OK Mac1 guys - how have you set up your ETB fuel sender? I set mine up by bending the bar so that it reached bottom of tank when empty - or so i thought. I can put 2 gallon in from cans before gauge starts to read above zero, when full up to the filler neck it only reads approx 75%.

Ive obviously done something wrong. I dont know if the float is hitting an internal baffle or not - i dont really know where the baffle is in the Mac1 tank. Any advice greatly recieved. Im not sure if i just need to turn the sender so it rises and falls in a different part of the tank or if ive cocked up the shortening.

I have the opposite problem - I set it up to do the same as yours (I thought), but now the gauge hits zero when there is a good 10 litres left. Can't be arsed to remove the rivets on the boot cover to get at the sender and rebend it

Started to think about this but got ahead of myself.
Do you have a wee sketch of the sender layout? Started thinknig the arm could be too long but then how would it read zero? If you set it to read zero when at tank bottom maybe you have to adjust the contact at the potentiometer ( if that is what it has) Filling may not effect the sensor straight away so would stay at zero longer. Then when the float hits the tank top there may be some small amount of sensor left that doesn't get used. This could show as not full.

Basing that on taking a sierra one apart. Maybe yours is different and some one will tell you the right way to go.

Just thinking out loud.

I guess if the float is only approx 1" off the bottom of the tank it will have a few litres in it but as its only approx 7 gallon tank losing 2 is a big percentage. I dont mind being within 5 litres it just seems like a right faff on to fine tune it.

If iam hitting a baffle at higher levels, lengthening the arm to get closer to the bottom will in theory make it worse higher up.
I know i cant orientate the sender front to back as width of tank isnt wide enough to get full swing. Hole is at one end of tank so i have tried to get it to swing to the right (when stood at back of car looking forward). If i shorten the arm to miss a baffle (assuming there is one in there) then it will read worse at lower levels.

Im obviously missing a key bit of data here. Has anyone got it working more accurately usiong the Mac1 tank?

Nope I'm no closer. When my tank is full my petrol gauge read 3/4 full too.

(I knew it was full becuase my feet started to get wet.)

I'm thinking that we need to have the arm level at the pivot point (to read full at the gauge) and the put in another bend downwards (at full) as I'm thinking that the weight of the arm is too great for the float to be on top of the petrol and as its too heavy the float is half submersed (or worse) giving us the 3/4 full reading

Ive just spoken to Mark. He has suggested:
1. first thing to do is take the sender out whilst still connected to gauge and check the angles for zero, 50% and 100% - either measure the angles or mark on a piece of paper.
2. Then draw the tank outline on paper (ie top, bottom, sender location, bottom bowl and baffles). Sit the sender on it and make the 'S' bend in the arm such that the float position remains in line (ie draw an outline of sender when straight, bend the arm so that the float stays on same centre line just further up) and just above bottom of tank when straight down or at the zero reading angle. On same piece of paper mark the zero, 50% and 100% points (angles). This way you can simulate that the sender arc will read at the correct points. Modify arm bend to calibrate.
3. Only other thing to check is have a look in tank and check where baffles are to ensure arm will not hit them when travelling.

At zero there will always be fuel in bottom of tank (5 litres of fuel in bottom will just wet the bottom of tank - ie only a few mm's depth).


Does this make sense - tricky to explain in words. All theoretical at the mo - havent tried it yet to prove.



Emsfactory - what you have said is sort of what Mac#1 have suggested. Just instead of adjusting the pot itself adjust the arm to do same thing. ie start by working out where the full and zero points are on the arm - they may not be at zero degs and 90 degs - and bend arm to allow travel through these two datums.

[Edited on 15/2/06 by DarrenW]

Are there any baffles in the petrol tank????

mine looks like a mountain range aprox 4 bends in it to give full range of movement and no fouling took a bit of working out but is very acurate especially at low end where its importantnot to run out. worked it out by offering up and bending so it reaches full droop and not quite touching bottom of tank the apply w shape bends to allow full movement without quite reaching top of tank but not affecting low point never run out of fuel yet so cant be far wrong and done 200 miles on a tank

Not Mac #1 but I set mine up the following way..

Bend sender approximately and fit

Ground tank to chassis

Turn Tank upside down...ensure gauge reads "Full"

If not quite right, remove, rebend and start again

[Edited on 16/2/06 by stevebubs]

Do you know if the arm is reaching it's maximum travel at the top?

If not, the float will hit the top of the tank before it reaches it's maximum travel and will never read full.

Pat...

Mines like BigRich's loads of mends.
I positioned mine on the outside of the tank so I could see the travel when the arm was in a high and low position.
Once satisfied I but it in the tank and checked it didn't fowl anything.

I guess its just a potentiometer. In that case use a multimeter to measure the full throw of the arm (resistance). then put it in your tank and see if the measurements are the same at high and low.

Have a good read of the instructions that come along with the ETB guages, as long as the float almost touches the bottom and top of the tank, the guage should read fairly accurately. Im sure mine is full of lots of bends and kinks to get it to read properly.

Well would you believe it - looks like my tank zero point is quite close - i ran out of fuel this morning on way to petrol station!!!!! I stuck a gallon in and it is just reading around 3%.

This has foxed me as when i first put fuel in (tank dry) i thought it took about 2 cans (2 gallon) to get it past the zero point. I must have done something wrong.

I now also know that when the engine stops there isnt enough weight in these cars to coast along to get to the petrol station!!! Oh and they are most likely to run out when it starts raining

As an aside does anyone know what sort of consumption to expect out of 2.0 pinto running 38DGAS. Mine seems quite thirsty, im guessing 20ish mpg. Maybe the novelty factor isnt helping (heavy right foot and all that!). I havent tried it properly yet but seem to have to put fuel in quite often - this is possibly a mind trick thing seeing as the tanks are a lot smaller than tintops.

What capacity is the Mac1 plastic tank. The other reason i thought i had 2 gallon in at zero is that it took another 5.5or so gallon to fill it. If it i scloser to 6 gallon then this all starts to stack up.

I think they are 8 gallons - 30 litres

i seem to think mine took about 30 quid to fill so about 30 litres sounds pretty close

I can confirm 30 litres now. i ran out on Wednesday = tank empty. Put £5 in (approx 5 litres). Only did 6 miles and it took another 25 litres to fill it up the neck.

Ok - When i stuck 5 litres in the gauge was reading approx 4% (2 tenths of naff all basically). So at zero i have 4 litres (basically a wet splash on bottom of tank). This means zero point is bang on. All i have to adjust is the max point cos float must be topping out on tank when gauge only reading 78%. Easy fix. (In fact i might leave it. I was more concerned about the lower level).

Thanks for all your help.