It doesn't matter if the tank is full or near empty.
When the truck is warmed up, it fires right up.
When it's cold, on level ground, it has to crank a few times.
Parked facing uphill, Almost acts like it's out of gas.
Parked facing downhill, fires right up just like if it was warmed up.
What the heck is up with that?
Fuel pump is running at 15#.
Something screwy in the VP-44?

 

Try "bumping" starter before you start the truck, so the lift pump can prime the IP,
Is there a vacuum in the tank? (try loosening the fuel cap, at night, before the next days cold start, this should eliminate the vacuum sucking the IP empty theory, well my theory anyway)

 

You don't have to bump the starter to do that.
Just trurn the key on.
The ECM primes it.
I wish I could remember what changed that may have caused this.

Any input is appreciated.

 

"Bumping" the starter runs the pump of 30 seconds or so....... much longer than the normal key-on prime. This will displace more air in the lines if that is the problem.

 

I have a switch on mine that bypasses all of that.
Priming isn't the issue.
It's the fact that it starts fine when parked downhill that has me scratching my head. I can see why you guys are going down this path, but with my current set-up, that should be the last thing causing it.

I have heard of too much lift pump pressure causing a hard start.
How would parking it headed down hill affect that?

How much lift pump pressure is too much?

Thanks for the input so far.
Keep 'em coming guys.

 

Did you loosen the cap?

 

i am confused, do you have a 24 valve with a vp 44 or is the problem with the '92 in your sig.? or is it the one in the bus chassis

 

It's the 98.5 I sold my Brother in-law.
Same one that had a 1" pipe plug just fall out of the intake.
It's been great four 3-4 years and now it's driving me nuts.
There is a reason you don't sell stuf to family.
Guilt is a powerful weapon.

Cap on, cap off, same.
Now, the tank is vented to atmosphere. What effect would this have?
Meaning....the hoses were reconfigured when the new bed (Big tex flatbed) was put on.

 

check your return line check valve, i don't know any thing about it other than what i've read on this forum... do a search, maybe you'll get lucky