T350 Cutting our when it’s Hot
Discussion
Hello all. I’m going to try my luck on the Speed Six section as I’m not having much luck elsewhere. My T350 is cutting out when it’s up to temperature. If I’m stuck in heavy traffic it will cut out. If I let it idle until warm it will cut out. If I leave it in the sun for a good few hours it will not start. No power to the fuel pump relay. If I open the bonnet in this situation it will start about 10 minutes later. When it cuts out when it’s been running and it’s up to temperature the fuel pumps do not prime. If you leave it 10 to 15 minutes it will start. Off you go, get caught In more traffic, it will cut out. Again and again. The fuel pump relay is red hot at this stage. So far I have bought two new fuel pump relays. I have bought and installed a new fuse box. I’ve changed the HT leads. I’ve bought six new spark plugs. I’ve re-earthed both fuel pumps to a decent earth. I’ve put a new crankshaft sensor in. I’ve done a voltage drop test which gave me ridiculous readings. 0.8 volts on the positive side and an unbelievable 270 volts on the negative side. On a 12 volt system. I should be getting readings of 0.5 volts on both the positive side and the negative side. I’ve done ten voltage drop tests. All achieving the same results. I’m either doing something wrong or something is seriously wrong. Anyway, I’m not too sure where to go from here. I’m at a loss. Worst case scenario is that the ECU is failing and that is VERY expensive. Does anybody have any ideas as to what my problem could be?
Edited by martin996uk on Monday 28th May 22:04
Purely a guess as no experience personally, but wonder if the fuel is vapourising causing a vapour lock....this from Wiki -
A vapor lock is more likely to develop when the vehicle is in traffic because the under-hood temperature tends to rise. A vapor lock can also develop when the engine is stopped while hot and the vehicle is parked for a short period. The fuel in the line near the engine does not move and can thus heat up sufficiently to form a vapor lock. The problem is more likely in hot weather or high altitude in either case. This could cause the pump to work harder/creating greater draw and heating up the relay.
Are you noticing higher engine temps or changed the fuel?
A vapor lock is more likely to develop when the vehicle is in traffic because the under-hood temperature tends to rise. A vapor lock can also develop when the engine is stopped while hot and the vehicle is parked for a short period. The fuel in the line near the engine does not move and can thus heat up sufficiently to form a vapor lock. The problem is more likely in hot weather or high altitude in either case. This could cause the pump to work harder/creating greater draw and heating up the relay.
Are you noticing higher engine temps or changed the fuel?
My engine temperature seems normal. The first fan cuts in at about 85/86 degrees and the second fan cuts in at about 91 degrees. It never goes higher than that. As for fuel, I’ve only ever put in Shell V Power for the last 5 years. How would you sort out or check a vapor lock?
Edited by martin996uk on Wednesday 30th May 14:01
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