Fuel System Questions

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cutchaguy

Fuel System Questions

Post by cutchaguy »

When I put the key in the ignition and turn it, I hear the fuel pump working...sounds like a buzzer under the car. Is this supposed to continually running without the engine firing up?

I have that issue where my car starts fine, but after driving a bit and shutting it off, it won't start again without sitting a few hours first. Ideas?

My uncle and I feel that maybe one problem is that it is flooded and continues to stay flooded. Another could be that the fuel pressure regulator or a sensor of sort is not functioning correctly. It initially starts because of the cold start valve, but after the engine is warmed up, something may be giving false info so too much gas is being delivered and won't restart. Going to see if I can smell gas after it fails to restart.

I'm going to change the fuel filter as well. We're also thinking that if there is no fuel pressure in the line, that could be a telling clue as to the problem. Will try to change filter without depressurizing line first...but will have plenty of rags and pans around.

Today, I should have the throttle plate heater repaired and the new overflow bottle in place and am going to take it in to get the cooling system inspected and flushed. I also got a new thermostat to install regardless of whether the old is functioning or not because I saw the temp gauge go almost to redline. (Could be lack of coolant, lack of flow due to blockage as evidenced by all the crud in the throttle plate heater, or something else.) The radiator guy said he will pressure test it after flushing and inspecting and mark any spots on the hoses where he finds leaks or issues.
NebraskaSpider

Re: Fuel System Questions

Post by NebraskaSpider »

My fuel pump does the same, I think thats normal. You can see the fuel filling up in your fuel filter once you just turn the electricity on to the engine.

I dont know if this will relate, but I had the same problem on my dad's old ford tractor and it turned out that it was the ignition coil. He had the same problem it would start fine after sitting but if it dies or he stopped it, it wouldnt start. After replacing the coil, it starts right up everytime.
cutchaguy

Re: Fuel System Questions

Post by cutchaguy »

Hmmmm...we did think the spark was kinda weak... :idea:
rlux4
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Your car is a: 1982 2000 Spider
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Re: Fuel System Questions

Post by rlux4 »

If you mean tht your fuel pump starts to run when you turn the key to the "on" position, that isn't how it should be operating.
The power for the fuel pump goes from the ignition switch when the key is in the "start" position. This power goes over to the dual relay. Another signal comes from the air flow meter when the flap is opened as air is sucked into the cylinders when the engine turns over. This signal goes to the 2nd side of the dual relay and when both sides of the dual relay are energized (ignition and AFM), the power is sent to the fuel pump. It's common to find that a PO has bypassed the dual relay when trying to diagnose a non start issue, most probably because they didn't understand the function. It won't hurt the pump to run before you crank the engine, the fuel would just circulate back to the tank. But, it leaves you open to running down your battery if the key is left in the on position for any length of time.
Ron
Ron Luxmore
rlux2n2@gmail.com
'82 2000 Spider: after 26 years between Spiders.
So Cal Mark

Re: Fuel System Questions

Post by So Cal Mark »

if the 4 injectors and cold start injector are in perfect condition, running the pump constantly isn't a huge problem as Ron stated except for the potential of running the battery low. But, if the injectors leak at all, you stand a good chance of flooding one or more cylinders.
A potential cause of long crank times when hot is the possibility that the fuel system doesn't hold pressure. If the pressure bleeds off with the engine off, you can experience vapor lock in the fuel rail. You'll need a pressure gauge for diagnosis
rlux4
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Your car is a: 1982 2000 Spider
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Re: Fuel System Questions

Post by rlux4 »

Excellent point, Mark.
Ron
Ron Luxmore
rlux2n2@gmail.com
'82 2000 Spider: after 26 years between Spiders.
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