S40: TPS - readings

[960kg]

EFI 121 MAF fault codes for 1855 T4

If the signal is Too High, Too Low, intermittent or permanent

If faulty MAF the Engine Fan will run for 10 minutes only, regardless of what you are actually reading.

[dtm]

Hi 960KG,

Mine does not present any fault code. Did a fault code sweep last Wednesday and nothing. Today, no engine management light, sow I'm guessing if there is a fault with the MAF it is not showing on the ECU.

mitchyboy01, from what I can see from your signature, your car is not exactly stock. Would that alter the MAF readings/values?

My T4 has a MBC doing 1.2bar boost, but that's it. I'm running LPG.

Regards,

Daniel

[mitchyboy01]

All T4s should be around 3gs at idle mate. Mine did not show a fault code at all hence me taking so long to diagnose the problem. Im just telling you my own personal experience.

Mitch

[960kg]

Mitch ,just a question as things don`t seem to match up!

On another site you say that you believe your MAF is maxing out at 195g/s
about 250bhp

So why did your Dyno run say 285bhp??

What has happened since?......although on here we never see eye to eye as we come from different angles of thought.

I am on the track of your fuel return system as the reason a T4 doesn`t have one is because the fuel has to be kept at 50 degrees for optimum performance.

[mitchyboy01]

Originally Posted by 960kg

Mitch ,just a question as things don`t seem to match up!

On another site you say that you believe your MAF is maxing out at 195g/s
about 250bhp

So why did your Dyno run say 285bhp??

What has happened since?......although on here we never see eye to eye as we come from different angles of thought.

I am on the track of your fuel return system as the reason a T4 doesn`t have one is because the fuel has to be kept at 50 degrees for optimum performance.

Just because the maf is maxed it doesnt mean the ecu wont add more fuel. It just means the load calculation is out so afr isnt as optimum as it could be after the maf is pegged. The ecu uses other ways to calculate such as VE and rpm. The T4 fuel system struggles at figures approaching 300bhp and beyond so a return line is essential. The T4 fuel system is inadequate when tuning these cars as without a return flow is compromised. My car hits 195gs at around 3krpm

[dtm]

Thanks mitchyboy01,

I appreciate that, but my questions was regarding the spec changes you made to your car, this is, your turbo at idle could be pulling more air then a stock one, nut no matter, I will try another MAF to check readings and go from there.

Thanks again mitchyboy01,

Daniel

[mitchyboy01]

Originally Posted by dtm

Thanks mitchyboy01,

I appreciate that, but my questions was regarding the spec changes you made to your car, this is, your turbo at idle could be pulling more air then a stock one, nut no matter, I will try another MAF to check readings and go from there.

Thanks again mitchyboy01,

Daniel

800rpm idle needs the same airflow regardless of turbo. If it had no turbo it would still need the same amount of air to turn the engine at idle. Remember the car is in vacuum so the cylinders are sucking in the air required.

[mitchyboy01]

Originally Posted by dtm

Thanks mitchyboy01,

I appreciate that, but my questions was regarding the spec changes you made to your car, this is, your turbo at idle could be pulling more air then a stock one, nut no matter, I will try another MAF to check readings and go from there.

Thanks again mitchyboy01,

Daniel

Another maf test is divide your bhp by 0.8 and this should be your grams/sec. So flat out if your car is stock 200bhp you shoud see around 160g/s. If youve upped boost by a few psi expect slightly more

[dtm]

Is that measure in any gear with WOT or is it best to check in fifth gear WOT?

Thanks,

Daniel

[mitchyboy01]

Originally Posted by dtm

Is that measure in any gear with WOT or is it best to check in fifth gear WOT?

Thanks,

Daniel

I would put it in 4th and rev it out. Have g/s on your screen in a big box so easy to see. I tried to graph it but it was harder to make out when driving.