Electrical Fuel gauge problem

S

SSSnappy '89

Member

Nov 20, 2022

39

3

8

Auburn, AL

Dec 17, 2022

#1

• Dec 17, 2022

• #1

I replaced the entire fuel pump and float assembly a month ago. Car wasn’t driven much for several years and noticed that the fuel gauge wasn’t reading correctly on startup a while back so figured the float had gotten fuel logged. Fuel gauge was showing about 1/3 or so with a full tank. I had a new fuel pump and float/sending unit installed. After the new install, fuel gauge still shows about the same. Also, cluster oil pressure gauge reads (and has for decades) readaround 60-70 psi at all temps which is pretty wrong based on the stepper oil pressure gauge that is installed. Other dash gauges (temp/volts) seem to be correct. I searched the forums but didn’t find much relevant info. I know that grounds can be an issue, but what other things do I need to check?

 

AeroCoupe

lube between the nut and the face. I know my lubes

Founding Member

Oct 28, 2001

5,771

3,909

183

Claremore, OK

Dec 18, 2022

#2

• Dec 18, 2022

• #2

There is a slosh module for the fuel gauge that could be bad and may cause issues with the other gauges. I would recommend that you go to this thread and scroll down to jrichker’s post on "fuel gauge trouble shooting procedures".

What fixed YOUR fuel gauge? 87-93

So my 1988 GT fuel gauge was stuck on full and the fuel light did not work. (bought it this way) I replaced my instrument cluster with a 1989 unit with 140mph speedo so I could upgrade. After this my fuel gauge read 1/4 and the fuel light works and was on. But when I add fuel it goes to FULL...

www.stangnet.com

 

Last edited: Dec 18, 2022

Reactions: General karthief

S

SSSnappy '89

Member

Nov 20, 2022

39

3

8

Auburn, AL

Dec 20, 2022

#3

• Dec 20, 2022

• #3

Thanks for the tip! I checked it out; good info.

 

T

TimC

Member

Apr 24, 2022

13

6

13

Illinois

Dec 21, 2022

#4

• Dec 21, 2022

• #4

I went thru jrichker's fuel gauge list last summer due to similar complaints on my 87. Narrowed it down to the "anti-slosh" module. Ordered one from NPD and it fixed my multiple gauge woes. NPD is quite proud of those things.....

 

AeroCoupe

lube between the nut and the face. I know my lubes

Founding Member

Oct 28, 2001

5,771

3,909

183

Claremore, OK

Dec 21, 2022

#5

• Dec 21, 2022

• #5

I have heard some have replaced just the cap in the board and that fixed their problems.

 

S

SSSnappy '89

Member

Nov 20, 2022

39

3

8

Auburn, AL

Dec 21, 2022

#6

• Dec 21, 2022

• #6

TimC said:

I went thru jrichker's fuel gauge list last summer due to similar complaints on my 87. Narrowed it down to the "anti-slosh" module. Ordered one from NPD and it fixed my multiple gauge woes. NPD is quite proud of those things.....

Click to expand...

Same here. And yes they are quite proud of them, but I guess when they're the sole source they can be that way. Mine arrived today.

 

S

SSSnappy '89

Member

Nov 20, 2022

39

3

8

Auburn, AL

Dec 21, 2022

#7

• Dec 21, 2022

• #7

AeroCoupe said:

I have heard some have replaced just the cap in the board and that fixed their problems.

Click to expand...

I might try that after I put the new board in. If the capacitor replacement works I could keep it as a backup, but probably other parts on it are getting close to end of life.

 

AeroCoupe

lube between the nut and the face. I know my lubes

Founding Member

Oct 28, 2001

5,771

3,909

183

Claremore, OK

Dec 21, 2022

#8

• Dec 21, 2022

• #8

It’s mostly the caps that have a finite life. Typically that is all that is wrong with the ECU’s on these cars as well.