EFI231 Fault code, P0171
 

Hi folks,

My Volvo FCR has found fault code EFI231 - Long term fuel trim part load. My OBD2 reader interprets this as fault P0171. As this fault occurs when the engine has warmed up maybe there is a fuel pressure problem?

I have no economy issues, the car goes like a rocket on rails when asked to do so by my right boot. The MAF is a new Bosch type. I have found that a pipe from the turbocharger compressor inlet routed under the dizzy lid to under the inlet manifold that seems like a bodged repair by a previous owner. As this pipe has a vacuum in it I am wondering if air is being sucked in. I performed a temporary repair until I get a new pipe ordered and also replace the dizzy lid and rotor arm (possibly causing high engine RPM misfires as they are in really rough condition) and the lambda light stayed out for a while. Back on now though! :(

Is there anything else I should look for?

Cheers

Martin
VOC 23739
'97 S70 T5 AUTO
'67 P1800S

Have you looked at this elbow?

http://volvospeed.com/Repair/vacuum_lines.php

Thanks Chris,

I checked the turbocharger end yesterday - that was OK, and I have just checked the distal end by the power steering pump as you suggested. That's OK too.

I am thinking my 'temp' repair isn't as good as I had hoped!

Cheers.

Martin Rimmer
VOC 23739
'97 S70 T5 Auto
'67 P1800S

If your hose has had any type of repair then this could suggest that it may be broken in another place, normally out of site behind the inlet manifold, in between the two elbows...
A crude but effective temporary repair is to run some 4mm samco from one to the other of the elbows, running under the fuel rail...
http://i35.photobucket.com/albums/d1...e/4c65c5f8.jpg

Thanks Jod! I will do that.

Cheers,
Martin