2014 with near engine stall upon startup...

[jmden]

More info...

This issue appears to becoming more of a regular issue. After running an errand, came back 10 minutes later and the stalling issue upon startup happened again--went down to just below 250 RPM and then managed to 'catch' and run normally from that point on. This was a different presentation that what has been typical the past year and a half.

Took a chance to call into a local radio show run by several local shop owners. One had seen this before and found that the fuel pump was running at the ragged edge of 'normal parameters' and in certain situations would cause problems that the computer would then adjust for momentarily. In this situation, the computer never threw a code and check engine light didn't come on either. (Still can't believe there's no code or check engine light as badly as this thing stumbles.) It took this shop owner quite a bit of effort, research and time to figure out this issue with this other rig. I wonder if the dealership just hasn't been willing to spend the time to dig that far.

I don't want to and shouldn't have to spend any more time and money on this, but if I've got a bad fuel pump, I'd rather find out now than when I'm 1000 miles from home back in the middle of nowhere.

Situation sound familiar to anyone?

 

[k9education]

This issue appears to becoming more of a regular issue. After running an errand, came back 10 minutes later and the stalling issue upon startup happened again--went down to just below 250 RPM and then managed to 'catch' and run normally from that point on. This was a different presentation that what has been typical the past year and a half.

Took a chance to call into a local radio show run by several local shop owners. One had seen this before and found that the fuel pump was running at the ragged edge of 'normal parameters' and in certain situations would cause problems that the computer would then adjust for momentarily. In this situation, the computer never threw a code and check engine light didn't come on either. (Still can't believe there's no code or check engine light as badly as this thing stumbles.) It took this shop owner quite a bit of effort, research and time to figure out this issue with this other rig. I wonder if the dealership just hasn't been willing to spend the time to dig that far.

I don't want to and shouldn't have to spend any more time and money on this, but if I've got a bad fuel pump, I'd rather find out now than when I'm 1000 miles from home back in the middle of nowhere.

Situation sound familiar to anyone?

Well you can check the voltage at the fuel pump for any voltage drops and check pressure with a fuel pressure gauge before you run out and pay for a new fuel pump. If neither of those reveals an issue, I would move on to something else.

 

[jmden]

This winter I've been experimenting with this issue by using only super unleaded. Since I have been using super unleaded, I have not had this issue rear it's head one time--and this over a approximately 2 month period so for with temps down into the teens F.

If I use Costco or Chevron regular I have the issue. If I use Costco or Chevron super I don't have the issue.

It's really not the big of a deal overall. But it is so consistent with regular and then doesn't happen at all with super that it's a bit of a head scratcher. Anyone run into anything like this before that has come up with a reason for this to occur?

 

[stamp11127]

To verify it is fuel related try the same test with a different brand of gasoline. If it is octane related the brand doesn't matter.

 

[jmden]

Yep, like I said, I used both regular and super from Chevron and regular and super from Costco with the same result. Interesting...thoughts?

 

[stamp11127]

Try a third vendor to rule out the same delivery vendor dropping fuel at both locations. If it happens with a third vendor then you are looking at the octane rating difference. That would lead me to examine static timing. I'm going to assume Ford is still using the variable valve timing. Are you using the correct weight oil?

 

[jmden]

K. 5w-20. Only get it changed at Ford dealer.

 

[jmden]

http://www.expertswrite.net/ford-5-4l-triton-3valve/variable-cam-timing.html

Looks like variable cam timing...

 

[jmden]

Went to a Shell and have used over a tank of 87 octane Shell now. So had the issue with Costco and Chevron 87 octane. However, with Shell, I only had one start up so far that had the near stall and it wasn't as bad as with the other fuels.

Thoughts?

 

[jeff kushner]

jmden,

I'm going to throw this out there only because it just MIGHT help...on both of my earlier Expy's with the 5.4L engine, there was a 90 degree bend rubber fitting on the passenger side of the engine, near the firewall that wore a hole in the bottom from rubbing on the engine. Once the hole was there, the engine would do exactly as you describe.

It was as if once the engine developed enough vacuum to overcome what was being lost due to the hole, the rpms would recover...in 1-2 seconds.

I don't know if it even applies to your year but I'd rather give you info that doesn't help, then to not tell you something that might help!

I found it by wrapping my fingers around the tubing starting at the throttle and sliding then toward the front of the engine as my GF started the truck. Once I found it, a wrap of duct tape confirmed the issue.

good luck,

jeff