[gowen]

I recently bought a 1998 Beetle with the 2.0L engine. The gas gauge alternates between working and not working. where working equals "reflects true amount of gas" and not working equals "needle falls all the way down to nothing, just as if it was resting when the car is turned off."

I drove it to get gas today and it showed me a very low "in the red" with the little yellow LED lit. Then it dropped to nothing and the light turned off. Then I got to the gas station and put 13.8 gallons in, and it showed full at 0 miles. Then it dropped to nothing at +8 miles, returned to showing full at +18 miles, and back to nothing at +19 miles.

Any idea what would case this? Bad sending unit in the gas tank? Degraded wiring between tank and console? Gremlins in the console?

Just figured I'd ask about cause here in case it's a trivial thing that I can fix; it'll go to my vw repair shop otherwise.

 

[billymade]

I had a goofy fuel tank gauge; it ended up being the fuel level sending unit, on the original VW oem VDO pumps, it is a separate removable part screwed into the body of the fuel pump.

This would require removal of the fuel pump; if the pump is old you might consider, rolling the cost of the sending unit, into the purchase of a new pump, a oem Bosch fuel pump is revised with a integrated fuel level sending unit and includes a new rubber tank seal.

Checking the cost effectiveness of the sending unit and another pump; may help your repair direction, parts purchase. Looking on FCPEuro's website; the fuel level sending unit, by itself is in the $63 (Bosch) to $155 (genuine vw), price range, so a new pump, maybe a way to go with a whole Bosch fuel pump, being in the $150 range?

For diagnosing the problem; I ran a scan with VCDS by Ross Tech and there was a factory VW trouble code, for the fuel level sending unit being defective. Also, with a scanner like that; you can do a output test on the speedo cluster and confirm, the gauge is working as it should.

Once, the fuel pump is removed; you can inspect the level sending unit and follow the resistance testing procedure, outlined in the service manual.


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[billymade]

Fuel Pump Assemblies (69740) - Fuel Pump Assemblies - Bosch Auto Parts - Liferay DXP

Bosch supplied the industry’s first fuel injection system with a high pressure electric fuel pump in 1967. Since then, Bosch has stood at the forefront of fuel system technology, providing fuel pumps to virtually all vehicle manufacturers. Compared to conventional fuel pumps, Bosch Pumps deliver...

www.boschautoparts.com

Bosch Fuel Pump Assemblies (69740)

Fuel Pump Assemblies (69740) - Fuel Pump Assemblies - Bosch Auto Parts - Liferay DXP

Bosch supplied the industry’s first fuel injection system with a high pressure electric fuel pump in 1967. Since then, Bosch has stood at the forefront of fuel system technology, providing fuel pumps to virtually all vehicle manufacturers. Compared to conventional fuel pumps, Bosch Pumps deliver...

www.boschautoparts.com

NOTE: the VDO

Continental Fuel Pump Module Assembly; In-Tank Module | 1J0919087J

Continental Fuel Pump Module Assembly; In-Tank Module | 1J0919087J - Google Search

228-233-001-003Z Fuel Module - 04103590350367

228-233-001-003Z Fuel Module - 04103590350367 - Google Search

VDO online parts catalog:

Find products for your vehicle

Search for your vehicle, year, make and model. Find the products you need. Quick and easy.

us.continental-aftermarket.com

VDO sells a pump with or without the fuel level sending unit.

Also, DO NOT; buy a cheaper, aftermarket fuel pump, from the typical auto parts stores; they cause drivability issues, seem to be defective out of the box and cannot seem, to provide the needed fuel volume, under load. We have seen bad aftermarket pumps installed by members and then, they couldn't figure out, whey the car ran bad! Stay away, from brands, like Hamburg Technic, URO , O'Reilly's Import Direct, Airtex, etc.

The only ones we see work correctly; are those from VDO/Continential, genuine VW/VDO or Bosch.

Lastly, it always a good idea; to replace the fuel filter and fuel pressure regulator at the same time and this insures, the fuel system, performs at top levels.




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