LCR Stage 2 MAF g/s

[matylad]

I think I know the answer to this question but I just want to confirm. Just recently car has been hesitating and feeling a bit flat. I ran some logs last night and my MAF reading peaked 240g/s at 6500 rpm. I suspect that the MAF is over reading and in need of replacing...again.

Mods are Revo stage 2 linear with supporting hardware, B5 v2 TIP with JR filter

Cheers,
Matt.

 

[sambryant]

Could be a boost leak. Sometimes with a boost leak it can allow more air to pass the maf, meaning it can read more.

 

[sambryant]

Or a faulty maf or your map over reads gs

 

[ibizacupra]

240g/s would seem to be a tad optomistic.. ~300bhp level of airflow

Swap maf would be a starting point with a known good one.

 

[matylad]

Thanks for the replies guys. I was expecting somewhere around the 220 g/s TBH. It has been running okay for a year or so something has changed (clip slipped or goosed MAF). I'll test for boost leaks and see if anything shows up.

Cheers,
Matt.

 

[ibizacupra]

have a look at your fuel trims on 032..
An under reading maf would show fueling adaption on block 001 to increase so I would expect the opposite to occur if the mad over reads.. 001 would go negative to achieve the fuel request from expected airflow

 

[matylad]

Thanks Bill,

I did log block 032 last night and I am seeing negative percentages in the 2nd Lambda column of block 032. This ranges from -23.4% to -25% across the RPM range.

Matt.

 

[ibizacupra]

Thanks Bill,

I did log block 032 last night and I am seeing negative percentages in the 2nd Lambda column of block 032. This ranges from -23.4% to -25% across the RPM range.

Matt.

kinda like I was expecting from a severely over reading maf sensor.

airflow sets initial fueling, which then gets trimmed by the lambda to achieve the requested afr....

EG: if over reading 20% of airflow for example, its also initially fueled for this extra (not real) airflow, and lambda goes, hell, I need to pull back out -20% of fuel also.. (example maths to show the point not exact)

New MAF is what I would try first at this point.

Only other thing I have seen on BAM engines (only oddly) is blocked fuel pressure regulator filter screen, from decomposing rubber fuel line) - obvious when removed to look at it.. But given your uber high g/s I dont expect this is the root cause but will mention it as plan B.

 

[matylad]

Thanks for the input Bill, new MAF being sourced. Fingers crossed.

Matt.

 

[wild willy]

Is your screen still in place on the air mass housing.