Question about 2003 Pontiac Sunfire

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My car wont start unless i bang on the fuel pump why?

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The fuel pump bearings are worn out, this makes it stick, replace it.

Posted on Apr 30, 2010

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  • Master
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Your fuel pump needs replacing, the brushes that deliver power to rotating part of the motor (called the commutator) is stopping on a segment of the commutator witch is losing contact with the brush, a percussion on the pump body or in the case of an in-tank fuel pump a percussion to the underside of the fuel tank will momentarily make contact and allow the commutator to spin thus allowing normal operation of the pump, when the pump stops again, randomly it may stop on the segment afflicted with the poor connection and the proses starts again, until finally any amount of shock will not start the pump

Posted on Apr 30, 2010

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  • Master
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Either there is a blockage or it is faulty.I would suggest a replacement and using a fuel filter before the petrol flow to the pump.This would stop debri or dirt from going into the system.Hope this helps.

Posted on Apr 30, 2010

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Posted on Jan 02, 2017

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SOURCE: wont start

throttle body air intake mix is cracked i hope i said this right
right now my mind is waken up

this will be connected to the air filter and assembly take the whole assembly out and try and start vehicle
if vehicle runs you have a crack in throttle body air intake housing this will need to be replaced

cloged fuel filters there is usually 3 one in the engine compartment one on chassis and one in the gas tank called the sending unit this has a filter on it
the gas tank filter only needs to be replaced every 100 thousand miles

timing might be off
sparks not connected all the way or improperly wired
computer took a surge and now wont run replacement of computer is needed
vacume leak at master cylinder
capasitor ignition coil bad <<< spell check
alternators these days are mostly being remanufactured the only true brand new alternators are the ones that come from dealer
batterys are reman. too sometimes they have a dead cell in them
at one point in my life i had to go back 4 different times with alternator and battery for the same problem
this is a win loose win kind of senerio

from the sound of the vehicle only runs off a jump the alternator and or battery is bad

i hope this helped you in discovery of vehicle problems

Posted on May 29, 2008

  • 1 Answer

SOURCE: wont stay running

its your fulepump

Posted on Nov 27, 2008

  • 344 Answers

SOURCE: 93 volvo 850 glt changed the fuel pump now car

Check your fuel pressure to ensure proper pressure to the block, also did you replace the fuel filter.

On a side note: 3 things a automobile needs to run

AIR-make sure you have a clean air filter and your MAF (mass air flow sensor is plugged in) if you pulled your breather to innspect anything, there is a possibility that it came unplugged or you unpluged it and forgot to hook it back up, a car wont start without it being plugged in if equiped

SPARK-Make sure your car has juice to the plugs, if the plug doesnt fire the car wont run, if you have to pull each plug and ground them to the engine block to see if they arch. If not trace the problem down (if you changed the fuel pump you have some mechanical skill and should be able to troubleshoot a spark issue)

FUEL-Check for proper pressure, dirty fuel filter(s) and if your system has a return line, make sure your hoses didnt get crossed cause this will damage the engine and regulator.

Hope this helps Thanks for using

Posted on Jan 22, 2010

  • 978 Answers

SOURCE: my car starts, but it wont stay running

idling jet carburette

Posted on Feb 16, 2010

  • 501 Answers

SOURCE: replaced fuel pump & still car wont start on 97 olds 88

You have to check for spark and fuel pressure. The 3800 motor can have a bad module (sits right below the coil pack, as well as bad coils. Also check for fuel pressure. I put a brand new dealer pump in a 93 Olds once and it was not putting out enough pressure to engage the injectors. Section 4 in a Hayes manual found at most Advance and Auto zone stores will give you the fuel pressure reading you need.

Hope this helps.

Posted on Mar 07, 2010

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