1.6 non turbo .....strange sudden no fuel problem...

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dkmc
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1.6 non turbo .....strange sudden no fuel problem...

Post by dkmc »

This one's a bit unlike any I've read about here before.....

Somewhat hard starting occasionally for the past few months, but no major fuel leaks on the pump. Some weeping and 'oily build up' here and there only. Past week, a couple of 'spells' of hard starting, thought I'd replace the fuel filter soon..... :roll:

Drove it last night, started fine, now this morning, nothing.
NO fuel at the pump. Acts like the solenoid is not working, but I checked it and it SEEMS to work fine.
However, NO suction at the pump inlet.

I'm at a loss on this one.....could it be broken vanes in the delivery pump or is there a drive key on the pump rotor that may have sheared??

I have spare engines, I can change out the pump, but want to be sure it's not something I'm overlooking here.

dk
tawney
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Post by tawney »

There are several guys on this forum more familiar with the pump than I, but I'll give you my 2 cents. The vanes may be worn, but it's really doubtful that either they or the key are broken. If the pump has no fuel inside it then its ability to suck fuel is greatly diminished: remove the 'out' bolt on top and pour fuel in it, then check for suction/vacuum on the inlet line. If you have a clear fuel line from filter to pump, you'll be able to see if air is getting pulled into the pump. If it's sucking air then suspect some kind of blockage: possible culprits: filter, screen on pickup in tank, vent line. If the vent line is blocked, the pump will create a vacuum in the tank after running for a while, and under some conditions it can suck the fuel out of the pump when you park.
81 Pickup 1.6NA; '86 Cabriolet with 1.6 TD
82vdub
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Post by 82vdub »

There are several reasons why it won't start. The answer is, most likely, found on this forum. Use the search feature and read, read, read the posts that come up that will give you good ideas and troubleshooting tips to try. You can also read:

viewtopic.php?t=7057

viewtopic.php?t=7070

viewtopic.php?t=7048

And search and read more.
Everybody else lists their cars here - but not me.

I have too many to count
dkmc
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Post by dkmc »

More info........
"Looks" like it's not the pump!
Looks like it's not pulling fuel from the tank......
I can suck on the line and 'get fuel' without much effort.

The engine runs fine on a bottle........


???????

dk
tawney
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Post by tawney »

The problem could still be related to the vent line that runs back to the tank: if it's clogged, a vacuum will build up in the tank while the engine is running making it hard for the pump to suck the fuel in, but once the vacuum is equalized, sucking on the fuel line would move the fuel easily. To eliminate it being the issue, just blow back through the vent line; it's the 'fuel' line that comes into the engine compartment right behind the fuel filter and just comes to an unceremonious end somewhere right behind the passenger side headlight, or sometimes the end of it is tucked into a hole in the body on that side. If you can blow air through it back into the tank, then it's okay and you'll have to keep looking for the cause of the problem.

I had the clogged vent line problem before, and my tank imploded to about half its original capacity; if you find the vent clogged you might check for that too.

Steve
81 Pickup 1.6NA; '86 Cabriolet with 1.6 TD
dkmc
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Post by dkmc »

..MORE info.......

Well.......checked the fuel lines and ran it without the filler cap.

NOW starting to think its weak suction from transfer pump......enough to
pull from a bottle, but not from the tank......?
Also when running, lots of foam in the fuel coming out of the pump when I crack the OUT fitting.....is foam normal there? I don't think so.....

Might try an electric pump for now.......

Any thoughts?

thanks!

dk
Fatmobile
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Post by Fatmobile »

Have you pulled the "OUT" bolt and cleaned the screen?
There's a little screen in the bolt,... doesn't happen often but it can get clogged then fuel has a hard time running through the pump.
It doesn't usually cause air in the pump though.
Foam is common for awhile after you get fuel to flow through the pump, it even gets pulled back from the tank into the filter.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
dkmc
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Post by dkmc »

Have not but will check the screen.......

The problem is a leak in the pump someplace "in the back"....drips on the block. Suspect the cold start shaft seal. Overnight, the pump leaks down dry and then no fuel for initial start up. It drips off the back of the oil pan about 1 drip every 10 seconds.

Any info on the right seal for the main shaft and the CS shaft?
Are there seals made that live longer with the low-low sulfur fuels?
I will get another pump and replace the seals before I install it, as
this is my only car for now.

dk
Fatmobile
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Post by Fatmobile »

If it's the NA pump, the bosch seal kit number for that is DGK126.
It doesn't include the shaft seal,... which # I can't remember right now except that it was upgraded and the last number is now 12
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
dkmc
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Posts: 50
Joined: Sat Sep 22, 2007 12:14 pm
Location: Upstate NY (among the cornfields)

Post by dkmc »

yes........NA pump. (old fashioned I am) :wink:

And I have lernt paitence and non-passing-ability !
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