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maldini · Posted: Sat May 08, 2010 4:34 pm Post subject: Boxer 16v - Idle advise needed!

Im actually pleased the way the engine is running, but the Swedish MOT-staff are not impressed.

The engine was oscillating between below 2000 - slightly above 3000rpm with a steady pedal when one tries to achive 2500rpm steady idle. I've had the idle valve off, cleaning it as good as I could and the sprayed some 5-56 in it before i had it attached again.

With the engine off it's possible to hear the throttle click-noise from the switch just as the throttles are about to open, which sounds all ok. BUT, when I moved the throttle switch so that it was on all the time, it was possible to keep a steady idle at, e.g. 2500rpm. This does not feel right, but it is running normally.

However, at the MOT it failed the exhaust requirements at 2500rpm, and it had the following readings (requirement in brackets).

CO 1,9 (0,3)
Lambda 0,94 (0,97 - 1,03)

So, it's running rich, but the lamda sensor is new (original bosch), so why is that? Should it not compensate? If I disconnect the air mass meter the engine is running very rough, and almost stalls. When I disconnect the temp sensor (to the motronic) the engine stalls directly.

Any thoughts or advices?

I think the next step for me is to buy a wide band lambda sensor, so i can see what's happening when I do different kind off suff. But advices are very welcome anyhow.

evans · Alfa Arna Joined: 15 Nov 2006 Posts: 23 Location: Greece

I guess it might sound really silly as an answer, but have tried with another AFM unit?

BigAl · P4 Joined: 06 May 2003 Posts: 2995 Location: U.K Surrey

Have you checked the output from the CTS "temp sensor"?
It maybe giving an incorect output making it run rich or a steady faulty one which will make the ECU run default mode limp home run rich mode and maybe fluctuating between the 2 states.

You can also check the output from the Lambda sensor to see whats happening by using a DMM "multimeter" on the black lead, you should see about 0.45V fluctuating higher and lower, around the 0.2 - 0.8 i think.
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maldini · Posted: Thu May 13, 2010 10:24 am Post subject:

maldini · Posted: Thu May 13, 2010 10:59 am Post subject:

BigAl · P4 Joined: 06 May 2003 Posts: 2995 Location: U.K Surrey

Hi maldini Smile

,
C = Coolant, have a look at this for correct CTS readings
http://www.alfa-restoration.co.uk/jetronic/tempsender.html

The Lambda sensor has 1 black wire, the signal and 2 white wires, the 12v to heat it up. Just peel back the rubber cover on the black wire, attach the + from your DMM and the - to the battery.
Do you get the problem when the engine is cold?
Have you tried with the lambda sensor disconnected?

I have used that description, it is quite good Smile

What is the history on the car, how long have you had it, any problems before, what year is it, does it have a cat, what are the emission laws in your country, have any mods been done, like the 5 min AFM mod, that will make it run rich.
20 questions over Smile

Maybe some history and some pics in the introduce youself could clear up a few things Smile

Welcome BTW
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x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

lee16v · Posted: Thu May 13, 2010 2:19 pm Post subject:

A related question to this.......
When is the TPS supposed to 'click'? On mine it's just after the throttle starts to open. Are you meant to have it set up so that the TPS opens before the throttle or is mine normal?

Admin · Posted: Fri May 14, 2010 12:19 pm Post subject:

Hi

From memory the TPS has 3 positions, the first of which is under 5 degrees of throttle opening.

All the best

Keith
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lee16v · Posted: Sun May 16, 2010 3:29 pm Post subject:

Cheers Keith. Would seem as if mine is working ok then. Should there be an audible click on all three positions then? As I can only hear it on the first.

bobbber · Posted: Wed May 19, 2010 10:42 pm Post subject:

Lee, three positions, so should be two clicks.

From idle (switch in idle position). Slight bit of throttle, the butterflies move a bit and then the first click (switch in open throttle position). Continue to open the throttle and just before it hits the bump stops, second click (switch in full throttle position).

Any further questions, please ask! I'll explain the entire thing at spa. Three months I spent reading the bloody documentation on the 33 injection system... think I *just* about understand it now! Laughing

The series III documents are very Alfa garage orientated, where they understand all this stuff already. The series II injection supplement has all the information (and explanations) you need. Remind me to bring you a copy in exchange for the rubber

aid pipes you promised Wink

BTW... Keith, when I put

, it comes out as kittens! Laughing

B
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lee16v · Posted: Thu May 20, 2010 5:13 am Post subject:

Cheers for the info dude. I don't seem to have the full throttle click then...... Confused

The rubber s e x pipes are all cut and ready for insertion!! Laughing

Admin · Posted: Fri Jun 04, 2010 3:38 pm Post subject: