Had car on Rollers today - We have issues

[mikecmr]

Ok some of you know the spec of the car rs4 turbos, precats removed and a re-map, got it on the rollers and only produced 239bhp at the fly-wheel which im quite gutted about, having it on the vag-com showed that the maf isnt running correctly. Print out also shows that its only running 7.8psi peak output, can all this just be down to a fuked maf?

thanks for your help

mike

[Nige_RS4]

Car is most likely in limp mode - could well be the MAF but get it checked for error codes via vag-com or VAG1551 - better way to diagnose problems!

[mikecmr]

cleared the errors that it had but the maf one would not go peak power was at 5600rpm at 7.8psi lol

[mikecmr]

i had it on a shareware vag-com last week and came up with this error

- Mass Air Flow Sensor (G70): Supply Voltage

well think it was this one after looking through the site

http://wiki.ross-tech.com/index.php/16484/P0100/000256

[KayGee]

Mike,

In answer to your question, yes it can. Easy way to check is to unplug it and see how she goes. Would only recomend doing this for a short period. Xchange MAF is not to bad around £70. Several people will have spare MAFs also, you running a S4 or RS4 MAF? Also what year?

[ZeroK66]

yep prob in limp mode because the maf is so bad. Pressure test the inlet, get a new MAF on there and off you go.

You should have just disconnected the MAF and then done another run... would have probably given you full boost and a decent power run. You could still try this, if the MAF is that bad you will get in the car and instantly notice the difference at such low power.

Good luck

[mikecmr]

tried running it with maf disconnected after the power run, on the way home, and still seemed the same but it was an error on vag-com that couldnt of been cleared so think its still in there, sadly local audi garage isnt open till tuesday so works van here i come haha

[ZeroK66]

Hi Mike, local audi garage prob wont be able to diagnose all faults! Obv have the MAF replaced and error codes cleared. But I wouldnt advise driving it too hard till the inlet is pressure tested. If you have vagcom check your requested boost vs. actual boost and that will give you a good idea if you have a leak or not!

[s4woody]

but when in limp mode will it request proper boost and only give u limited boost or surely wont the ecu stop the full boost request and keep it in limp with limited boost if any..
surely checking requested boost he,ll have to boot it..

[rolskii]

If you disconnect the maf, you run in limp mode, thats the same as in limp mode restricted boost at least ... limp man .....

[MarkB]

if you diconnect the N75 it's like running in limp mode, no boost above a mechanical wastegate default

[KayGee]

Not true, MAF disconnected is not in limp mode. Full boost should be available. Several chip vendors disconnect MAF to disable limp mode. If the car is still not right with MAF disconnected then we need the codes and vagcom logs to be able to help further.

Rgds

Kaygee

[rolskii]

just seeing who's awake......

.... not me

[KayGee]

[mikecmr]

cool well iv ordered vagcom set off rosstech so soon as that gets here i can start doing some tests