Thebluelion
Newbie
Hi there. My 99 Yukon 5.7 has been dead nuts reliable. It has a few options one being a block heater. Recently we had a deep freeze, and I knew I'd have to drive wife to a medical appointment on a snowy day. Block heater had never been used, so I ran a cord and plugged it in. Next day I go to unplug it, and notice the gfci had tripped. We load up, I notice the temp does not appear to be anything but dead cold, and when I start it, it spins over for a good 5 secs longer than normal and stumbles to life. Never in my years of ownership has it done anything but fire up like a healthy sbc.
Driving to appt, as my wife is going on about something I'm focused on the slight stumble I can't tell if I'm feeling or not. Maybe a slight hesitation leaving a red light. Barely noticeable. After sitting in the parking lot of appt for about 45 minutes, we go to leave and as I turn the key she just keeps spinning over, and sounds like it's trying to fire 180 degrees out. I've got my wife and three year old, it's snowing, and I try it a few more times out of desperation even though it sounds like it's about to grenade the starter. Again, it sounded like it was just turning over and would periodically try to fire waaaay out of time and working against the starter, then right back to turning over. I call a tow company, and they are booked solid due to snow, 3 hr wait. After sitting for a solid hour and just thinking, I decide to try it again. Fires up with just a slight drag, but idles fine. I decide to head directly home. Has no issues, runs as normal.
I'm now nervous to take her out again, in case I get stranded. I have ran two separate OBD scanners for codes, nothing found. Idles at 650. Starts right up in the driveway. I checked when cold, let it idle until up to temp, shut off, start up...still no issues. Has never thrown a CEL.
Does this sound like a failing Crank Position Sensor? Think I electrically damaged something plugging in a shorted block heater? Have you heard of a shorted factory block heater? I have not tested fuel pressure, and I know making assumptions isn't best course, but it really felt like the only issue was when it was trying to fire was completely incorrect, as if timing was out bad. It seems like that would point at the crank position sensor before ignition control module, cam position, or distributor/coil? It has new wires, plugs, and has been lovingly maintained.
I don't want to fire the parts cannon, but with no codes, and can't get it to repeat, not sure what to do. I need my confidence back. I have taken this girl off grid deep into PNW wilderness area for weeks at a time now im worried about leaving neighborhood. Thanks.
Driving to appt, as my wife is going on about something I'm focused on the slight stumble I can't tell if I'm feeling or not. Maybe a slight hesitation leaving a red light. Barely noticeable. After sitting in the parking lot of appt for about 45 minutes, we go to leave and as I turn the key she just keeps spinning over, and sounds like it's trying to fire 180 degrees out. I've got my wife and three year old, it's snowing, and I try it a few more times out of desperation even though it sounds like it's about to grenade the starter. Again, it sounded like it was just turning over and would periodically try to fire waaaay out of time and working against the starter, then right back to turning over. I call a tow company, and they are booked solid due to snow, 3 hr wait. After sitting for a solid hour and just thinking, I decide to try it again. Fires up with just a slight drag, but idles fine. I decide to head directly home. Has no issues, runs as normal.
I'm now nervous to take her out again, in case I get stranded. I have ran two separate OBD scanners for codes, nothing found. Idles at 650. Starts right up in the driveway. I checked when cold, let it idle until up to temp, shut off, start up...still no issues. Has never thrown a CEL.
Does this sound like a failing Crank Position Sensor? Think I electrically damaged something plugging in a shorted block heater? Have you heard of a shorted factory block heater? I have not tested fuel pressure, and I know making assumptions isn't best course, but it really felt like the only issue was when it was trying to fire was completely incorrect, as if timing was out bad. It seems like that would point at the crank position sensor before ignition control module, cam position, or distributor/coil? It has new wires, plugs, and has been lovingly maintained.
I don't want to fire the parts cannon, but with no codes, and can't get it to repeat, not sure what to do. I need my confidence back. I have taken this girl off grid deep into PNW wilderness area for weeks at a time now im worried about leaving neighborhood. Thanks.
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