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Parksy
13th August 2013, 10:19 AM
Hi all

I was wondering what people have thought about the gauges in the gq dash,
Mainly the fuel and oil pressure ones when it came to accuracy. I find myself filling up with petrol early because I'm not sure how low the gauge actually goes. Can an aftermarket unit be easily fitted using the factory sender unit?
Does the oil pressure gauge actually work? When I switch the ignition to on, but not with engine running, the pressure gauge does go up, and when the engine is turned on, it rises again and does change slightly when the throttle is blipped, but I'm still skeptical about its accuracy. When warmed up it says pressure is about 1-2 bar. Does this seem right? Curious to know what everyone's readings are on this gauge.

Thanks all

Andy

mudnut
13th August 2013, 10:36 AM
As with any electrical gauge, the reading depends on its voltage supply. On longer trips, the battery will be fully charged, so even with the regulator doing its job properly, I have found the gauges read ever so slightly higher. My petrol gauge is very inaccurate between the quarter marks. 70 to 80 kilometres from full to 3/4. Up to 120ks then; hang at half full for ages. After that it falls away to 100km to 1/4 and I have never had the guts to see how far it will go to empty. My oil pressure gauge alters with engine temp as well. So as the pirates say; "Its more like guidelines than rules."

mudnut
13th August 2013, 10:57 AM
I just turned the ignition to on, and my oil gauge stayed at zero until the engine was started.

Parksy
13th August 2013, 12:22 PM
Thanks mudnut, I don't feel so bad about the fuel gauge now, but I think I'll go aftermarket with the oil pressure.
Cheers!

mudnut
13th August 2013, 12:50 PM
Sorry, Parksy, that's all the info I've got. Forum members with more experience may be able to advise you if it is a good idea to upgrade the sensors or not, and which units are the best to get.

taslucas
13th August 2013, 12:51 PM
Lol yeah my fuel gauge is slowly getting worse. When I fill up it only goes to just above 3/4. It stays there till I actually have 3/4 fuel left then it reads fairly accurately down to half. Then below half it drops away real quickly (quicker than I'm using fuel). Best way to check is to put a jerry can of fuel in the back and drive till you run out (which is about a quarter below the empty line lol

Pezzer
13th August 2013, 08:25 PM
When I pulled the sender unit out of my Maverick I found that float arm was short and showing empty 60mm above the base of the tank, so have lengthened it to show empty 15mm from the tank base. In my Hilux it would go to within 8mm when showing empty.

Parksy
13th August 2013, 09:30 PM
Thanks pezzer, might have to give it a check. How did you check it btw? Was the sender still in place when you checked?

Pezzer
13th August 2013, 11:12 PM
It was when I dropped the tank and pulled the sender unit, I noticed that the float was still above the pickup by quite a bit when it was hanging so I measured lengths as if installed and checked the tank depth, would never of known otherwise.

MC97GQ
14th August 2013, 10:08 AM
Lol yeah my fuel gauge is slowly getting worse. When I fill up it only goes to just above 3/4. It stays there till I actually have 3/4 fuel left then it reads fairly accurately down to half. Then below half it drops away real quickly (quicker than I'm using fuel). Best way to check is to put a jerry can of fuel in the back and drive till you run out (which is about a quarter below the empty line lol

I agree Tas,

But also set your trip meter, and drive it as far as you are game or until it does run out. My fuel gauge seems to work ok but I still set the trip meter everytime I fill up.

It's a little peace of mind.

Mark

taslucas
14th August 2013, 10:16 AM
Yeah trip meter is a good idea but my driving can be vastly different sometimes. The TB42 will use hardly any fuel cruising gravel roads at 70 k/hr but she chews it when I'm feeling "playful" lol

Parksy
14th August 2013, 10:30 AM
I do like to use the trip meter, but there are some days where I don't fill up completely which makes the system useless.

Having a look at fuel gauges on eBay,
It appears they run off specific resistance readings, ie 0-90 ohms. Anyone measures the resistance on the patrol fuel sender from empty to full?

mudnut
14th August 2013, 12:13 PM
According to the workshop manual: At full 4.3 ohms. At empty 74.3 -84.8 ohms. I wonder if the gauge is adjustable?

Parksy
14th August 2013, 01:26 PM
Might be worth checking, but those figures aren't too far off on one of the gauges I was looking at, might have to investigate further on this. Cheers mudnut!

Safari Njema
15th August 2013, 03:52 AM
I agree with Taslucas that it goes a long way below the empty line but I have never had the nerve to allow it to run out completely. I always thought that's an absolute no no with a Diesel engine!

BigRAWesty
15th August 2013, 06:37 AM
A pretty fool proof way is to drop the contents of your tank at say 1/8 tank and measure.
This paired with the measuring of the float position will give you the best outcome.

If you want to test the diesel just carry a couple of spanners to crack the fuel line and a jerry can full of juice.. When it conks out top up and prime it.. A bit of a PITA.

My gauge will go a full needle width gap below the e line and still be good.. That was black top though..

mudnut
15th August 2013, 09:36 AM
This thread reminds me of a Seinfeld episode, where Kramer goes to a caryard to test drive the same model of car that Seinfeld had bought. He sucked the salesman into driving the car until it ran out, just to see how far the needle went. That way, he could borrow Seinfeld's car and not worry about filling up... I seriously don't want to run out of fuel in front of a log truck, so I will just make sure I fill up before the empty mark.

liftlid
15th August 2013, 10:32 AM
A standard tank holds 95 litres, fill your tank when it hits the empty line then you will know how much fuel is left, it will be around 20 litres.

taslucas
15th August 2013, 12:18 PM
My problem is I have an aftermarket tank with no idea what size it is. I think the "run it to empty and carry a jerry can" is my only way if knowing

liftlid
15th August 2013, 12:21 PM
Oh ok do you know the brand? If you can measure the sides of the tank you could work out the area.

taslucas
15th August 2013, 12:50 PM
Good idea, I never actually thought of that! Haha.

Parksy
16th August 2013, 12:30 PM
I've bought myself a mechanical oil pressure gauge and some copper hose to suit, I was thinking of just removing the factory sender unit. Will this give me error codes on the computer? What size is the oil sender thread?

taslucas
16th August 2013, 01:16 PM
You could just put a T piece in where the sender is that way could have the original gauge and the mechanical gauge

Winnie
16th August 2013, 01:20 PM
I have been too scared to go much below 1/4 tank because it's so incorrect above that I have no idea what left. I'll get 450-470kms before it hits 1/4 and when I fill up its around 70L

MudRunnerTD
16th August 2013, 01:23 PM
I have been too scared to go much below 1/4 tank because it's so incorrect above that I have no idea what left. I'll get 450-470kms before it hits 1/4 and when I fill up its around 70L

So you have 25lt left which is Heaps mate. even on a bad day you have still got 150kms in the tank! My GQ has a fuel light too. I reckon your gauge sounds right mate if you have that much left and those kms.

MudRunnerTD
16th August 2013, 01:24 PM
You could just put a T piece in where the sender is that way could have the original gauge and the mechanical gauge

Thats what i have done and run both gauges. Both electric gauges and works great. The after Market is way more sensitive than the factory too.

Parksy
16th August 2013, 01:42 PM
Anyone heard of the tee piece breaking off because of the size of the original sender unit? That's my only issue with running the tee fitting. What size is the thread?

GQ TANK
18th August 2013, 03:42 PM
Re Gauge resistance:- At full 4.3 ohms. At empty 74.3 -84.8 ohms.

The set up for the gauge is basically a voltage divider - 2 resistor in series with a meter measuring the voltage at the junction of the 2. (one of the resistors is the tanke gauge)

I'm, using an ardunio microprocessor to display my LPG tank level - a estimate of distance left base on 24/l per 100k (i.e. 39l = 159Km) - also I had to average out the readings as the gauge jumps on bumps.

See the photo of the display and board - I have no added a Temp sensor - battery level sensor - and playing with a O2 senor at the moment.

Plus I now have set up a dimming control - as It was very bright at night time.

silverbak
18th August 2013, 08:57 PM
Best way to check gauge is drain the tank at home then put back in 10 or 20lt and check gauge reading. Then you will know that at x reading you have 20lts left in tank !!
cheers Tim