Question QUESTION: I have a 2007 Chevy Tahoe with the 5.3 and 150k miles. Yesterday while driving on the highway at speed the engine shut off. No warning, just stopped. Almost full tank of gas. The engine will crank but nothing happens. The engine spins freely. There is fuel pressure at the rail and good spark. Any thoughts?
ANSWER: GOOD MORNG ERIC, YOUR ARE SURE THERE IS GOOD FUEL PRESSURE AT THE RAIL.NOT JUST RESIDUAL PRESSURE? HAVE YOU CHECKED WITH A PRESSURE GAUGE OR JUST PUSHING IN THE SHRADER VALVE ON THE RAIL..IF THIS IS WHAT YOU ARE DOING TO TEST FOR FUEL PRESSURE YOU NEED TO HOLD THIS VALVE DOWN WHILE SOMEBODY CRANKS THE ENG OVER AND YOU WANT FUEL TO COME OUT THE ENTIRE TIME THE ENG IS CRANKING, NOT JUST THE FIRST SECOND OR SO..THIS WILL FOOL YOU ALL THE TIME. IF YOU CHECKED WITH A GAUGE YOU HAD ABOUT 50 LBS OR SO ?? OK NEXT STEP, YOU SAY THERE IS SPARK,GOOD NEWS.DONT HAVE TO WORRY ABOUT THAT..SO IF ALL ABOVE ARE GOOD.CK ALL OF YOUR FUSES IN THE CAB AND UNDER HOOD WITH A TEST LIGHT OR VOLT METER. CK PCM FUSE...IF ALL THE FUSES ARE GOOD. PULL A PLUG HARNESS OFF ONE ON THE FUEL INJECTORS GET A 194 LIGHT BULB AND BEND THE TABS STRAIGHT OUT. [SMALL MARKER BULB] INSERT THE TANGS OF THE BULB IN THE HARNESS,NOW HAVE SOMEBODY CRANK THE ENGINE OVER THE LIGHT SHOULD PULSE WHILE CRANKING [ON OFF ON OFF]IF SO THE PCM IS WORKING.IF NOT PCM HAS FAILED OR WIRING HARNESS IS AT FAULT. LET ME KNOW WHAT YOU FIND,GOOD LUCK TOM..
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QUESTION: I tried all of these and still no luck. Any other suggestions?
Answer HI ERIC,YOU FAILED TO TELL ME IF THERE IS PULSE TO THE INJECTOR HARNESS ??? IF NO, I SUSPECT WIRING HARNESS PROBLEMS OR PCM.[COMPUTER]PROBLEM..IF THERE IS PULSE AND AS YOU SAY,, THE ENG HAS FUEL PRESSURE AND SPARK,THIS SHOULD RUN. JUST AS A TEST GET YOURSELF SOME STARTING FLUID AND SPRAY IT INTO THE INTAKE WHILE SOMEBODY CRANKS THE ENGINE OVER, SEE IF IT STARTS LIKE THIS. IF IT DOES ARE YOU SURE THE FUEL PRESSURE IS GOOD ?? YOU MAY NEED TO TAKE THIS TO A SHOP THAT HAS GOOD GM SOFTWARE TO RUN A DATA SCAN ON THE PCM SYSTEM..IF ALL OF THE ABOVE IS GOOD,THE ONLY THING LEFT IS INTERNAL PROBLEMS OF THE ENGINE..LET ME KNOW IF YOU NEED MORE HELP..TOM
PLEASE READ ALL OF THIS BEFORE ASKING ANY QUESTIONS. IF THIS CHEVY SECTION IS MAXED OUT.YOU CAN REACH ME IN THE OLDS/BUICK SECTION. Will answer questions from 6:00am to 10:00pm all days [EST][[[ NO DIESEL OR PAINT QUESTIONS]]] will answer all 1965 to present QUESTIONS ON ALL GM'S on mechanics of these cars. Keep in mind i am not there in person i am going on what you are telling me !! PLEASE IF ASKING A QUESTION GIVE ME AS MUCH INFO AS POSSIBLE. THE MORE THE BETTER. SUCH AS YEAR,MAKE,MODEL,ENGINE SIZE. THIS WILL HELP ME HELP YOU. I will not be able to answer all questions because of some situations that i would really need to be there and see things for myself,such as electrical issues. In many cases i would need wiring diagrams. I can also give you an estimate on what the cost would be at our repair shop as an idea to help you. Keep in mind that my answer is ONLY MY ADVICE,ck with your mechanic as well.. >> THANK YOU, TOM..
I have been a ASE certified master mechanic for over 30 years and certified IN ALL 8 CATEGORIES,[engine repair,engine performance,auto trans,manual trans,clutches,steering and suspension,brakes,electrical systems,heating and air/cond. I am also a state CERTIFIED inspector for over 30 years. I do computer work [pcm]fault codes,pcm flashing,state inspection monitor readiness,repairs on exhaust,fuel service,[injection and carburetor,] charging system problems, running issues,alignments,frame problems,tire balance,struts and of course standard and anti-lock brakes.
Organizations nys state auto repair industry and ase group.
Education/Credentials high school,4 years of tech school,and many many hours of auto training with many gm classes and aftermarket training classes..
Awards and Honors ASE MASTER TECH CERTIFIED IN ALL 8 CATEGORIES.NYS INSP LICENSE AND A/C CERTIFIED
Past/Present Clients MANY CUSTOMERS IN OUR BUSY SHOP.