Fuel Pump Disable

JD1964 · Mar 13, 2014

I want to crank the engine but have the fuel pump off. What's the easiest way to temporarily disable the pump?

I'd like to avoid triggering a CEL if at all possible.

elarm1 · Mar 13, 2014

flip that trigger in the trunk

JD1964 · Mar 13, 2014

elarm1 said:
flip that trigger in the trunk

It's a hatchback. Is the switch behind the back panel somewhere?

elarm1 · Mar 13, 2014

Yes, its located behind back panel, left of the trunk lock. Trip it and it will disable the pump. Why are you doing this?

JD1964 · Mar 13, 2014

elarm1 said:
Yes, its located behind back panel, left of the trunk lock. Trip it and it will disable the pump. Why are you doing this?

Before I put the spark plugs in (so the engine will spin faster) I just want to spin it a bit to make absolutely sure the roller rockers clear the modified baffle in the valve cover.

I'll align the cover with two bolts just a few threads in. Then, while my helper cranks I'll hold the cover down and feel/listen for clearance problems.

That's my plan anyway.

elarm1 · Mar 13, 2014

Just disconnect the coil wire and fire away! No unscrewing or solonoids to trip

Edit... It doesn't have any plugs in. so whats the problem here? Just start the car with the gas pedal to the floor

JD1964 · Mar 13, 2014

elarm1 said:
Just disconnect the coil wire and fire away! No unscrewing or solonoids to trip

Edit... It doesn't have any plugs in. so whats the problem here? Just start the car with the gas pedal to the floor

Fuel line won't be connected at the point of the test. If I turn the key on with fuel line unhooked, gas will gush all over.

elarm1 · Mar 13, 2014

then plug it back up then floor the gas pedal when starting

JD1964 · Mar 13, 2014

elarm1 said:
then plug it back up then floor the gas pedal when starting

Flooring the pedal won't matter. The upper intake is not on yet.

JD1964 · Mar 13, 2014

I like your suggestion of the solonoid in the back. I'll do that. Thanks.

stykthyn · Mar 13, 2014

Flooring the gas pedal while cranking tells the injectors not to pulse. Either hook up the line and floor the gas pedal or trip the inertia switch. Honestly I would just spin it by hand with a wrench. If there is contact you will hear it.

JD1964 · Mar 13, 2014

Thanks again to both of you. I didn't know flooring the pedal prevents injectors from pulsing.

Are most other fuel injected cars like this too?

elarm1 · Mar 13, 2014

stykthyn said:
Flooring the gas pedal while cranking tells the injectors not to pulse. Either hook up the line and floor the gas pedal or trip the inertia switch. Honestly I would just spin it by hand with a wrench. If there is contact you will hear it.

Probably the safer method as less destruction would occur if something was screwed up

stykthyn · Mar 13, 2014

Option 3 wild be to bridge the starter solenoid on the fender with a screwdriver. This will merely bump the starter and not prime the fuel system.

88LX5.Oh · Mar 13, 2014

^ that's what I'd do. Don't have to take any panels off inside the car or anything. Just jump the solenoid, the small top pin to the big pin with the red wire going to it. Simple as that lol

7991LXnSHO · Mar 13, 2014

I do not know your year, but reach under the driver's seat and unplug the fuel pump relay.

JD1964 · Mar 13, 2014

stykthyn said:
Option 3 wild be to bridge the starter solenoid on the fender with a screwdriver. This will merely bump the starter and not prime the fuel system.

Sounds like the ticket. Good idea.

Not only does it not energize the pump, but the ignition stays dead too, correct?

Grabbin' Asphalt · Mar 13, 2014

Jumping the solenoid is easy to do, be careful using a large diameter screwdriver, the amp load can melt the contacts inside. You can use a small screwdriver or wire, both works fine.

jrichker · Mar 14, 2014

How to crank engine without ignition or fuel pump being powered on.
1 picture is worth 1,000 words...

Fuel Pump Disable

JD1964

there is enough sticking out to grab on to

elarm1

JD1964

there is enough sticking out to grab on to

elarm1

JD1964

there is enough sticking out to grab on to

elarm1

JD1964

there is enough sticking out to grab on to

elarm1

JD1964

there is enough sticking out to grab on to

JD1964

there is enough sticking out to grab on to

stykthyn

I want to measure mine. It doesn't look that tall.

JD1964

there is enough sticking out to grab on to

elarm1

stykthyn

I want to measure mine. It doesn't look that tall.

88LX5.Oh

7991LXnSHO

wanna catch the space herp

JD1964

there is enough sticking out to grab on to

Grabbin' Asphalt

jrichker

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Fuel Pump Disable

there is enough sticking out to grab on to

there is enough sticking out to grab on to

there is enough sticking out to grab on to

there is enough sticking out to grab on to

there is enough sticking out to grab on to

there is enough sticking out to grab on to

I want to measure mine. It doesn't look that tall.

there is enough sticking out to grab on to

I want to measure mine. It doesn't look that tall.

wanna catch the space herp

there is enough sticking out to grab on to

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