No start, troubleshooting woes
08-05-2015, 05:34 PM
#1
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No start, troubleshooting woes I did extensive forum search first, with lots of good ideas, some of which Ive tried, however, I am at the troubleshooting end of my rope so here goes.
2002 Z28.
Vehicle fine one day, next day no start. Here are conditions.
1. Interior lights, headlights fine. Battery checked and ok. Wiring ok. 12V at all terminal ends, battery, starter etc.
2. I replaced starter to be on safe side as car is 12 years old.
3. Replaced ignition fuse, starter relay. Even tried to jump the relay pins 30/86
4. Bypass VATS. Double checked and had same ohm reading on white wire side, as matched up to key ohm reading. (3.73) Used a variable ohm resistor to achieve the match. However, the ohm reading on the purple/white wire side is showing -16 ohms (??) I tried both keys and both keys are a 3.73 ohm reading on the chips.
5. All I get is a single "click" when trying to start. I have no loss of lights inside or juice at all. All instrumentation lights up initially, and I have never had the security light stay on. I can hear the click coming from under vehicle (presumably at the starter). I have the shims that came with the starter, however they don't seem to line up so I can at least try them.
Am I missing something? Could it be the BCM? Seems more likely something with or around the starter however it is receiving 12V, but I read on forum here somewhere about if the ohms don't match somewhere on the vats wiring, it could be the BCM??
Any thoughts from anyone. I am at a loss completely. Feeling pretty dumb right now, I read many posts on the forums here and tried damn near everything I read just for hell of it. I appreciate any help at all.
2002 Z28.
Vehicle fine one day, next day no start. Here are conditions.
1. Interior lights, headlights fine. Battery checked and ok. Wiring ok. 12V at all terminal ends, battery, starter etc.
2. I replaced starter to be on safe side as car is 12 years old.
3. Replaced ignition fuse, starter relay. Even tried to jump the relay pins 30/86
4. Bypass VATS. Double checked and had same ohm reading on white wire side, as matched up to key ohm reading. (3.73) Used a variable ohm resistor to achieve the match. However, the ohm reading on the purple/white wire side is showing -16 ohms (??) I tried both keys and both keys are a 3.73 ohm reading on the chips.
5. All I get is a single "click" when trying to start. I have no loss of lights inside or juice at all. All instrumentation lights up initially, and I have never had the security light stay on. I can hear the click coming from under vehicle (presumably at the starter). I have the shims that came with the starter, however they don't seem to line up so I can at least try them.
Am I missing something? Could it be the BCM? Seems more likely something with or around the starter however it is receiving 12V, but I read on forum here somewhere about if the ohms don't match somewhere on the vats wiring, it could be the BCM??
Any thoughts from anyone. I am at a loss completely. Feeling pretty dumb right now, I read many posts on the forums here and tried damn near everything I read just for hell of it. I appreciate any help at all.
08-05-2015, 10:18 PM
#2
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Was your battery checked for voltage only, or fully load tested? It should be closer to 12.8 volts, When off and when you try to crank the car you it shouldn't drop under 10.5 volts. I would check voltage at the starter and trace all the wires going to it first, it could be as simple as a loose or corroded wire or a weak battery. Bad batteries will still light up instruments etc but just fail at delivering the amps necessary to start a car sometimes.
08-06-2015, 03:04 AM
#3
need to check your battery and all connections to the battery again, i would bet anything that it is either the battery itself doesn't have enough cranking amps, or the connection is loose
08-17-2015, 01:11 PM
#7
TECH Fanatic
Bad or lose connection somewhere. Couple years ago i had this issue with sometime nothing happened when i tried to start.
After some troubleshooting i find a lose connection on the fuse marked "start"( Think it was marked "start" , was some years ago). Fuse is located in the engine compartment.
Since you said you hear a "click", in my case it was no noise at all so not sure if this helps?
After some troubleshooting i find a lose connection on the fuse marked "start"( Think it was marked "start" , was some years ago). Fuse is located in the engine compartment.
Since you said you hear a "click", in my case it was no noise at all so not sure if this helps?
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08-17-2015, 02:57 PM
#8
TECH Addict
I'd be looking for a damaged starter wire (the big ones). Resistance check is not going to do you much good as those wires are very large and a little damage wont show much resistance to a multimeter, but can show when a large amps draw is applied. Make sure the positive wire from the battery to the starter is in good shape (no corrosion, burns, fraying, etc.) also make sure all the grounds from the engine to the frame are good too.
08-18-2015, 10:57 PM
#9
TECH Fanatic
3. Replaced ignition fuse, starter relay. Even tried to jump the relay pins 30/86
4. Bypass VATS. Double checked and had same ohm reading on white wire side, as matched up to key ohm reading. (3.73) Used a variable ohm resistor to achieve the match. However, the ohm reading on the purple/white wire side is showing -16 ohms (??) I tried both keys and both keys are a 3.73 ohm reading on the chips.
5. All I get is a single "click" when trying to start. I have no loss of lights inside or juice at all. All instrumentation lights up initially, and I have never had the security light stay on. I can hear the click coming from under vehicle (presumably at the starter). I have the shims that came with the starter, however they don't seem to line up so I can at least try them.
Am I missing something? Could it be the BCM? Seems more likely something with or around the starter however it is receiving 12V, but I read on forum here somewhere about if the ohms don't match somewhere on the vats wiring, it could be the BCM??
Any thoughts from anyone. I am at a loss completely. Feeling pretty dumb right now, I read many posts on the forums here and tried damn near everything I read just for hell of it. I appreciate any help at all.
4. Bypass VATS. Double checked and had same ohm reading on white wire side, as matched up to key ohm reading. (3.73) Used a variable ohm resistor to achieve the match. However, the ohm reading on the purple/white wire side is showing -16 ohms (??) I tried both keys and both keys are a 3.73 ohm reading on the chips.
5. All I get is a single "click" when trying to start. I have no loss of lights inside or juice at all. All instrumentation lights up initially, and I have never had the security light stay on. I can hear the click coming from under vehicle (presumably at the starter). I have the shims that came with the starter, however they don't seem to line up so I can at least try them.
Am I missing something? Could it be the BCM? Seems more likely something with or around the starter however it is receiving 12V, but I read on forum here somewhere about if the ohms don't match somewhere on the vats wiring, it could be the BCM??
Any thoughts from anyone. I am at a loss completely. Feeling pretty dumb right now, I read many posts on the forums here and tried damn near everything I read just for hell of it. I appreciate any help at all.
You say that you measured 3.73 ohms on your key? Is that the resistance that you provided for the VATS bypass? There is no such resistance that low on our VATS. Try 3740 ohms and report back.