I bought a 94 AB coupe about a month ago and noticed that the lines on the gas guage don't move from the full postion even after a 100 mile drive. What could be the problem? Thanks!

 

Anyone?

 

Your sending unit has moved on to a better place.

Seriously though, the part is not cheap but it is a very easy DIY. I had mine out and tried cleaning it on the advice of this forum but that didn't work. When my money tree sprouts some buds I'll get to fixing it for good. Until then I just rely on the odometer.

 

......indianna, check your pm's for the fix......

 

Is the fix top secret or something? Mine is still broke too you know.

 

i hate a feakin' smart ***!....oops!......turned out i deleted it a few min ago..........awe....

 

Okay, so you aren't in a sharing mood I take it.

 

.i share but..."deleted it" directly after your comment.....

 

Do you know how much a sending unit costs?

 

Did anyone ever figure out how to fix this? My gauge is all over the place, 1 minute it says 1/4 tanks then 3/4 tank then somewhere in between

 

.........really bad 'eh?

 

So can you share the fix please?

 

...well, due to a smart-a$$ed comment made by an individual, the copy i had handy was deleted as in an aforementioned post. i have a copy somewhere on one of 6 discs but, it would take too darn long to locate it....

....also, i told they guy whom was looking for the "fix" to send me an
e-mail so i could send it to him that way, as i did not know how to post a text document with pictures on the forum...1 guy ruined it for another.......

 

I had the same problem, corrosion in the tank and on the sending unit. If the resistance goes to high or just opens, the gauge just hangs at about a half tank. I took my tank unit out, disassembled it, and very carefully sanded the 2 wipers and the wiper contact on resistor and the wire wound resistor. Took me about a good 2 hours and that doesn’t count removal. care, care, care is the key work here. Not a fast job and have to keep using an ohm meter to check progress. When I started on mine, it read open every where. When I got done, it was 95% good and that is good enough for the CCM electronics. I also have a fix for the accuracy of the gauge if you should get it working OK. The resistance numbers are as follows;

Tired of not having the gas gauge drop as you use gas. The inaccuracy was to much for me to stand so I investigated the problem. According to specs the float unit has a range of 0 to 90 ohms. I measured 20 to 110 ohms on my float unit. The 20 ohms representing the empty end and the 110 representing the full side (most other cars the low represented full but in the digital world they can do what the want).

The basic problem is the resistance doesn't not drop fast enough as gas is removed from the tank. I had to move the float arm to the 65 ohm point before it would indicate a one bar drop on the gas gauge. 75 to 110 ohms read full. It was not before I got down to about 37 ohms that I got a half tank indication on gauge. In reality the float resistance range is not properly matched to the electronics in the CCM. How to fix properly, you can’t unless you rewind the float wires (I don’t think so). So the best you can do (rather than redesign CCM) is to compensate for the problem. Make the resistance read lower faster as gas is burned. I added a 180 ohm resistor (yours might me slightly different) across the float unit, this will accomplish this. To little resistance and you will not get a full reading, to much and you are giving away accuracy which you a targeting in on. If I really really fill my tank I can get a full indication, if I let it click once or twice I might get a one bar down. I’m on the edge and I can live with that. But I do get more accurate readings right down to ¼ tank. Its not perfect, but I’m within 2 gallons or less when I get gas.

All you need to do is to add the resistor across the tank wiring. You do not need to take out the tank unit. Just remove the gas door and the rubber boot. Come back 6 inches or so from the tank unit and skin back the black and purple wires. I did not cut the wires, just removed about ¼ inch of insulation, wound the resistor ends around each wire and tape it
up. I don’t think I soldered mine because I was not sure of the resistor I wanted to use and how the whole thing was going to work out so wanted the option of removing it easy. So temporary became permanent 2 years ago. Hope this can be of use to some of you.

P.S. - There are 3 wires. Black is ground and gray is power for the pump. The purple wire was not indicated the color for the float in the GM book, think it was green, don’t know why.

 

......off topic a bit...pcolt, any more news/info on braking problem?....mine is to the point that there is practically none and the pedal is becoming a rock...i think it is a booster although it holds vaccum....

 

This is very interesting. I had a similar problem with mine. I ran out of gas several time with 4 bars showing on my gauge...very frustrating!!! and it would show full with only 2/3 of a tank. I measured the ohms and i got 5ohms when empty and over 100 when full. I tried bending the float arm a bit to see if i could compensate, but didnt completely solve the problem. I may try a resistor.

There is a tech tip on how to clean the sending unit. Maybe this will help you out. Check out the tech tips section. Maybe this is the "secret."

 

What? Are we 5 yrs old?????

 

........NO, are you?......the guy came up with a crappy comment as i stated above and since i was cleaning out my computer at the time, it would just as well become a casualty.......

 

i had the exact same problem...i think once you bent the arm (bad thing to do) , it'll never be accurate again unless you could compare it to another assembly...... mine works well and is accurate at this time......

 

Last I checked the replacement sending unit was like $400.00. I got lucky anf got one off of Ebay for $75.00.