Rich AFR and less boost

[CoCaine]

I have some problems for some while now with rich AFR and some boost problems and today I've looked at the MAF-turbo hose and founded a crack, should this explain the problems? ImageUploadedByTapatalk1355239490.591507.jpg
ImageUploadedByTapatalk1355239507.127001.jpg

Anyone can confirm that this will cause a boost leak and rich AFR?
Thanks in advance!

[driftin jo]

It won't cause it but if this is an indication of the
General state of your intake system i would say you
Have a boss leak from one or more places after turbo
That WILL cause it.

[Costash]

Don t get me wrong here but that leak it is after Maf isn t it?In this case the amount of air is not the one suppose to go in intake and the less air= rich mixture?or the leak should be on the pressure side to affect thr mixture.

[20Vcqdriver]

If thats the one between the MAF and turbo then it'll run lean as more air is being sucked in than is being measured by the MAF. As said if thats the general state of the engine bay I'd be looking at the breather system too

[CoCaine]

Yes, it's the hose from MAF to turbo. I thought that the air goes out, not that it will suck air. For me it doesn't make sense because I have rick AFR (green on my narrow band clock) not lean (red colour on the clock).

[CoCaine]

I've checked the vacuums also, everything is ok, IC hoses also ok, where should I look for other things that can explain rich AFR? My DV is ok, my n75 also, maybe the WG needs checking? Thanks!

[prj]

Yes, it's the hose from MAF to turbo. I thought that the air goes out, not that it will suck air. For me it doesn't make sense because I have rick AFR (green on my narrow band clock) not lean (red colour on the clock).

First of all, throw that gauge in a bin and use a proper wideband gauge.
All that shows is if it's richer or leaner than 14.7.

On boost that gauge must ALWAYS show rich, and this is correct.

The only thing that gauge of yours is good for is disco lights.

I've checked the vacuums also, everything is ok, IC hoses also ok, where should I look for other things that can explain rich AFR? My DV is ok, my n75 also, maybe the WG needs checking? Thanks!

You "checked" them. Please pressurize your intake with an air compressor until 0.7-0.8 bar and make sure the pressure does not leak out.

"Checking" them visually is a waste of time.

[bernsaudi]

jeeez!

[rynaqui]

That MAF hose looks proper knackered! Good luck solving your problem

[pasbogdan]

Don t get me wrong here but that leak it is after Maf isn t it?In this case the amount of air is not the one suppose to go in intake and the less air= rich mixture?or the leak should be on the pressure side to affect thr mixture.

Piston goes down with intake valve opened.It aspirates in this process(air and fuel).This vacuum condition is present all the way to maf.If hose between maf and compresor is broken aspirated air will get into engine "avoiding"maf.So lean mixture.
Also in boost vacuum is still present,but only between compressor and maf.Again if hose is cracked air will get into compressor by the crack and not by the maf.Again lean.
Any hose cracked with no boost will cause lean.
Hoses pre compressor on boost will cause lean and hoses between compresor and manifold will cause rich.
I guess your maf is before compressor and not on pressure side

[prj]

Also, that disco gauge shows nothing of consequence really.
You can't say if you are running too rich or whatever just based on the disco gauge.

On boost it will always show rich, because on boost you are running richer than 14.7 AFR.
On cruise it will go disco, because the mixture is oscillating between 14.4 and 15 AFR.

On over-run cutoff it will show "lean" because there is no fuel injected.

[Costash]

yeh get it ,I mixed up richer with lean.

[ManiacuV6]

Buy a good wideband gauge and you will know which is the AFR

[pasbogdan]

yeh get it ,I mixed up richer with lean.

And another common mistake is done when blaming ignition for rich.If combustion gases will not be burned more oxigen will get to sensor and lean will be.