, 2006 8:56 pm 
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it turns out it was my computer. there are two ways to turn on the fuel pump in my car. one way is for the computer to tell it to turn on, and another is if there is over 4 psi of oil pressure. what happened is for some reason my computer stopped sending out the signal to the fuel pump for startup, so i was cranking my engine until it built up 4 psi of oil pressure, then the pump turned on. I figured this out by using the mitchell site off of the napa homepage. I suggest it for everyone who is having electrical difficulty with their car. it is an excellent resource.



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PostPosted: Sun May 28, 2006 9:37 pm 
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good analysis! so, what did you do to resolve the problem of your computer not sending a signal?



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PostPosted: Mon May 29, 2006 12:31 pm 
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abbike18 wrote:
it turns out it was my computer. there are two ways to turn on the fuel pump in my car. one way is for the computer to tell it to turn on, and another is if there is over 4 psi of oil pressure. what happened is for some reason my computer stopped sending out the signal to the fuel pump for startup, so i was cranking my engine until it built up 4 psi of oil pressure, then the pump turned on. I figured this out by using the mitchell site off of the napa homepage. I suggest it for everyone who is having electrical difficulty with their car. it is an excellent resource.


Damn, that's awesome man! Good job!



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PostPosted: Mon May 29, 2006 12:49 pm 
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i had to replace the ecu ($80). but a warning to anyone dealing with ecu/ecm problems: if you find there is something wrong with the ecu, check the circuit for resistance before buying a new ecu. ecus require cirquit resistance of at least 20 ohms, and if you have a shorted circuit that blew your old ecu, a new one will blow right away, and it feels like crap to know you just threw $80 out the window.
My favorite way to diagnose ecu problems is to disconnect the ecu and find which pin is used for the problem you are having (for example, i was having fuel pump problems, so i found the terminal on the ecu connector that controlled the fuel pump) Then i manually put 12 volts into that circuit by sticking a pin into that terminal on the ecu connector. Low and behold, the fuel pump turned on. Check resistance in circuits before you do this cause you dont want to burn out the wires if there is a short in a relay or something.



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