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Amedee, Pontiac Technician
Category: Pontiac
Satisfied Customers: 26432
Experience:  ASE certified Technician advanced level specialist. Wisconsin certified emissions state inspector
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98 sunfire: 2.4 cranks but wont start..gas tank..fuel filter

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98 sunfire 2.4 cranks but won't start. i hear no hum from the gas tank when i turn it on so i replaced the fuel pump, fuel filter, relay and fuse and still nothing. i measured the volts dc on the bottom of the 4 pins on the relay with the key on and recorded 2 volts on one pin zero on the other three. so i assume i am not getting power to the relay for some reason. i jumper wired from the battery to the relay and could hear the pump run but could not get the car to start. Any suggestions would be greatly appreciated.

Does the check engine light come on with the key on?

Does the engine have spark when cranking it over?
Customer: replied 6 years ago.

no check engine light, but check gages, theft system, abs, brake, oil symbol, battery symbol and seat belt lights are all on.


how do i check for spark? take the cover off the engine and pull a spark plug? Oh, it also for a new fuel pressure regulator, plugs and plug wires 6 months ago.

Well this is your problem! Your computer is not even awake! Chances are you are missing a power or a ground to the computer causing it not to wake up. The only other possibility would either be a bad computer or the computer is being shorted out by another computer or a sensor.

I would start by checking all powers and grounds going to the PCM. THis includes all powers from all fuses, fusible links and even from the ignition switch.
If you need wiring diagram or a pin out chart of the PCM connectors, lets me know!
Customer: replied 6 years ago.
can you send me the wiring diagram or pinout chart and i will start checking from there.
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Customer: replied 6 years ago.
i must be an idiot. how do i use these charts. i tried to check the fuel pump relay volts on c2-08 with a voltmeter but got nothing. key was on, battery connected. why do i not get a reading?
I will walk you through this.

Turn the key on and check for 5 volts at the tps sensor on one of the three wires.

MAke sure your meter is set on the DC scale about 20 volts or so.
Customer: replied 6 years ago.
were is the tps sensor
ON the throttle body
Customer: replied 6 years ago.
ok. got 5 volts on the far left wire

Does the engine run on starting fluid?
Customer: replied 6 years ago.
yes but not for long. it fires a couple of times, then burps.
Are there any codes in the computer?
Customer: replied 6 years ago.
i do not have a reader and autozone reads them but only if i bring them the car which would require trailering. they are 30 miles away.
But the engine does have spark...correct?
Customer: replied 6 years ago.
yes. it fired when i sprayed the starting fluid.
Ok.. but just no power to the fuel pump...correct?
Customer: replied 6 years ago.
if the power goes thru the relay i had no power at the relay
Ok.. turn the key on and check to see how many powers are going to the fuel pump relay with the key on. One or two?
Customer: replied 6 years ago.
only 1 and it has 2 volts
What color wire has 2 volts?
Customer: replied 6 years ago.
i cannot tell. it is inside the fuse and relay box and does not readily come apart. The pins are labeled 30, 85, 86, 87. 30 is the one with power.
You need to have power on the pink wire with the key on and both on and power on the pink wire and the dark green/white wire at the fuel pump relay while cranking the engine over. Here is a wiring diagram.

Customer: replied 6 years ago.
i have power on the pink but not on the dark green. i am working by myself and cannot turn the engine over and do the meter check at the same time. does that matter?
YES... this is the signal wire from the computer. THis wire should go from nothing or ground to power with the key on (for 2 seconds) and then go off until you crank the engine over again and then it should go hot or battery voltage while cranking the engine over.

If not, then we might just have a computer issue going on here...
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