fuel gauge reading off
Thread Starter
Zen Vet Master Level VII
Joined: Mar 2016
Posts: 5,218
Likes: 1,174
From: Southlake, TX
fuel gauge reading off
Part 64 of the continuing saga...
I have everything working on my 82's fuel gauge system; dash gauge, new fuel pump, low fuel warning light, new fuel pick up. Everything is well sorted
HOWEVER...
My gauge seem to read somewhere between 1/8-1/4 off. When full to the top, the gauge goes over "F" for about 100 miles before it falls below "F", seems to be mostly accurate around 1/2ish and when it show empty (low fuel light on) there is about 5 gallons left.
I've been doing the wooden rod test method to confirm fuel levels.
So, are readings on the gauge consistent from the sender or do (or can they) fluctuate as resistance increases?
Is this "pull it apart again" and bend the float rod? Is there a rule of thumb for bending the rod (like a 1/4 of bend will equal a 1/4 tank movement on gauge"?
This is a PITA as my '82 has the fuel pump in the tank and plugging in the harness to test means I have to put the whole thing together or fuel will shoot out all over the place. There really is no tweaking option I can see.
An ideas?
I have everything working on my 82's fuel gauge system; dash gauge, new fuel pump, low fuel warning light, new fuel pick up. Everything is well sorted
HOWEVER...
My gauge seem to read somewhere between 1/8-1/4 off. When full to the top, the gauge goes over "F" for about 100 miles before it falls below "F", seems to be mostly accurate around 1/2ish and when it show empty (low fuel light on) there is about 5 gallons left.
I've been doing the wooden rod test method to confirm fuel levels.
So, are readings on the gauge consistent from the sender or do (or can they) fluctuate as resistance increases?
Is this "pull it apart again" and bend the float rod? Is there a rule of thumb for bending the rod (like a 1/4 of bend will equal a 1/4 tank movement on gauge"?
This is a PITA as my '82 has the fuel pump in the tank and plugging in the harness to test means I have to put the whole thing together or fuel will shoot out all over the place. There really is no tweaking option I can see.
An ideas?
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
The 1978-1982 fuel gauge required input is supposed to be linear but as you have realized it is not and never had been for that matter. The scale is 0 - 90 ohms input with 90 being full and 0 being empty. However, most senders will reach up to and sometimes over 100 ohms which will push the gauge past the full mark.
It's unfortunate but something you should come to terms with for sure... I the gauge is reading correct when it gets close to empty then that's what you need to worry about.
Willcox
It's unfortunate but something you should come to terms with for sure... I the gauge is reading correct when it gets close to empty then that's what you need to worry about.
Willcox
Thread Starter
Zen Vet Master Level VII
Joined: Mar 2016
Posts: 5,218
Likes: 1,174
From: Southlake, TX
Thanks- It makes sense if the ohms are reading over specs; then no amount of bending will cure the problem.
I'll take your advise and keep and eye on the empty part. Last time the low fuel light came on it took 18 gallons to fill. I think I have a 24 gal tank.
I'll take your advise and keep and eye on the empty part. Last time the low fuel light came on it took 18 gallons to fill. I think I have a 24 gal tank.
