Fuel Cell, stock fuel gauge

[ScHpAnKy]

Looking for more info on using the stock fuel gauge with an aftermarket (12gallon) fuel cell. The fuel cell in question is an RCI with level sender - 0-90ohm.

Car in question is an '89 325iX

The thing is, I already have it installed thanks to the PO - but no fuel gauge. I'd love more info on how I can avoid getting stranded with no fuel again (odo and trip meter both don't work)

[jlevie]

If you use a late model gauge in the cluster meat for a car with the 53L tank you can get the gauge to sort of work. It won't be accurate as that gauge expects a different resistance and the gauge will read backwards.

[TobyB]

Um, I think I'd put a stock tank back in it, myself....

Even in the racy cars, we're not sure that a fuel cell in the trunk is all that much
safer than the stock tank, as protected as it is.

Or get the GM (?) aftermarket gauge that matches the sender.

t

[ScHpAnKy]

If you use a late model gauge in the cluster meat for a car with the 53L tank you can get the gauge to sort of work. It won't be accurate as that gauge expects a different resistance and the gauge will read backwards.

If it's compatible, I'd rather use a '86 euro 325i cluster as the PO put "white-faced M-style gauges" from china in there now. Couldn't I add a resistor on one of the ends to match the resistance necessary?

Um, I think I'd put a stock tank back in it, myself....

Even in the racy cars, we're not sure that a fuel cell in the trunk is all that much
safer than the stock tank, as protected as it is.

Or get the GM (?) aftermarket gauge that matches the sender.

t

"Don't fix what's not broken" comes to mind, especially with all the snow that just got dumped on me, and with all the other issues with the car it's definitely way down my list. the setup works, and I love having the pump and filter right there too. But definitely prefer a gas gauge that works

[jlevie]

If it's compatible, I'd rather use a '86 euro 325i cluster as the PO put "white-faced M-style gauges" from china in there now. Couldn't I add a resistor on one of the ends to match the resistance necessary?

The level sensor for a 55L tank is 0 ohms for full and 59 ohms empty. The 63L tank gauge expects 0 for full and 118 empty. So if you use the later gauge with a 0-90 ohm sensor, which usually indicate 0 when empty, the later model gauge will read backwards and show some fuel remaining when the tank is empty. Adding a resistor will just move the scale.

I won't get into why using a fuel cell in an E30 is simply a bad idea. The only justification for that would be if it was required by racing class rules. And then you don't need a gauge and can run the car on time vs fuel load.

[ScHpAnKy]

The level sensor for a 55L tank is 0 ohms for full and 59 ohms empty. The 63L tank gauge expects 0 for full and 118 empty. So if you use the later gauge with a 0-90 ohm sensor, which usually indicate 0 when empty, the later model gauge will read backwards and show some fuel remaining when the tank is empty. Adding a resistor will just move the scale.

I won't get into why using a fuel cell in an E30 is simply a bad idea. The only justification for that would be if it was required by racing class rules. And then you don't need a gauge and can run the car on time vs fuel load.

So in the interest of getting it working with my early gauges, what would be required exactly?

I rather not go through the hours of work, hassle of locating and ultimately (and most importantly) money to swap in a fuel tank, filler, re-route the fuel lines and find the proper level sender to... make my gas gauge work?

I'm not saying a fuel cell is a great idea, but it's the hand I've been dealt - so I'm trying to make the best of it in order to have some idea of the amount of fuel without having to pop my nose in there.

[TobyB]

Then just hook it up and see what happens. It won't hurt anything, and eventually you'll
figure out how to decode how it reads
(as in, 'when it gets up to 3/4 of a tank, I better get gas')

What Jim and I are both saying is that it's not ever going to read 'right'. That doesn't mean
it won't read 'useful'.

If you want it right, the two options are aftermarket gauge (not expensive, not hard)
or stock sender with early gauge (not cheap, not easy)

hth

t

[603Racing]

I did some research on this a couple years ago for my e24 race car. There are senders you can buy and install for all sorts of ohm ranges. I found one that would work with the stock e24 fuel gauge. I ended up not getting it due to other more pressing repairs.

If you really want a working, accurate gauge, you'll have to find the correct range sender for your gauge or get another gauge that works for your sender. Or do what Toby and Jim are suggesting.

[LivingLegend06]

Fixing your odometer and estimating fuel level by mileage would probably be your easiest option.

Sent from my HTC6435LVW using Tapatalk 2

[ScHpAnKy]

I did some research on this a couple years ago for my e24 race car. There are senders you can buy and install for all sorts of ohm ranges. I found one that would work with the stock e24 fuel gauge. I ended up not getting it due to other more pressing repairs.

If you really want a working, accurate gauge, you'll have to find the correct range sender for your gauge or get another gauge that works for your sender. Or do what Toby and Jim are suggesting.

That seems like the best/cheapest option - I found a gauge that's a pretty good looking fit for it and even VDO has fuel gauges that would match the e30 look.

Fixing your odometer and estimating fuel level by mileage would probably be your easiest option.

Sent from my HTC6435LVW using Tapatalk 2

That's in addition to the fuel gauge, for sure, I need to rebuild the whole cluster in there now or get my euro gauges working

[nando]

a brand new fuel tank is what, $150?

why does an ix need a fuel cell? I know it was the PO, but I still don't get it. screwing around with mixing and matching gauges, fuel sensors, etc seems like a pain in the ass to me.