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Gm Tech (Cam)
Gm Tech (Cam), GMC Mechanic
Category: GMC
Satisfied Customers: 1686
Experience:  GM Grand Master Technician 2007. 14 year experience.
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Gmc suburban 1500: I'm having a problem with my 99 gmc suburban

Customer Question

I'm having a problem with my 99 gmc suburban not starting sometimes. Some days, starts and runs great with no issues. Other days, will start and immediately die. When this happens, it will not start even if I try a million times. If I let it sit until the next day, it may start right up with no problems. I've replaced fuel pump and wiring harness to fuel pump with no difference. All grounds appear clean and tight. ????
Submitted: 2 years ago.
Category: GMC
Expert:  Gary replied 2 years ago.
Welcome! My name is ***** ***** I will do my best to assist you with this problem.
when this acts up then stalls it will then just crank over and not fire up ?
Customer: replied 2 years ago.
seems like it fires for a split second and immediately dies. Fuel pressure at rail is 53
Expert:  Gary replied 2 years ago.
ok the odds are when this truck acts up the theft system that reads the key is not reading the ignition key and will put the truck into theft lock and shut off the fuel injectors
can you check if you have an injector pulse when this truck will not start up ?
Customer: replied 2 years ago.
how can I check that?
Expert:  Gary replied 2 years ago.
if you have a test light disconnect the big square connector right behind the throttle body of the injection unit
with the key ON connect your test light clip to a good ground and 8 out of the 16 terminals in that connector you unplugged should show 12 volts
then connect the test light clip to battery 12 volts and when cranking it over the other 8 terminals when cranking it over should blink your test light bulb
Customer: replied 2 years ago.
Ok. Thanks. I'll get on that and get back to you in a bit
Expert:  Gary replied 2 years ago.