S6 Still poorly - S2/S6 brains needed please!!

[HMS-S6]

If you've read my previous threads you'll know i have an S6 which is tyring its best to give me a nervous breakdown!!

The car is still running dangerously lean. The latest ideas were fuel pump and filter, have changed both of these along with a 3rd MAF sensor and no better at all - even on light throttle once around 3300rpm is reached, you can feel the car hold back and feel flat!!

However, i have made a very strange discovery to which i have no explination but i'm sure it is pointing to the cause of my misery

If i unplug the MAF sensor with the car running, it stops!! It will not start with it disconnected either!! If i can talk it into starting it barely manages to run at all. Something seems very wrong.

If i go to my other S6 which runs well and disconnect it, it hesitates very slightly for a second and then (i assume) falls to a base setting. Which is what i am used to on other cars i work on.

To me this points to something on the base fueling - does the camshaft position sensor controll the injector timing via the ECU? As the 'faulty car' has a cheap aftermarket item on it!

[kirvis]

is the black smoke comes out from exhaust?

[kirvis]

i had the same problem on my URS4. changet MAF, Lambda, injectors, even turbo.
but guess what I just had a big hole in one of the boost hoses. taped it up and

[UrS4boy]

i had the same problem on my URS4. changet MAF, Lambda, injectors, even turbo.
but guess what I just had a big hole in one of the boost hoses. taped it up and

Good idea. Motocrossmad, check the MAF to turbo hose for a crack or hole (which would lead to sucking in unmetered air. Remove the hose and examine very thoroughly. A new OE hose or a 034 silicon intake hose might be the cure.

[HMS-S6]

i had the same problem on my URS4. changet MAF, Lambda, injectors, even turbo.
but guess what I just had a big hole in one of the boost hoses. taped it up and

Just invested in a new intercooler and Samco hoses, plus all boost checked ok. Thanks anyway

[kirvis]

try to disconnect cats, and give her a go. they might be jammed

[HMS-S6]

try to disconnect cats, and give her a go. they might be jammed

Thanks, but on third set of those too, and tried without any

[kirvis]

sorry, but dont know what else that could be...

[HMS-S6]

sorry, but dont know what else that could be...

I know!! I'm a mechanic and its driving me up the damn wall!! My train of thought was that; The Maf sensor is there to refine an already good enough base fuel setting, if mine doesn't run without it there is a major problem with the base fueling of the car.

However i don't know if its not getting enough or if its getting it at the wrong timing!!

[kirvis]

if thed fuel would go at wrong timing, it would explode in ur exhaust

[RoadKill]

could you take i pic of your fual filter ? i had some thing on my S2 truned out some one had put a restricker on the fillter

[Acidburn]

Also check the FPR as i've heard of them going wrong.

[HMS-S6]

could you take i pic of your fual filter ? i had some thing on my S2 truned out some one had put a restricker on the fillter

Thanks but have tried bypassing it too

[HMS-S6]

Also check the FPR as i've heard of them going wrong.

Tried two and both give 5.5 bar

[dkw_dude]

How did this lean running start? Suddenly? Has it been running right before? Are you sure the chip and injectors match?
Is the crankcase ventilation system in good shape, no leaking hoses or valves (maybe you included these component while pressure testing it). If its not, unmetered air will be drawn in through there.
Keep working on it and you will get it into warp mode again!