86 Golf Fuel Issue

[uzzo2]

Hey guys, I think I am having a fuel supply issue with my car. For about the last month or so, if it sits for a couple of days, it's hard to start. I assumed it was glow plugs even though they all checked good, I went ahead and replaced them. But if it sits for more than a day without being started, it's hard to start. The last couple of times it happened, I noticed that it had a skip for just a brief second when it started up. This has me thinking that fuel is somehow draining back towards the fuel tank when it sits. I know in my days of being a truck diesel mechanic, most of them have check valves somewhere along the supply line to prevent this from happening. Is there something similar on these vehicles is what I'm wondering? And if so, where are they located?

[82vdub]

Sounds like the fuel is siphoning back to the tank. Check your supply and return lines (even the little one's on the injectors) for signs of leaks that could allow air in, a restriction in the fuel line (under car water separator/check valve, in-tank screen, fuel filter), and the inlet seal of the IP could be bad.

[uzzo2]

Sounds like the fuel is siphoning back to the tank. Check your supply and return lines (even the little one's on the injectors) for signs of leaks that could allow air in, a restriction in the fuel line (under car water separator/check valve, in-tank screen, fuel filter), and the inlet seal of the IP could be bad.

Thanks 82, so any air getting in, even from the return could cause this problem? You say that there is a check valve under the car. Do you know where it's located at?

[82vdub]

If your car has a water separator system under the car, there's usually a check valve with it (I believe). The water separator is under the passenger seat area, under the car. You'll see it if your car has it.

[Fatmobile]

That does sound like it's syphening back to the tank,
the check valve by the water seperator should stop this from happening but many people remove them because it clogs and restricts the fuel line.
Most water seperators are removed first chance too.

[damac]

This problem has been with me since I got my jetta over a year ago and my old f250 diesel. Sadly its all I know thus far.

I took the time to clean my tank pickup and blow all the lines with compressed air as well. I yanked the stock water seperator out of there and tried check valves in each side as well as without. I replaced the complete runs on each fuel line with some clear hoses at the tank and in the engine bay.

On my jetta, although I cannot see fuel leaks at this time, I have to assume its the pump. Thus far I have experimented with numerous used pumps that I have just resealed and now regret that. I should have started with a good known pump with my rebuilt injectors and got it timed right.

On mine if you watch the clear hose from filter to ip, every morning there is a big air pocket. This delays starting a tad as it purges itself. And you can hear car stumble and puff white smoke and the engine doesn't have a cackle noise as the pump tries to stay alive. Then usually within a minute it picks up and smokes a tad until driven and when its warm it runs great.

There was some brief periods where the car held prime, seemed like it was when the car was nose down for whatever reason. Then even in the cold the car would fire right up and it just sounded angrier, but not missing all over the place and putting on the white smoke show.

I have read that the pumps mainshaft being worn can lead to air sucking in when off and have to wonder if that is the case for me. I took apart a pump for fun and I could see some of the egg shape wear side to side it had. You could just detect a rattle when rocking the shaft back and forth. My current pump on the car is even worse. I am just assuming that the .001" fit between it and new bushings wouldn't show such a rattle.

[uzzo2]

If your car has a water separator system under the car, there's usually a check valve with it (I believe). The water separator is under the passenger seat area, under the car. You'll see it if your car has it.

Thanks again guys, I don't know if my car has it or not. I should know as many times as I've been underneath it, but I wasn't looking for it either. I know the filter has a water separator on it. The guy I bought the car from put a filter housing off of an older model rabbit, so it just takes the spin on filter. I'm just wondering if I could cut the fuel line between the filter housing and the IP and put a small inline check valve there. What do you guys think about that?

[82vdub]

You can buy a small low psi low flow electric fuel pump and that may solve the issue. I added one of these on my old winter diesel Jetta when my car observed the same hard starting issues. I didn't want to rebuild the IP on a car that I got for $50 and had major rust. So, I put a $50 pump and tied that to the fuel shutoff solenoid and never had a problem after that. This clearly is a bandaid to the situation, as if it's allowing air into the fuel system somewhere at the pump, it's only time before it's so bad that you will have to do something about it. I just didn't want to spend the money on that car. I used it for 3-4 winters, and after the seat started falling through the floor for the second time (I had it welded up), I quit driving it.

[uzzo2]

You can buy a small low psi low flow electric fuel pump and that may solve the issue. I added one of these on my old winter diesel Jetta when my car observed the same hard starting issues. I didn't want to rebuild the IP on a car that I got for $50 and had major rust. So, I put a $50 pump and tied that to the fuel shutoff solenoid and never had a problem after that. This clearly is a bandaid to the situation, as if it's allowing air into the fuel system somewhere at the pump, it's only time before it's so bad that you will have to do something about it. I just didn't want to spend the money on that car. I used it for 3-4 winters, and after the seat started falling through the floor for the second time (I had it welded up), I quit driving it.

Well mine's not in that bad of shape, the body is still pretty solid except for dents and dings from hitting deer with it. I'll check everything else first and if I still continue to have problems with it, I'll just pull the IP off and have it rebuilt. I was considering upgrading to a newer model jetta with a TDI a while back. After researching prices on them, I decided I would just keep this old golf and try and keep it running halfway decent.

[82vdub]

Just about any car sitting in weeds in Georgia will be in better condition than one driven daily in Wisconsin

The outside of the body wasn't too "bad", rust wise, but the bottom of the car was really bad. I was afraid to touch nearly everything under the car for fear that it would break off, or tear some of the chassis/suspension/floors off the car.

[uzzo2]

Just about any car sitting in weeds in Georgia will be in better condition than one driven daily in Wisconsin

The outside of the body wasn't too "bad", rust wise, but the bottom of the car was really bad. I was afraid to touch nearly everything under the car for fear that it would break off, or tear some of the chassis/suspension/floors off the car.

Man that's a shame, that looked like a nice little car. I am just wondering if you can find one in pretty good shape and use that rubberized undercoating, would that deter the salt from the roads up there?

[Una]

Nothing short of pure stainless steel or carbon fiber will save a car in the rust belt. It's a real shame.

[82vdub]

Rustproofing works at keeping rust away. However, as with anything, it's never 100%. If you get a little stone chip that takes away the rust coating, then things will start to rust from there. Same with paint. Paint protects metal, until something chip the paint and allows rust to start. Imagine soaking your car for 4-5 months every year in a constant salt bath and see what you end up with. That's what it's like in the rust belt. People from the south have no idea what real rust is, and how to wrench on a car from the north.

[uzzo2]

People from the south have no idea what real rust is, and how to wrench on a car from the north.

You are 100% correct, and I have absolutely no desire to find out either
I don't see how anything but a polar bear could live in that part of the country in the winter.

[82vdub]

I don't see how anything but a polar bear could live in that part of the country in the winter.

I am beginning to feel this way the older I get.