power loss diagnosis

[tuffcitycruiser]

so about 3 months ago, i was at the gas station adding a fuel conditioner as per usual before filling up, and when i was screwing the cap back onto the bottle, the little seal inside the cap fell into the tank . i called my trusty mechanic (radd cruisers in duncan, who are sadly no longer specializing in cruisers) and he said that the risk of doing any serious damage was minimal and i was cool to drive home. i have been driving the truck since with any issues (keeping the tank fairly full most of the time).

however, about two weeks ago, i began experiencing a loss of power that occurs randomly. the loss of power is about 30% from normal and is not accompanied by any noise or increase/decrease in water temp or oil pressure. it is however accompanied by a loss of boost, approximately 15% less. fuel, air and oil filters all changed about a month ago. also at about the same time, the engine would (and still does) turn off sometimes turn itself off when cold starting. it seems that the loss of power does not occur when the tank is less than 1/8 full.

my theory is that the cap seal that fell into the tank is getting jammed up against the fuel feed tube, not allowing enough fuel into the engine. any thoughts?

i pulled up the carpet in the back to see if i could remove the sending unit to see if i could find the cap seal floating around and hopefully pull it out but the screws on the unit are impossibly rusty to remove . is there any other way of getting that sucker out without pulling out the tank?

and, should i stop driving the truck until i get this fixed ?

cheers

 

[roscoFJ73]

I also doubt the seal is the problem because the fuel pick up looks like this ,but it could be coated in crud like this one.
Ive also seen pieces of plastic get wrapped around them.The plastic floats above the pick up away when the tanks full.

You could drain the tank,there is a bung underneath. You might be able to see somthing there with a small mirror and light.
You could also soak the rusty screws in a solvent and see if they loosen up after a few days.

I would keep driving it for short distances if you need it for work.

 

[Fantom]

To remove the crews I have used this in the past with great success:
http://www.kmstools.com/lancer-15pc-1-2-drive-impact-driver-2734
it's a manual impact crew driver that you hammer down on (manually) while holding it. It has removed some of the worst screws I've found.

I also doubt that is the issue, unless the little filter is very dirty, which is possible. Now when you notice the "loss of power" does it feel like starvation of fuel or sputtering or just lack of power and normal engine operation, normal RPM?
So it does not happen when fuel is ABOVE 1/8th of a tank?
When you changed all that stuff, you bled it correctly? (sorry, have to ask)
How are the fuel lines from the tank, rusty?
Have you checked the linkage to for the "throttle"? on the firewall? Mine was starting to occasionally act up and I noticed that when I pressed the pedal I did not get the response I used to. Granted, in my case it was less random, but who knows. The linkage on the fire wall was getting sticky when I pressed on the pedal it would some times bend the linkage and not actually move the cable.
You can try running a temp fuel line to a 20L jerry can (mounted inside or outside) and run the truck like that and see if the problem continues.
That's all I got right now.

 

[tuffcitycruiser]

I also doubt the seal is the problem because the fuel pick up looks like this ,but it could be coated in crud like this one.
Ive also seen pieces of plastic get wrapped around them.The plastic floats above the pick up away when the tanks full.

You could drain the tank,there is a bung underneath. You might be able to see somthing there with a small mirror and light.
You could also soak the rusty screws in a solvent and see if they loosen up after a few days.

I would keep driving it for short distances if you need it for work.

Right on. Thanks for the help. I guess I should have a look at the fuel feed either way to make sure it isn't covered in crud. Cherrs

 

[tuffcitycruiser]

To remove the crews I have used this in the past with great success:
http://www.kmstools.com/lancer-15pc-1-2-drive-impact-driver-2734
it's a manual impact crew driver that you hammer down on (manually) while holding it. It has removed some of the worst screws I've found.

I also doubt that is the issue, unless the little filter is very dirty, which is possible. Now when you notice the "loss of power" does it feel like starvation of fuel or sputtering or just lack of power and normal engine operation, normal RPM?
So it does not happen when fuel is ABOVE 1/8th of a tank?
When you changed all that stuff, you bled it correctly? (sorry, have to ask)
How are the fuel lines from the tank, rusty?
Have you checked the linkage to for the "throttle"? on the firewall? Mine was starting to occasionally act up and I noticed that when I pressed the pedal I did not get the response I used to. Granted, in my case it was less random, but who knows. The linkage on the fire wall was getting sticky when I pressed on the pedal it would some times bend the linkage and not actually move the cable.
You can try running a temp fuel line to a 20L jerry can (mounted inside or outside) and run the truck like that and see if the problem continues.
That's all I got right now.

It feels like fuel starvation, without any sputtering. Ie. at any given rpm there is less power with normal engine operation.

It does happen when the tank is about 1/8, more than if the tank is close to being empty. Again, the loss of power appears random but occurs less frequently if there is less fuel in the tank, something I totally don't understand. If the tank is closer to full, the problem can last for quite a while - like an hour or two, or even a day or two. When the tank is closer to empty the loss of power occurs less frequently and lasts for less time. Very strange.

I have used the same fuel additive since I bought the truck six months ago.

Fuel lines look ok, not great though.

Good tip on running another fuel line to a jerry can - I think I'll give that a try.

Thanks for the help!

 

[tuffcitycruiser]

I also doubt the seal is the problem because the fuel pick up looks like this ,but it could be coated in crud like this one.
Ive also seen pieces of plastic get wrapped around them.The plastic floats above the pick up away when the tanks full.

You could drain the tank,there is a bung underneath. You might be able to see somthing there with a small mirror and light.
You could also soak the rusty screws in a solvent and see if they loosen up after a few days.

I would keep driving it for short distances if you need it for work.

Forgive my ignorance, but is the fuel pick up in that photo also a part of the sending unit that I am seeing in my FSM??? Never taken a gas tank apart...

 

[roscoFJ73]

Forgive my ignorance, but is the fuel pick up in that photo also a part of the sending unit that I am seeing in my FSM??? Never taken a gas tank apart...

By sending unit,do you mean the for the fuel gauge? Yes its all on the one float,the fule pick up is at the bottom and the sender is at the top from memory.

Are you sure you are not sucking air .As the tank gets lower ,the feed pump has to work harder and I was wondering if it could be getting some air in there.

Setting up an alternative fuel supply is a good idea and so is attaching a piece of clear hose to see if there are any bubbles of air in the lines.

 

[tuffcitycruiser]

By sending unit,do you mean the for the fuel gauge? Yes its all on the one float,the fule pick up is at the bottom and the sender is at the top from memory.

Are you sure you are not sucking air .As the tank gets lower ,the feed pump has to work harder and I was wondering if it could be getting some air in there.

Setting up an alternative fuel supply is a good idea and so is attaching a piece of clear hose to see if there are any bubbles of air in the lines.

Right, I thought they were a part of the same unit. My fuel gauge is not working and I have already eliminated any problems with the connections between the sending unit and the cluster in the dash, so I need to replace the whole unit anyhow. Was just putting it off because of the rusty screws.

I'll try the clear hose and the alternate fuel supply and hopefully I can the culprit. Thanks again for the help.