No fuel
 

i have a 1996 chevy silverado 2500 that has a new lift pump, sending unit & tank. It does not have fuel coming out of the air release valves. It does not have the same click it did before, but does have a faint click. What are the possibilities?

When you say "click", what is "clicking"?

The lift pump? The relay? etc....

Also, you say air release valves. You only have to open the black plastic valve on the top of the filter to bleed air. This allows the fuel to fill the FM and purge the air from the top, just where you would want to purge air from. The "T-valve" is actually the water drain for the FM and "bleeds" from the bottom of the FM, which is contrary to what you're trying to do; bleed out the air....

No fuel from the water drain is useful info though, it means you're not getting any fuel at all to the filter manager.

But, until there's more info to go on, I'll go for the "standard answer" to these type of problems:

1. Fuse

2. Grounds

Since you're OBDII, the Oil Pressure Switch shouldn't be a factor as the PCM will trigger the lift pump if the OPS is bad. The OPS is (for the most part) redundant for lift pump operation on an OBDII truck. The OPS will run the lift pump until it is "craps out", then the PCM senses the lift pump is not running and triggers the LP relay itself. Heck of a lot of redesign work when they just could have put a better OPS in the truck in the first place......or used the OPS to trigger a properly sized relay with the 12v feed to the pump. Meh......I guess it was cheaper to rework the programming and add some wire to the harness than design and build a new OPS or circuit......

There's a long shot possibility that your filter manager screen is clogged solid, but I've never seen one so bad that it won't flow at all. I've had one that light wouldn't shine through and it still flowed fuel. I'd estimate 90-95% of the time the FM screen has been removed with a previous filter change and missed on re-installation anyways, so it's entirely likely yours is already MIA if you can't find one in your FM....

The other possibility is the pick up tube strainer, commonly referred to as the tank "sock".

:pca1:

Thank you, I will look into it & see if I can give you more info.

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I changed the filter when I bought the truck. Where is the filter manager at?

The filter manager is the housing the fuel filter is in.

"filter manager" is the name stanadyne uses for it because it houses the filter, screen, water and air bleeds, the WIF sensor and the fuel heater....


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Ok, so I can pull it apart & clean it. I did have dirty fuel in it before it stopped running. I had put in some used fryer oil blended with kerosene & the truck quit while pouring it in. I dropped the tank, cleaned it changed the lift pump & sprayed deep creep into the turbo to start it up. I drove it for a while then no fuel. there was particles in the oil. It could have plugged the screen. the "sock" was falling apart & could have the screen flakes with oil crud in it. I will look there. Thanks.

Well, that's important info that would have been good earlier.

If you haven't already changed the filter for a new one, you should do it now....The main filter (in the FM) is a 5 micron filter (or a 10 micron depending on whose specs you accept) and cruddy wvo will plug it up pretty quick if the wvo hasn't been properly processed.


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thanks

It has a fuel loss from time to time. it has a new fuel lift pump, fuel sending unit, fuel filter, fuel relay, the fuel filter housing has been cleaned. I took the line off the fuel out put of the lift pump and turned the key on & it sounded like it was sucking air, it had air in the filter cap also. What could be the problem?

Your last description makes it sound like you have an air leak downstream from your lift pump.

Possible causes are a poor connection, deteriorated rubber line or a rusted line with a pinhole....

Thank you, I will look into it. I guess I need to drop tank again to find it. Will do.

Nope.

This problem isn't in the tank.

It's the external lines from the tank, not internal.

Assuming the lines are the problem that is....


*edit*

Hmmm, I'm now wondering if you altered the lines at the tank hook up and mistakenly hooked up the fuel line to the return fitting. If you did, it sucks air. If you didn't alter the lines then no worries. I don't think the stock lines will interchange between feed and return...different sizes and whatnot.

they were different sizes, yes. but i had dropped the tank a few times & it was hard on the fuel line. I did run some bio through it also which eats already old lines. I will replace the old line, what is the line that slips onto the top of tank? it doesnt screw in like the other 2 lines.

It's been a while since I've looked, but the two screw on lines should be feed and return, the push on line should be the vent that connects to the filler tube.

Don't quote me on that though....

funniest thing,,,lol,,,It seems to be a broken ground side post batt cable was to blame. go figure, now the a/c button lights up to. I did take the line off to check it from the tank & it seemed loose from dropping tank in winter 200 miles south of chicago. So, with the major gunk cleaned out of filter housing, new lift pump, relay, tank & sending unit it is spinning like a top. I put some sea foam in the filter housing to start truck with so it cleaned out the injectors well! I think it is all good now! truck started & ran fine. I will keep you updated. This is one reason why I like diesels is there can only be so much wrong with them. Thank you for taking time to help me sort it out.

Well, I test drove it. & it lost fuel again. I started fine a few times & I ran it for a min before I took off it stopped again while test driving it. about 50 yards after accelerating and then slowing down then it just cut out. No fuel out of the air bleeder on top of fuel filter. what else could it be?

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Also, if I did switch the 2 lines comeing out of the front of the fuel filter, what would happen? like if I took the line to the T & switched it to the line into the fi pump?

It wasnt sucking air, after rewireing the lift pump it was pumping way more fuel. It wasnt sucking are it was just running weak.

well, i put a new pmd with a new lift pump on & the lift pump is now the next day it will start the truck, then it barely lifts any fuel at all the next day. What could be up with it?

Try loosening the fuel cap. There's a vent in it and if it doesn't work properly too much vacuum builds up in the tank and the lift pump/ ip has to fight too much to pull fuel from the tank.

Some vacuum on the tank is normal though....


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