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[TheBoy]

Can't work through that crap, Excel is an office self-abuser's tool I have managed not to master.

Besides, your code reader is not legal in the UK

[TheBoy]

Long term trims look OK, though. Although I slightly suspicious of some of the readings around the short term trims.

Wonder if the stupid code reader is struggling to gather so much info. Try again, just gathering o2 and trim related data

[jtypecav]

OK used a really cheap and nasty sensor to double check. Software didn't support recording - but had a passenger watch it closely!

Generally tracking in line with use of accellerator pedal. From -1.X% up to about 12% near full throttle. When the EML comes on and cyl 4/6 cut out this becomes dead 0 and doesn't vary at all.

Interestingly, with a long enough stretch of road on 3clys it will rev above 4k rather than drop another one. ANy use?

Going to go back to the other sensor and just record out xls of data for fuel trim if required!

[jtypecav]

Right.

Something that has been niggling me since the start is corroborated by the TPS load

If you keep it at PARTIAL LOAD it will pull cleanly to the red in motion with no EML!

If you depress the accelerator more the TPS displays INVALID


Not only does it not display "FULL LOAD" like my Ascona does (X30) but if TPS states INVALID, it's only then at 4K that it goes into limp?!

So this issue only occurs when more throttle is in play. (Hence why I'd swapped throttle body AND pedal senders earlier!)

This has got to lock it down a bit more I hope!

[TheBoy]

So this issue only occurs when more throttle is in play. (Hence why I'd swapped throttle body AND pedal senders earlier!)

Still the wrong diagnostics method.  Are you getting exactly same readings with original sensors?

What is MAF reading at idle, and at 2000 rpm?

[jtypecav]

I've never diagnosed something like this before, happy to learn from a boss! 

Original sensors read pretty much exactly the same - just added up to 5v a bit more and the symptoms prevailed.

On last run 10 mins ago MAF @ idle was:

RPM 646   V 1.37   KG/H 14

In motion at 2K RPM upwards till EML:

RPM   V      KGH
1.847   2.16   56
1.899   2.1   56
1.941   2.14   55
2.021   2.1   53
2.05   2.12   54
2.11   2.1   54
2.159   2.33   73
2.262   2.61   107
2.436   3   158
2.647   3.31   205
2.924   3.41   256
3.212   3.61   262
3.476   3.73   262
3.765   3.73   262
4.033   3.8   262
4.326   3.92   262
4.52   4.04   262
4.626   4.02   262
4.824   4.08   262

EML ON - RELEASE ACC THEN final reading

4.636   1.96   44


Is the 262 a healthy maximum?

[TheBoy]

MAF looks OK, but whats it like at 2k in neutral, on the drive

[jtypecav]

On idle on drive

2.09   1.82   36
2.057   1.8   34
2.004   1.78   33
1.962   1.73   31
1.945   1.78   33
1.936   1.78   34
1.945   1.82   35
1.995   1.82   36
2.092   1.9   41
2.161   1.88   40
2.202   1.9   39
2.242   1.88   39
2.272   1.88   40
2.296   1.9   39
2.317   1.88   40
2.321   1.92   41
2.334   1.86   38
2.339   1.88   40
2.356   1.88   38
2.356   1.88   39
2.35   1.86   39
2.317   1.84   36
2.263   1.78   34
2.2   1.84   36
2.067   1.69   27

Quick Rev:

2.099   2.22   63
3.427   3.55   262
5.878   3.71   262
6.34   2.18   59
5.741   2.25   65
5.142   2.2   61
4.45   2.14   57
3.803   2.04   52
4.152   3.78   262
6.28   4.2   262
6.267   2.18   59
5.652   2.2   62
5.056   2.1   62
4.367   2.1   55
3.747   1.98   44
3.183   1.9   41
2.634   1.75   32
2.132   1.67   27
1.636   1.53   20
1.282   1.57   25
1.077   1.45   16
907   1.41   14
845   1.71   28

Any use?

The invalid TPS reading bringing on the EML is still bugging me. It's the only event that correlates directly to the limp.

[Andy H]

The invalid TPS reading bringing on the EML is still bugging me. It's the only event that correlates directly to the limp.

With live data (& engine not running) you should be able to gradually open the throttle & watch the TPS reading increase smoothly from 0% to 100%. I think the TPS on a DBW engine has two potentiometers inside it so if one decides to read full throttle when it shouldn't the ECU can decide that it has an invalid TPS reading.

On a DBW engine the TPS has to fail safe so the ECU probably watches the mass flow reading and declare the TPS reading as invalid if the mass flow reading doesn't make sense for the given throttle position. Cheaper for GM to sell you a new TPS (even if it isn't necessary) than fight a class action over cars zooming off at full throttle .

MAF failures are much more common than TPS failures hence the interest in the mass flow.

[jtypecav]

This is really interesting. Makes a lot of sense too.

I have an X30XE MAF here. Is it the same? Do those figures look OK? Any other figures of interest?

[Andy H]

Steady; treat the problem like a crime scene, gather the evidence first and work out what caused the problem. If you go changing items at random you risk destroying the evidence you need to fix it.

The DBW MAF has a built in air flow temperature sensor that the cable throttle MAF doesn't have.

Finally: I am just spouting theory, TB has the equipment and the practical experience to use it properly. I would wait for his response. While you are waiting you could search for some threads (from about a year ago) when people posted up their live readings to help in this situation.

[jtypecav]

My enthusiasm stems from the fact I'm two weeks into having the car.

It has a (not worth the paper it wasn't written on) 30 day or 1000 mile warranty and if I don't fix it in this time I won't be able to claim back the bits that were wrong with it, or at at least get some compensation for my time as it had thrown the light and lost coolant 20 mins from the dealer. Only reason I didn't take it back there and then was because I realised the leak wasn't the block and had assumed despite they fact they had deleted the codes knowningly that with the help of the forum I was pretty sure we could get to the bottom of it!

Despite sounding to the contrary, I'm fully signed up to following expert advice on here step by step! 

[Andy H]

My enthusiasm stems from the fact I'm two weeks into having the car.

It has a (not worth the paper it wasn't written on) 30 day or 1000 mile warranty and if I don't fix it in this time I won't be able to claim back the bits that were wrong with it, or at at least get some compensation for my time as it had thrown the light and lost coolant 20 mins from the dealer. Only reason I didn't take it back there and then was because I realised the leak wasn't the block and had assumed despite they fact they had deleted the codes knowningly that with the help of the forum I was pretty sure we could get to the bottom of it!

Despite sounding to the contrary, I'm fully signed up to following expert advice on here step by step! 

Excellent!
TPS is attached to the throttle pedal pivot & therefore a pig to get to (unless you like lying on your back in the drivers footwell  ) I seem to recall someone getting a quote for a new TPS and being surprised by how expensive it is 

I hadn't realised that the clock was ticking. Given the cost of a TPS that might explain why the codes had been cleared

[RobG]

My enthusiasm stems from the fact I'm two weeks into having the car.

It has a (not worth the paper it wasn't written on) 30 day or 1000 mile warranty and if I don't fix it in this time I won't be able to claim back the bits that were wrong with it, or at at least get some compensation for my time as it had thrown the light and lost coolant 20 mins from the dealer. Only reason I didn't take it back there and then was because I realised the leak wasn't the block and had assumed despite they fact they had deleted the codes knowningly that with the help of the forum I was pretty sure we could get to the bottom of it!

Despite sounding to the contrary, I'm fully signed up to following expert advice on here step by step! 

Excellent!
TPS is attached to the throttle pedal pivot & therefore a pig to get to (unless you like lying on your back in the drivers footwell  ) I seem to recall someone getting a quote for a new TPS and being surprised by how expensive it is 

I hadn't realised that the clock was ticking. Given the cost of a TPS that might explain why the codes had been cleared

DBW`s have two, top of throttle pedal & incorporated into throttle body

[TheBoy]

MAF looks approx right, but still looking for that steady 2000rpm reading