While iv been waiting to get another run with my mates diag plugged in .....I can't drive and screen shot with my gap tool iv been giving the car a general health check.

It has no fault codes just the shudder iv put a can of bg44 threw it the last few days and today I smoke tested the engine to check for any vac leaks....all good no leaks.

I played about with my gap tool and started checking fuel pressure and the like it's meant to have 1400 at the fuel rail I'm getting 800ish









Bearing in mind the car performs well shudder aside I would not say it's slow it's no slouch and no codes.

Iv only found x1 post about high pressure fuel pump failure on here and that gave a fault code.

The plot thickens......need to check this out under driving conditions not just idle and high engine revs on the driveway.

Well complete bum steer under normal driving conditions fuel pressure is normal which is over 2000 psi. Will do a new post about engine readings and measurements found until I can get a better read out of the gearbox.

Found out how to log info on the gap tool and find it again here is a screen shot of the gear box on a run




Wow I can even add or remove each wave from the screen on gap tool

My 5.0 fuel trims are almost identical to those. They've barely changed in the 8000 miles I've done since the timing chains were sorted.

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Thank you David, dingg1 did say they were nothing you worry about but I want to investigate it just to be sure iv done everything I can before pulling the trigger on a new tc. If it needs the tc doing iv made arrangements with my mate and mechanic to do it for me.

I'm also happy to go with rrphils recommendation on sussex autos who supplied me with my solenoids to recondition the tc am struggling to find the cost new compared with getting it reconditioned.

So the latest scans of the engine plus turbine speeds each over at least 15 seconds at set constant speeds.

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Here are the other screen shots from additional data we collected today on the run scan tool used....snap on.

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Sorry to take so long to reply. I've been away for a few days.
I still don’t see anything in the traces that convinces me that the torque converter lock-up clutch is misbehaving, though it’s really difficult to tell unless the engine speed and turbine speeds are superimposed.
I hadn’t realised that you had the IIDTool. Are you able to record the engine and turbine speeds using the IIDTool and post up the results on here as a .csv file so that I can look at them in detail?
I’m very aware that recording live values for the 6HP28 transmission appears to be far more problematic than for the 6HP26. I suspect this relates to the change by ZF from the Bosch electronics module to a Continental one, rather than being a fault with the GAP tool.

Phil

Thanks for getting back Phil.
I'm still learning about all the gap tool functions I will try to record the data in a file and upload it

Seems this shudder is historical to the car the service history shows a flush, filter and friction modifier add 15k miles ago. Ie shudder fix

Mine was about 13k miles on from a gearbox flush when the judder started on mine, done by a LR indie for last owner. No have mention of any magic potion being added then. Happy to report that so far the refurb I had done has worked, even though it wasn’t economically sensible really. 2010 Supercharged

RRPhil wrote:

We really need to see the engine speed and turbine speed overlaid on top of each other to be able to visualise the speed difference. We’re looking for a low speed vibration around, say, 1Hz and I just can’t see that in the traces. The data needs expanding so that the X-axis is a period of around 5-10 seconds or so.

Gsxr1250dave has kindly provided me with live values from his L322 for engine speed and turbine speed in a .csv file measured using the IIDTool, which makes it easy to see what’s going on.

In the trace below you can see that the turbine speed is constant (because the vehicle speed is constant and the turbine is connected directly to the wheels via the transmission, transfer box and axle gearing) yet the engine speed is fluctuating by around 75rpm or so, at a frequency of around 1Hz. The vehicle speed for this condition is 55mph in 6th gear. Clearly the torque converter lock-up clutch should be locked solid in this condition and the engine and turbine speeds should be identical.

As the solenoids (including the EDS2 solenoid which controls the torque converter) have all been replaced with new ones, the only conclusion I can make is that the lock-up clutch in the torque converter is faulty (mechanical or hydraulic issue) and needs to be replaced.

Phil

Thanks Phil