1998 GMC SIERRA STARTS/DIES. +SECURITY LIGHT

  • Tiny
  • garwoodv6
  • 1998 GMC Sierra

Computer problem
1998 GMC Sierra V8 Four Wheel Drive Automatic 200000 miles

Intermittent problem: starts and immediately dies. When this occurs, engune can be made to start and runs as long as I add fuel through air intake at crankcase ventilation breather tube. Sometimes, problem will resolve itself after doing this for a coulpe of minutes, but at other times it doesn't help- truck dies as soon as I stop adding fuel. New Fuel filters, new Injection spider system complete and new fuel pump/gauge sender module no help.

In my past experience chasing this problem I do not recall the problem clearing up in 10 minutes, or 30 minutes. Problem disappears overnight in most cases, although it has occasionally lasted for several days.

I have been chasing this for 1-1/2 years to no avail, except to pay 3 mechanics to NOT find the problem.

Updated Engine computer (Flashed the PROM) 6 days ago. No Start condition hasn't occured YET since update, bit I'm not expecting the problem to have been cured by this.

Was just made aware of a "Passlock 2" security system that could be the culprit, but unaware of how to properly troubleshoot (or bypass as a troubleshooting method) when problem occurs. I now recall seeing "Security" illuminated on the instrument panel while driving at odd times in past months, but have not related this to the "No Start" condition. Need to wait for next failure and leave key on to see if "Security" goes off.

Only other trouble was a failing O2 sensor wreaking havoc on the computer. Although it would start, it was making truck run horribly on/off. Would generate random multiple misfire, codes for 2 other O2 sensors instead of itself. I found it by disconnecting one at a time, and problem went away. Now computer correctly indicates this O2 sensor has no output. I don't THINK this is related to the "No Start" condition?

Do you
have the same problem?
Yes
No
Sunday, June 20th, 2010 AT 4:48 PM

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