99 yukon starts then dies

[CiCi]

My 1999 Yukon SLT will start then immediately die. This just started this morning. Can some one direct me where to start looking please. I've read some things on a passlock system but am wondering about the fuel pump as well.

 

[SunlitComet]

well easiest first check is what does your security light do when this happens?

 

[Nick1266]

If you can get a scanner on it and pull a code that's a good way to start. Otherwise look into throttle body sensors and the maf sensor. I've had several vehicles do that when either the maf sensor or tps sensor take a crap. Also ran into that with fuel pumps and security issues

 

[CiCi]

I didn't check the security light, just kept trying to start. I just went out and the truck cranked right up no problem. Does this point to this passlock security thing

 

[SunlitComet]

if it fails in some way the light will typically stay on. your key has no chip really it is the lock cylinder and sensor that do the security work.

 

[AlyssaB]

if it fails in some way the light will typically stay on. your key has no chip really it is the lock cylinder and sensor that do the security work.

Mine is doing this randomly as well, it's started on the second try and stayed on every time except once when I had to restart it probably five times. I got copies of the original key because there was only one and those stupid metal keys are so tiny that I can't get a good grip to unlock these stiff locks. So I got new keys with a thicker plastic head on them. Would a copy of the original key cause problems with the security function? Now that I think about it, this has only happened since I began using the new keys for a few weeks

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[Gzes]

Vacumbleaks? My ranger had one and did same

 

[SunlitComet]

the vehicle is not dependent on who make the key or what it is made of and long as it cut properly.

---------- Post added at 02:15 AM ---------- Previous post was at 02:12 AM ----------

also if the passlock system failed to register a pass signal from the lock cylinder it would have not let it work 5 restarts later.

 

[AlyssaB]

Did we ever figure out what the problem was? My Yukon still does this randomly. The security light doesn't flash or stay on and the truck eventually starts. I've seen a bunch of suggestions about letting the security system reset but mine doesn't need that so I'm thinking my problem is not security system related. I can also hear the fuel pump come on every single time I set the key to on, even when the truck won't start.

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[ccapehartusarmyINF.(ret)]

AlyssaB
its possible your fuel pump is going bad when my pump was going bad my tahoe often would never start on the first try and you could always hear the fuel pump when they key was on