Ok gents I'm working on a customers 08 f450 he says it occasionally stalls when he's coming to a stop I've got a particulate filter pressure sensor code so I record the freeze frame on it and clear the code. i drove the truck home tonight, (25 mile trip one way) it runs great for the first 18 miles all freeway then I get to the off ramp and it dies. No bucking surging nothing, like someone turned the key off, No codes yet 10 minutes it fired up again, next stop dies again. I look at the data stream and see fuel rail pressure at ~80 psi then I crank it and hits ~500 psi, no start. Let it sit, crank it fuel pressure hits 2200 psi and fires up then idles around 6000psi. As I'm pulling into the house it dies again. Same fuel pressure readings ~500 cranking and the filter pressure sensor code is back. Any ideas would be appreciated thanks
Bryce

 

Hi Brycemc,

I'm going to move this down to the 6.4L forum, the folks down there will be better able to help you out with this.

 

Yeah I posted it there. After I posted here I realized we had a 6.4 section

 

Hi!!!

From your description I would look at the fuel filters if they haven't been changed lately. Secondly I would look at the grounds. It sounds as if you are a mechanic as am I. That's where I would start if I were you. Not trying to be a smart#ss just trying to help.......

Bob C

 

I'm a mechanic but not too familiar with the 6.4. I thought about grounds but it only stalls when you're coming to a stop. I'm leaning towards the high pressure pump. This morning on the way in I can put the truck in neutral while coming to a stop and keep the rpms around 12-1500 and it would stay running where if I leave it in drive and come to a stop it just dies. No surge nothing. Almost like somebody just shut the key off

 

Transmission down shifting? When stopping? Try shifting manually with first & second gear. Rather than neutral.

 

Bad sensor is where i would start.

 

I think fuel filters...

 

If filters haven't been changed with in the last 15-20k miles then I would start there 1st. If unable to verify when fuel filters were last changed I would start there.

Us 6.4 people change our fuel filters every other oil change about every 10k+/- Most of us know to use the severe service guide lines.

PS: Always and only use Motorcraft or Racor filters. ( oil & fuel )

 

Well I pulled the cat off and found a hollow case where a dpf should be so the customer picked up a programmer to delete the dpf and since he lives where there are no emissions we got that squared away so far the truck has 250 miles without incident

 

RU saying the truck DPF was deleted untuned? And the guy didn't know it? Hard to believe, I did that on accident once by shutting down the tuner. The truck went into Exhaust cleaning and I could smell the diesel right away. it was ugly.

 

Yeah the guy bought it at an auction about 2 weeks ago

 

Interesting, wonder how they kept it from cleaning during the drive through the auction? shut it down quickly I guess. Or, I was also thinking the thing might have been tuned and they just took the tuner when they traded the truck. The truck was tuned, just the owner didn't know how or with what. That's happened to guys on here before. Still, must have been a pretty sad tune if it was causing all the shut downs.

 

It would run great for about 20 minutes then it would just shut down. I don't know what the story was before he got it