general observation about fuel pumps being cooled

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Oct 15, 2005
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sebring, florida
ive had this trouble with my car where it would intermittenly stumble and die. i knew it was fuel related because when this would happen my fuel pressure would drop and if i removed the fuel line, air would come out under pressure instead of gas. sometimes it would start back up. sometimes i would have to get towed home. its happend 3 times now. upon advice from this forum i dropped the gastank to have a look at the fuel filter and the fuel pump. what i found is that dodge has a rather interesting way of mounting the fuel pump in my stratus.
the fuel pump is contained in a canister inside the fuel tank. the fuel pump has 2 inlets, and 1 outlet. when the pump runs, it sucks fuel off the BOTTOM of the tank through the first inlet, through a filter sock. this fuel gets pumped into the canister where the fuel filter is located. the canister serves to bathe the fuel pump in gas at all times so that it can remain cool. the fuel pump picks up gas from the canister and pumps it into the fuel line and filter and finally out to the engine.
my problem i found out was that the filter sock on the bottom of the tank was clogged up solid. i removed it and was barely able to blow any air through it at all. so what happens when the filter sock is clogged like this? the pump does not get bathed in fuel. it probably runs hot. when the fuel level in the canister drops below the pumps pickup it starts pumping air and my engine stumbles and dies. i verified this by running the canister, pump and sock in a gallon milkjug with the top cut off. i put the assembly under the car and started it up. with the clogged sock in place, the canister initslly fills with fuel, slowly. and the engine starts. eventually the canister is unable to maintain a high fill level and the pump goes dry. so i removed the filter sock and tried again. now the canister fills up quickly with fuel and the pump remains bathed in fuel. my fuel pressure stays good and the engine runs normally.
so what i found out from this is that under normal conditions, my pump remains fuly bathed in fuel and does not get warm. even if my tank is nearly empty. as long as theres enough fuel to keep the canister full, my pump remains happy.
this blows the throey out of the wayer than running a tank low makes a pump run warm.
my next observation, i cant find a replacment sock ANYWHERE for sale. everyone wants to sell me a replacment canister assembly, including a new pump, new sending unit and new pressure regulator. i only need a little dinky sock. the new assembly is about $400 from dodge. its about $150 for an aftermarket chinese unit. i tried to clean the sock but its just not working. i think im going to have to either run without it, or nut up and buy a new assembly.
 
Thats an interesting way of doing it and I would agree as long as there is enough fuel in the tank the pump will stay cool for your vehicle. But most pumps dont have such a good setup and are just sitting in the tank. Thats B/S about not finding a sock. For something that can be killed by outside influences it should be a separate part.
 
Can you post a picture? And list the model and year?

I don't have an answer for you but there is a good chance someone on BITOG will know of a source for filter socks or be able to suggest a good kludge.
 
oh and its a 2.5 v6 automatic. but i think the fuel strainer, canister and pump for this car are the same from 95 to 2000, reguardless of what engine is in it.
 
at first i just tried blowing through it. no dice. i could barely get any airflow at all even with all of the pressure of my lungs. i tried soaking it in diesel and then putting a few lbs of compressed air through it. no dice. i tried engine degreaser. no dice.
at that point i cut the sucker open. this strainer is more than just a coarse sock. its got about 10 layers of fibreglass mesh that is super fine. i cut a 1 inch square out of the bottom to allow fuel to bypass the clogged parts and then i could clean it out.
the fuel pump in the canister also has a strainer. so my car has 2!. i figure ill be OK using the cut strainer since theres a secondary one in the canister that feeds the fuel pump.
while i still had the canister out, i shimmed the fuel pressure regulator up with a few stainless washers out of my eyeglass repair kit to regain factory fuel pressure. this praticular car has a returnless fuel system, so the pump and pressure regulator are all in the tank. with 180,000 miles my oem regulator was just a bit low, about 10psi. i verified this by hooking the fuel pressure regulator up to a regulated air supply of my air compressor and slowly increasing the air pressure untill air came out. it started venting at about 36psi. factory spec is 45psi. i used like 3 washers and got it to vent at 44psi.
i put everything back in the car and attached a preesure gauge that is long enough so i can see it while driving. here are smoe more observations. it maintains 44lbs of pressure at idle. my car will idle for 45 seconds with the fuel pump relay disconnected before ti starts missing. during normal cruise it stays at 44psi. even if i run it through the gears at full throttle it keeps the 44psi spec. thats 1psi off factory and "close enough" for me.
i know that im going to be cutting my fuel pump life short by doing what i did with the filter sock, but since theres a secondary sock in the canister i feel better about it. and i really dislike the idea of buying a new canoster assembly from the dealer. the $150 chinese units scare me. so for not the car runs great. ill probably leave the pressure gauge on the fuel line so i can monitor fuel pressure for a week or so to make sure everything is working properly.

i tell you guys something. modern cars are starting to get to have a disposable status. they are built to run 100,000 with little to no problems. after that, little things like this, or a timing belt can really eat up a weeks or even 2 weeks pay. before i did the timing belt on this car i called the dealer to see what it would cost for them to do it. they quote me a thousand dollars even. thats $1000. granted this is a fwd v6 and you have to remove the power steering pump, a motor mount, front bumper, fender wells, alternator, etc to change it but thats alot of money for an average person to drop. i ended up doing it myself for about $70 in parts and a weekend of relaxed wrenching.
i can remember when it was the normal thing to do to take a broken alternator or starter in to a rebuild shop and have it rebuilt. now you cant even find rebuild kits for those things anymore.
it seems like the trend use to be to replace whats broken or going to break soon. the current trend seems to be to replace whatever is broken, along with everything else that is within 1 foot circumfrence of the broken part.

sorry this turned into such a rant.
 
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