Question 1998 Chev. C-1500, 4.6L V6 EFI, 5-spd man. P/S, P/B, no a/c.
Problem: No spark to spark plugs. Plenty of fuel. Checked # 1 and #5 plug for spark the old-fashioned way (holding against block) and also checked output of Ignition coil using inductive pickup and timing light; no flash at all. Removed Ignition coil module and ran resistance tests rec'd in the Chilton's GM Full Size Trucks repair manual. All readings exactly as indicated in the manual. Engine stopped running as I was going down hiway, and here's a weirdness that I saw on the controls: When the engine stopped firing, the fuel gauge needle went clockwise, all the way past "Full" and pointed in the 3 o'clock position, which is way off the Empty-to-Full scale, and it just stays there. That struck me as very peculiar. "Full" would be a 1 o'clock position. "Empty" would be about an 11 o'clock position. I'm wondering what to check next. Presumably there's some kind of ignition control module somewhere, but I haven't found it in the Chilton's book. Appreciate any advice you might be able to provide.
Answer HI DON FROM TEXAS,OK LETS START WITH THE GAUGE PROBLEM. REMOVE ONE OF THE BATTERY CABLES FOR A FEW MINUTES AND RECONNECT AND SEE IF THIS TAKES CARE OF THE GAUGE..THIS IS USUALLY CAUSED BY A SPIKE IN THE ELECTRICAL SYSTEM. COULD OF HAPPENED WHEN IT STALLED OUT. AS FAR AS THE IGN MODULE. THIS IS ON THE PASS SIDE OF THE ENG WITH THE COIL IT IS RIVETED TO THE COIL BRACKET.. S10 BLAZERS ARE THE SAME WAY..YOU MAY WANT TO ALSO CK THE PICK UP COIL WHICH IS INSIDE THE DIST HOUSING UNDER THE ROTOR..THESE DO FAIL AS WELL. DEPENDING ON WHAT MONTH OF THE YEAR THIS WAS BUILT THE IGN MODULE MAYBE UNDER THE DIST CAP AS WELL. ONCE YOU REMOVE THE CAP YOU WILL KNOW RIGHT AWAY... MAKE SURE THE ROTOR DID NOT BURN ON THE UNDERSIDE OF IT CAUSING IT TO SHORT OUT ON THE DIST SHAFT..NO SPARK 99% OF THE TIME IS USUALLY MODULE,COIL OR PICK UP COIL. LET ME KNOW IF YOU NEED MORE INFO..TOM..
HI DON,GLAD YOU FOUND THE PROBLEM.. THIS WORRIES ME A BIT HOWEVER.. FOR THIS FUSE TO GO BAD SOMETHING MAYBE LURKING BEHIND CLOSED DOORS....CARRY A EXTRA FUSE WITH YOU JUST IN CASE. CK ALL OF YOUR WIRING HARNESSES TO SEE IF YOU NOTICE ANY HARM TO THE HARNESS ANYWHERE..GOOD LUCK TOM.
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Thanks Tom. Engine runs fine now. The problem was a 20A fuse to the ECM. Once replaced, the fuel gauge went back to normal (when I turned the key to the "run" position) and, when I engaged the starter motor, the engine started immediately. The fuse looked good when held up to light; it still does. Only a VOM revealed that it was bad.
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.
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