My 1998 chevy blazer 4.3l stalled the other day and can't get it running. It starts but only runs for 4-5 seconds before stalling. I hooked up the OBDII reader and it thru a "P0108". The fuel pump is now very loud also, like twice as loud as before (loud "whurring" sound). When the pump died previously (no sound/operation), i was able to tap the gas tank and get another start out of it. Now, it starts and runs for a couple seconds, so not sure if its something different. Could a bad MAP sensor (that the P0108 code points to) cause these symptoms? Is it likely the pump (replaced about a year ago), could it be the fuel filter plugged, or fuel pressure sensor? Im lost and not a lot of funds.

Thanks

 

Very doubtful the MAP sensor is causing the problem.

1. During the few seconds that the engine runs, is the "SECURITY" light in the instrument cluster illuminated or flashing?

2. Could be a restricted fuel filter. Easy to check it, remove it and see if you can blow through it easily.

3. This vehicle is not equipped with a fuel pressure sensor, (definitely not the problem ).

4. Could be a problem with the fuel pump. Check fuel pressure and leakdown at the service port next to the distributor. Most auto parts stores rent/loan them for free, and sell them for around $40. Let us know when you have one available, and we can guide you through the tests, (very simple, & takes about 15 minutes).

 

Thank you for the feedback.

I ordered a AC Delco fuel filter and a fuel pressure tester which should be delivered on Friday.

1) When I get home tonight, I will see if the security light flashes when I start it. i think I looked for that initially, but might have missed it.

2) As soon as I get home Friday I will ping the forum for instructions.

Thanks again.

 

Another question: Would the fuel filter being plugged cause the fuel pump to get louder? Also, would that Passkey or whatever its called security feature also have that effect on the fuel pump? I'm hoping its not the fuel pump.....

 

A restricted fuel filter will cause the pump to work harder and get louder and or change pitch.

When the Passlock system detects a possible theft situation: The "SECURITY" light will come on or flash, and the BCM will command the PCM to shut off the fuel injectors. The pump will continue to run for about 2 seconds after the engine stalls, then the PCM deactivates the fuel pump relay. There is a sensor in the steering column, behind the ignition lock cylinder, that checks the key you're using. If it doesn't recognize the key, Passlock goes into action. The sensor can fail, and not recognize ANY key. Your clue to that is the SECURITY light coming on or flashing. If no light, Passlock is not the problem.

 

Ttied the passlock and here's what I got:
1) Turned key to on and ABS and SECURITY light came on
2) Engined turned then died and ABS and security light stayed on for a couple seconds then turned off.
Could it be a Passkey issue?

 

If the security light stays on, it's a Passlock issue. If the light goes off when, (or after) it stalls, it's not a Passlock problem. Get your hands on a fuel pressure tester and let us know when you have it