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V10 no start when hot

2974 Views 65 Replies 8 Participants Last post by  Professor Eggman
So I'm almost able to drive my 2006 V10 after a year, but I cannot get the engine to start after the coolant gets up to temp. When the engine is cold, or slightly warm, I can kill it and it will start right back up. When it's up to temp, if I kill it and immediately try to restart, it just cranks. I'm reaching the end of my ideas to figure this out. Here is what I've done so far to try to change this:

Fresh fuel
Removed and cleaned fuel pumps/filters, new fuel filter
Hardwired fuel pump to run continuously
Added jumper cables to another running engine to add starting power
Released pressure in coolant system
Opened PCV to atmosphere
Removed coolant temp connector
Removed coolant return temp connector
Opened ECU to check for corrosion: appears all intact, no areas of damage or corrosion
Checked all fuses and relays

Currently, cam position sensor is still reading "signal out of range", so signal return wire has been removed from ECU wire harness. This leaves "no signal" fault.
Also, Steering Angle sensor is not working despite all wires being intact and voltages present, leading to steering and steering wheel electronics faults.
Batteries and related grounds are in good condition, with batteries being kept on a charger/tender.
I'm also posting before and after scans of the hot no-start, as well as video of it cranking while hot.
If I can solve this, I'll finally be able to drive this beast on a regular basis.
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Just had a similar problem with my 2009 R50, which turned out to be where the positive cable from the rear battery connected to the switch under the passenger seat no longer properly connecting to the terminal in the plug. Okay cold, but as it didn't take too long till the current in the lead caused it to heat and then the connection became worse and it became an intermittent connection, and quite hot. the lack of connection when hot caused the switch to recognise a difference in voltage, so the motor would crank once or twice then stop, and subsequent efforts did nothing. Trying to bring in the second battery by left-turning the key did nothing, a jump start under the bonnet would get it underway again.

Can't claim to have found it myself, a good auto-elec chased it down when I pointed him at the switch.

Good luck.
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