Stalls at idle while rolling downhill

[Woody3]

Here’s a weird one:

New to me B2. Stalls every time I pull into my driveway which is at the base of a steep hill. As soon as I push in the clutch and the engine drops to idle it stalls out. Only when facing down hill. Starts up again and will run with throttle. Runs fine otherwise (so far…)

Any ideas on where to start?

 

[Uncle Gump]

Honestly... it doesn't make a lot of sense. But it is what it is.

Does it have the two fuel pump system?

Low pressure in tank pump and frame mounted high pressure pump?

Also... does it change depending on how much fuel is in the tank?

 

[Woody3]

@Uncle Gump: Yes on two pump system, though I haven’t visually verified the pump in the tank. It looks like the high-pressure pump at the frame rail has been replaced recently.

I thought of the fuel level in the tank as a possible issue and I just filled up when it did it again.

I’ll be doing some more test run tomorrow and will post updates to assist with Diag.

 

[Woody3]

Ok so after a week of driving the B2 I have some more data on the stalling issue:

Engine stalls intermittently during down shifting from 3-2 and 2-1. Stall occurs when the clutch is depressed and the engine is supposed to momentarily return to idle speed. Most pronounced during engine braking. Happens every time i try to enter my driveway after going downhill shifting 4-3-2 and into 1 to climb the uphill driveway. When it stalls it will start right back up with a key turn.

It seems like the idle speed drops/bounces below an acceptable rpm when down shifting in the lower gears. This doesn’t happen/is not noticable when driving on level ground or shifting during acceleration.

ideas?

 

[Woody3]

Definitely happens after a long engine break situation the most. Idle drops off and engine dies immediately after pressing in clutch. Totally annoying and dangerous. Any ideas here?