16 replies to this topic

[pezley]

Morning all, bit of advice needed. Have a nice idle on a cold start all the time the throttle is open, after a minute or so it drops to about 800rpm and blurbs up and down sounding rather bumpy. I have replaced the MAF, plugs, cleaned throttle body and checked for air leaks with a smoke machine. All come up clear. Anything anyone else can recommend?

[myles]

Fuel pump?

[Bandris11]

I would consider getting the injectors checked/cleaned with high pressure also. May be the cause...

[siztenboots]

vacuum leak , you see where the fuel pressure pipe T 's into the throttle body and another pipe joins that junction and heads down the back "Recirc" , well unplug the Recirc and cover over the T hole and it should idle smoothly. The only other vacuum taken is brake servo and the fuel tank vent.

 

 

[pezley]

vacuum leak , you see where the fuel pressure pipe T 's into the throttle body and another pipe joins that junction and heads down the back "Recirc" , well unplug the Recirc and cover over the T hole and it should idle smoothly. The only other vacuum taken is brake servo and the fuel tank vent.

 

 

 

Ah, thank you. I'll give that a try. Would the garage not have picked up on that leak when running the smoke machine through it ? 

[siztenboots]

if you have a scanguage you would expect to see around 3.5g/s on the air mass meter , and the ignition around 12°

 

also check what the water temp sensor is reading as its using this for the automatic choke adjustment

 

if the battery is low, the voltage demand will cause extra load and the ecu should compensate

 

if the AMM is unplugged it will nearly stall then pick up at a raised idle rpm.

[g1977]

Couldn't this be an EGR issue?

[techieboy]

Not on a turdo. No EGR fitted.

[siztenboots]

EGR only fitted on the base spec model

[oakmere]

The fact it only starts after a minute or so after a cold start means it is ok in open loop. But when closed loop activates a sensor is giving a bad reading. Could be the O2 sensor.

[pezley]

Can I diagnose the O2 sensor with an ODB and Torque for android ? If so I can check when I get home

[g1977]

EGR only fitted on the base spec model

 

Now now....

[Mangham54]

 

EGR only fitted on the base spec model

 

Now now....

 

 

Or as I usually call it... Peasant spec.

 

Had a VW dealer spill his coffee all over the showroom floor when I asked him to show me the Peasant spec Up!

[siztenboots]

see there is the top of the range, your turbo

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and then there is 2.2 in silver

[g1977]

Well if you guys are just disappointed you didn't get an EGR, to help with NA/Turbo relations, happy to donate this fine piece of engineering.

[thoughtless]

Pezley, did you ever get to the bottom of this? what eventually fixed your issue?

[siztenboots]

it will be air getting in after the throttle body , there should be a healthy consistent vacuum reading

 

see bottom of page ( http://www.gregsengi...cuum-gauge.html )