| Fuel Pump Delay [message #765197] |
Tue, 06 June 2006 21:42 |
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On my 93 Jeep Cherokee 4.0L, there is a delay of about 40 seconds from
turning on the ignition switch to the fuel pump relay closing and
activating the pump and charging the injector rail to 40 psi. This
delay is present only when the ignition has been off for several hours.
If the vehicle was recently driven, there is no delay from ignition
switch on to the fuel pump relay closing and activating the fuel pump.
There are no trouble codes.
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| Re: Fuel Pump Delay [message #765262 ] |
Wed, 07 June 2006 13:43 |
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My first move would be to see if the relay's coil was being denied
power for the 40 seconds. You need to investigate that. The only other
possibilities I could think of would be that the relay or fuel pump are
somehow binding/sticking... and it takes the 40 seconds to come to
life.
www.telstar-electronics.com
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| Re: Fuel Pump Delay [message #765271 ] |
Wed, 07 June 2006 16:06 |
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In article
<1149622951.939020.321840 [at] u72g2000cwu.googlegroups.com>,
"iPlay1515" <TheLegMan [at] gmail.com> wrote:
> On my 93 Jeep Cherokee 4.0L, there is a delay of about 40 seconds from
> turning on the ignition switch to the fuel pump relay closing and
> activating the pump and charging the injector rail to 40 psi. This
> delay is present only when the ignition has been off for several hours.
>
> If the vehicle was recently driven, there is no delay from ignition
> switch on to the fuel pump relay closing and activating the fuel pump.
>
> There are no trouble codes.
You need to diagnose whether this is an electrical delay or a
fluid pressurizing delay. Sounds like the fuel lines are
draining down after an extended sit.
Try turning the key on for ten seconds, off for ten seconds, on
for ten seconds off for ten seconds to pressurize everything, if
the engine starts quicker, you know it the fuel draining back.
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| Re: Fuel Pump Delay [message #765330 ] |
Thu, 08 June 2006 15:20 |
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Problem Solved
Replaced the Powertrain Control Module (PCM)
$175.00 Advanced Auto $75.00 Core Limited Lifetime Warranty
The delay in the check engine light operating when the ignition switch
was turned on was the most significant symptom. The check engine light
comes on after the PCM completes an initial internal self test which is
very short. If the check engine light is not on, either the lamp is
bad or the PCM is not operational. Without the PCM, the fuel pump
relay will not operated since it is directly controlled by the PCM.
The delay in the check engine light and the delay in the fuel pump
running were the same.
aarcuda69062 wrote:
> In article
> <1149622951.939020.321840 [at] u72g2000cwu.googlegroups.com>,
> "iPlay1515" <TheLegMan [at] gmail.com> wrote:
>
> > On my 93 Jeep Cherokee 4.0L, there is a delay of about 40 seconds from
> > turning on the ignition switch to the fuel pump relay closing and
> > activating the pump and charging the injector rail to 40 psi. This
> > delay is present only when the ignition has been off for several hours.
> >
> > If the vehicle was recently driven, there is no delay from ignition
> > switch on to the fuel pump relay closing and activating the fuel pump.
> >
> > There are no trouble codes.
>
> You need to diagnose whether this is an electrical delay or a
> fluid pressurizing delay. Sounds like the fuel lines are
> draining down after an extended sit.
>
> Try turning the key on for ten seconds, off for ten seconds, on
> for ten seconds off for ten seconds to pressurize everything, if
> the engine starts quicker, you know it the fuel draining back.
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| Re: Fuel Pump Delay [message #765332 ] |
Thu, 08 June 2006 15:49 |
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In article
<1149772831.000995.223530 [at] j55g2000cwa.googlegroups.com>,
"iPlay1515" <TheLegMan [at] gmail.com> wrote:
> Problem Solved
>
>
> Replaced the Powertrain Control Module (PCM)
> $175.00 Advanced Auto $75.00 Core Limited Lifetime Warranty
>
>
> The delay in the check engine light operating when the ignition switch
> was turned on was the most significant symptom. The check engine light
>
> comes on after the PCM completes an initial internal self test which is
>
> very short. If the check engine light is not on, either the lamp is
> bad or the PCM is not operational. Without the PCM, the fuel pump
> relay will not operated since it is directly controlled by the PCM.
>
>
> The delay in the check engine light and the delay in the fuel pump
> running were the same.
The delay in the check engine light coming on was not mentioned
in the original post.
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