04 Sport Edition Fuel pump issues

[Mario4993]

I have an 04 Sport Edition with close to 220k miles on it. I believe I'm having fuel pump issues, but not certain. The car turns over just not the engine. Also, its very hit or miss. Some days it doesn't have any issues at all and other days it struggles every time I turn it on. So my question is, is it a fuel pump or something else?

Advise is much appreciated!

 

[mrpurplepenguin]

I have an 04 Sport Edition with close to 220k miles on it. I believe I'm having fuel pump issues, but not certain. The car turns over just not the engine. Also, its very hit or miss. Some days it doesn't have any issues at all and other days it struggles every time I turn it on. So my question is, is it a fuel pump or something else?

Advise is much appreciated!

A bit of clarification please:

What do you mean by "the car turns over just not the engine"? Do you mean it cranks easily, but won't start? Otherwise, is it sluggish to crank (does the starter motor sound like it's trying pretty hard)? Might be low battery...

What do you mean by "it struggles" sometimes when you turn it on? Is it idling rough? If so, does it do this more frequently when it's been sitting a while (does it start okay when the engine is warm)?

Why, specifically, do you suspect the fuel pump is the problem as opposed to weak spark / low compression / etc.?

Is the check engine light on, and if so what are the error codes?

Finally - do you have a V6 or V8? 03-05 V6 are known to semi-rarely blow the head gasket at the #6 cylinder, this causes rough idling for ~30 sec after startup.

I don't know if the 4Runner fuel pump does a priming cycle once the key is turned to run, but if you suspect the pump you can try this:
Turn the key to run, but don't start the car yet (the fuel pump should run to pressurize the fuel system)
Wait a few seconds, then turn the car off
Turn the key to run, but don't start the car yet (the fuel pump should run to pressurize the fuel system)
Wait a few seconds, then turn the car off
Start the car
If that helps alleviate the problem, your fuel check valve might not be holding pressure in the rail. This would make the car hard to start after it's been sitting a while (once the rail pressure has bled down), and require a longer cranking time (to give the fuel pump time to pressurize the fuel system).

Hope that helps!

 

[Mario4993]

A bit of clarification please:

What do you mean by "the car turns over just not the engine"? Do you mean it cranks easily, but won't start? Otherwise, is it sluggish to crank (does the starter motor sound like it's trying pretty hard)? Might be low battery...

What do you mean by "it struggles" sometimes when you turn it on? Is it idling rough? If so, does it do this more frequently when it's been sitting a while (does it start okay when the engine is warm)?

Why, specifically, do you suspect the fuel pump is the problem as opposed to weak spark / low compression / etc.?

Is the check engine light on, and if so what are the error codes?

Finally - do you have a V6 or V8? 03-05 V6 are known to semi-rarely blow the head gasket at the #6 cylinder, this causes rough idling for ~30 sec after startup.

I don't know if the 4Runner fuel pump does a priming cycle once the key is turned to run, but if you suspect the pump you can try this:
Turn the key to run, but don't start the car yet (the fuel pump should run to pressurize the fuel system)
Wait a few seconds, then turn the car off
Turn the key to run, but don't start the car yet (the fuel pump should run to pressurize the fuel system)
Wait a few seconds, then turn the car off
Start the car
If that helps alleviate the problem, your fuel check valve might not be holding pressure in the rail. This would make the car hard to start after it's been sitting a while (once the rail pressure has bled down), and require a longer cranking time (to give the fuel pump time to pressurize the fuel system).

Hope that helps!

Thanks for the reply and to clarify.

-Its a V6.
-By struggle I mean, it tries really hard to turn on but the engine doesn't start. Then on the second or third try it fires. Typically a very hard idle for about 10-30 secs. if i give it gas there is no rough idle at all. This happens during both cold and warm starts.
-check engine error code comes on only when trying to start. Nothing else. it just flashes when the car starts running and then turns off about 5 secs later.
-I kind of hear but not like it was before. That's why i have the feeling its the pump.
-Could it be a filter stopping the flow?

 

[mrpurplepenguin]

I'm inclined to think it's not a fueling problem if you can give it gas when it's idling rough to get it to smooth out (higher revs = more fuel required, which would be a problem if the pump or filter were limiting flow / pressure).

Do you have a code scanner, or can you borrow one from an auto parts store? Even though the check engine light goes out, it still stores the code in memory (it should be stored as "pending" or something similar). It might be something like P0300 or P030# (random or cylinder-specific misfire) if it's flashing during rough starts. If it's P0306 (cyl 6 misfire), that might be telling...

Can you pull the spark plug on cyl #6 and see if it's damp? My reasoning is your symptoms are similar to a blown head gasket, which typically affects the earlier V6s at the #6 cylinder. When the engine is off, coolant leaks into the cylinder which prevents it from running smoothly until the coolant is burned off (~30 sec or so).

The fuel filter is part of the pump assembly in the tank and (as I understand) generally doesn't fail/clog much.

Did your symptoms suddenly start happening one day, or has the startup been degrading for a while?

 

[Fuzzy Fingers]

Lost a fuel pump in my 07 V6. The warning I had was the fuel gauge quit working. A couple of weeks later, I was on the side of the road. Haven't heard of an intermittent fuel pump failure. Good news if you do have to do the fuel pump, there is a hole in the floor under the drivers side back seat that gives you access to fuel pump.