I test drove a 1997 that a friend of mine owns but I noticed a couple of things that I need some diagnosis help. It has 84K miles and has no noticeable oil consumption and no smoking.

1. I heard a low volume but constant motor running sound from behind the Driver's seat area. It sounds like a continuously running antenna motor, (from earlier models), but muffled. My guess would be a Fuel Pump that is acting up-but just a guess.

2. I heard some "knocking" but only briefly after cruising at 35 mph and then just nudging the gas. There was no knocking at hard acceleration and none at take off or cruising, and it did not last long. My concern is that I would hear any knocing at all with the anti-knock sensors in the C5.

3. The owner had already told me that his LR tire pressure reading has been intermitantly showing the tire as "flat" and yesterday the DIC flashed a Service Tire Pressure Monitoring System message. With the previous issue with the LR pressure reading how probable is it that it is just the Tire Pressure unit for the LR tire and am I right that these cost about $130-$150?

Any and all input and response is greatly appreciated. He is not trying to sell the car but is letting me buy it for what the Chevy dealer has offered him as a trade-in. This makes it a very good deal but I do not want to have a major headache and cost if I can avoid it.

Thanks,

Barry

 

Your probably right about the fuel pump noise behind the seat. The car really has two pumps one on one side of the car and the other on the other side of the car. And at $500 a piece make sure the guy selling it fixes unless you want to pay that. Thats if the pump is bad. Could be a bad fuel regulater thats causing the pump to run all the time. Check fuel pressure and see if it holds for about 15 mintues you will know something real quick.
about the knocking could be the lower end bearings or something not right with the engine. I would check to make sure the engine was in sound condition, by doing a compression test.
about the LF sensor tire monitor it could be just a bad sensor or a wire short don't know unless I knew the Code, not sure how much one costs.
If your trying to buy it get all the total of the parts cost and present them to the guy to knock that much off or have him fix it. But since he's trying to get rid of it, I am thinking there's more to his story.

 

1. The early C5's like yours have an older design fuel pump, and they were noisy. If it bothers you, upgrade to the later model pump.

2. Not sure what the noise is, but your motor can ping even with the knock sensors if you are using low-grade fuel or have some other issue. With the tall stock gears, you can certainly lug the motor.

3. The first generation TPS sensors can be had from forum sponsors at $85.00 each. You should expect all of your sensors to die very soon, the batteries are now (at least) 9 years old.

 

Yeah - my '97 has a noisy fuel pump. Sounds like you described, a little motor running... cause thats what it is.. lol I wouldn't worry about it...

Other stuff i don't know about - haven't ran into those issues.

Good Luck to ya


Dan

 

The 97s had very noisy fuel pumps. The updated units that came out in 99 were much quieter. I never had any knocking from my car while driving it. Of course it spent several hundred miles on the track each year and didn't get a lot of carbon build up.
Bill

 

If the motor is not really knocking, sounds like a $13-15k car; this is what the market is typically willing to pay for the 97/8 cars with 75k plus miles

 

 

Thanks everyone. I am having it checked out at a Chevy dealer in Atlanta today that does alot of Corvette work. I will let you know what they say.

He is actually on selling because he is about to take delivery of an '07 coupe. He was going to trade it in and I was helping him with the negotiation on the new one. The dealer is offering him $12,500 and he is willing to let me buy at that price, so it is a pretty good price as long as there are no major surprises lurking.

Thanks again-I will let you know what I find out.

 

There is really ONLY ONE fuel pump in a C5 fuel system. The drivers side tank has the pump installed in the pick/sender assembly. The passengers tank has a Siphon Jet that pushes fuel to the main tank. When the main pump is running a small amount of fuel is sent over to the passengers tank to the jet pump and the fuel is siphoned over to the drivers tank. It will fill it all the way up to the cross over pipe and any left over runs back into the passengers tank.

Yes,,,, the 97 and early 98 C5 fuel pumps were a bit noisy. They actually pump more fuel than the early pumps. The noise is nothing to be concerned about if the car is running normally. like it was previously stated,, if it bothers you, you can change it out later.

As for the engine noise, LS1 and LS6 engines can and do carbon up and they can have cylinder knock. You can and should carry out a De-Carbonization procedure using Sea Foam. It works very well and will most likely solve that issue.

As for your tire pressure sensors and Key Fob, they operate on a radio frequency that gets picked by the RFA module in the drivers wheel well area inside the trunk. If your FOBs are working normally your sensor battery or the sensor it self is defective. There are vendors that sell re manufactured sensors for considerably less. They basically replace the internal battery and test it. There pretty fail safe.

97 98 C5's had a known TAC (Throttle Actuation Control ) module issue. As the previous owner if that module was ever changed out with an up-dated (newer) TAC module! If not, that probably should be accomplished. It could cause the car to enter the Limp Home Mode and strand you.

Bill C

 

At $12,500 get now!!!

 

Thanks eveyone for the information.

Good and bad news though. He took it to the dealership where he is buying the new 07 to have it checked for me as I was out of town at the NCRS show in Orlando.

The good news is that everything checked out and the tech said the sound was the fuel pump but that it was very common on the 97's and that it was not excessive, he could not recreate the knocking but in fairness I did lug the engine a bit and the knock was very brief, and the LR trie pressue monitor did need to be replaced.

The bad news is that while he was there he checked on the status of his car, (being dealer traded from a NC dealer), and while checking they realized it did no have On Star as his wife wanted. The dealership then scrambled and did another search and found the color/option combo he wanted at another dealer in the Atlanta area so they worked out a new deal and the dealer went to pick it up for them. While they were waiting the used car manager saw them and said that he had a buyer on lot that really might be interested in his 97.

He told them that he was actually not going to trade it in but instead was going to let a friend buy it for the trade in price. Amazingly enough they were able to immediately up their offer to him from $12,500 to $13,500, and with the tax savings on the trade amount it was as if he was selling it for $14,300. He did call me and tell me what was happening and I let him out of our deal, (of course he had to pay for the inspection that was done).

So now he is home with a new 07, some other guy took home his 97 at almost the same time, and other than learning a bit more about early model C5's, I am at home with nothing. He is a member of the NCRS chapter that I chair so I felt it best to let it go and wait for the next deal to come along. You win some and you lose some-but at least the search continues.

Thanks again for the information and advice.