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Using Individual Fuel Correction - AFR variation between banks on V8


Ian C
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Hi,

 

I am in the early stages of setting up a 1UZ in a kit car and have noticed an imbalance between the wide band Lambda sensors in the two exhausts and would like to know whether this would be considered a problem.  The difference varies between 2 & 5% at idle and generally decreases as the RPM rises, the engine is currently running on a base map supplied when the Link Storm was purchased.

 

The injectors were flow tested before fitting and were position to equalise the flow between the two banks of cylinders.  I initially suspected an air leak but fitting new seals and spraying round the injectors with Easy Start when running have eliminated this possibility.  The sensors are monitored by an Innovate DLG-1, with the additional LC-2 for the second sensor, the wiring & sensors have been swapped between sides but the difference stays consistent with the even bank (Lambda 1 on the log) running leaner than the odd bank.

 

I am considering using the Individual Cylinder Fuel Correction option in Table mode and setting a correction table for use on cylinders #2, 4, 6 & 8 (which are running leaner than the odd cylinder bank).

 

Does this seem like a reasonable option and can I confirm the that the number in the table is a percentage correction to the fuelling.  Log of run after fitting new seals and current map attached.

 

As always any suggestions or advice gratefully received

 

Regards,

Ian

https://drive.google.com/file/d/1JdBsdyr4qAmCpfMDGqpVpKJs4047ej6-/view?usp=sharing

 

https://drive.google.com/file/d/1VLZUC_1RwH8PPGQIBsLO2wbX40e08VfX/view?usp=sharing

 

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I had this same issue on my 1uz on the low end as you have described.  I did use the individual corrections to "even out" the fueling off the lambda sensors as you have also described.  Worked perfect.

Numbers in the individual correction table is additional percentage added.

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Brad,

 

Much appreciate your welcome & speedy response - nice to know I am not alone!

 

What was the scale of the difference on your 1UZ and what correction did you apply?

 

Thanks again,

Ian

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Also make sure you pull the sensors out of the exhaust and do a free air calibration on them.  You cant swap sensors on an innovate controller without redoing the calibration everytime.  And there is no guarantees it was correct in the first place.  

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Adamw,

 

Yes I have calibrated the sensors IAW the Innovative instructions each time I have swapped them around - as an aside I suffered excessive infant mortality failures with the Bosch 4.9 sensors until I read the article published by NZEFI (see below).

 

As both the DLG-1 & the LC-2, with calibrated sensors, showed that the off side exhaust was leaner (higher AFR reading) than the nearside would you agree that using the Individual Fuel Correction is the right way forward?

 

Thanks for the response,

ian

 

Why Bosch LSU wide.doc

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5 minutes ago, Ian C said:

as an aside I suffered excessive infant mortality failures with the Bosch 4.9 sensors

Rant time...

That is just innovate being innovate.  They used to also spit out the very robust NTK and LSU4.2 sensors at the same rate in the old days when they used to work with those sensors before the LSU 4.9 was even invented.  

They control the sensor completely differently than it was ever designed to be controlled so the controller is very sensitive to sensor response time.  The founder Klaus was a very smart guy that invented this new measurement strategy which gave very fast response and made control cheap/easy at a time (20years ago) when wideband controllers were a very expensive tuning tool not affordable for consumers.  You can read his patent here:  https://patents.google.com/patent/US6978655.   But when Klaus sold up shortly after the first LC1 was released their wideband controllers never got any improvements or fixes since.   Every innovate controller produced since is just a copy/paste and has the same issues the first ones had 20 years ago. As soon as the sensor ages a little or gets too hot or too cold, the innovate will report it as Error 2 or 8 and innovate will tell you the sensor has "failed".  It has not failed and will still work on any other LSU4.9 controller that uses proper control.  With Innovate controllers it is generally not thermal shock as per the NZEFI article.  So dont throw away any sensors the innovate tells you have "failed" until you try it on a non-innovate controller - 99% of them wont be failed. 

You can tell Im not a fan - my old boss used to have 8 of them on his engine dyno.  We used to go through 8 sensors about every 2 full dyno days there.   I still have a filing cabinet full of his "failed sensors" - I'll go through about 2 a year on my dyno - and that is usually only because I drop it. 

 

41 minutes ago, Ian C said:

showed that the off side exhaust was leaner (higher AFR reading) than the nearside would you agree that using the Individual Fuel Correction is the right way forward?

You certainly could, but if it is only 2-5% at low RPM I personally wouldnt bother.   

 

 

 

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BU##ER, as they say in (the less well bread parts of) UK - I wish I had asked before reading Innovate's excellent marketing hype & investing in the DLG-1 / LC-2 combo.  I have had nothing but trouble with the lambda set up but always thought it was down to my inexperience with the set up.

 

So now the big question - what would you replace it with??

 

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It is all a case of stables & horses for me at the moment, think I would like to start again!

Thanks for your response.

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This is interesting!
Ive got the same issue, 1UZ non vvti, Link Thunder, dual Bosch 4.9 LSU (Using thunder onboard Lambda controllers)
BRAND NEW ID1050X injectors - I thought the 30 year old stock injectors were to blame, put new ones in and the imbalance remained..

Bank 2 is always richer than bank one at idle, but for the most part balances out when airflow through the engine picks up.

Now that I think about it, Its possibly got to do with the position of the throttle body on the non vvt 1uz being on the side of the plenum.
Its odd though that Ian C is having a rich bank 1, where my bank 2 is rich

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On 6/25/2022 at 8:37 PM, driftae76 said:

Now that I think about it, Its possibly got to do with the position of the throttle body on the non vvt 1uz being on the side of the plenum.
Its odd though that Ian C is having a rich bank 1, where my bank 2 is rich

It can be either an air distribution issue as you mention where the air favours one side more than the other - or a "charge robbing" effect when you have 2 adjacent cylinders on the same side which are also next to each other in the firing order.  So the 2nd cylinder is trying to pull air/fuel from the same part of the plenum that the first cylinder just took the air /fuel from.  On the 1U (and SB chevy) this is Cyl 5&7, they normally run leaner than the others.  

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@driftae76I have had various ecus on my motor(autronic sm4, g4+ extreme, g4x extreme) they all exhibit the same behavior.  Ive also had various versions of inlet setups(stock upper and lower, ported stock upper and lower, cable ITB, and dbw ITB) once again, all exhibit the same behavior.  Its primarily a low throttle/airflow issue.

I have purely used the individual cylinder correction on the leaner bank to bring it up to match the richer.  And this is solely used at idle and very low rpm and throttle until the sensors began to match. 

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