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Vr6 engine bucking under throttle


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Hello,

My VR (I have the 2.9 Syncro variety) is bucking pretty badunder throttle especially al low rpms, until about 2000-2500. and vibrates at idle as the needle can't seem to stand still. I changed the coilpack, MAS sensor (it was busted), spark plugs *NGK the cheaper ones with only one thingie that lights up" , spark leads. What now ? Also the car seems not to be able to burn all the fuel as there is a strong fuel smell coming from the exhaust.

Should I check injectors ? Possibly a bad distribution chain install, things not aligned properly ?

Fuel pump ?

Other sensors not working properly ? VAG shows all things running fine now that I replaced the MAS sensor. Does it show me the fuel and oil pressure, what are the nominal values for this ?

Could the Motronic computer be screwed up entirely, but I guess it would not show up on the VAG software then ?

Any help appreciated.

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Hello' date='

My VR (I have the 2.9 Syncro variety) is bucking pretty badunder throttle especially al low rpms, until about 2000-2500. and vibrates at idle as the needle can't seem to stand still. I changed the coilpack, MAS sensor (it was busted), spark plugs *NGK the cheaper ones with only one thingie that lights up" , spark leads. What now ? [/quote']

Do you mean MAF or MAS?

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Yes the mounts are ok, i changed the transmission side mount a while ago. I mean the thing that measures air volume which is connected to the intake boot http://www.corrado-teile.de/shop/store_files/1/images/product_images/thumbnail_images/10480_0.gif. I think i saw these 2 terms used for the same thing MAS and MAF or I might be wrong.

so today I checked the compression on the cilinders, 5 of them were about 11 kg/cm square and one was about 9 kg/cm square which I understand it's within spec.

I'll look at the injectors next.

I also measured fuel pressure with a gauge connected to one of the fuel lines to the right of the intake manifold and the reading were about 2.5, 3 bars . Isn't that a bit low ? I searched the net for fuel pressure regulators and found that the ones up until 95 are Bosch 3 bar and after that they change to Bosch 4 bars. What's the truth ? Remember I have the 2.9 VR, dunno if it makes any difference.

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Well you mean this software right ? http://www.034motorsport.com/images/image/tech%20articles/20vt_chip_docs/rs2_vag_com_id.png

Well isn't that connecting to the ECU and getting the codes from it ? Is there some other method that I can read the ECU ?

Sorry i'm confused. You probably mean just getting a Check Engine on the dash without actually connecting the cable on the dash to some computer ?

I did this and after an Auto Scan VagCOM showed me the MAF sensor error, after I replaced the MAF I get no other error codes.

So if the sensors are not reporting in Vag com does this mean they are good or can they still be broken ?

thanks.

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