ok I woke up this 7:00 am morning and started my vette. When I started it a aweful rattling like noise was coming from what I think was the engine or exhaust....I pull out of my driveway and was freaking out.....I put the car in drive, drove 3 yards and the noise went AWAY! didn't here it at all on the way to work....

Then,

At noon i went on my lunch break and the same thing happens and to make matters worse i tried to turn it off and it would turn off!!!!

it was just making a sputtering noise like it was out of gas


I eat lunch for about 30 min and go to start it again and the noise doesnt apear....

VERY CONFUSED PLEASE HELP!!!!!!!!!!!

2000 C5 72,000 miles HELP!

 

Bump

 

go glen can you help me????????????

 

Hello Neil, the "bump" I gave your post was to move it up and let the REAL experts in here get a chance to read your post. When the move down during the day sometimes a post well get missed and "fall off" the board before one of the real techs in here can read and reply to them. The first thing I would ask you to look at is- have you pulled to codes off of the DIC? Here is how that is done-
READING YOUR C5 Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.

Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once that is done come back to this post and list the codes you find here (make sure you list all the codes and the "H" and/or "C" after the codes. That will help folks to assist you.

The only thing I could tell you at this point (which does not make a lot of sense to me, because I am more used to working on Carbureted cars and not those with fuel injection like the C5) is that it sounds like your car is "dieseling". The older cars with carburators would sometimes get carbon built up on the piston head or intake valve area. When those carbon deposits got hot enough they would actually continue to burn fuel after the ignition (and therefore the spark plugs that would normally "light" the fuel) was turned off. I am not sure that is a possibility with a fuel injected car because in theory the fuel supply is stopped when the ignition is turned off.

 

Rattling noise......maybe bearing noise due to low oil pressure on startup? how's your oil pressure showing?

 

Does your car have long tube headers? Have you looked under your car car for anything obvious? Is the car any louder when your driving? Where are you located? When you have time you really should fill out your profile it allows people to help you out more easily.

 

didnt check my oil pressure untill i was about 50 yards down the road....and it read fine....the temp was running cool as well.....the rattling sounds like im not getting oil to the engine on the initial start-up...its almost liike a bag of marbles is sitting on-top the head

 

i dont think i have long tube headers the only thing that has changed to it to my knowledge is a borla exhaust and a cold air intake


and no when i put it in gear and drive 3 yards the sounds completely goes away


I live in Houma, Louisiana.....and yes it damn hot down here

 

And the DIC codes????? as in post #4.?????

 

the guy i bought the car from said that it probably is the solenoid not engaging the flywheel.....when i turn the engine on (when it has been sitting for hours) and rev it up the noise goes away


Aslo the oil might be to think and not lubricating the engine right away

 

Maybe as simple as a putting on a Wix oil filter on that doesn't bleed back as bad. I'm all about the simple fix.

 

Until you pull the codes and let us know what you have if anything we are just sitting on the sidelines waiting on you. Also give us some info on mileage and any work done on the ignition system, like how long the plugs have been in, etc.