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I have a 2004 VW Golf 4 TDI and I’m having issues with fuel system. The car dies and it’s very hard to start it. Find out that the fuel pump in the TANK was cloged up. I cleaned it 3 times already but it still cloges up in 2 week period.
So my question is: can it be that the rubber fuel lines are deteriorating? PS: sorry for my English.
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What is it clogging up with?
It may just be a pump going bad. Fuel pumps can start to pump weaker and weaker until they start to run intermittently.
Since you also have an injector pump, you won’t notice a weak pump until it just fails to run, then the injector pump has to pull fuel through the restrictive pump in the tank.
You likely have a pump thats failing. When you clean it, it will run but pump weakly and gets weaker until it just fails to run. Replace your in tank pump. I DO NOT recommend just replacing the fuel pump inside, unless you know you can get everything apart and keep the O-rings, rubber vibration dampers and plastic parts from breaking/falling apart. (Since you say you’ve cleaned the pump, I don’t know how far you’ve taken the pump assembly down to) Its generally much easier to buy the whole assembly aftermarket for another 30-50 bucks than just buying the fuel pump itself.
Also, to help in your searches for parts/service; The in-tank pump on a TDI is referred to as a “Lift Pump”
Not sure what you mean by pump getting clogged up but if your pump isn’t getting clean fuel you may need to flush the fuel tank. usually not a problem for most diesel cars, than again it is VW – they use really poor quality parts.
[quote=”skim3544″ post=33286]Not sure what you mean by pump getting clogged up but if your pump isn’t getting clean fuel you may need to flush the fuel tank. usually not a problem for most diesel cars, than again it is VW – they use really poor quality parts.[/quote]
+1 Agreed.
Diesel engines like clean diesel, and if your tank is dirty and you keep running it in dirty diesel you will just keep creating problems for your self.
Clean the tank, and clean it good.
How are you clean the screen and unclogging the fuel pump?Thank you for the answers, but I already said that I cleaned the tank and uel pump 3 times, fuel pump was changed a year ago it can not be failing. The tanks bottom gets covered in like melted rubbery stuff. I need to clean the tank for the 4th time this weekend but still can’t figure out where it comes from.
[quote=”strokermk4″ post=33348]Thank you for the answers, but I already said that I cleaned the tank and uel pump 3 times, fuel pump was changed a year ago it can not be failing. The tanks bottom gets covered in like melted rubbery stuff. I need to clean the tank for the 4th time this weekend but still can’t figure out where it comes from.[/quote]
Make me want to say “are you sure you are cleaning it well enough?”, but i will lay of the blame.
When you clean out the tank every time does there happen to be water in the tank, you’ll be able to tell since the water will want to sink to the bottom of the diesel, and is a different colour.
Do you use the same place to fill up? Maybe their diesel has a lot of particulates in it, or water, or something else wrong with it. I’ve seen it happen twice. A station in a town called Hope B.C(where Rambo First Blood was filmed) had a place that when the gas was test it was 40%+ water. So it does happen. (by the way this isn’t likely)
Do you leave the tank cap off a lot?
Are you even sure its the first stage fuel pump?
If they are only lasting two weeks i would do a lot of digging in these area to find the real problem.
Make sure to pump at a gas station that has a lot of diesel traffic. Also check the condition of the fuel pump gasket – these VW gaskets break apart and fall into the gas tank over time.
Ah. YES, the black nasty gunk is the rubber fuel lines and rubber isolators around the pump (Or the remains of the old lines). Its like thick, black tar that sticks like paint when it starts to dry. This will immediately clog a new pump if not removed before a new pump is installed.
I’ve found that wiping the tank completely dry then rinsing it out with isopropyl alcohol and wiping that out will leave a spotless tank. Isopropyl alcohol cuts that black rubber mush very nicely. One small bottle form a grocery store will be enough and a roll of GOOD quality shop towels.
If you have ANY rubber fuel lines in the tank, they NEED to be removed. The only place there would be any is between the pump and the top plate. You need to buy (expensive) special submersible fuel hose for inside fuel tanks. Regular fuel hose will get soft and mushy within a few months. New fuel pumps come with clearish flexible fuel hoses instead of rubber now. If you did not replace the whole fuel pump assembly with a NEW unit, then all of the rubber o-rings and rubber isolators inside there is also be what is making the black gunk. Also, even the large rubber ring around the top plate can get soft and start to “ooze” into the tank and cause the same issue. If you touch anything rubber in the tank and it leaves a black mark, that rubber needs to be replaced and is the source of your black gunk.
After reading I was wondering if it was a fuel issue and not an issue with dirt in the tank but now that I think about it perhaps the parts of the fuel system are deteriorating. I would find this odd however since I would think they would use parts that would NOT degrade under normal use.
[quote=”EricTheCarGuy” post=33419]I would find this odd however since I would think they would use parts that would NOT degrade under normal use.[/quote]
Generally, this doesn’t happen. However I see this commonly on vehicles that have sat for a few months at any time and/or let the fuel begin to break down. Or sat a few weeks with very low fuel and the rubber started to crack. If the fuel begins to “go bad” and break down, the bad fuel rapidly breaks down the rubber. I have also seen this in a TDI VW where someone had put gasoline once in the tank, drained and refilled with diesel. The short time the gasoline was in the tank, it started to break the rubber down inside and out until eventually a hose ruptured inside the tank as well as gummed up the entire fuel system over several months of operation afterward. And once the rubber even begins to break down and soften, it is rapidly accelerated.
Finally found some time to change rubber fuel lines in my TDI. It seems that really helped, engine runs smooth, no in tank fuel pump noise in the car, this weekend I desided to take off the fuel pump just to check if there is any nasty stuff on pump filter/screen – nothing. New fuel lines fixed the problem.
I’m very gratefull to all who helped to found the source of the problem. 🙂
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