Priming problem in latest version.

Hello there.

So after a couple of months without flying the Mustang, I decided to spend more time with it again, with oil bug fixed, detonation effects introduced and whatnot.

I've already noticed some primig-related startup issues during occasional flights of last few weeks, but now, after more thorough testing, I'm sure something changed in fuel installation modeling by one of last small game updates.

I get an impression, that priming pump isn't working as it's supposed to be (well, it surely doesn't work as it did). In older versions of the module the standard procedure was: prime cold engine for 3-4 seconds (warm weather map), run the starter, when the engine catches up move the mixture lever.

Now, I can hold the prime switch anywhere between 2 and 8 seconds (tested on spring and summer map), yet the engine will not catch no matter how long I crank it. But as soon as I click the primer while the engine is cranking, it catches up perfectly exactly after 4 seconds of this "secondary" priming. It's almost as if the priming pump doesn't work at all when the engine is stopped.

Same happens in TF-51D.

Any thoughts?

Found in the manual page 75. 5. Primer Switch

5. PRIMER SWITCH. The Primer switch is used to prime the engine with fuel. The switch is spring-loaded and needs to be held ON (up) position to execute a prime. When the primer switch is held ON, fuel passes to the primer lines and into the induction manifold. Usually 3 or 4 seconds are sufficient to prime a cold engine. One second is usually sufficient for a warm engine. The engine should be primed only when it is turning over.

Oops!

@Jansgi: Thx for opening our eyes to that detail, now correctly implemented in DCS's P51d, bringing it even closer to reality than what it already was!

Good catch! I've been doing it wrong, then. Looks like I need to rebind some keys so that I can hold more things down at once.

I wonder what the various real-life P-51D manuals say about this. Hmm, I should go digging.

Good catch! I've been doing it wrong, then. Looks like I need to rebind some keys so that I can hold more things down at once.

 

I wonder what the various real-life P-51D manuals say about this. Hmm, I should go digging.

After digging trough google and many youtube clips I have found 2 different procedures. 1st is where you prime the engine before cranking it and if it doesn't fire after a few rotations they prime more while cranking the engine to start it. 2nd is where they prime and crank the engine at the same time to start it. But I'd guess if you start it by the book/manual you prime the engine during the cranking.

I've had no problem priming first and then starting and I've been flying the P-51 almost exclusively lately.

Found in the manual page 75. 5. Primer Switch

 

5. PRIMER SWITCH. The Primer switch is used to prime the engine with fuel. The switch is spring-loaded and needs to be held ON (up) position to execute a prime. When the primer switch is held ON, fuel passes to the primer lines and into the induction manifold. Usually 3 or 4 seconds are sufficient to prime a cold engine. One second is usually sufficient for a warm engine. The engine should be primed only when it is turning over.

Yep, I know that. The problem is, however, a couple of pages later, in a paragraph about startup procedure, the same manual instructs to prime only before cranking the engine :D . That's how it used to work about two-three game updates ago. Which version is correct then?

Priming stopped engine is also the same as the real life P-51K manual says. True, it does also mention flipping the switch again for one second when the engine is underprimed and turning over, but in DCS, during first startup attempt, we have to keep it on for 4 seconds flat, no matter if previously it was underprimed, primed, overprimed, whatever... A step in direction of higher simulation fidelity? I'm all for it, but something doesn't quite add up here.