MarkieMark
Friend of Leo's
'08 Ford F-150, Intermittent no start/no crank. Right?
Could be one of I think 5 engine options or so, but I doubt it makes any difference at this point. 4.2 and 4.6L are common, followed closely by the 5.4L Then the other options.
And I am assuming there is no third party/aftermarket security system installed...
(If so, back up)
Intermittents are a constant thing in my world. "It always works for the mechanic" is a thing.
A couple of things come to mind, IE: where I would start if that repair order landed in my in-box. (Assuming the problem wasn't currently readily reproducible)
Many Fords up into the range of that year had a fairly common issue with the wire between the relay and starter getting hot, damaged, loose at the starter. Many times requiring splicing in a new pigtail/connector. So the first thing I would do is carefully examine the small wire at the starter for signs of looseness/getting hot. Of course I'd check the other related connections while I was at it.
Next I would proceed to attempting to reproduce by copying the sequence of events the customer described, which sounds like a "hot soak" condition. In other words, get the vehicle hot, shut it off and let it sit a short period and try to start it.
This can become tedious and time consuming, but the fact is, if it is working, it is very difficult to accurately diagnose. everything is likely to test perfectly fine.
So lets say I have had the vehicle 2 days, tried to reproduce it many times to no avail. We have to decide- Gamble on an educated guess based on experience?
It could be a number of things. There were a couple of good guesses and several very bad ones in the replies so far.
In my experience, based on having worked on hundreds of similar vehicles and the OP's description so far, likelihood of a failing starter is at the top of my list. Followed perhaps by the starter relay (In the central junction box, under hood)
Followed closely by a possible worn/intermittent ignition switch.
Battery isn't likely based on the description.
While the Neutral position switch can of course cause a no-crank, the fact that you thought to fiddle with the shifter, and it made no difference, and that the tow truck driver fiddled with it and it made no difference, and it started at the shop (possibly after a cool down cycle) tells me that is unlikely.
One last possibility is the Powertrain control module, which in this case "gives permission" for the relay to operate, but that would be a last guess/worst case kind of approach IMO, only after ruling out all other usual suspects.
Many of the other suggestions offered in the thread here like crank sensor, fuel pump, etc. would result in a crank/no start, so I can rule those out.
The suggestion it has to do with the "evaporation device" (??) is simply wrong either way, since it has no effect on starting- cranking or not.
Just some food for thought from someone who has been through this stuff a few times!
Could be one of I think 5 engine options or so, but I doubt it makes any difference at this point. 4.2 and 4.6L are common, followed closely by the 5.4L Then the other options.
And I am assuming there is no third party/aftermarket security system installed...
(If so, back up)
Intermittents are a constant thing in my world. "It always works for the mechanic" is a thing.
A couple of things come to mind, IE: where I would start if that repair order landed in my in-box. (Assuming the problem wasn't currently readily reproducible)
Many Fords up into the range of that year had a fairly common issue with the wire between the relay and starter getting hot, damaged, loose at the starter. Many times requiring splicing in a new pigtail/connector. So the first thing I would do is carefully examine the small wire at the starter for signs of looseness/getting hot. Of course I'd check the other related connections while I was at it.
Next I would proceed to attempting to reproduce by copying the sequence of events the customer described, which sounds like a "hot soak" condition. In other words, get the vehicle hot, shut it off and let it sit a short period and try to start it.
This can become tedious and time consuming, but the fact is, if it is working, it is very difficult to accurately diagnose. everything is likely to test perfectly fine.
So lets say I have had the vehicle 2 days, tried to reproduce it many times to no avail. We have to decide- Gamble on an educated guess based on experience?
It could be a number of things. There were a couple of good guesses and several very bad ones in the replies so far.
In my experience, based on having worked on hundreds of similar vehicles and the OP's description so far, likelihood of a failing starter is at the top of my list. Followed perhaps by the starter relay (In the central junction box, under hood)
Followed closely by a possible worn/intermittent ignition switch.
Battery isn't likely based on the description.
While the Neutral position switch can of course cause a no-crank, the fact that you thought to fiddle with the shifter, and it made no difference, and that the tow truck driver fiddled with it and it made no difference, and it started at the shop (possibly after a cool down cycle) tells me that is unlikely.
One last possibility is the Powertrain control module, which in this case "gives permission" for the relay to operate, but that would be a last guess/worst case kind of approach IMO, only after ruling out all other usual suspects.
Many of the other suggestions offered in the thread here like crank sensor, fuel pump, etc. would result in a crank/no start, so I can rule those out.
The suggestion it has to do with the "evaporation device" (??) is simply wrong either way, since it has no effect on starting- cranking or not.
Just some food for thought from someone who has been through this stuff a few times!