Fuel Guages

[rafa]

Hi all.

For some reason my fuel Guages have started showing 3/4 full instead of full. Seems intermittent. Is there a simple fix?

Cheers.

Marty

[NP99]

Start by checking the earthing..

[threedogs]

X 2 earth problem like NP99 suggests

[Cuppa]

Can anyone explain this 'checking the earth' process, preferably specific to the vehicles that Rafa & I have, leaf cab chassis. I have lived with the same problem. If it's just a matter of the main earth to chassis connections, that' not the problem, at least not in my case. I have added extra earth connections. Dropping the fuel tank to get at the connections on top of it seems like a big drama. Is this what is required? It is so frustrating to be able to see all those connections on top of the tank, but just out of reach.
Really though I think it is more likely a dry solder joint in the pcb behind the dash, as someone else has described previously, which is nightmare stuff for me. Not a job I want to attempt myself, but fearful if I take it to Nissan or an auto electrician it could take a long time (& LOTS of cash) to find the cause. Rafa does your sub tank misread too? Mine does, & occasionally the speedo needle, but the problems are intermittent & unpredictable. Much of the time it works ok, but I cannot trust it. Shits me.

Cuppa

[altech]

GU fuel gauge ,I'm so use to mine being out ,I just go by my trip meter of 400 kms per LPG tank of 90 litres .......... regards Alex

[megatexture]

Can anyone explain this 'checking the earth' process, preferably specific to the vehicles that Rafa & I have, leaf cab chassis. I have lived with the same problem. If it's just a matter of the main earth to chassis connections, that' not the problem, at least not in my case. I have added extra earth connections. Dropping the fuel tank to get at the connections on top of it seems like a big drama. Is this what is required? It is so frustrating to be able to see all those connections on top of the tank, but just out of reach.
Really though I think it is more likely a dry solder joint in the pcb behind the dash, as someone else has described previously, which is nightmare stuff for me. Not a job I want to attempt myself, but fearful if I take it to Nissan or an auto electrician it could take a long time (& LOTS of cash) to find the cause. Rafa does your sub tank misread too? Mine does, & occasionally the speedo needle, but the problems are intermittent & unpredictable. Much of the time it works ok, but I cannot trust it. Shits me.

Cuppa

Unfortunately with so many issues like you are having it is more likely behind the cluster like you suspect and I agree that would be a pain in the ass. Can you get an aftermarket fuel guage cheaply and tap into the sender wires where you can reach them on the way to the dash to see if you get the same level as your dash, if it is then you have ruled out the instrument cluster, it must be the sender.

[Cuppa]

Thanks for 'confirming' my nightmare MT!
Your suggestion of a separate fuel gauge fits if just one gauge were affected, but despite my best attempts at wishful thinking I don't believe that the cause being sender units in both tanks is likely, particularly as there is a relationship between the misbehavior of both.
Can anyone tell me how many arms & legs (approx $ value would be good) I'd need to sell in a worst case scenario where the instrument cluster needed replacing. Would going to a Nissan dealer or an auto sparky be the best course? I'm guessing Nissan would just want to replace, but how likely is it that an auto sparky would be prepared/able to fault find/repair on the back of the dash cluster.
Living with the issue locally isn't hard, but I must admit I want to be able to trust the instruments for touring & especially any long desert trips.

Sorry if this is a hijack Rafa, but I'm assuming it may also be helpful to you.

[megatexture]

Would it be easier to get an instrument cluster from a wreckers ? Fix any suspisous joints on that one and do a clean swap for minimal down time and labour cost

[Cuppa]

Would it be easier to get an instrument cluster from a wreckers ? Fix any suspisous joints on that one and do a clean swap for minimal down time and labour cost

Another good idea, And another 'yes but' answer......... problem for me would be a)recognising any suspicious joints, & b) fixing them. Have never had anything to do with such things. If I tried I could easily envisage multiple attempts at removing & replacing the dash not knowing if everything was working or not.

Now there's an opportunity for someone familiar with that sort of soldering work. Buy dash clusters from a wreckers, test them to ensure they are working correctly & then sell them to folk like me with a guarantee they are fully operational. I'd buy one if it only meant pulling the dash apart the once. ANY TAKERS? Rodney would you be the man?

Out of interest would the mileage recording of my vehicle be retained, or would it show the mileage of the donor vehicle?

Cuppa

[rafa]

I have been thinking more about when mine started to go wrong, my auto electrician wired in a red arc dual battery system to the third battery in the pod to charge while driving, from the second battery under the Bonnett, he ran a heavy duty positive wire to the third battery, then earthed to the pod. I noticed over the last couple of weeks that the third battery was not charging properly, He has comeback saying may be earthing to the aluminium body was not satisfactory. And has run a heavy duty her back to the chassis. I think this is around the same time that my fuel gauges were mucking up, could it be a coincidence? I am yet to see the error come up with the fuel gauges with the new earth, I will post more later