VT 355 supercharged AFM issue

[shane1]

The maf is a good one . It seems happy to read higher, just the g/s won't go with it . The fuel cut is actually 200 rpm higher than the commanded if you set it to 5700 it cuts at 5900 , set to 5800 it cuts at 6000 set it at 6000 it runs rough at 6000 and cuts at 6200 . That is a hard cut I'm talking about. A lot of things like the soft hard cut rpm , canister purge , throttle follower etc are not yet defined in VT like they are in other xdfs, not a big issue just means everything is not quite as it seems. I've had this thing on the dyno all day and haven't achieved a thing. I'm thinking a 4.5 inch pipe or a arm clamp at 10400hz may be the only way to fix it. The supercharger runs its own belt .

[shane1]

All the logs run the g/s past the 256 limit but the engine runs rough from that point exactly . It's not that the arm won't read it it's something it the conversion of the afm hz to g/s calculation in the ecu where it does not like It.

[antus]

see if you can get a log with the right adx. that'll help. if your seeing 256g/s and your not using the right xdf, and its scaled by a factor of 2, could you really be hitting the 512g/s limit? I dont know. I know thats a lot of air..... I dont think so because I think the hz is right in your log... but not sure...

[delcowizzid]

ide allmost be looking at the ignition module its tied into the injector power feed line maybe the load when on boost is loading it up.what plug gaps you running.maf power is shared with purge solinoid ac relay and o2 sensor heaters

[Jayme]

nah its not the adx... I can see the correct reading if I open it with the stock adx and change the calculation as the1 said. so if the1 says they read fine up way past what you have seen, then perhaps your PCM is on the fritz? have you got a spare one to try? the circuit that reads the hz off the airflow meter could be damaged? either that or the V8 code has got a bug in it that the v6 code does not have? the1, have you got a bench and tested the v8 code reading at high hz?

[shane1]

I'm more concerned that the bin isn't correct for the extended g/s tables I assume there must be a modified calculation in the bin somewhere yet if I check my bin with a std bin there doesn't seem to be any hidden hex mods? I'll check the module tommorrow , I did wonder that but have run std modules to 16 psi without to much drama previously. Might just power the arm up separately to test it .changed plugs no difference even opened the gaps up to check spark strength .

[delcowizzid]

nah its not the adx... I can see the correct reading if I open it with the stock adx and change the calculation as the1 said. so if the1 says they read fine up way past what you have seen, then perhaps your PCM is on the fritz? have you got a spare one to try? the circuit that reads the hz off the airflow meter could be damaged? either that or the V8 code has got a bug in it that the v6 code does not have? the1, have you got a bench and tested the v8 code reading at high hz?

yeah bench test pic here

[Jayme]

was that v8 pcm or v6 pcm ?

[delcowizzid]

what injectors is it running you havnt run out of injection time at that rpm have you doesnt a v8 at 6000rpm only have 10ms to deliver fuel

[Jayme]

nah duty cycle 87% in the log