fuel cut at full boost...? why?

[rs200]

my friend have a problem with fuel cut at full boost ... 1.4 bar.. s4 (aan)

why did Motronic do that? to save the engine from over boost and lean mixture?

can somebody explain that to me?

thanks..

Igor

[prj]

Boost leak.

Fuel cut is simply MAF based. If MAF reading exceeds XX at a certain RPM -> Fuel cut.
(this is simplified, it's actually a load limiter...)

But generally yes, this limiter is there so you don't max out your injectors, causing lean mixture and detonation.

[rs200]

before few years on my car was fuel cut too , but the problem was N75 valve..

in his case N75 is good. so we can go to look for boost leak or MAF problem ?

thanks Dmitri

[prj]

Look for boost leak first.
Also if boost has been raised above what the software is made for using mechanical means or a separate boost controller, you can get the same issue.

[driftin jo]

Have you tried cleaning the electrical connector to the MAF ?
I have had boost cut twice and it was only this connector that caused it , it's worth trying this first before spending hours testing for boost leaks only to find there is none .

[prj]

I agree, check the connector and error codes first.

[Audi-Porsche Avant RS2]

Sorry, I have a question, ABY, AAN and ADU Motronic, when there is a problem cut fuel or ignition?

Thanks!

Alessio

[rs200]

yes when done the fuel cut the "CHECK" light come on and after few second shut down... but 100% 2224 error code fuel cut...

so the I thing it is a maf problem, we will check everything , and will find the problem.. I HOPE SO...

thanks guys for a help..

[prj]

Motronic will:
* Progressively retard ignition and cut boost if knock is detected
* Cut boost if you go over max boost specified in boost chip
* Cut fuel if you go over max load specified in fuel chip.

For example, if you have a leak somewhere, a lot more air will go through the MAF than actually into the engine => AFR goes rich => eventually you hit fuel cut, because Motronic wants to protect you from maxing out your injectors.

But of course if MAF contact is bad or MAF reads wrong, then the same issue will happen, because Motronic will think that more air is going into the engine, than there actually is.

[Ross]

I had this same problem, read all the threads, figured I'd recently had the MAF plug off and cleaned it, must be a bigger issue... after some head scratching and no confidence in the car I cleaned the MAF connector and it hasn't reoccurred since. Definitely worth a try along with a leak test.

Cheers
Ross

[rs200]

thanks ..

tomorow will Benky come to me and we will try to fix that...

this is engine bay of Benkys 200 20v.. what do you say? looking good ?

before:



AFTER:



I'v done whole work, and they use AAN motronic

[benky]

Yes, Igor but you forgot to upload a picture when all was done
This is picture where you can see what it looks now.

[rs200]

hahhah .. yes I forgot...

but people on this forum obvious don't like your engine bay... my fault.. where did I go wrong...?

[Tonks4x4]

It's a bit too White for me but still looks nice clean and tidy :thumbs

[newsh]

Yeah, well tidy and white is after all the new black