Alfa Pages

[paulhide]

Thanassis knows his stuff.
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Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188

[Dr A. 33 1.5IE]

Hello everyone,

News update... with a friend of a friend we decided first of all to check the continuity of the lambda sensor cables just to find out that the wiring is just fine (for your info by sorting the lambda's sender wires the sort could be read by the pins 7 and 24 on the ECU connector... if anyone wants to repeat a similar testing please remone the black wire from the battery to avoid damaging the ECU).

Then and after warming up the car to running temp we meassured the voltage of the lambda sender which when cold the voltage read staedily 4.5 volts and as soon as it was warming up started to drop and all of a sudden it started to fluctuate between 0.5 and 8 volts continuously. Thus the lambda sensor already changed with a new one three weeks ago has to be replaced once again (more money to spend).

To be sure about it we also tried another idea that is to fool the ECU. Knowing that the lambda draws when fylly warmed up and in operation 1.5 volts, using a few resistors and a 1.5volt AAA battery, plus an old lambda sender connector we created a little circuit that through the car's battery was giving out 1.5 volts and what a miracle the car run as it should!!!

Anyway I hope it works this time. The little circuit did.

Another question I have for you though is someone dropped the idea of keeping the lambda sensor but droping the catalyst at least until the next MOT in two years time from now. What do you think about it? Does anyone has got rid of the cat and still the car goes through a MOT without a problem?

Chears once again!
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

[gritsop]

Hi,

Just a few notes here.

L sensor reads about ~ 0.45V on idle. The voltage fluctuates when the revs are high and should have a range from as low as 0.2V to as high as 0.8 V as the sensor understands that the gases are either coming from a lean or a rich mixture. The voltage doesnt exceed 1 V no matter what otherwise the mixture is very rich, thus no combustion can take place.

I dont get the idea with the battery. The L sensor has two connectors

1. Black connector which is always 12 V at the terminals in order to drive the preheating device
2. single connector which feeds the ECU with data.

Did you have constant power to the heating device and then "play around" with the battery and the resistors in order to fool the ECU? (actually play the role of fluctuating between 0.2 and 0.8 V)

Did you see voltage above 1 V as I am getting confused about that.

The catalyst shouldnt be removed. Unburnt aromatic hydrocarbons are the cause of carcinogenesis that the catalyst converts to harmless substances, so it is not a good idea to do so.

Regards,
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Thanassis Gritsopoulos
1991 Alfa 33 1.4 IE
2001 Alfa 147 1.6 Distinctive

http://www.alfa-restoration.co.uk
Parts Shop: www.alfa-restoration.co.uk/shop

[Dr A. 33 1.5IE]

Dear Thanassis,

You are correct ... the voltage values were actually 0.45V on idle and 0.15V when fooling the ECU that the lambda runs properly. Actually the lambda does fluctuates between 0.2 and sometimes 1V on most cars but a new lambda should have minimal deviations from 0.15-0.2V.

Anyway I should have the new lambda and cat installed later this week so I should be back with an update.

Thanks
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

[Dr A. 33 1.5IE]

Dear friends,

The fight to sort out my Alfa has come to an end with the problem still remaining.

The car spent the last two months at the garage, a hell of a lot of things were changed and tested but the mechanic has not found the cause of my problems.

As a last and desperate measure asking for your help, I repeat the issues that the car develops.

Under acceleration the car in all gears (at a lesser extent in 5th gear on a motorway) develops some cuts in power as if one moment the power is on and the next moment you can feel and hear the engine holding back a bit. Also under full acceleration the car revs a bit slower towards the rev limiter although the engine sounds alright. In addition on a motorway with 5th gear, before the problem appeared, flooring the gas pedal gave the car decent acceleration getting easily above 140kms/hr (even up hill). Now on the straight it takes ages to get up to speed and uphill the engine note changes but the speedometer stays stuck at the current speed (with a very little tendency to increase the current speed). All these get a bit better with the aircon off.

And still we could not find the cause of this loss in power.

What could it be my friends?

Thanks once more for your time...
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

[gritsop]

If I remeber correctly your 33 is distributorless, correct? There is a sensor on the flywheel that reads crankshaft position and feeds the data to the ECU. Since you tell that the car does not pick up under acceleration it looks like it is out of timing. Since timing is adjusted from this sensor then focus on it.

Morever there is a chance the problem lies on air leaks. There is a gasket right below the intake manifold. Again if this gasket is by any reason cracked or falling apart false air will disturb correct running.



It is a long shot but worth mentioning

Regards
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Thanassis Gritsopoulos
1991 Alfa 33 1.4 IE
2001 Alfa 147 1.6 Distinctive

http://www.alfa-restoration.co.uk
Parts Shop: www.alfa-restoration.co.uk/shop

[gritsop]

Any progress on the issue?

Regards,
_________________
Thanassis Gritsopoulos
1991 Alfa 33 1.4 IE
2001 Alfa 147 1.6 Distinctive

http://www.alfa-restoration.co.uk
Parts Shop: www.alfa-restoration.co.uk/shop

[Dr A. 33 1.5IE]

Dear Thanassis,

Nothing has been changed. The last thing that I checked was the ecu relay next to the fuel pump relay. When I opened the metal cover on top of the coil there was a melted plastic piece that half of it fell off. I removed the rest very carefully and the only changed on car's behaviour was that the power cuts are still there but shorter in time.

Changing that relay which proved burned out the only thing I have managed to find out was that this drop of plastic melted on the relay's coil is there intentionally to hold the coil's wire in place!

Anyway I do not know what to do. Finally a couple of days ago I managed to find the relay responsible for the fuel settings. Mine is a Black colored relay sitting on a brown base. Next to it is another relay grey in color. The funny thing is that all three relays do have the S30 code under there casing.
Removing those relays improved the hicups a little.

I am really desperate to sort it out but at the same time as it runs relatively well and it starts at least everyday, I will just live with it until i get a new car (meaning when I will win the lotto!!!)

Any ideas are welcomed.

By the way the gaskets under the manifolds have been replaced. It does not looks like an air leak... I think!

Chears my friend
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)

[33bits]

One of the most common parts i sell on the series 3 33 is the fuel pump, very common part to break, i think its always worth fitting a new one just to have peace of mind. Someone i know has a few new ones for sale at £35 each.
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155 sportpack
33 16v Sportwagon
33 Permanent 4
33 16v (for sale)
156 JTS sportwagon
contact me for any 33 parts. Alex, 07896-327708

[Dr A. 33 1.5IE]

33bits thanks for your message.

I have already installed a much newer fuel pump and fuel pressures checked.

I do not know what else to check!!!
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1994 Alfa 33 1.5 IE Cat. 220.000Kms and still going strong!!! (Από την Αθήνα και τώρα στην Λευκωσία)