Technical Car Problem Diagnosed by Fiat Dealer - Can't be Right!

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Technical Car Problem Diagnosed by Fiat Dealer - Can't be Right!

Re: Oil Pressure Warning Fiat Stilo 1.8 16v

I always understood that pre and post cat. Lambda sensors were referred to as Sensor 1 and Sensor 2 in fault code descriptions, and Bank 1 and Bank 2 referred to each side of a "V" engine, as with these generic examples:

P0130 O2 Sensor Circuit Malfunction (Bank 1 Sensor 1)
P0136 O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)
P0150 O2 Sensor Circuit Malfunction (Bank 2 Sensor 1)
P0156 O2 Sensor Circuit Malfunction (Bank 2 Sensor 2)

Does the 1.8 engine have a dual manicat?...... That would require 2 pre and 2 post cat. Lambda sensors. Perhaps they are referred to as Bank 1 and Bank 2 for the 1.8 engine.

Well that makes sense. Now you have me confused.

Perhaps its just depends on the diagnostic software being used, language translation perhaps .. ?
 
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Re: Oil Pressure Warning Fiat Stilo 1.8 16v

It seems the 1.8 does have a dual manicat, but just to confuse it even further, it has 2 pre and 1 post cat Lambda sensors. :confused:
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Re: Oil Pressure Warning Fiat Stilo 1.8 16v

It seems the 1.8 does have a dual manicat, but just to confuse it even further, it has 2 pre and 1 post cat Lambda sensors. :confused:
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So failure of "BANK 1 SENSOR 2" lambda on a 1.8 Stilo would be the pre-cat Lambda sensor that is closest to cylinder 4(as sensor 1 is closest to cylinder 1) ?

And failure of "BANK 2 SENSOR 1" would be the post-cat Lambda ?

It would appear the "BANK/SENSOR" relationship varies depending on the engine design.
 
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Re: Oil Pressure Warning Fiat Stilo 1.8 16v

So failure of "BANK 1 SENSOR 2" lambda on a 1.8 Stilo would be the pre-cat Lambda sensor that is closest to cylinder 4(as sensor 1 is closest to cylinder 1) ?

And failure of "BANK 2 SENSOR 1" would be the post-cat Lambda ?

It would appear the the "BANK/SENSOR" relationship varies depending on the engine design.

I would interpret "BANK 1 SENSOR 2" as the left hand (closest to no 1 cylinder) post cat. sensor (the only post cat. sensor on the 1.8 engine) and "BANK 2 SENSOR 1" as the right hand pre cat. sensor.

http://www.obd-codes.com/faq/what-is-bank-1-and-bank-2.php
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Re: Oil Pressure Warning Fiat Stilo 1.8 16v

I would interpret "BANK 1 SENSOR 2" as the left hand (closest to no 1 cylinder) post cat. sensor (the only post cat. sensor on the 1.8 engine) and "BANK 2 SENSOR 1" as the right hand pre cat. sensor.

http://www.obd-codes.com/faq/what-is-bank-1-and-bank-2.php
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But that link is referring to a "V" engine design, not the normal straight design.

BANK 1 being the side of the "V" that has cylinder 1 and BANK 2 being the opposite side of the "V" ..

Now I'm really confused .. :ROFLMAO:

So, the 1.8 Stilo for example has 2 Catalytic Converters and as a result has 2 Pre-Cat Lambda but only 1 Post-Cat Lambda.

In this case(straight engine design) BANKs 1-2 must mean Pre and Post Cat due to there being multiple sensors before and after the Cat.

But for a "V" design BANKs 1-2 must relate to either side of the "V", I'm guessing that's because a "V" design engine doesn't have multiple Lambda before or after each Cat ?
 
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Re: Oil Pressure Warning Fiat Stilo 1.8 16v

But that link is referring to a "V" engine design, not the normal straight design.

BANK 1 being the side of the "V" that has cylinder 1 and BANK 2 being the opposite side of the "V" ..

Correct, but I believe that in the unusual case of a dual cat. on an inline engine, BANK 1 and BANK 2 refer to each of those two cats.

So, the 1.8 Stilo for example has 2 Catalytic Converters and as a result has 2 Pre-Cat Lambda but only 1 Post-Cat Lambda.?

Correct. (y)

In this case(straight engine design) BANKs 1-2 must mean Pre and Post Cat due to there being multiple sensors before and after the Cat.

No... I believe that BANK always refers to one side of the engine, or in the case of a dual cat system fitted to an inline engine, to one of the two cats. It never refers to an individual sensor, i.e. front centre or rear.

But for a "V" design BANKs 1-2 must relate to either side of the "V", I'm guessing that's because a "V" design engine doesn't have multiple Lambda before or after each Cat ?

Yes... BANKs 1 & 2 (usually) relate to either side of the "V", but it's because a "V" engine has two seperate exhaust systems (one each side) and, therefore two seperate pre and post cats in each system.

For example, generic codes:

P0142 O2 Sensor Circuit Malfunction (Bank 1 Sensor 3)
P0162 O2 Sensor Circuit Malfunction (Bank 2 Sensor 3)

refer to Sensor 3. No engine (other than a radial engine) is going to have more than two banks of cylinders. Therefore Sensor 1, 2 and 3 can only refer to a sensor's numerical position along the pipe.
 
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Re: Oil Pressure Warning Fiat Stilo 1.8 16v

but it's because a "V" engine has two seperate exhaust systems (one each side) and, therefore two seperate pre and post cats in each system.

I've just spoke to a friend who's son is a mechanic, he said:

BANK = Exhaust

A "V" engine can have twin or single exhaust.

For example an old Rover SDI(V8 single exhaust) and lets say it has a fault, BANK 1 SENSOR 3 that would refer to a fault on the 3rd Lamdba Sensor downstream of the engine. Because there are 2 Cat's in a single exhaust system there's the usual Pre and Post Lambda's plus another located between the Cat's. So 1 exhaust, 2 Cat's and 3 Lambda's.

If as you say:

BANK = Side of "V" engine.

What would the fault code be if the same 3rd sensor failed when the "V" engine has a single exhaust?

So my guess is my friends son is correct but I'm still not 100% sure . :shrug:

The only thing I am sure of is that BANK doesn't mean Sensor .

Edit.
I've just been looking at a few V8 exhaust systems to see if it would help.

A single exhaust for a V8 can have 2 Cat's and 4 Lambda Sensors ... :confused:
 
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Re: Oil Pressure Warning Fiat Stilo 1.8 16v

Perhaps I should have said a "V" engine has two seperate exhaust manifolds. Which in the case of the Rover SDI, and some other V8 engines can join together under the car into one exhaust pipe and silencer(s).

As the car has no cat(s) mounted in the individual manifolds, (I can't remember whether the SDI had a cat in it's single under car exhaust pipe even) then all Lambda sensors would be referred to as bank 1 for the purposes of fault code descriptions.
 
Thanks everyone for the replys, I have built a computer inside my Stilo, and it is connected to the ECU, now I can have loads of information about what's happening to my car.

Ok So took the car on the motorway and find out something weird with the MAF sensor. Before getting on the motorway, on my 2 gear, 1/4 throttle, My MAF is reading 40g/s is that possible? And while driving and getting even Larger number.

See picture for more information. Some things don't add up. I thought at Full throttle you should only get max 8g/s.

I have also attached the Excel Doc

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theyre tracing your throttle position sensor readings quite closely i wouldnt worry about it... do you have a specific map sensor/fueling issue or just the Lambda fault?
 
P0170 is still fuel trim error also but in Bank 1 (where we would expect to see it on an inline engine)... HERE

Potential causes include a vacuum leak, unmetered air leaks Fuel saturated engine oil Leak in turbo air charge hoses (if equipped) Possibly bad O2 sensor (If Mercedes, may require adaptation with M-Benz compatible scan tool.) Oil contamination in MAF connector or O2 sensor connectors. Also check ignition coils, cam and crank sensors, and oil sensor for leakage contributing to oil intrusion in wiring harness. Defective MAF (Mass Air Flow) sensor (especially on Mercedez-Benz and other European autos.)

im a little stumped as to what it could be... all your sensor traces seem good. MAF values can be anywhere from 3 g/sec - 90 g/sec.

whats your trim values?
 
I'm posting back following the cutting off problem, The car hasn't been cutting off that much with the cold weather , when as the temperature gets higher , the cut off more often. I've uploaded a video , you can see the problem more in details. Its been a year now with the same problem no one seems to know what it is, including fiat dealers! Someone told me the maf should stay over 3.5gs but when the car idles bad its around 2.8 - 3.4gs . Is that something normal?

https://www.youtube.com/watch?v=xTA0Q3KOiYk&feature=youtube_gdata_player
 
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