Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: Dave69 on February 01, 2014, 10:21:54 AM

Title: CJ7 fuel gauge
Post by: Dave69 on February 01, 2014, 10:21:54 AM
just a simple question,

typical fuel gauge not working.

to check is this a simple case of disconnecting the sender and the gauge should rise to show full (O/C)

Which part normally fails, sender or actual gauge?
Title: Re: CJ7 fuel gauge
Post by: Bulldog67 on February 01, 2014, 11:29:55 AM
Oooooh i know I know :ace:

this the sender
Title: Re: CJ7 fuel gauge
Post by: j33pky on February 01, 2014, 12:34:18 PM
Now let ade have the computer back Mrs bulldog :icon_winkle:
Title: Re: CJ7 fuel gauge
Post by: eastryjeep on February 01, 2014, 12:48:29 PM
Nah, I've been through at least 3 gauges on my CJ7.
What usually happens is that the ballast resistor in one of the two gauges (cant remember which, but Lightys will tell you) fails and either one or both of them burn out. Or the damn things get too much condensation on them and short themselves out all on their own!
Never had a fuel sender pack up in more than 30 years of owning the same Jeep!
Regardless of that, a few mins with an AVO meter will tell where the fault lies. If you really want to check the fuel sender empty, then drop the tank, remove the sender and test that the resistance reading changes as you move the float arm up and down.
However if it were me, I'd check the instrument cluster first for a good earth, then the gauges themselves, then put the meter on the fuel gauge wires behind the dash and check for change in resistance as you feed in a few litres of fuel, then do the same again at the sender to check the integrity of the wires to the dash.
Once youve found the problem bear in mind that the loom in a CJ isnt exactly new and you may want to take the opportunity to replace the old wiring or at least renew the connectors.
Title: Re: CJ7 fuel gauge
Post by: Bulldog67 on February 01, 2014, 01:48:41 PM
Now let ade have the computer back Mrs bulldog :icon_winkle:

 :hysterical: :hysterical: :hysterical:

and who wins then Dave :popcorn:
Title: Re: CJ7 fuel gauge
Post by: Dave69 on February 01, 2014, 02:21:42 PM
don't really want to drop the tank at this time of year so i will pursue the gauge connections and wiring then see what happens
Title: Re: CJ7 fuel gauge
Post by: Bulldog67 on February 01, 2014, 02:43:48 PM
Should be a hole in the tub to access the sender unit
Title: Re: CJ7 fuel gauge
Post by: Nosebolt on February 01, 2014, 03:36:05 PM
Should be a hole in the tub to access the sender unit

no there shouldn't, least not on any CJ I've worked on
Title: Re: CJ7 fuel gauge
Post by: eastryjeep on February 01, 2014, 05:31:16 PM
And I dont remember saying anything about dropping the tank being an easy job, but certainly no simple access panel from above in a CJ, maybe you could take that as testament to how reliable the sender is?
Make no mistake though, that skid plate under the tank is damn heavy!
So dont say you weren't warned eh!
Title: Re: CJ7 fuel gauge
Post by: Bulldog67 on February 01, 2014, 09:10:39 PM
Should be a hole in the tub to access the sender unit

no there shouldn't, least not on any CJ I've worked on

weird, mine does :017:

I guess its just cooler than yours  :greggmo:

The Chief has one as well as the AMC senders are wank - which is why I just had that one replaced as well

Perhaps its a V8 v ghay engine thing :003:
Title: Re: CJ7 fuel gauge
Post by: bigjeepzj on February 01, 2014, 10:04:09 PM
you don't need a fuel gauge in the chief
you just fill up every time you pass a petrol pump
Title: Re: CJ7 fuel gauge
Post by: bigjeepzj on February 01, 2014, 10:05:00 PM
sorry you do
Title: Re: CJ7 fuel gauge
Post by: Bulldog67 on February 01, 2014, 10:33:22 PM
jerry cans :icon_winkle:
Title: Re: CJ7 fuel gauge
Post by: Bubba on February 01, 2014, 10:35:45 PM
Its not the sender  not normaly its the gages they are paired and the voltage regulater/stabaliser has sex with it self and then that it somtimes nithere work but the fuel one always fails
Title: Re: CJ7 fuel gauge
Post by: Bubba on February 01, 2014, 10:36:54 PM
Should be a hole in the tub to access the sender unit








Not in a cj7 in an8 yes
Title: Re: CJ7 fuel gauge
Post by: Bulldog67 on February 01, 2014, 10:38:52 PM
good job I never bought that sender you tried to flog me then
Title: Re: CJ7 fuel gauge
Post by: Dave The Sparky on February 01, 2014, 11:06:14 PM
Should be a hole in the tub to access the sender unit
Not in a cj7 in an8 yes

An 8 shouldn't have a hole for the sender unit either,like most vehicles its drop the tank time :icon_rolleyes:
Title: Re: CJ7 fuel gauge
Post by: Dave69 on February 01, 2014, 11:56:34 PM
hoping for the gauge as the bash plate and tank look a pain to drop due too weight
Title: Re: CJ7 fuel gauge
Post by: Nosebolt on February 02, 2014, 12:05:02 AM
it's not that bad, 3 bolt on one edge, 4 on the other, 2 pipes from the filler and 2 or 3 small bore pipes up top, just remember to put a jack under it before you take out the bolts.
Title: Re: CJ7 fuel gauge
Post by: Bulldog67 on February 02, 2014, 09:16:04 AM
Just shows why the Chief is superior, bit more thought gone into the build
Title: Re: CJ7 fuel gauge
Post by: Dave The Sparky on February 02, 2014, 09:38:44 AM
The Chef just a large estate car with a roof and a bit of carpet to cover that access hole, thats the difference.

You may as well of just bought a Volvo...................................................Oh you did :003:
Title: Re: CJ7 fuel gauge
Post by: Dave69 on February 02, 2014, 09:59:53 AM
it's not that bad, 3 bolt on one edge, 4 on the other, 2 pipes from the filler and 2 or 3 small bore pipes up top, just remember to put a jack under it before you take out the bolts.

thats the easy bit, getting it out fixed and back again before the monsoon season restarts is the tricky bit
Title: Re: CJ7 fuel gauge
Post by: Nosebolt on February 02, 2014, 11:00:45 AM
it's not that bad, 3 bolt on one edge, 4 on the other, 2 pipes from the filler and 2 or 3 small bore pipes up top, just remember to put a jack under it before you take out the bolts.

thats the easy bit, getting it out fixed and back again before the monsoon season restarts is the tricky bit

 :hysterical: :hysterical:

know what you mean, it's a bitch not having permanent use of a workshop
Title: Re: CJ7 fuel gauge
Post by: Dave69 on February 02, 2014, 09:10:21 PM
bugger now noticed i need to replace the axle seal. as diff oil has now contaminated the rear shoes
Title: Re: CJ7 fuel gauge
Post by: eastryjeep on February 15, 2014, 03:47:44 PM
Err, how many feet you got then Dave?
Title: Re: CJ7 fuel gauge
Post by: j33pky on February 15, 2014, 07:02:42 PM
The Chef just a large estate car with a roof and a bit of carpet to cover that access hole, thats the difference.

You may as well of just bought a Volvo...................................................Oh you did :003:


That's a bit bitchy you gimp!!
Title: Re: CJ7 fuel gauge
Post by: Bulldog67 on February 15, 2014, 07:18:38 PM
He drives the least attractive out of all Old Iron so its not even worth biting