406 2.1 td

Hi the factory setting is 2 bar (absolute pressure) 1 bar relative (14.7 p.s. i. to 1 bar) .lots of things can cause this low pressure e.g.r. valve sticking , vacuum problems etc... if you give me more symptoms i may be able to help all the best mark... p.s. class engine mate !!!! i love these !!

Hi Mark,

A bit not in the subject, but I'm curious : it seems pretty unusual to give boost pressure as absolute, is it ? I mean, every boost pressure specs I've seen give them as relative.

Regards, G.T

Hi g.t the reason why i gave it in both measurements is if its read via the m.a.p. sensor via parameters its in absolute pressure not relative.And if its just via a boost gauge its obviously in relative .If you have no access to read parameters etc.. via a scan tool or similar just read the output from the m.a.p sensor at idle (which will be as close to 1000 m.b. as poss) note down the output voltage then at max boost this should double as a rough guide. Its not unusual to see it as absolute its just what literature you've read it from ;-) all the best mark

Hi Mark,

Ok, so I assume the sensor reports a value while ignition is on and not the engine, so the ECU can calibrate its readings ?

Quite true. Anyway when they give a pressure

Thanks for the information. As far as I can see the car is working perfectly well except for the wastegate. I don't know how to test the egr valve but nothing untoward is happening as far as I can tell. I plan to put a boost valve in the line to the wastegate and control the operation of the wastegate that way. Have you any experience of these valve or of gaining access to the turbo area without removing the engine?

Thanks, Bob.

MARK B pug m.t. via CarKB.com wrote:

Hi bob its up to you mate .... but i'd be wary of putting a boost valve on the turbo .To get to the turbo(for remove and refit say) its sub frame off im afraid not a nice job.i'm glad my fellow m.t .and i just diagnose 'em now and don't have to fit the parts!!... all the best mark