hey all.

what could cause a car to drive like shit while warming up, until coolant reaches EXACTLY 50ºC (on p3gauge)? i tried finding all maps that would have 50 or 50.25 or anything close to it as an exact axis value with no success.

car still has cats and SAI, but no flaps. autotech HPFPS. no issues at regular temperatures, just drives like a clogged carburator even with light light throttle until 50C. at 50C it magically changes and gets perfect. its like im missing a "max value" map or something, or a cat heating/SAI routine config.

thanks!

edit: med9.1.1 v8 s5 at.

how could no flaps make it suck bad at 49 degrees, but instantly clear at 50+ degrees?

SAI shouldnt influence, as the air goes after the exhaust valve...

as for the flaps, from the FR, thats all i found regarding warm up: "During heating, interpolation is performed between map KFLBKHOMS and map KFLBKHOKHS with flbkkh."

both maps are already zeroed, as flaps were coded out. but i cant find anywhere to compensate. the engine expected a richer mixture (as a choked carb), but doesnt get it.

B_sthdrhsp -> Bedingung (Start mit Kraftstoffhochdruck in HSP = Condition start with high fuel pressure in HSP) -> modtm_out (Bedingung Start mit Kraftstoffhochdruck in HSP = Condition start with high fuel pressure in HSP). from FR, "engine mode depending on engine coolant temperature". this triggers bdemodst, "engine mode for start and warm up"

so we get to FB BDEMST 2.130.0. the text explains, among other stuff:
For non-homogeneous operating modes, the start enrichment fst_w or the post-start/warm-up enrichment fnswl_w must be less than or equal to the threshold FNSWLMX.
Background: Enrichment increases torque during lean operation. For monitoring purposes, it is therefore necessary that the enrichment remains below the FNSWLMX threshold to limit the additional torque.

if we keep following fnswl_w, we get to FB ESNSWLA 1.10.3, where it says:
The correction factors are only calculated if the calculation of the post-start or warm-up factor is also active in the ESNSWL (B_fnsoff / B_fwloff = false). The Correction factor fnswlk_w is permanently included in the factor fnswl_w in the ESNSWL. Therefore, fnswlk_w = 1.0 is set if the correction factor in the ESNSWLA is not will be updated more. The influence of the charge movement flap is only calculated when post-start or warm-up are active. Of course, the calculations only take place if a charge movement flap (SY_LBK>0) is present.

so i feel this is the right path.

in FB GK 21.110.2, it reads:
In block FVST, the factors fgru, fst_w (and at SY_ESNWS>0 fwnws) or fgru, fwe, fnswl_w (and at SY_ESNWS>0 fwnws) become the input control factor (fvst_w) after the start. for lambda combustion chamber = approx. 1 calculated.

after trying to find where fnswl_w comes from, all i got was the attached picture, so its not an output from an actual map. honestly i still dont know where it comes from, but i decided to check the other words from the marked square, and searching for B_stendes, i found a map called VSTARTMV, which similarly to VHDP, has only one number, equivalent to the volume of the HPFP, which is 300mm3 for my car (this one actually shows as 301.5900, but who cares. i got upgraded HPFPs, as informed in VHDP with the new value of 452.3800, BUT NOT HERE, WHICH SEEMS TO BE WHAT MATTERS WHEN IN THE WARMUP ROUTINE. YAY!

i will post here if this is what needed change.

Yeah because you are theorycrafting instead of just looking what mode it's running using the logger.