Fuel tank sending unit and meter testing procedures

[Gypsie]

I tried to search for this topic but had no luck. I pulled the fuel tank on my 80 vanagon and removed the sending unit to see if there was a prob that could be repaired or if I needed a new unit.

It appeared to be new(er) but that don' mean jack, I know.

I thought I would test it's function by reconnecting the batteri\y and turning the key to the on position to see if there was any reading. nothing happened.

My questions:

Is there any way to test the sending unit with a meter to assure it is doing what it is supposed to do?

Is there a way to test the meter to assure it is doing what it is supposed to do?

bentley mentions VW testing unit but I wonder if that is a fancy way of saying multimeter.

I'll go work on cleaning up stuff and check in later

[dtrumbo]

If it's like the late-bay senders (and it probably is) you should read about 80 ohms with your multimeter when the sender is in the down (empty tank) position and close to zero ohms when it's in the up (full tank) position. If it reads open (infinite ohms), it's toast and needs to be replaced.

You can test the gauge by grounding the violet/black wire that goes from the gauge to the sender. When grounded and the key on, the gauge should read full. If it doesn't, there's a wiring problem, the gauge is bad or the voltage stabilizer (vibrator) is bad.

[Gypsie]

Okay,
So I dropped the tank. changed the grommets, snapped the little plastic dohickey off of the top of the overflow tank, (just like kayakwesty said to be careful not to do) went to the upullit to get another, came back with a bucket load of really cool vanagon parts that I wouldn'ta had had I not snapped the dohickey...tested the sender (worked fine)... cleaned and painted everything, reninstalled the tank, kicked Hambone in the head for good measure, (twas surely an accident....wink) and then pulled the instrument cluster to find that my aolternator resistor and several others were fried, potentially the voltage stabilizor as well.

Planning on heading back to the upullit to retrieve the insturment cluster I saw on one of the Vanagons, P'raps I will then have a gas guage that works as well as the alternator and oil pressure light.


Moral of the story...the upullit yard is fun and kicking Hambone in the head is not as fun as it sounds.

[IFBwax]

We found out barely in time as we installed a new gauge in the Pickle, that my vibrator was bad. With Colin at the back and me watching the gauge, the thing started pegging way beyond full.. then the sender started smoking and I could see wisps of smoke at the fuel gauge as well. Killed the ignition and we replaced the vibrator and then it was all good. But I think we were real close to frying a new gauge.

It might be good to have another pair of eyes up front when you finally do your thing.

[Gypsie]

Methinks I did myself in with repeated baattery charges without disconnecting the battery when my alternator was going belly up. Lazy sumbitch that i am.

Most of the little diodes in the insturment cluster show sign of being really hot.

I have been futzing and have decided to start with a fresh (used) instrument cluster. The one at the U-pullit has a clock too and the harness has the connection for it!

I will keep the old one for parts but think that starting fresh is the best bet for now.

Though the vibrator does sound interesting.

[Gypsie]

Okay, new dilemma.

The task of getting the gas guage working has blown up into a full on 'operation'

Sender works fine, instrument panel is 'Okay'. Installed new voltage stabilozor, to no avail.

Been tracking down wiring connections and getting resistance readings from all over the place.

I wanted to get the charge indicator light working, just cause. Even after having a volt guage installed (thanks again Hal! You 'da hairy man!)


So the other day I headed out to the Monday at the Lab and the bus died.

After much time spent assuring that all the electrical work I did did not create this problem I checked fuel flow. Long story short I changed the filter and found the main line out ot the tank had become clogged with 'something'>

I cut open the old filter and found some sort of gelatenous substance in the filter box?????

Someone suggested that this may be part of the filter design (Bosch Plastic type) as a chemical dessicant to remove moisture?

I am a bit concerned that there are 'bergs' of this stuff floating around in the tank. I cleared the line with a hunk o' wire and flow began immediately with no chunks coming down the pike.
When I had the tank out I shook it up pretty good to listen for clanky things and found none.

Ideas??

[Gypsie]

Hello.....tap tap tap...is this thing on?


Anyway I thought I would check in to let y'all know I have tracked down and repaired the gas guage issue, as well as the pre-ignition instrument lights issue.

All is well, though I am still curious about the gelatenous substance in the fuel filter.

It may be some silicone based rtv i used for the fuel sender seal. Perhaps sloshing gas kept this in a liquid state and it was sucked into the filter. and the clog in the out port of the tank the same?

Seemed like alot of rtv, much more than I thought I used. At least I have a quick resolution in mind if I get the same 'no fuel' symptoms in the future.

I have lots of rejuvinated electrical connections, a new voltage regulator, voltage stabilizer, and voltmeter. All good stuff, even if the gas guage issue was a result of an overlooked connection when i bought the rig in may of '07.

Long story short:

It was sitting in a field for 18+ months and had been ripped into to attempt a hotwire to setal it. Loose wires were reconnetced by myself. One wire had been pulled from a connection at the ignition switch meant to hold two leads. I rewired the loose lead to another connector and this error created this whole frustrating mess.







DOH!

[bretski]

I've never heard of gel inside the filter. My thought is that it was something in the tank. Keep a couple spares handy in case more junk "comes down the pike."

Glad to hear your electrical issues got resolved!

[hambone]

Betcha it was the RTV. You pulled off the sender a couple times when it was wet with RTV.