VegasNaturist

Not really a question, just passing on some info that may be of use to others...

'Bout a month ago, we went to Saline Valley in DVNP to enjoy the hot springs. On the way in, the truck started bogging down badly. I'd get this BWWWAAAaaaaa, and the truck would almost stall, but wouldn't. I had almost no power but was able to nurse it to the springs. Figured if we're going to get stuck, we'd rather be where there are other people. Anyway, I noticed when the truck would bog down, I heard a distinct ticking from the fuel pump area. The ticking would go away if I let off the throttle till the engine would catch again. Interestingly, the truck seemed to be fine the next day. For those not familiar with Death Valley, the springs are 55 miles from pavement and on the other side of a mountain range. I wasn't going to take a chance on driving it out and getting stranded on the mountain.

Now I'm trying to figure out what's happening. Only 2 things can make a fuel pump tick. Check valve problem, or relief valve problem. Which is it? What's causing it? Checking voltage, pressure, regulator op's, etc. Everything seems fine (now!). WTF!!

Fuel pump is relatively new as is the fuel filter (Toyota). So I bite the bullet and go for the fuel pump thinking the PO replaced it with a cheapie and it's just weak. The ticking because the check valve is opening and closing due to low pressure. Not quite making sense because when I checked pressure, it was within specs.

I drop the tank, pull the pump, and look in the tank. Oh...My...God...!!! Understand, the truck has never been out of SoCal, SoNev so rust would be the last thing I'd have thought. The inside of the tank was so full of rust I couldn't believe it. Bouncing down the backcountry roads must have dislodged all that rust and it plugged the pick-up screen causing the pump to cavitate, causing the check valve to "bounce". When the truck sat overnight, the rust must have settled enough to allow the pump to pump.

Advise? If you're having fuel pump issues, drop the tank and look inside. Mine is currently at a radiator shop getting cleaned. And the truck gets a new pump and filter...

John

4wd4fun

You can heare your fuel pump? Ive never heard the one on my 88 4runner it doesnt even buzz when I turn the key on but it still starts every time

VegasNaturist

That was the thing. Under normal circumstances you won't hear your fuel pump, except possibly a momentary whirrr as the pump develops system pressure when you first turn the key. During this episode, I could make the pump tick by playing with the throttle. As I pressed on the throttle more, the truck would bog down like I was running out of fuel, and the pump would tick. If I let off the throttle basically to idle, the pump would stop ticking and push fuel. That's what led me to believe my pump was going bad.

The tank had an incredible amount of rust with big flakes as well as a fine powdery, silt like sediment. Driving down the bouncy, washboard road dislodged all that sediment so it was floating around in the fuel. The silt was probably plugging up the sock while allowing a very small amount of fuel to pass. Enough to idle, maybe a little more, but not enough to run at any real speed. The plugged sock caused the pump to cavitate, causing the check valve to "float" or "bounce" making an audible ticking sound.

The point is if you're having fuel starvation issues with your truck, It might behoove you to drop the tank and have it cleaned out to remove the rust and sediment. Any good radiator shop should be able to do this at a nominal cost ($75 in my case).

John

RUNNING 4

I am having the same issues and I decided to replace the tank with a new one. It would cost me just about the same to have it cleaned and sealed.

4wd4fun

if that's true somethings wrong somehwere else. the pump only runs when you are cranking the engine or the engines running- never when just turning the key "on".

VegasNaturist

Let me clarify, "turn the key" to the cranking position...

John

Keith B.

Assuming the truck lived in SoCal/ NV as you say, then the PO was either a) A moron who thought that there's no harm in always keeping the gas tank nearly empty, or B) A teenager, who possibly could be excused for not knowing.

kornhuskerwizard

anyone know what fuel pressure spec is?