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Gary
Gary, ASE Certified Technician
Category: GMC
Satisfied Customers: 17155
Experience:  GCM master tech over 25 years
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Got a 2005 gmc SIERRA 4.3..got good fuel pump pressure..has

Customer Question

Got a 2005 gmc SIERRA 4.3..got good fuel pump pressure..has good spark..got it running using starting fluid and it cranked fine rest of day..let it sit for 20 hours and it won't crank..still has correct fuel pressure and fire..has to be something not letting injectors spray or something huh
Submitted: 2 years ago.
Category: GMC
Expert:  Gary replied 2 years ago.

it could very well be

do you have a test light on hand ?

Customer: replied 2 years ago.
No I don't ..not even by truck..my buddy was,suppose to bring snap on computer home to figure it out but that's not happening. Tell me something
Customer: replied 2 years ago.
U there
Expert:  Gary replied 2 years ago.

ok if it has 55 -62 PSI key ON engine off and has spark and if you add starting fluid the engine will run then this issue will come down to contaminated fuel usually water in it take a good fuel sample in a clear glass container and check for any seperation which gas floats on top of water

if the fuel is good then either the injection is not being told to send in fuel or the injection unit is bad

its best to unplug the big fuel injector connector and with the key ON see if 6 out of the 12 terminals in the connector you unplugged shows 12 volts if they do connect a test light with the test light clip to battery 12 volts then cranking it over see if the OTHER 6 when cranking it over will blink your test light bulb

if it does the injection unit is bad

if NO blink then either the theft system is somehow activated not reading the key correctly shutting off the fuel injectors or the computer is bad

keep in mind you can always get me back for FREE through this post with any follow up with this question anytime even after you rate us here at Justanswer !

Expert:  Gary replied 2 years ago.

yes

sorry had a lot of typing to do

sorry for the wait