Fuel Gauge Problem
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
What I found was the resistance reading from the one in the tank was a steady 33 ohms. Bounced the rear and varied about 3 ohms...not much.
Put 90, then 50 then 40 ohms on the CCM connector and saw what the gauge showed me each time. Full at 90, half at 50 and one bar less at 40. Not to bad.
What I ended-up doing was to spread the pins apart on the CCM side of the connector and closed the contacts on the fuel sender side connector to make a better connection. Have to be very careful doing this, but it improved the reading I got on the fuel gauge.
So other than cut the mating connectors off and replace it with something else....nothing more I can do. The reading is better now, not off as much. Will have to see what the next tank full shows me.
Put 90, then 50 then 40 ohms on the CCM connector and saw what the gauge showed me each time. Full at 90, half at 50 and one bar less at 40. Not to bad.
What I ended-up doing was to spread the pins apart on the CCM side of the connector and closed the contacts on the fuel sender side connector to make a better connection. Have to be very careful doing this, but it improved the reading I got on the fuel gauge.
So other than cut the mating connectors off and replace it with something else....nothing more I can do. The reading is better now, not off as much. Will have to see what the next tank full shows me.
Last edited by LannyL81; Jan 4, 2011 at 10:56 AM.
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
The fuel gauge reading with it all apart was at four bars. Put it all back together and went on an errand...fuel level went from 4 bars to one bar above half full and stayed there.
I took the connector apart again and put jumper wires between the mating connectors. Fuel level showed four bars...which is close. Put connector together...fuel level went to one bar above half. I can wiggle wires around and nothing. Must be a dirty contact, even though I have used contact cleaner on all.
I have purchased the contract extraction tool, new contacts and the crimping tool....going to replaced all of them and hopes this fixes the problem for several years.
I took the connector apart again and put jumper wires between the mating connectors. Fuel level showed four bars...which is close. Put connector together...fuel level went to one bar above half. I can wiggle wires around and nothing. Must be a dirty contact, even though I have used contact cleaner on all.
I have purchased the contract extraction tool, new contacts and the crimping tool....going to replaced all of them and hopes this fixes the problem for several years.
Last edited by LannyL81; Jan 8, 2011 at 06:02 PM.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
When I added my resistor back in 06, the readings were within 2 gallons or less and I was happy. But in the last year or so I have noticed a change as it is reverting back to where I started from. I have not explored the problem as of yet and don’t want to disturb anything. When I get a block of time I'm going to take another look and see what I can find.
It does bother me though that it has gotten worse and it was so good for so long.
It does bother me though that it has gotten worse and it was so good for so long.
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
I think you previously mentioned this, but the thing to do is take a resistance reading at the CCM connector. Which of course would involve taking the center console out, the radio trim panel and the radio to get at the CCM. That is alot of time.
One thing that I noticed but did not check into further was when I was watching the fuel gauge level change by putting different resistors or jumpering between the mating connectors...I only turned the key to ON, I did not start the engine each time I made a change....but after putting everything back together, I get in the car to leave and the fuel level is right back at one bar above half again. This appears to be the lowest it will go.
I do not know if the CCM does something different with the engine running vrs not. Maybe it is just putting the fuel door back on that makes that connection resistance change.....do not know.
My next step is replacing the contacts in both connectors and then go from there.
One thing that I noticed but did not check into further was when I was watching the fuel gauge level change by putting different resistors or jumpering between the mating connectors...I only turned the key to ON, I did not start the engine each time I made a change....but after putting everything back together, I get in the car to leave and the fuel level is right back at one bar above half again. This appears to be the lowest it will go.
I do not know if the CCM does something different with the engine running vrs not. Maybe it is just putting the fuel door back on that makes that connection resistance change.....do not know.
My next step is replacing the contacts in both connectors and then go from there.
Instructor
Joined: Dec 2009
Posts: 162
Likes: 18
From: Newark ca
you can always plug in a new (or existing) sender unit and watch the guage as you move the float arm thru it's travel. If all ok, just bend the float arm to compensate for the difference in accuracy. If it's one thing i've learned in the automotive field it's that new parts never fit or are correct!
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Actually I was going to suggest this along one of the lines that "MrVett" has. You might have done this, but remove the pump and sending unit out of the tank. Put it on top of the rear of the car and connect the connector. Pull the fuel pump fuse. Then turn the key on and you can move the float arm and watch the fuel gauge. You can then determine if electrically (it's resistance swing) that it can change from a full tank to a empty tank and turn on the low fuel indicator light.
If that is good, then you can consider bending the float arm.
If that is good, then you can consider bending the float arm.
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
I tried bending the float arm....made no difference in mine. The CCM is "seeing" resistance from what I think are corroried contacts. The gauge will show correctly when I put jumpers between the mating connector at the fuel sender...and for a short time when I mate the connector. Then it goes back and stays at the one bar above half full....that is as low as it will go due to the resistance in the contacts....or somewhere.
I should have tried my other fuel sender when I had it apart to see what it did....but then again...it is the original one I took out that started this whole thing.
I should have tried my other fuel sender when I had it apart to see what it did....but then again...it is the original one I took out that started this whole thing.
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
Well got the contract extraction tool, new contacts and the crimping tool. Replaced all seven contacts..yes even the one that is for the second ZR1 fuel pump, put it all back together and fuel gauge shows one bar below full. Right where it should be.
Have to wait and see how the fuel gauge works on this tank.
Have to wait and see how the fuel gauge works on this tank.
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