Hard start, when warm outside.

I recently have finally gotten my truck registered, and have been driving it to school, and filled my front tank as it was getting low, because of this I switched to my rear diesel tank, and had a small amount of white smoke coming out of the tail pipe. I figured it might have been that I just slightly overfilled my oil when I changed it last and it would go away in a few days, and I'd just keep an eye on the level. I continued to monitor the oil level, and It didn't change at all, and I figured I would look at it this weekend when I had time. The next day It started up fine in the morning, and behaved normally (except for the slight amount of white smoke from the exhaust) until that afternoon, when I went to start my truck, it struggled to start (turning over, but taking ~15 seconds to start). I figured it might have just been a one off thing, and waited to see if it would do it the next day, It started and ran fine in the morning, but when the afternoon rolled around, It still had a hard start, but this time it seemed to start faster. after that for two days, I had no problems with it whatsoever, until this afternoon, after i got out of school, I went to the gym, and when I started it to leave, It ran for a very short time before dying and having another hard start. Once i finally did get it to start, I switched it to the front tank and babied it home. It didn't seem to have any problems after that, and the white exhaust smoke went away. Does anyone know why I'm having this hard start? it only seems to do it when it's warm out.

Edit: The rear fuel tank was at about 1/4, and I was parked on a slight downhill slope at the gym

There are a fair amount of stickies and tech 101 threads here that will answer your questions.
But look at these first in the tech section



1 showerheads
2 air intrusion
3 i.p. lifespans of 1-125 k before being an issue
4 fsv
5 hot start i.p.
6

Do put your trucks stats in your sig line so we can see what we're looking at...

I vote for #5 on CKB's option list. I have been known to be wrong though.

IDIBRONCO said:

I vote for #5 on CKB's option list. I have been known to be wrong though.

Click to expand...

Trick question
#'s 3-5 are interchangeable...
Sorta

I don't believe it's being caused by a bad i.p. because it was a somewhat small amount of smoke, and it would only have problems cold starting when it was warm outside, never once it had warmed up. I switched to the front tank which had much newer diesel in it and it didn't act up when I took a trip to wally world earlier. Could this be contaminated fuel? Possibly leaky return line? if so, is there a definite way to test for these>