# vr6 turbo 12v with 95mm maf idioling backfireing/intermitant missing , bit of help needed



## adaptorman (Dec 12, 2007)

others maybe haveing this issuise ,ive a obd1 vr6 turbo 640cc runing a 4pin maf sensor, 
problem is the 100mm maf tube.
due to were my holset hx40 is located its only around 12inch away from the turbo and a airfilter on the end , due to room issiuses,
ive no vag fault codes unless i unplug the maf ( and the engine will idiol richer but smooth and nice /drive fine)
soon as the maf plug is replaced the afr is all over , intermitantant missing, backfireing in the inlet manifold when trying to drive, ramondy stails,
i assumeing its due to having no flow straighters in the tube plus length of tube and turbo swirl affecting the mafs performace ,anyone have any advise before i have to start relocating the turbo and some how make a longer tube


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## vergessen wir es (May 12, 2010)

No CEL (or trouble codes) doesn't mean anything on OBD1.
I've had a bad MAF without CEL or codes and other bad parts that were never detected.
How sure are you that your MAF is good?


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## zoidmk5 (Sep 17, 2006)

what software are you using to run 640cc on an OBD1?


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## adaptorman (Dec 12, 2007)

ive tryed my maf pipe/filter on my friends and it dose idiol , but varies 12/15afr , i tryed his on mine seemed better , ill go try another maf , ps whats cel? as he stated my maf pipe wasnt long enoegh , ie too close to turbo causeing issuises


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## adaptorman (Dec 12, 2007)

custom 25 30psi


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## vergessen wir es (May 12, 2010)

CEL, check engine light or MIL, malfunction indicator lamp = presence of DTCs Diagnostic Trouble codes
EIEIO


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## adaptorman (Dec 12, 2007)

im in the uk , and i dont have one as its this lots fitted in my mk1 golf caddy 4wd with mk3 vr6 instrument cluster , ive checked vag.com today and no faults 

this was how the afr used to be , 
http://tinypic.com/r/nmdruh/7


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## vergessen wir es (May 12, 2010)

Trust me it can happen. OBD1 can allow out of spec sensors and not show any faults.


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## adaptorman (Dec 12, 2007)

lol i belive you as im sure its happerning  thing is would u acturly buy a new maf ? or i can make another exhaust manifold to have a longer intake pipe(approx 6inch, or buy some honycone flow straighter , as usely companys selling the maf houseing dont sell it with the item 
as ive had this engine holding 30psi 11.5afr without problems other then this idiol issuise


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## vergessen wir es (May 12, 2010)

If I were you I might mock up an extra long inlet track, with hose even and the hood off if need be just to prove the theory of MAF turbulence.


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## adaptorman (Dec 12, 2007)

i did attempt a mock up idea off a extra 5ft 100mm tube with airfilter on the end , but didnt work , i assume too long or no flow straighters ,, ill go make a couple and give it a try, cheers


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## adaptorman (Dec 12, 2007)

this is the room issuise and ive tryed asorted pipes to move the maf, foward ,middle and backwards,but isnt helping, so made a trail airflow strighter in the filter see if it helps/


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## adaptorman (Dec 12, 2007)

slight turbo changed and alterd a few bits


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