C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Having weird, hard to start (sometimes) problem!

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Old 12-10-2002, 12:13 PM
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Hawaiian Punch
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Default Having weird, hard to start (sometimes) problem!

My car sometimes has a hard time starting, whats weird is that sometimes, it starts right up, at times it starts and immediately quits, it does this a few times then it will start, with or with out the gas pedel down, sometimes it satrts barely, it just chugs along then idles fine, the car it self while driving it runs good. I've changed the coil, cap & rotor, fuel filter, IAC, throttle position sensor, plugs, wires, ignition module, I've even checked the timing several times, still haveing the problem! can some one help? our who wants to buy the car for $1.75 (Plus tax) :lol:
Old 12-10-2002, 12:28 PM
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John Row
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Default Re: Having weird, hard to start (sometimes) problem! (Lo-Blow)

Check your fuel pressure. Could be you've got a pressure regulator or fuel pump problem. You've replaced almost everything else!

When you turn the key on (without starting the car), does the fuel pump start immediately, run for a bit, then stop.


[Modified by John Row, 11:29 AM 12/10/2002]
Old 12-10-2002, 02:36 PM
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Hawaiian Punch
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Default Re: Having weird, hard to start (John Row)

Check your fuel pressure. Could be you've got a pressure regulator or fuel pump problem. You've replaced almost everything else!

When you turn the key on (without starting the car), does the fuel pump start immediately, run for a bit, then stop.


[Modified by John Row, 11:29 AM 12/10/2002]
What should I be looking for when I do this test? "im going to go see right now! I'll reply back in a few minutes.
Old 12-10-2002, 02:51 PM
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Default Re: Having weird, hard to start (Lo-Blow)

O.K! checked for the fuel pump to sound off and it I did'nt hear anything, so what does this mean?.....anybody? :confused:
Old 12-10-2002, 04:44 PM
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John Row
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Default Re: Having weird, hard to start (Lo-Blow)

The fuel pump should come on briefly (1-4 secsond) to pressurize the fuel rails to ~38 lbs. The fuel rail should hold the pressure for quite a long time after you turn off the key (mine held for 30 minutes, then I got bored and forgot to check again).

The pump doesn't make very much noise, but you should hear it. You might get someone else to turn the key while you put your ear on top of the gas cap. If you don't hear it then, put a new fuel pump on order. At least be sure wiring connections are good. An intermittant fuel pump might just be a poor ground.

Be very conscience of the fuel pump noise when the car starts/not starts. If you don't hear the pump and it doesn't start, you might have found a problem.
Old 12-10-2002, 06:11 PM
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Hawaiian Punch
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Default Re: Having weird, hard to start (John Row)


The pump doesn't make very much noise, but you should hear it. You might get someone else to turn the key while you put your ear on top of the gas cap. If you don't hear it then, put a new fuel pump on order. At least be sure wiring connections are good. An intermittant fuel pump might just be a poor ground.
Where does the fuel pump ground to? in other words where can I find the ground to the fuel pump? Anybody? :confused:
Old 12-11-2002, 12:52 AM
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John Row
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Default Re: Having weird, hard to start (Lo-Blow)

Pull the fuel door off and the filler cover. The pump is right below it. Follow the wires. I'll look in the manual to see if gives anything more definite.

JR

Manuals weren't much help on locating where the pump is grounded. Looks like it could be on the halo just behind the passengers ear or on the frame behind the passenger seat.


[Modified by John Row, 9:50 AM 12/11/2002]
Old 12-12-2002, 01:33 AM
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John Row
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Default Re: Having weird, hard to start (John Row)

In my manual it says that the pump comes on for 2 seconds to charge the fuel rails.

It goes on to say that if it doesn't see "ignition reference" within 2 seconds of cranking it shuts off the fuel pump. In my case that would indicate an optispark problem. Not sure if the L98 has anything similar, but you might take a look at the distributor.
Old 12-12-2002, 10:03 PM
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Default Re: Having weird, hard to start (sometimes) problem! (Hawaiian Punch)

Put a fuel pressure gauge on the schrader valve on the fuel rail and turn on the ignition to pressurize the rail. Turn off the ignition and see how long it takes to lose fuel pressure. If it drops very fast, you have one or more leaky fuel injectors which makes the a/f ratio too rich for a normal start.

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