You have to laugh

[stewart]

Well guys,

I am slowly getting around to putting some miles on the car which has now been registered for several weeks. Having made some major progress on improving the brakes, sorting out a minor oil seepage and improving lots of little issues I am starting to feel a little more confident driving around.

Next week the air con gets hooked up, front springs get uprated to 300lbs and I should be fitting a bigger brake master cylinder to improve pedal feel.

Yesterday however, having collected it from the workshop I set off for some work appointments. I'd done about 50km I guess when the car started to miss a little, lose power and then coast to a stop. Not on some quiet little back road, but on a major freeway, with almost no verge, on a blind corner.

I sat there panicking with the drivers side of the car in the middle of the 'slow' lane calling the workshop then the road assistance to get me out.

Towed back to the workshop and some investigation later it was revealed that .......I'D RUN OUT OF PETROL!!!!!

Now, who felt a right wally then! The thing is, the fuel gauge read 3/4 full!

Luckily no harm done except to pride and to pocket to cover tow costs. Now I have a new job. Work out the resistance on the Veglia fuel gauge and on the sender unit in the tank and get a tricky little box made up to make them talk to each other better.

Funny thing was, the night before in discussions with Paul (OZstratos) the topic of fuel tanks and capacity and gauge readings had come up. How much fuel is left when your gauge reads empty he asked!

Glad I found out now rather than on my way to Melbourne in a couple of weeks when I could have been stuck on a remote country road out of mobile phone range!

Ah well!:rolleyes:

[Stratos]

Stewart,

It's even better when it happens on a rally - especially when you are only 2 stages from the end, and in line to score your best ever result. :rolleyes:

[Bernard]

What a WALLY EDNA !!!!!

remember coming back from Italy we had 4 gallons swilling around INSIDE the car as spare because of the fuel strike in the UK at the time ?....dont feel too bad it also happened to me with Sue in the car....she was really impressed !

Bernard

[CorseChris]

Originally posted by stewart
....Work out the resistance on the Veglia fuel gauge and on the sender unit in the tank and get a tricky little box made up to make them talk to each other better.

Hi Stewart,

The Veglia gauges are a Wheatstone bridge design. You might find it's easier to balance the bridge with your given sender and get accurate readings by adding a parallel resistor on the upper half of the bridge to the sender. This is actually pretty easy to do physically as this leg is between the +12v terminal and the sender connection.

I matched my Veglia gauge to a VDO dip tube sender in this way and it works perfectly across the entire range. From memory, it was 75ohm.

Only down-side is that the current passing through sender and meter is a bit higher than originally intended but not dangerously so.

I'll do a drawing if you need one.

Chris

[ANDYG]

Yes please Chris, see you tomorrow.

[CorseChris]

Andy,

If you are coming over in the Corse we can probably do the job on the spot. I'll bring a decade box home just in case.

There is one assumption though - that the dip tube goes all the way to the bottom of the tank! If it doesn't, the gauge will lie at the bottom of course since you'll still have fuel in it :)

See you tomorrow.

[stewart]

Chris,

Thanks very much for the offer, I'm not going to turn that down!

Any diagram or additional explanation to allow me to do this myself would be gratefully accepted. As you say though I need to check that the sender does go all the way to the bottom and I can check that as I have the dimensions of the sender somewhere. If I am lucky I even checked it at the time it was fitted and will have made a note somewhere.....:confused:

Thanks again in advance.

David, I would have been less panicked and more annoyed to have run out on the rally, but I guess you put that one down as a bad day!

Bernard, I do remember that fuel strike, but those memories of potentially running out of fuel also bring back the memory of someone who on that last day squeezed into a Stratos race seat with a big hotel key in his pocket and didn't know it was there for a hundred miles or so....Talk about a wally, it must just be habit!:p

cheers

[David May]

Even if the sender is long enough to reach the bottom of the tank, it probably won't start to move until you've got a couple of inches of fuel in there - using that last gallon is always a blind risk! If you want to be really accurate, you have to sink the sender into a little recess in the bottom and have it poking out a bit at the top too!

Dave May

[CorseChris]

Originally posted by stewart
Chris,

Thanks very much for the offer, I'm not going to turn that down!

Any diagram or additional explanation to allow me to do this myself would be gratefully accepted. As you say though I need to check that the sender does go all the way to the bottom and I can check that as I have the dimensions of the sender somewhere. If I am lucky I even checked it at the time it was fitted and will have made a note somewhere.....:confused:


Stewart,

Again, sorry for the slow reply - I have been off work again concentrating on doing the bodywork on my car.

I'll do a drawing and post it up ASAP, but in the meantime, in words....

Gauge has 3 terminals, +12v, ground and sender. Sender has 2, gauge and ground. On my setup which had a 60ohm VDO dip tube sender, I added a 75ohm resistor between the +12v terminal and the gauge terminal at the gauge itself. Location isn't important, it was just easy to put it there. I think the original sender that the gauge was intended for is around 200ohm at empty so the problem using the VDO sender was that it never shows below about 2/3rd full or so (3/4 in your case).

By far the best way to make sure the thing is doing what you expect is to remove the sender and gauge from the car, rig it all up on a 12v supply or battery (via a fuse!) and play with it at each end of the range to make absolutely sure it's doing what you want. I wouldn't advocate using a resistor lower than about 50ohm as the currents would start getting a wee bit high for my liking. Worst-case current is with a full tank and on my setup was about 200mA. As long as you keep the values in this sort of range, a small wattage resistor is fine (1/3W is perfect).

As I mentioned before, the gauge is a bridge design so is pretty much independent of supply voltage within a reasonable range (say 10 to 16v or so). Much better than those awful bi-metal things.

Out of interest, the VDO gauge designed to go along with the sender I bought was also a Wheatstone bridge design like the Veglia items and they had provided a calibration adjuster inside it as well. This adjuster worked on the opposite leg of the bridge to the sender (which is a better idea) but this isn't easily accessible on our gauges so I didn't opt for this route.


Let me know how it goes.

Chris

[stewart]

Chris,

Thank you very much for that info. I have been away with work the last week, so sorry about the lack of reply.

I'll digest and set something up in the next week or so. Removing the gauge and the sender in the short time available before my big drive in two weeks with all the other things that have still to be done is unlikely, but I should be able to improve the situation and 'fix' properly at leisure now.

I'll let you know how I go.

Thanks again!