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Rob Currie
Alfa Arna
Joined: 29 Sep 2003
Posts: 5
Location: Irene, South Africa
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 Posted: Mon Sep 29, 2003 7:47 am Post subject: Bosch ML4.1 diagnosis |
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I have a 33 1.7 16v with the ML4.1 injection system. The engine is running very rich at idle and often stalls when lifting off the throttle and coming to a stop. I bought the car new in 1994 and the dealer supplied the car with the catalytic converter removed as we did not have unleaded fuel yet in South Africa. I haven't checked whether the Lambda sensor was replaced but I presume it was. The car ran fine for many years but recently it has been stalling. It seems like the engine temperature sensor is working because there is a definite point when the engine seems to 'come on song' when it has warmed up for about 5 minutes. I have downloaded the info on the self diagnosis testing and I proceeded to make the tester and connect it up. My problem is that when I connect it the diode immediately comes on. I tried closing the switch for 5 seconds as per instructions thinking that this first event wasn't mentioned in the text, but nothing happens - the diode just stays on. The only way I can get the diode to go off is if I start the engine. The ECU Bosch part no. is 0261 200 142. Is there maybe a different test procedure or is the unit bust?
Forza Ferrari 
Rob Currie |
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graeme
Alfasud
Joined: 16 Mar 2003
Posts: 64
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| Posted: Mon Sep 29, 2003 6:17 pm Post subject: Motronic |
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I've found that rather that closing the switch for 5 seconds, I count to ten and it works.
_________________
16v p4 In pieces. |
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Guest
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| Posted: Mon Sep 29, 2003 6:59 pm Post subject: |
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I've tried closing the switch for 5 sec, 10 sec 20 sec,.... I held the switch closed while switching on the ignition. I pulsed the switch. I tapped out Ave Maria in morse code on the switch. I wired it to my Hi-fi and played the Italian National Anthem followed by the German National Anthem to it, but the diode refuses to blink. The only thing left to do now is wire a pentolite booster into the system 
I think I will pay a visit to my mate at Dastek (he invented the Unichip).
I'll report back on his advice.
Rob |
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Scott Sander
Alfa 33
Joined: 20 Feb 2003
Posts: 419
Location: Sydney, Australia
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| Posted: Tue Sep 30, 2003 12:32 am Post subject: |
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Rob,
Check that the tester has been built correctly. Correct pin out and LED around the right way.
_________________
Scott Sander
'91 Alfa 33 Boxer 16V Monza - Awesome
http://www.sanderfamily.com |
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John w 33 16v
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| Posted: Mon Oct 06, 2003 6:56 pm Post subject: ML4.1 |
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Hi,
I think that your lambda probe is dead.
If you can get the fault code device working, it will probably give the code for 'Lambda reaches maximum/minimum' etc.
I put a cheapo Lambda in my car when doing major overhaul work 2 years ago which I thought was ok. It never really ran sweet especially when hot and had an intermitant flatspot.
I got the lambda fault code off the car, and so decided to change the lambda for a pucka BOSCH item.
WOW!!!- The car is like a different machine, no flatspot, smooth idle, more responsive etc etc.
Don't get the lambda from Alfa as they'll charge you about £100. Get it from a Bosch supplier (part no I THINK is 0258003060). Mine cost £59 from Allparts who are a trade cash/carry type place.
Cheers
John '93 33 16v |
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