8835thL98

The weirdest most unexpected thing happened today, and on top of that today is the one year anniversary that ive owned this car.... :mad :cuss :mad

Ok, since I've owned this car I've replaced the following...
-Spark Plugs -Brake Booster
-Wheel Bearings -Rotor and Coil
-All Gaskets -O2 Sensor
-Fuel Filter -Air Filter
-Alternator

Today I was driving and my car was running normal, everything was going good, and then while im sitting at a light the car dies. I put it in Park and start it back up, and start driving to check my volts, and yes they were fine.
So about a half mile down the road at a stop sign it dies again. So I put on my hazards and try to start again but it doesnt start, eventually after 5-6 tries it does. Again I drive about half a mile and it dies while im driving and i just start coasting, dash lights, and power brakes still working. I come to a stop and try to boost it up one more time and it starts smelling like gas, so i got out and walked to my uncles which was near by. (fortunatly) We get in his truck and go to start looking at things and at first he thinks it's my fuel pump but, when i try to start it it pumps gas but doesnt start, just hesistates like its going to. Then he says he thinks it might be my coil (which i replaced anyway tonight) because i wasnt getting as much spark as i should since its the original one. So we replace that and try it again and nothing happens. We mess with it for a few more minutes then start turning the ignition and giving it gas and it starts up and had a REALLY weird ROUGH idle and it sounded like it was a motorcyle, the exhaust sounded totally different. It does'nt run by itself, only by when the person inside gives it gas. We try and drive it back to my house after we get it started with the nasty ugly idle and again, half a mile it dies. So we push it back to his house. Now i know its flooded, but I dont understand why its idling so rough, and why the exhaust sounds like a motorcycle and also why it wont stay running by itself. :cuss Can somebody please help me out, this really pissed me off today.:mad IM me if you have more questions to ask me... Thanks a bunch!

I've also checked for spark, which still works, and the cap on the fuel rail still spits out fuel when you take it off and push the button down.


[Modified by -=Persephone=-, 10:11 PM 1/12/2004]


[Modified by -=Persephone=-, 10:11 PM 1/12/2004]

VetteNoob

Any error codes?
Have you checked for fuel pressure and spark?
Try to disconnect your MAF and see if it runs with it disconnected.

Im sure others will offer more suggestions, but that should get you started.

SPEED750

I would start by checking fuel pump pressure. Just because its running doesn't mean that your getting full pressure.Also check the fuel filter, if it's very old or clogged it might be a problem.Sound like a fuel delivery problem.Your exhaust sound funny because it's only running on a few cylinders. :cheers:

DON M

My car pulled the same stunt on me. I tried to pull the codes and nothing would come up. The trouble shooting guide said no codes at all=computer. I put in a rebuilt ECM and all was well. The fuel smell was coming from unburned fuel comming out the exhaust. The ECM wasn't firing the plugs.

8835thL98

ttt

65Z01

If you have a buddy with a 3rd gen F-body TPI ask to swap out his MAF.

When mine died I tried the usual diagnostics like looking for codes, unplugging it, etc to no avail. Finally when I swapped in the MAF from my IROC the Vette started up and ran like a champ.

If that works you should remove the air cleaner in front of the MAF and carefully look into it as someone shuts off the ignition to make sure the sensor wires glow bright red for two seconds after shut down. If not replace the burn-off relay and try your old MAF as the sensor wires may just be crudded up from lack of cleaning.

tlc85

I bet the ecm isnt firing one side of the injectors. check both sides with a check light. do a search of injectors. also check the fuse.

8835thL98

I asked a friend and he said it could be my cap because its still my original one (since ive replaced plugs, rotor and coil) and over time it gets corroded and dirty causing it not to pass by as much spark as usual which would lead to only some of my cylinders running, right?

Z06_BluByU

might be aplugged converter...

ittlfly

:iagree: I was thinking the same thing.

Steel Blue 91

:iagree: Could be one of the pre-cats has clogged. Especially with the progressive nature of the symptoms.

rick lambert

:iagree: But don't get :mad ,just remove the cat-you can knock out the platinum honeycone and re-install the now empty cat-but you might want to try a piece of flex tubing before you destroy the insides of the cat. :rolleyes:

Z06_BluByU

now if it is a plugged cat.. not only to you have to replace the cat.. but you have to fix the whatever go bad in the first place (probably that over rich mixture made the cat overheat causing it to melt solid).

I would test in the following order:

02 sensors... use a scan tool or a volt meter to test and see what they are reading.. 500mv is normal (or stoich) 0 is the leanest end of the spectrum and 1000mv is the richest.. they should fluctuate rapidly but the average of the fluctuations should be around 500 mv..

look at your lterm and sterm counts if you have a scanner.. is the computer picking up the fact that the exhaust is rich? next move on your handy tech 1 scanner (or equiv). with the engine cold (let it sit overnight) turn the engine on and check the IAT sensor, the Oil temp sensor and the coolant temp sensor.. they should all be relativly close.. the oil temp will probably be the lowest.. that is normal. if something is way off replace that sensor.. next check to make sure your TPS sensor is reading 0% at idle and that you IAC is between 20-60 IAC counts at idle.. if either of those is off replace. Following that I would check the MAP sensor and or MAF sensor if you have one.. it should be round 30-50kpa at idle.. unless you have a big cam.. if your over 50kpa on a stock cam at idle with the A/C off, the engine warm and the car in park it could be an indication of a vaccum leak..

next on to mechnical issues
due a Fuel pressure check and fuel pressure leak down test.
(this can diagnose if the problem is fuel filter, fuel pump, fuel pressure regulator or fuel injector leaking or stuck open).
2. If FP checks out ok.. I would ohm the injectors to verify they are all within ohm of each other.. The should be someplace around the 12.9 range.. these are low impedance injectors.
next to an injector leak down test.. to do this you need a special tool that can fire just one injector for a set amount of time.. it plugs right in to the injector.. then you pressurize the fuel system and first one injector for the set time and note the fuel pressure drop accross the system (at the FP guage @ the schrader valve in the fuel rail). repeate this process for all 8 injectors and make sure you re-pressurize the system between each cycle.. the pressure in the system should go down the same amout for each injector.. if not replace the faulty injector..

from there verify spark at each cyl. is strong and each cyl is firing.. also do a visual inspection of the plugs...

this could go on and on.. but i think you have some starting points on how I would approch the problem.. however, please ntoe there are several ways to go about this.. good luck!
:thumbs:

65Z01

If you are thinking clogged pre-cat you can (after lots of Liquid Wrench) drop the front Y to see if that cures the problem.

Of course it won't then go closed loop because the O2 sensor is in the Y, but you can at least see if idle smooths out while warming up.