First day back and the Gti fails me (management fault)

[CIarkie]

Need a push in the right direction or a thread link on the following fault (i searched with no luck):

Have recently fitted a new Cat and front pipe to my ABF mk2 and during this period have removed the air inlet mainfold and all associated vacuum hoses and sensory clips. I have driven the car 50 miles since putting back together and this morning it seems my ecu is in a 'safe mode'.

The rev limit has dropped to around 1400 rpm and wont go any higher just bounces off, and by the smells of things its running rich. I take it my engine work has caused this but the delayed fault has puzzled me.

Been thinking vacuum hoses, maybe disconnecting battery or a faulty sensor, hopefully someone has experienced this. Opinions much appreciated. The light obviously is long gone and i have time to try something before tomorrow comes.

 

[m0rk]

There is no safe mode.... more likely you've not plugged something in properly & it's vibrated loose

 

[CIarkie]

Would this occuring bring a fault readable using the computer? and also could the lambda sensor, or a new cat cause a fault like this.

Thanks for the reply, it was mention that removing the vacuum hoses could cause issues and maybe a reset/disconnection of a battery maybe required or also a back pressure change in the exhaust could muck things up.

 

[m0rk]

it's possible it showed a fault if you have vag-com

well worth checking all the connections though - my money is on vacuum or throttle sensor

 

[CIarkie]

OKay have checked all connections and everything seems perfect. I was thinking lambda sensor or maybe the air flow sensor as the mixture and engine running is all over the place. Not up to knowledge on the throttle sensor.

 

[robreidmotors]

Did you replace all the gaskets and clean the surfaces?

Also you will need to disconnect battery to reset the ecu as when you take off the throttle body it takes a little time for it to allign itself apparently. It might be possible in this allignment period for the plugs to get soiled so may be worth 1. disconnecting battery then 2. clean plugs.

Also maybe the lambda sensor was not connected properly?, and if using old one in your new pipes you need a special sealant.

 

[CIarkie]

Quick update for future searchers

With the help of a very knowledgeable friend and his VW software i was able to run the computer through the car. The fault which caused the problem is no signal (intermittant) from the air inlet manifold sensor.

Reset the codes and even disconnected the battery for 10 minutes to reset everything but the fault only cleared for about 30 minutes before raising its head and preventing rpm above 1400. So new sensor will be ordered, until then no ibiza and back in my girlfirends little Saxo.

Cheers for the technical help and a point in the right direction

 

[robreidmotors]

Hope it works.

As its been running rich its a good idea to clean the spark plugs when its put right, and maybe stick some fuel treatment in the tank and quick spray of throttle body cleaner in the tb. Then all should be nicely nicely.

And it can seem to take a day or so for the ecu to relearn things, i found that after getting my cambelt done and timing redone, then resetting by battery disconnection.