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Discussion Starter #1
Hi guys,

Please could you tell me what problems does a faulty lambda sensor cause and can Bosch lambda sensors be used on an alfa 147 selespeed? My mech says that he thinks we have faulty lambda sensors so I am looking for the cheapest option if possible, such as can it be changed ourselves (and by ourselves I mean by my hubby whilst I watch over him) :lol:

Also we seem to have a problem with our 3rd gear. Changes from 2nd to 3rd and 3rd to fourth can be heard very loudly! Mech says that this means the "sincrow" (please accuse my spelling as I am spelling it based on how it sounded to me) is on it's way out and we have approx 6months before we lose 3rd gear.

So is this something that we can also buy and change ourselves? The problem is that Chris is very busy and we cant aford to be without the car for 2 or 3 days at a time and I feel like if we can start doing the basics on the car then it will make us feel a lot better about being Alfa Owners.


Twice we had to have the car towed to Chris for the most basic of things and now we have absolutely no free tows from our insurance for another 10 months! That was The first time was a burst water pipe and the second time was that they had not connected the airflow "thing" correctly.

Thanks in advance guys.
 

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You do get a universal type lambda sensor from NGK, Bosch and Denso. You need to know what type your car has. Normal or wide band and this is done by checking if it is a 3, 4 or 5 wire sensor. Buy the same type, but the plug connector will be wrong, so carefully check the wiring to connect it correctly to your existing plug.

The sincro ring will have to be fitted by a gearbox specialist.
 

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Vana the easiest is to get a OE Lambda especially if you want to do it yourself and the 147 use more than one so which one is failing?
As for the synchromesh on 3rd that’s not a diy job and will unfortunately take more than a day or two to fix. You have to remove the gearbox disassemble it replace the synchromesh reassemble and refit the gearbox. After that the selle will need calibration.
 

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Discussion Starter #6
Thanks for the advice Turbonutters. I am not sure which Lambda sensor needs replacing. Any idea on what the price would be to price replace all? I believe there are four in total or am I mistaken? The only thing I know is that Chris mentioned something about one on or near the exhaust being faulty and is the reason why the exhaust is blowing out blue smoke and our fuel consumption seems to be a bit high. Been a hectic few days so once I go on leave hubby will have some time to sort out the car.
 

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I will start with the ones on the manifold the others do not change the fueling.
I will advise that you get old 145, 155 or early 156 2.0 manifold and downpipe to replace the rubbish cat manifold. The cat Manifolds crack and get blocked which will cause a lot of problems.
The lambdas will not cause blowing out unless it’s not screwed in properly. A leaking manifold will also influence consumption and could result in burned valves. Lambdas only work in closed loop situations typically on part throttle as soon as you give it a lot of stick the ecu ignores it.
You might need a bit more diagnostic testing on the car.
 

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Discussion Starter #8
I think I do need to do more diagnostic testing on the car as Chris recently told me that he replaced the manifold. It does not smoke all the time but every now and then it does. More especially when starting up. Yesterday when I got to work, just as I pulled into my parking spot, large clouds of smoke were coming out. I had only pushed it to a max of 140km for a few minutes just to overtake another vehicle but had kept to a constant of about 110km on the freeway. I have been back to Chris four or five times already to try and figure out what is going on but he insists that we have nothing to worry about. I will go to him this weekend to sort out this Lambda sensor story and to run diagnostics on my car.

I will check the fuel consumption again. Maybe it has been corrected after the manifold was changed. Hubby had been using the car since it was last at Chris (replacing the manifold) and I only started driving it since yesterday so I cant be sure of how the fuel consumption is at the moment.

Once I get a more detailed report from Chris I will post it here.
 

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The smoke could be old oil and rubbish in the exhaust. Did he replace the manifold with another 147 unit? A bit of spirited driving will heat it up and cause smoke. Just a little something I have experienced on old systems. Rubbish in the cats will also mess around with the Lambda readings.
 

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Discussion Starter #10
The smoke could be old oil and rubbish in the exhaust. Did he replace the manifold with another 147 unit? A bit of spirited driving will heat it up and cause smoke. Just a little something I have experienced on old systems. Rubbish in the cats will also mess around with the Lambda readings.
That sounds like it could be the answer. Will confirm this when we speak to him tomorrow. Thanks so much for always giving me such useful advice Turbo.

I do have one more question. Hubby keeps asking me to findout if our car can be dyno tuned and what do we need to do for this?

Right now we have done nothing for the body, we are focused on getting everything on the mechanical side sorted out.
 

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If you want to dyno it you will need a Unichip or someone who can reflash it.
 

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Discussion Starter #12
I am not to keen on putting in a chip as I heard it can cause problems with the car's "computer". What does reflash mean?
 

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With a re Flach they change the program in the management system. A uni will not damage the car if installed and set up properly.
 

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Vana what TN is saying, is the std management is not adjustable and therefor a dyno tune does not have any value. By fitting a Unichip it makes the std management adjustable. This helps when there were changes made to the car that the management can not adjust to automatically and is mainly changes to timing and fueling.

It is not always a solution as the Alfa management is a partly closed loop setup. What this means that at low revs and low throttle openings the the system can not be adjusted, not even with a chip fitted. As in this range(loop) the lambda sensor determine the parameters of how much fuel is to be delivered. Above this the management's "map" can be adjusted by a Unichip on a dyno tune. But that will not solve the lambda sensor issues or economy while cruising. For this reason my GTV is very heavy on fuel in town but good when cruising at high speed.

For interest sake, the management of the 3.2 GTVs and GTAs are supposed to fully closed loop according to the technical specification. But there are still power gains with a Unichip after a better air filter and de-cat/exhaust.
 

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They can not map fueling in closed loop but timing is another story. All you need is an experienced person doing the mapping.

The Alfa ecu can be remapped but unfortunately not by the local shops.
Bottom line the best you can do is making sure that all sensors are perfect then the car will set itself to the best possible settings.
 

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Discussion Starter #16
Thanks a lot for the explainations guys. It worried me because my mech had very clear instructions. He would never work on our car if we ever used anybody else and if we had the car "chipped".

Anyways I have a much better understanding. Have not managed to check my lambda sensors, I think Chris is closed already.

When Lambda sensors are faulty can it be picked up when a running diagnostics on the car? I am still working so can only start sorting things out when I go on leave after the 22nd.

Also just thought I should mention that I have not see any ore smoke in the past couple of days.
 

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Good the smoke was possibly caused by old rubbish in the cats.
Yes diagnostics will pick up the Faulty lambda. The rubbish in the cat could have unsettled the lambda so for all we know it’s happy again.
I agree with your Mec. It is bad to jump around and let other people work on a car since he knows the history.
 
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