Page 1 of 2 12 LastLast
Results 1 to 10 of 16
  1. #1
    Join Date
    Dec 2008
    Location
    Newcastle upon Tyne
    Posts
    1,908

    1UZ-FE: Lambda variation between banks

    Hi,

    Having a little play with the engine when I should be getting on rebuilding the car, fitting body etc - but in these strange times you get your fun when you can.

    Noticed early on that there was a difference between the Lambda readings from the side pipes and decided to investigate. The difference is not huge (I think?) being approximately 13% higher on the nearside (odd cylinders) than the offside. I have confirmed that the difference is real, rather than a calibration error, by swapping the sensors, Innovative channels & ECU between sides.

    Is this a "known" issue with the 1UZ and, if so, is it within the acceptable limits? Is a 13% variation something to worry about?

    The more you learn the more you realise how little you know!

    Ian
    Last edited by Ian C; 23-06-20 at 07:43 PM. Reason: typo
    Pilgrim Sumo Mk3; IVA Apr. 2014; RV8 3.9 EFi ; Cosworth T5; Granada Donor
    Phase Two underway - Conversion to Japanese

  2. #2
    Join Date
    May 2004
    Location
    Finchampstead, Berkshire, UK.
    Age
    55
    Posts
    3,714
    Ian,
    13% is a huge variation. Exhaust leak? Injector not squirting? Injector stuck open? Plug burn out? Valve not sealing? Time to start investigating sadly.

    Regards

    Jim
    GD Mk3 Jag based
    Supercharged LS1
    GD J1M

  3. #3
    Join Date
    Dec 2008
    Location
    Newcastle upon Tyne
    Posts
    1,908
    Jim,

    That's what I feared, still, means I can play with the engine a bit longer!


    Thank you (?) for the reply!

    Ian
    Pilgrim Sumo Mk3; IVA Apr. 2014; RV8 3.9 EFi ; Cosworth T5; Granada Donor
    Phase Two underway - Conversion to Japanese

  4. #4
    Join Date
    Feb 2011
    Location
    Northampton
    Age
    42
    Posts
    4,244
    Here's an idea to fix it (no idea if it will fix it...)



    My DeDion build diary..
    Hon Sec of the Digidash branch of the Unpopular Kit Car Design club

  5. #5
    Join Date
    Dec 2008
    Location
    Newcastle upon Tyne
    Posts
    1,908
    Aaron,

    I am sure that this was meant in a humorous spirit lifting sense but I have to tell you it fell short! Sending pictures of an admittedly beautiful, if a bit blingy, ITB set up does not lift my spirits or help in any way!

    Surprised to see the original coils are still in place as I would have thought they'd have gone down the COP route.

    Thanks for your suggestion anyway but I am afraid that the mundane approach of checking the plugs and injectors will be my first task.

    Take care,
    Ian
    Pilgrim Sumo Mk3; IVA Apr. 2014; RV8 3.9 EFi ; Cosworth T5; Granada Donor
    Phase Two underway - Conversion to Japanese

  6. #6
    Join Date
    Feb 2011
    Location
    Northampton
    Age
    42
    Posts
    4,244
    People often tell me I fall short it's 'coz I've only got little legs. Ahem.

    I don't know the story of that particular engine - the photo is from a 3D Printing forum; he's 3D printed the prototype intake runners (that's the part you can see in blue) before having them cast. Very neat process, though his runner design looks quite compromised - presumably space/packaging constraints.

    BTW, when you say higher .. to be clear, are we talking higher or lower, numerically, and AFR or lambda? If it's numerically higher in either case (leaner) I'd be looking at an exhaust leak as the most likely culprit for such a large swing - also what are the absolute numbers? Beyond a certain point, if the AFR reading were accurate, you'd expect the engine to be struggling..

    Oh and are you in closed or open loop at this point? I'm not sure if the 1UZ has per-bank control in closed loop, I assume so and that your sensors also feed back to the ECU and not just the gauge?

    Questions, questions.. actual helpful ones this time
    My DeDion build diary..
    Hon Sec of the Digidash branch of the Unpopular Kit Car Design club

  7. #7
    Join Date
    Dec 2008
    Location
    Newcastle upon Tyne
    Posts
    1,908
    Aaron,

    I don't know at the moment whether the problem is the higher or lower lambda reading as the engine has not yet been tuned and is evidence by the difference between the two banks. The difference could be caused by a faulty plug, making that bank's lambda richer, or a faulty / blocked injector making the other banks lambda lower. Whether the figures are lambda or AFR is irrelevant as I am looking at the percentage difference between the two sensors, but I do prefer AFR as the numbers are bigger!?


    Once the cause of the imbalance between the two banks is established and, hopefully, rectified I can start to tune the engine. At this stage the ECU is not providing any correction to the fuelling but once the fuelling has been set up it will run in closed loop.

    Take care and thanks for the interest,

    Ian

    Pilgrim Sumo Mk3; IVA Apr. 2014; RV8 3.9 EFi ; Cosworth T5; Granada Donor
    Phase Two underway - Conversion to Japanese

  8. #8
    Join Date
    Nov 2003
    Location
    West Midlands UK.
    Posts
    3,007
    I'd go for plugs first and/ or sticking injector second.

    The correct way to check this is by carrying out a flow check on the injectors. Turboshed on You Tube https://www.youtube.com/channel/UCuT...PoRah7GkLOPQBQ has a great tutorial on matching injectors and measuring flow rates. Mind you he is aiming for 1000 bhp out of a LS400 for under £1000 so he can be a bit OCD. So far he is at 750 bhp at about the same £spend and has realised he needs cams and headwork. The cams and heads are standard with just a skim on the pistons to lower compression to allow 30psi boost.

    The non correct way is to put half a litre of gunwash ( ie cheapest thinners you can get) into your fuel tank and run the engine to give the injectors a bit of a clean.

    Three guesses which one I would do?

    Cheers,

    Tony
    Supply by blagging, engineering by bodge......

  9. #9
    Join Date
    Dec 2008
    Location
    Newcastle upon Tyne
    Posts
    1,908
    Tony,

    That's the plan, going to swap over the plugs side to side & recheck. Then it will be the injectors which I think are more likely to be the cause.

    I have watched all the episodes of the Scottparts TurboShed series (they are quite close by and do a lot of their drifting at Teesside Autodrome where I have done a number of track days - was hoping to catch up with them this summer!!), not quite up to Binky's level of OCD but gets close. I did "refurbish", i.e. replace the seals & filters, and test the injectors but it was just a "do they click" test. I did try to clean them by squirting contact cleaner down them when energised but never did a flow test.

    Assuming one, or more?, injectors are faulty that will give me the opportunity to replace some or all of the injectors so I may try to follow their example and set up some form of flow test - I seem to have some of that OCD stuff too!?

    Take care,

    Ian

    Pilgrim Sumo Mk3; IVA Apr. 2014; RV8 3.9 EFi ; Cosworth T5; Granada Donor
    Phase Two underway - Conversion to Japanese

  10. #10
    Join Date
    Apr 2012
    Location
    Wrexham
    Age
    48
    Posts
    561
    Would a IR gun be helpful for checking any of this, checking each cylinder?
    Regards
    Gav
    AK Ls1/t56
    Body on April 2014
    Passed IVA March 2017
    Registered April 2017.

Page 1 of 2 12 LastLast

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •