Got a mates 9-3 Turbo on the drive B204E engine just failed its mot on emissions , not showing any fault codes. High 02 readings and from obd2 diagnostics last night we are showing a high long term fuel trim (15%) so short story is its overfueling.

Its had a new o2 sensor and cat, New thermostat and new fuel pump and fuel pressure sensor + all new silicon vacumn hoses recently.

It now passes emissions at idle but not at Fast idle – still a few % too high

It is popping on overrun , and hunting at idle. But other than that it pulls like a train and drives grand.

I am fair certain its going to be an air leak between the MAP and the turbo OR a faulty MAP leading(but i think this would throw a code) to overcompensation with fuel.

Im struggling to convince him though – anything i can do that will pin point it to that area. – all my petrol engine tinkering comes in the form of N/A Carb engines.

OR on the other hand any other ideas for where to look for a fault on this engine.

EDIT * ARRRRGG Wrong forum. Can you move it please mods ?

wrong forum indeed – try saabscene, full of saab geeks. Nothing to do with volvos though…

will do , i had a google round some saab forums but by large all they were talking about was getting more power from their engine and moaping about saab shutting its doors….

If its over fueling it could be because it still thinks its in cold start. I would check the temperature sender as if its fault it may be sending a signal to the ecu saying the coolant temp is at -20 degrees so stay in cold start. The sender may not be the same as the one for the gauge.
I had thi on an old 900 turbo, it was just corrosion on the connector but caused high resistance and same problem.

Ncb. Cheers for the turner you sold my mate i had to build it for him – it lovely

The sender appears to work fine . Fine on theresistance and the eobd reader is showin the corresponding coolent temp to what it should be/what the gauge says

email andy on brookesaab@gmail.com

day time only

Take it to a specialist with the SAAB specific diagnostic tool. Plenty of fault codes go unread with a generic fault reader.

/voice of experience

Was tech2 we were using johnnystorm

Issue was pin pointed last night.

Leak in the joint in exhaust right before the lambda. Only visible with soapy water but plain to see when you did.

good when that happens – when it all makes sense. Previous Saab 900 had a bizarre loss of power, at top end, turns out there was a crack in the air intake hose, only visible when hose was fully inflated..

Do a GT test, spray silicone spray on the hoses to see if its sucking in air. my alfa failed on emissions turned out it was sucking in air after the MAF

Ah right, glad you were using a Tech2. Went on a right wild goose chase with mine. Not helped by main dealer giving duff advice too.