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5.3 Vortec Stalling @ Idle

Old 02-19-2019, 03:24 PM
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Default 5.3 Vortec Stalling @ Idle

Iíve been troubleshooting several issues with a 5.3 thatís been installed in a FJ60 Landcruiser. The truck originally had issues with the APP sensor but I was able to address it with a new harness going to the TAC module. Currently the truck will run fin while driving but when parked at idle the truck will run for approx. 10-15 minutes and then just shut off. Engine coolant temp stays right at 205 and intake temp is around 85. There is no EVAP system on the truck and they also deleted the purge sensor at the intake. I know I have some venting issues with the fuel tank because every time I fill up the cap almost shoots off. I tried leaving the cap off and that bought me another 5 minutes, Iíll be checking for a tank vent as soon as it stops snowing. Can anyone think of anything else I should be looking at besides venting the fuel tank? Thanks in advance for any help!
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Old 02-19-2019, 04:31 PM
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is it throwing any DTC's? Have you data logged it?
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Old 02-20-2019, 05:20 AM
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I had a similar issue in my LS rock buggy. It would run for an hour or so depending on how warm it got. Plastic 12 gallon fuel cell with supply/return in a 2" front facing fuel sump & rollover vent valve on top rear. Fuel pressure would start to flutter and eventually drop out. Stall, stall, stall for the rest of the day. I would have to let it sit for sometimes an hour before it would prime fully and start. Sometimes it would fire right back up but it would repeat shortly after. On very steep inclines fuel would slosh past the rollover valve and into the vent line. The fuel sitting on top of the rollover valve wouldn't let the tank vent. Pressure built up to the point that the cell looked like a balloon which is when I noticed it. The fuel pump would overload causing fuel aeration and excessive current draw through the 40A relays to the point that the coil would drop out or straight up melt. Sometimes it would run fine all weekend. I carried about 10 relays in the buggy just to get me back to the trailer. Huge pain in the ***. I ended up rewiring the entire circuit with new fuse block, 10 AWG marine grade wire/connectors, Bosch relays. I flipped the tank so the sump faced the rear and added a Holley hydramat fuel pickup, -8 AN /-6AN lines and new Walbro 392 fuel pump. I also moved the return from the bottom of the tank to the old vent location and the vent line to the front of the fuel cell and went to an in tank rollover valve. Been fine ever since. I think the issue was a combo of undersized wire, heat, excessive pressure and a weakening fuel pump

Last edited by dookiemax; 02-20-2019 at 05:33 AM.
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