Manager Forum

Customer brought in this 05 F250 with a 6.0L diesel and 119,000 on the clock. The issue is that when ambient temperature is say above 80degrees, the engine is extremely hard starting. Cold ambient temperature start is excellent. The PCM is showing no codes and after checking the system, I am not sure what direction to turn. Anybody seen this and would suggest what to look for?

I would check fuel pressure when cold and then when warm on a no start, 45psi is spec. possible map or ect. Can check map and ect readings when cold then warm. possible fuel contam. poss pcm? Good luck. hopefully someone else may have some insight later on.

when it fires up when above 80 is there a lot of black smoke and a need to clear it? there is a pressure sensor attached to a tube on the drivers head. or at least that's where all the ones i've seen are. the tube will get all plugged up with crapolla and cause all sorts of start issues. it's been my experience that this may or may not throw a code.

They also have a lot of issues with internal oil leaks

Ok. Here is an update on this one. The owner says that he can start the truck engine, head to work, stop in at a convenience store for say 15 minutes or so, come out and engine will crank over but will not start. No smoke. Nothing. If he waits say close to an hour then it will start, run rough for a little and then smooth out and be fine until he stops again. Sitting longer allows it to restart. Only in warmer temperatures. With the scan tool connected, the ICP reading is at 21% at idle. The ICP pressure is 580 psi. I am thinking that perhaps we may have an o ring issue on these injectors. What think? Or is this a case where compression is getting up through the injector and putting air into the fuel system? Otherwise the engine runs like a scared rabbit.

You need to get the truck in the shop hot and see what the ICP is cranking, the FICM will not fire injectors below 500psi, also these have lots of cam/crank sensor issues.

Yes, I am aware that the FICM needs to see at least 500psi and maybe slightly more to be able to fire the injectors. I suppose what i need to do is to disable the injectors so I can crank it over long enough to see cracking ICP pressure. Will that work? I suspect that we are in the right field with this vehicle.

No need to unplug the injectors, if the pressure is the problem you will be able to see that on a scanner during a no start event. If the system is all OK, I gennerally see the presure build enough in two seconds or less on a hot restart.

didn't these have egr issues.

I would watch the pids and evaluate after that.

I would look for oil pressure leaking off in the high pressure oil system.

We had one of these early 6.0L's with a very similar concern. We dissassembled the engine to the point of the injection oil supply branch tube (which is also a common issue, and for which there is an updated kit...) we isolated the leakage to the driver's side head gallery and it ended up being an o-ring that was leaking off the oil pressure. On cold start the pump could overcome the leakage enough to fire the injectors but when the oil was hot it could not.

These things are tough to test for and you may have to "search and destroy" - take off the turbo and intake as needed to access the oil branch tube, maybe even pull the valve covers for a visual...

Be sure to post your fix.

Edit: Just to clarify, the o-ring we found to be bad was not an injector o-ring, rather an oil gallery seal between the high pressure oil rail and the head. I expect an injector o-ring could cause the same leak-off problem though.

Gerald

Yes well, I am somewhat suspicious of the high pressure oil system as the source of the hot hard starting. When the engine is cold, the ICP percentage goes up in the 30s which is high. So, I suspicion there is a slight leak on say an o ring such as you are mentioning. It would be nice if I could somewhat zero in on where the leak may be but perhaps I will need to get the truck back in and do what i define as exploratory surgery.

Ford has no way to isolate either

I am wondering if there is any way to pressurize the system without the engine running. That's probably wishful thinking.

I think I say a way somewere but cannot find it so maybe not.

all symptoms sound like a high pressure pump.

steven kiser wrote:all symptoms sound like a high pressure pump.

That the pump would be leaking? or unable to keep up with demand?

Tim Martin wrote:Ok. Here is an update on this one. The owner says that he can start the truck engine, head to work, stop in at a convenience store for say 15 minutes or so, come out and engine will crank over but will not start. No smoke. Nothing. If he waits say close to an hour then it will start, run rough for a little and then smooth out and be fine until he stops again. Sitting longer allows it to restart. Only in warmer temperatures. With the scan tool connected, the ICP reading is at 21% at idle. The ICP pressure is 580 psi. I am thinking that perhaps we may have an o ring issue on these injectors. What think? Or is this a case where compression is getting up through the injector and putting air into the fuel system? Otherwise the engine runs like a scared rabbit.

Ok. I have a little more to add. The customer says that this problem actually began late last summer and somewhat disappeared over winter. Now that higher ambient temperatures are arriving, the problem is also recurring. Not necessarily worse but present. Again, cold engine startup is fine, after running for say an hour and shutting it off, trying a hot restart within a half hour results in a no start. Later the engine will start after some cool down.

You really need the truck in the shop to runt he PIDs during a no start problem, sounds like probable HP oil problem, but could just as likely be a cam or crank sensor problem. Does it have any codes? As for pump or seals, I lean towards seals, the pumps I have replaced were no starts at all. As for checking it, the best I have been able to figure out, is you can check the pass side by removing the valve cover and the IPC sensor, apply air pressure to the hole that the sensor screws into, this will presureize the pass side oil manifold, the supply tube has a check valve in it that will keep the air pressure on that side nad not allow you to check the driver side that way. One guy told me he took an old supply tube and removed the check valve and commands the IPC closed with jumper wires and he says that he pressureizes the whole system that way. I have never tried this, so I am not sure of how well it works, but he swears by it.

If I want to check the cam and crank sensors with my lab scope, what am I looking for? I mean what kind of signal? I have not checked these sensors on the diesels yet? I have also suspicioned them as possible faults aas well although I would a thunk that they may set a code if not functioning as they should.