I have a 1999 GMC Jimmy 4.3 L I took a fuel pressure reading at the schrader valve which was low so I replaced the fuel pump and fuel filter but the vehicle still wont run it acts as though it starts for a second but then just cranks when i open the door I notice the security light flashes could the passlock system be in anti theft mode not letting it start can I bypass the passlock system?

SOURCE: TPS in a 1998 GMC Jimmy

the tps is ususally at the side of the throttle body opposite where the throttle cable / tv cable mount.
sometimes it won't start, run, or run erratically. there are ways of testing this unit (by output voltage) before you commit to buying a new one. to test it you will need a dvom (digital volt ohm meter).

just a note: straight from the book... "a broken or loose tps can cause intermitten burst of fuel from the injector and an unstable idle because the ecm thinks the throttle is moving."

mike loshbough

• 1011 Answers
• Posted on Mar 22, 2009

SOURCE: 2000 gmc jimmy wont start fuel pump comes on and cuts off...

the fuel pressure if leaking could cause this the regulator is located under the intake plenum but you should smell gas .if you dont then most likely the pump is bad ,the pump will come on for 2 seconds when the key is on then go off it will not stay on with just the key on only when you crank it will it .so have your fuel pressure checked with a gauge.

Bruce Bracey

• 1000 Answers
• Posted on Apr 30, 2009

SOURCE: 99 GMC Sierra Pickup: Crank but no start. starts

The theft light issue is a good observation. Have you replaced the key tumbler or an ignition component lately? Has there been a lightning storm close very recently?

What the flashing security light is indicating is an attempt to relearn the key you are using.
Turn the key to run position, allow light to flash for 10 minutes, when light stops flashing turn ignition to OFF position for 5 seconds, turn ignition to run position and start over. Do this for 3 consecutive cycles, the the theft system will relearn the key cylinder code and store it once again.
Try that first before you go any further.
Let me know what you find.
Regards,

SOURCE: 2000 GMC Jimmy won't start

i had the same problem and replaced the fuel pressure regulator. Cost about $45 at advance auto store or about $90 at napa auto stores. Once i replace that my truck started right yup and runs like a champ

SOURCE: looking for instructions to bypass, remove,disable

Your problem may be a bad ignition lock switch it is a common problem usually caused by worn ignition keys. I would get a new key and see if that don't solve your problem. If that don't work then you need to replace the lock itself they have a security feature built in them that won't allow the car to start unless the proper key is installed (sometimes a new key works) this prevent thieves from taking your car by using a screwdriver or by hot wiring ...This security feature is in the lock itself not in the key GM did put it in the key but not for your vehicle