[ade146]

Hello all Im trying to solve a puzzle with my car which may be cheaper or quicker with help from the forum.

Car is 05 73k mapped and owned for 18months. History is after 6months dpf blocking even after long trips. In the end I removed it and car was smokey but drove well. I have diagnostics but couldnt really solve the soot issue and around this time I reset MAF adaptations which seemed to reduce soot slightly. Car shortly afterwards was mapped and I asked them to adjust smoke map. Problem now solved car is quick and not smoky.

Problem I have just noticed from graphing MAF that it hits a hard limit of 200g/s. This equates to approx 225hp. I only noticed after graphing MAF as it hits a platform of 200 after 2000rpm. It could be it is hitting the max 5v of the sensor or there is a 200g/s limit set somewhere or it really can only suck that amount of air. Car has no issues and feels quite fast. What sort of numbers are others seeing? Anyone know if it is using map or maf on high boost? I do know at idle it pulls 16g/s or so which is similar to my mates 335. His pulls over 300g/s but he does have a new style MAF.

I dont want to just buy a MAF for the sake of it as generally the numbers look ok until its on max boost.

Thanks

[ukbeemerboy]

I'd check the map. Can you put the car back to stock and retest?

[ade146]

Nope that isnt easily done Im afraid. I suspect if it was standard 200g/s would be about right. There must be enough standard ones on here, I was hoping someone would tell me what they are getting before I go to the trouble of putting another map on it.

[ade146]

Im not aware of anything in the map that restricts mass air. I suspect the maf as on the E46 they were always having issues and these cars are using the same maf. The dpf masks the problems though. I know there have been enough people on here with dpf issues and I am wondering if in fact they are MAF issues.

[m1bjr]

Not surprised it was smokey - there's extra fuel dumped in to clean up the hot DPF during a regen.

Blocked DPFs are often just down to a temperature sensor issue....

Why not ask the tuning experts that remapped it.
They must know the capbilities of that MAF unit surely?

[ade146]

Thanks for your reply I am not sure what the pressure delta criteria is for a regen but after removing the dpf the drop was zero so doubtful it was trying to regen. The experts with the remap was a bloke with a rusty astra. I doubt he knew much about the span on the maf. I have a friend who does auto diagnostics for a living and he doesnt know. What I need is for some guys from here to tell me what they are pulling. General rule of thumb seems to be maf g/s x 0.8 = hp. That makes my car low but it certainly doesnt feel like it. My conclusion so far is that maf isnt having much bearing on full load. Can anyone confirm that?

[ade146]

OK with everyone buying bt obd readers torque and inpa cables someone must be able to have a look. At idle I get 55kg/hr or at 70mph 70g/s