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Discussion Starter · #1 ·
In shopping for a 2003 fuel filter, I can only find the next tier down from the OEM level part. I would prefer the original part for my needs, but can adapt. I would like to know if this is a supply chain temporary condition, or a permanent manufacturing decision at GM, and would appreciate any information.

I know a lot of C5 parts have been discontinued, just would regret if I bought now and later on the situation changes for the better, an unlikely result. I'm not a fuel filter connessour or anything like that, just want to do the best I can for the car, since this will be in there for a long time.

I had read that the OEM rotors have directional cooling fins, but use only one casting, so the left side is, in effect, cast backwards. when installed. I would prefer to keep things simple and not start changing parts around in such a critical system, but it wouldn't be the first time. right now my buying priorities are avoiding Chinese rotors and all the issues they bring with them, and maximum swept area, no pretend race car stuff. any buying suggestions are welcome , for a stock set up.
 

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Don’t know about fuel filters but for brake rotors I would look into power stop. Brakes for the street or the street and track. EBC is also a good brake product. Rock auto is another place to shop around. Then there’s always GM parts online which is their company parts store. It’s kinda of hard to navigate but you will find if the part has been discontinued or no longer available as I have found for several C6 parts. Happy hunting and good luck.
 

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The GM filter/regulator for C5 is a part that shouldn't exist. Because it sucks. Like Optispark or Crossfire fuel injection it was used for a few years and dumped.

For reference this part was created in 1999. The C5's debut was in 1997 and1997-1998 had just a filter and a return line that connected to the rail with inbuilt regulator. So it didn't even last a full generation of the Corvette's production. In 2005 at the very start of C6 with just a 405hp rating GM understood the filter was a restriction that created pressure differentials at higher flowrates in the context of fuel injectors with a flowrate high enough to happily pass any debris small enough to make it through the sock in the tank and felt so that they dumped the filter forever and the regulator moved to the pump where the return path could stay as short as possible so the pressure can stay stable throughout a larger flowrate range.

Electronic fuel injection with electric fuel pumps by the manufacturer started with a regulator and a return line mounted to the fuel rail. And the return line ran the full length of the feed line. We realized this created fuel rail pressure variations based on flowrates. The more fuel that flowed down the return path the higher the fuel pressure would be at the rail. The GM filter/regulator greatly shortened the return path and added stability to the fuel rail pressure across a broader flowrate range. And this was the great advantage to the filter/regulator. For C6 GM made the return path even shorter.

So for C5 what I personally like to do is remove and toss the filter/regulator where it belongs and purchase an adjustable high pressure fuel regulator with some carefully selected -AN fittings and build a direct replacement for the filter/regulator. And then you don't have to worry about changing the filter. And BTW, if anybody is counting the industry suggests we change fuel filters twice annually. But this is forever..



And because it is an adjustable fuel regulator if your psi at the rail is off at all you can do something about that. Which always was the downside of the aftermarket filter/regulators. They are always off by a few psi and you can't do anything about it but try another.

And about the rotors, for C5 there are left and right rotors. But for C6 GM decided to save money and there are only front and rear rotors.
 

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Discussion Starter · #4 ·
thanks for the informed reply. I always enjoy knowing as much as possible about my machines, but I will have to put the suggestion of modifying for the better , for another day, if ever. I have a regrettably long list of need for the car, and some other needs have priority.

While I have the interest, in practicality I would just be aping another's knowledge, without the understanding for correction if things malfunctioned. replacing parts is more my speed, I know how to do that, if you don't count mistakes as other than opportunities to earn.

I will just take comfort that the design isn't more screwed up than it is, and I am just replacing out of caution, the car has been sitting unused, not from failure after over 120,000 miles. later on in my model year, the fuel system was made even harder to work on. I never much worried about fuel filters , beyond the obvious need to screen out any trash, since gasoline is a solvent. I am surprised at a six month service interval for a fuel filter, unless one is operating in the third world. my car was built in oct of 2002 for the 2003 mode year and I doubt the filter has ever been changed , but it is of course, possible.

My primary issue is within the fuel tanks, I think. steady uninterrupted running causes the gas gauge to flip to empty all of a sudden, I think the tank transfer might be lazy, and as one tank drains, it reaches an unbalanced outcome outside of what the computer understands and flips to empty. I have read there is a service bulletin on resetting the computer perimeters, but most say deposits on the sending units are the problem, and just replace the stuff. I know bottles of fuel additives had no effect, and the car runs only top tier gas. the fuel filter was just an easy why not target, knowing it had been sitting around . I also plan on having the injectors serviced, because of sitting around .

To revisit my rotor question, are the castings indeed right and left directional parts, because I had read that while they were labeled right and left, they were all the same casting. additionally I still want to avoid Chinese sourced parts, and don't think GM has the same concerns. However, I also know replacing the stock parts is the easiest way to satisfy the OEM design intentions, which given the lawsuit potential of the car, would have to be pretty good, and have always met my needs.
 

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How long has it been setting? I hope no more than a year. Alcohol gas sucks once it evaporates it leaves behind some nasty $hit in the fuel system. Not as bad on an injection motor as a carburetor. It reeks havoc on a carburetor. Good luck hope it’s not to difficult to bring back to life.
 

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The C5/C6 Corvettes use saddle tanks. These cars use the return path to force fuel through a line with a transfer jet design built into the line so it picks up additional fuel from the passenger side tank and throws it over to the drivers side tank but only based off the amount of fuel being returned. That is at idle there is alot of fuel being sent from the rh tank over to the primary lh tank but if we unplug the fuel rail and just try to pump out the gas we will only drain the lh tank because there will be no fuel sent down the return path so there will be no transfer jet operation.

There are 2 fuel level sensers. One in each tank. The controller looks at the levels of both and filters it out to the one gauge. What you are experiencing is a failing sensor. The early style rheostats used just one thick hard contact point that eats through the printed circuit but also only provide just one point of contact. The replacement sensor will have many little fingers for contact pointS on the printed circuit. These are more stable and live a longer life.

From your description you need to replace the LH sender. Every second the car is runing it is trying to send fuel to the LH tank so in pracptice when the tank is at 1/2 full the rh tank is empty and the lh tank is full. When the tank is at 3/4 the lh tank is full and the rh tank is half full. When you are at 1/4 tank the rh tank is empty and the lh tank is half full. When the sensors fail they register empty. If your fuel gauge drops to empty you either have both sensors failed or just the lh senser.

However some late model C5 cars had the C6 fuel system installed. These cars do not have easily accessible fuel pumps and you must lower the rear sub frame and remove the diff and transmission for proper access to the transfer tubes to remove the tank. IF you have one of these cars with the fuel senders that go in from up top you really should do both together just because of how much labor is involved to get to them.
 

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Discussion Starter · #7 ·
The C5/C6 Corvettes use saddle tanks. These cars use the return path to force fuel through a line with a transfer jet design built into the line so it picks up additional fuel from the passenger side tank and throws it over to the drivers side tank but only based off the amount of fuel being returned. That is at idle there is alot of fuel being sent from the rh tank over to the primary lh tank but if we unplug the fuel rail and just try to pump out the gas we will only drain the lh tank because there will be no fuel sent down the return path so there will be no transfer jet operation.

There are 2 fuel level sensers. One in each tank. The controller looks at the levels of both and filters it out to the one gauge. What you are experiencing is a failing sensor. The early style rheostats used just one thick hard contact point that eats through the printed circuit but also only provide just one point of contact. The replacement sensor will have many little fingers for contact pointS on the printed circuit. These are more stable and live a longer life.

From your description you need to replace the LH sender. Every second the car is runing it is trying to send fuel to the LH tank so in pracptice when the tank is at 1/2 full the rh tank is empty and the lh tank is full. When the tank is at 3/4 the lh tank is full and the rh tank is half full. When you are at 1/4 tank the rh tank is empty and the lh tank is half full. When the sensors fail they register empty. If your fuel gauge drops to empty you either have both sensors failed or just the lh senser.

However some late model C5 cars had the C6 fuel system installed. These cars do not have easily accessible fuel pumps and you must lower the rear sub frame and remove the diff and transmission for proper access to the transfer tubes to remove the tank. IF you have one of these cars with the fuel senders that go in from up top you really should do both together just because of how much labor is involved to get to them.
thanks man, I had my suspicions , but little practical experience. Your informed reply helped confirm what I thought I had finally figured out as my best repair path, and I count myself lucky to have stumbled onto a 2003 , with most of the later years design advantages, but built early enough in the 2003 run to still have the outside fuel pump. There are a lot of things that could go wrong, but I finally settled on corrosion aa the most probable cause.

I large part of my used car buying decision was customer and aftermarket support for the corvette line, feeling I could always get parts and information more easily as the car aged. The problem is a wildly overestimated my desire to work on cars in my old age, it used to be no big deal.
 
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