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TF135
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Gottit! :)
I'll get the laptop up+ running, load PSan, find my way around it, get the current unmolested stepper setting (I'm curious to see the factory setting too) and report back in due course.
Then I'll use your excellent info to set it all up correctly. That's a real result...happy...:)
And thanks for sharing your experience; I'm sure you've 'wised up' loads of us!
 

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TF135
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Well, last night I burned some midnight oil + got a laptop up-and-running..
Loaded PScan this afternoon, tried it on the car, fumbled around the menus, got some live data and thought I'd share it.
135980


Car was started and left to idle for ~10mins so probably not sufficiently warmed-up. Looks like I've got some adjusting to do though. Thanks for providing the 'push' Julian :)
ps wouldn't it be good to have an ideal screenshot to compare; somewhere to find out about 4deg, 875rpm, 25clicks and 34kPa etc...
 

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15 to 20 minutes of driving around and then it would be useful to see the COMPLETE readout at idle, not just the first few parameters.

I did another drive around yesterday and, without changing the idle screw, the number of steps dropped from the previous 25 to 20 steps, 4 degrees and RPM 875+-10 (on the nail). It is as if the MEMS has made further stepper adjustments and nailed it and RPM by itself (20 steps being right at the bottom of the range 20 to 40 steps at hot idle) - idle rock steady whether engine cold or hot. The vacuum was a steady 35kPa at hot idle which is also on the nail.

My strong advice is put into a single spreadsheet each set of idle results (one of the lines of output which represents the norm). Every time you do an adjustment, record the 'typical' output at hot idle so that you build up an audit history. This way, in the future, if things go wrong, you can refer back to the spreadsheet to compare with the norm when everything was hunky-dory.

In the live readings, I got the following outputs changing during the run that I had not seen before::

Overrun fuel cutoff
Radiator fan
Highspeed fuel cutoff

The engine appears to be behaving as it should.

I think that it is important that after making a change (1/4 turn of the idle screw max at a time), allow the MEMS to adapt over 30 or so miles before making another change. Reset the TPS every time after you adjust the idle screw so that the MEMS believes that the TPS is indicating 4 degrees actual throttle opening.

I am guessing but 48 steps (which may drop slightly when the oil is above 85 degrees C) may only need a 1/4 turn clockwise to get the hot idle right (ie throttle opens which should reduce the number of steps to closer to 25 steps). You may need a couple of attempts at it to get it right. You may think that you have got it right and then the stepper cuts in and it all changes again. Patience is key.

When all is running fine, I would open up the air duct and have a look at the throttle and see whether it looks close to 4 degrees open as extra confirmation of its position. So many threads indicate that just resetting the MEMS TPS reading is enough to fix idle problems (5 accelerator activations et al). In my case, this was not the case. I needed to

1. Have Pscan to get the full set of outputs from which you have a better chance to diagnose the cause if a poor idle
2. Check the physical throttle and get as close to possible to a physical 4 degrees
3. Be patient and allow time for MEMS to adapt to the new settings.

PS: I bought and fitted one of these - 10mm-120mm 2:1 Heat Shrink Heatshrink End Cap Glue-Lined Tube Tubing Wrap Black | eBay - 10mm X 30mm which I cut to length and replaces the anti-tamper plug that you will destroy in order to get to the idle screw.

 

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TF135
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This morning I drove it 'till warm then let it idle as I set up PScan.

As a newbie a little less stressed, but I still had to turn ign off then on a few times while it scanned. (Why is this, and why does it need the occasional re-scan?...)

I went out before your post so didn't scan everything but I got some satisfactory 'hot' data :

oil temp 98C, coolant 100C (105C when fan cut in due to being stationary), manifold 38kPa, Idle 925rpm (desired - ECU parameter?) act 900-950rpm fluctuating, stepper 42-44clicks (44best at 926rpm)

1/2 turn clockwise from start point raised the hot idle quite a lot and even 1 full turn a/clockwise didn't lower it at all, so I put it back to original happy to live with what I had (which wasn't as far out as yours...)

38kPa manifold didn't change nor did stepper at 44clicks. That, and 'Desired idle speed at 925rpm' actually close, made me think that my own settings might be close to 135 factory standard and may be naturally different from your VVC. So, getting more confident :cool:.

I didn't manage to find and affirm the EKA code - perhaps another day - but to actually see the figures that others have advised/quoted 'in the flesh' was quite refreshing.

Yes the tamper-proof plug sits crazily on top of the idle screw atm :)...I have some heat-sink tubing and some self-attenuating tape; I'll try these first.

Thanks for sharing. I got a lot out of this post.
 

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mgf
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Discussion Starter #26
When you renew the throttle body or the IACV valve, it MUST BE SETUP corrrectly on T4. There is no other way to set it up other than on a T4.
When I changed from the 48mm trottle body to the 52mm I was advised by this forum to turn on the ignition and depress the accelerator 25 times to let the ECU reckonise the new body. I did this and it worked fine for many years. With the emissions so high at the last NCT Test ( Your MOT ) I decided to get a new 52mm body and its the new one that's revving high. The car never went on diagnostics. I will try tomorrow to hold the pedal down for 30 secs or so with ignition on and see how it goes. It has'nt over revved since the NCT and had her out all day Sunday on the motorway.
Thanks to all for the replies very much appreciated to get the views of those on the forum.:LOL:
 
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