Both my 83 rabbit AND my g/f's 76 300d suffer this problem.


The IP is loosing it's "prime."


The cars will run fine when warmed up. But after sitting for an hour or so, they will be hard to start (both have working GP systems) White smoke is usually put out.

It takes some cranking and a lot of "pedaling" to get the cars fired up. I have to sit out and "babysit" the rabbit to get it to stay running for the first few mins. before it idles at all, w/o stalling.




I don't see this problem covered at all on here. I can't be the only one with this problem...

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-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)

First thing I guess at would be a loose connection somewhere between the
tank and the IP that allows air to enter the fuel system.
Loose hose clamps,old cracked plastic(by now they look brownish/yellow)fuel
lines (on the MB),old cracked rubber lines.The VW MAY have a fuel/water
separator (underneath the passenger side chassis,just forward of the rear
wheel...funny looking square box with a knurled plastic wheel you'd turn to
bleed off the H2O...Notorious for breaking off...might allow air in?)mine did.
The lift pump on the MB is always a favorite location.

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'84 300SD sold
124.128

I plan on replacing most "soft" fuel line on both cars.

The harder line found on the MB, is that Standard, lowes silicon hose? Can I snap these off their fitting and replace with the lowes stuff?


The rabbit has a fuel filer with a bung at the bottom for draining out water. Filter's new.

I've NEVER seen a primer pump like the one on her MB. It's located right on the filter. seems to work, as I see NO leaks when pumping. Her car only started doing this after I replaced the primary fuel filter (on a w115, this is no easy task, they really hid this thing!)

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-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)

I would encourage you to purchase new OE parts for the lines that run from the lift pump to the secondary filter and onto the IP. These lines come with the banjo attached and I'd not recommend you try to add your own hose to the existing fittings.

Additionally, I'd be curious as to whether the check valve in the IP might be causing you any issues. It's the bolt that's right at the outlet of the IP where the line returns to the secondary. If the spring is weak, it could be allowing the fuel pressure to drop during extended periods of shutdown.

with the VW, theres no way of tracking down an OE...I'll see how much the lines would cost for the MB.


Are we talking the check valve on the MB or the VW? The VW has a "rebuilt" Bosch VE pump. The PO said it's a fresh rebuild from some shop in CA, but according to him the "new" tires were good (they were heat stamped....they're 14 years old and dry rotted)

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-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)

BC is talking about the check valve on the Mercedes.

Where is the VW's water separating filter...In the engine Compartment...
or on the underside of the chassis?

__________________
'84 300SD sold
124.128