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Hey guys and gals!

New to this thread but love it so much!! so much help and love for enthusiasts here!

my problem is engine codes on drivers bank. rough idle, rough running.

So far ruled out coil packs swapped them and put new ones on.

spark plugs are new

Injectors were sent out had #8 ,#7 ,#6 ,#5 fail. after ceaning and static test #8 needs replacing the rest are good to go.

I played swap the injector with good ones but still a miss on #8 ,#7 ,#5 .

please help me here!!

1)Fuel pump that runs that bank??
2)Cam variators??
3)Plugged Cadillac converter??

at a loss here
 

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1.) look at the fuel trims
2.) not likely
3.) a Cadillac converter? Really? I'm gonna assume it was trivia night with 4 buck pitchers at the local tavern here..? Jason
 

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I read a fee replys regarding cam timing? Also can a fuel rail fail? looks fool proof to me?


Really trying to avoid the dealer here but am not opposed to them if there Maserati specific equipment can help narrow it down
 

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@Jason haha thank you so much for your response! I feel like you are the expert around these parts!!

1) How can i look at fuel trims? dealer specific computer?

2) sometimes a rattle when cold but not loud at all.

3) catalytic converter haha sorry about spelling. I had issues on ford trucks with Cats plugging up and causing these issues.
 

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@Jason 1) is there a better scanner i can buy to allow me to see the fuel trims?


2) so i assume A plugged cat would not throw miss fire codes on these types of engines? I did assume if it was plugged that the whole bank would be throwing codes.
 

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You should be able to see it with any generic OBD2 scanner....Go into the data stream..Compare bank 1 and 2...I would remove upstream O2 sensor on that bank and see if it runs better....Jason
 

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Fuel trim is the balance between gas and air maintained by the ECU. If it is different between the two banks, the most likely cause is a faulty O2 sensor. There are both left and right upstream and downstream sensors. The upstream O2 occurs before the catalytic converter, while the downstream one is after. The upstream one should have fairly quickly changing reading while the other should be changing much more slowly.

To see if it is a failing converter or an O2 sensor failure, a rough check can be done using an infrared thermometer: after the car is warmed up and running, the pipe immediately downstream from the converter should be hotter than the pipe coming from the engine and leading into the converter. If this is the case, your converter is good and you are likely needing to replace the downstream O2 sensor, which have a higher propensity to failure than do the upstream ones.
 

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Fuel trim is the balance between gas and air maintained by the ECU. If it is different between the two banks, the most likely cause is a faulty O2 sensor. There are both left and right upstream and downstream sensors. The upstream O2 occurs before the catalytic converter, while the downstream one is after. The upstream one should have fairly quickly changing reading while the other should be changing much more slowly.

To see if it is a failing converter or an O2 sensor failure, a rough check can be done using an infrared thermometer: after the car is warmed up and running, the pipe immediately downstream from the converter should be hotter than the pipe coming from the engine and leading into the converter. If this is the case, your converter is good and you are likely needing to replace the downstream O2 sensor, which have a higher propensity to failure than do the upstream ones.

I learn a lot from you...Fuel trim that is different between the two banks is mostly caused by an O2 sensor? How about a vacuum leak just on that bank? I have never heard of checking an O2 sensor with a temp gun...Just keep going...I need some more entertainment.....Jason
 

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There are lots of videos on how to do this:

It is one of the few ways to test the catalytic converter with basic tools. I'm glad you're entertained! :)
 

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Thank you for the tip...Here is one for you...The upstream O2 sensor goes bad way more often than a downstream because it is subjected to higher temperatures..I'm sure you knew that? Keep keyboard banging and googling stuff...I still trying to get past your higher tire pressures wear out wheel bearings...It's a long weekend, please don't disappoint with all these internet theories.:thumbsup:...J
 

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There are lots of videos on how to do this: https://www.youtube.com/watch?v=wrNtn3MkwG8

It is one of the few ways to test the catalytic converter with basic tools. I'm glad you're entertained! :)

I'm pretty sure you replace a lot of catalytic converters from the comfort of your keyboard.. For the record, using a temp gun to determine a bad catalytic is pretty inaccurate...You knew that? Maybe you should write a Youtube review of the video you shared? J
 

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I believe the primary 02 sensors (prior to cat-converter) are what the ECU references when setting the fuel trim levels. The secondary 02 Sensors (after cat-converter) mainly let the ECU know that the cat-converters are working properly.
 

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I'm pretty sure you replace a lot of catalytic converters from the comfort of your keyboard.. For the record, using a temp gun to determine a bad catalytic is pretty inaccurate...You knew that? Maybe you should write a Youtube review of the video you shared? J
Yes of course, it only gives you a rough indication, but it is one of the few ways you can get an idea if you don't have the proper scan tools. Maybe you should review a video on forum etiquette?
 
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