Fuel Sending unit technical question?
Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 2,831
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From: Corvette, It's a state of mind Anywhere, USA
Fuel Sending unit technical question?
Well, I have read alot of posts about this common problem with the C5's and I finally got bit by it this morning. My fuel guage went from Full to Empty in one fell swoop and immediately my "Check Guages" light came on with a message on the DIC "Low Fuel". Well, I knew this wasn't true since I just filled up two days ago and I don't even go through gas that fast! So, I just hit the Reset button to clear the DIC and about a minute or so later, the "Check Guages" light went out and it did not return the rest of the way to work. I strongly suspect that the Fuel Sending unit is going bad. My question is: "Were these units just badly designed by GM or just poorly constructed? This seems to be an all too common problem with C5's and I was just wondering what really is causing this from a technical view point?" It seems like a very simple problem and possibly an oversight when they put these things together. Any info on this will be very helpful. Peace. :cool: T-Bone.
Burning Brakes
Joined: Dec 2000
Posts: 993
Likes: 5
From: Cincinnati Ohio
Re: Fuel Sending unit technical question? (T-Bone98)
T-Bone98,
Chevrolet issued TSB #01-06-04-022 to address this problem. It involves replacing a sensor and strainer and/or the RH fuel sending unit.
This is a very common problem and another example of the poor design and engineering of C5 components.
You may want to speak with your dealer/service advisor to see if Chevrolet will repair the problem for you at no cost. It is an expensive repair. Good luck.
1999 White C5 Coupe
Chevrolet issued TSB #01-06-04-022 to address this problem. It involves replacing a sensor and strainer and/or the RH fuel sending unit.
This is a very common problem and another example of the poor design and engineering of C5 components.
You may want to speak with your dealer/service advisor to see if Chevrolet will repair the problem for you at no cost. It is an expensive repair. Good luck.
1999 White C5 Coupe
Drifting
Joined: Jun 2000
Posts: 1,338
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From: Fontana CA
Re: Fuel Sending unit technical question? (T-Bone98)
You should check to see if the TSB covers your vehicle and problem. I think the TSB covered a condition where a screw that was too long was causing the float to hang-up. This resulted in a reading that was too high and caused people to run out of gas when the gage still showed fuel in the tank.
If your sending unit has not already been replaced under the TSB I say try to get it replace that way. The worst they can say is no.
The sending unit in my '01 failed in the same manner as you describe. It started out as an occasional problem then got more and more frequent. The dealer replaced it under warranty and it has been fine since.
If your sending unit has not already been replaced under the TSB I say try to get it replace that way. The worst they can say is no.
The sending unit in my '01 failed in the same manner as you describe. It started out as an occasional problem then got more and more frequent. The dealer replaced it under warranty and it has been fine since.
Team Owner
Joined: Jun 2001
Posts: 20,246
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From: Katy Texas
Re: Fuel Sending unit technical question? (T-Bone98)
My question is: "Were these units just badly designed by GM or just poorly constructed? This seems to be an all too common problem with C5's and I was just wondering what really is causing this from a technical view point?" It seems like a very simple problem and possibly an oversight when they put these things together. Any info on this will be very helpful.
My dealer suspects the electrical connections to the devices are improperly put together at the factory, allowing them to short out in some circumstances. When I asked if anyone who had both senders replaced had to go back a third time, no one said anything, so perhaps that means once the dealer replaces both sending units they tend not to fail.
And as I always mention, if a fuel sender unit is bad, then it's pumping capacity can also be affected. Get them replaced before you get stuck in traffic one rainy day, out of gas, but still having 1/3 tank left. ;)
:cheers:
Former Vendor
Joined: Apr 2001
Posts: 10,976
Likes: 21
From: FL
St. Jude Donor '13
To answer your question,the right sender has 2 faults.One,the sender strainer can contact the float arm causing the float arm to stick,resulting in an inacurate gauge.2nd,the siphon jet pump part of the sender can become airiated prohibiting fuel from being transfered to the left tank.This is why some run out of gas even though the gauge indicates fuel (fuel in the right tank but none in the left tank,the one that feeds the motor)...The updated right sender has an improved strainer and sipon jet pump to correct this...
As for the left sender,the sensor on the sender which is simply a resistor is prone to an open circuit.When the open circuit is detected by the PCM,the gas gauge drops to "E"...The updated left sender has an improved sensor resistor...
As for the left sender,the sensor on the sender which is simply a resistor is prone to an open circuit.When the open circuit is detected by the PCM,the gas gauge drops to "E"...The updated left sender has an improved sensor resistor...
Drifting
Joined: Feb 2001
Posts: 1,421
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From: Henderson, NV
Re: (C-5 TECH)
Hi all,
Just an interesting side note here to add. When I was on a trip from LA to Vegas, I had this happen to me. RIGHT AFTER I had filled up completely, I made a sharp left turn(90 degree) and then a sharp right turn (90 degree) onto a highway in palmdale area and the guage went to "E" and the warning light came on. I thought "Do I have a gas leak?" and pulled over to check the underside and road behind me. NOTHING. So, I got in the car, started it up, and it was normal from then on, full tank. Weird, huh!
Steve
Just an interesting side note here to add. When I was on a trip from LA to Vegas, I had this happen to me. RIGHT AFTER I had filled up completely, I made a sharp left turn(90 degree) and then a sharp right turn (90 degree) onto a highway in palmdale area and the guage went to "E" and the warning light came on. I thought "Do I have a gas leak?" and pulled over to check the underside and road behind me. NOTHING. So, I got in the car, started it up, and it was normal from then on, full tank. Weird, huh!
Steve
Advanced
Joined: Aug 2001
Posts: 84
Likes: 0
From: St. Peters MO
Re: Fuel Sending unit technical question? (T-Bone98)
Have you pulled the codes to see which side it is? I replaced my left side sensor myself as I am out of warranty. I got the part whole sale for about $25 bucks. I think the dealer estimate to fix this was almost $400. :mad
The install is not too bad and I have all the instructions. The sensor replacement instructions are not in the service manual they come with the part. Hope this helps.
The install is not too bad and I have all the instructions. The sensor replacement instructions are not in the service manual they come with the part. Hope this helps.
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Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 2,831
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From: Corvette, It's a state of mind Anywhere, USA
Re: (C-5 TECH)
C5-Tech,
Thanks for the technical explanation, I always wondered what really causes this in detail. You explained it perfectly! I take from your explanation that to solve this problem for good you must replace BOTH sending units to be sure, is that correct? From looking at the codes I believe this is happening on the right side for now. Peace. :cool: T-Bone.
Thanks for the technical explanation, I always wondered what really causes this in detail. You explained it perfectly! I take from your explanation that to solve this problem for good you must replace BOTH sending units to be sure, is that correct? From looking at the codes I believe this is happening on the right side for now. Peace. :cool: T-Bone.
Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 2,831
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From: Corvette, It's a state of mind Anywhere, USA
Re: (Blackjetvette97)
BlackJetvette97,
In my case I was traveling in a straight-line at about 75mph on the freeway when the fuel guage went suddenly to zero, lights and "Low Fuel" message came on and then the Fuel guage went back to Full, reset the DIC message, "Check Guages" light went out about a minute later, has not come back since. I think I am going to get this checked out just in case because I plan on going down to the Keys, in about 2 weeks and I do not want to run out of gas in the middle of the 7 mile bridge if you know what I mean!!! Peace. :cool: T-Bone.
In my case I was traveling in a straight-line at about 75mph on the freeway when the fuel guage went suddenly to zero, lights and "Low Fuel" message came on and then the Fuel guage went back to Full, reset the DIC message, "Check Guages" light went out about a minute later, has not come back since. I think I am going to get this checked out just in case because I plan on going down to the Keys, in about 2 weeks and I do not want to run out of gas in the middle of the 7 mile bridge if you know what I mean!!! Peace. :cool: T-Bone.
