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MembersPage/DavidBlades/FuelTest (2006-03-29 06:03:46)

VE Table\n

k[0]=14 1C 24 2C 34 3C 45 4D 55 5D 65 6D
r[0]=05 0A 0F 14 19 1E 23 28 2D 32 3C 44

n[0]=20 27 50 70 93 A1 A6 AA AD B2 B4 B4
n[1]=24 28 4F 74 91 A1 A6 A7 A9 B1 B1 B1
n[2]=28 2C 50 75 91 A0 9F A0 A1 A9 A9 A9
n[3]=2C 30 50 74 8E 99 9A 97 9A A1 A1 A1
n[4]=30 34 50 73 89 93 93 92 91 9A 9A 9A
n[5]=34 38 50 6E 83 89 8A 8C 8F 8F 8F 8F
n[6]=38 3C 50 65 7A 81 83 84 84 84 84 84
n[7]=3C 3F 50 5D 6F 78 78 78 78 78 78 78
n[8]=3C 3C 50 5F 6F 78 78 78 78 78 78 78
n[9]=39 3C 50 5F 6F 78 78 78 78 78 78 78
n[A]=3A 3C 50 5F 6F 78 78 78 78 78 78 78
n[B]=3A 3C 4E 5D 6D 76 78 78 78 78 78 78 


'''Lambda Table'''

k[0]=14 1C 24 2C 34 3C 45 4D 55 5D 65 6D
r[0]=05 0A 0F 14 19 1E 23 28 2D 32 3C 44

l[0]=37 37 2D 2D 2D 2D 2D 2D 2D 2D 2D 2D
l[1]=39 37 32 32 2D 2D 2D 2D 2D 32 32 32
l[2]=39 37 37 37 37 32 32 32 32 32 32 32
l[3]=39 39 37 39 39 39 39 39 37 39 39 37
l[4]=39 39 37 37 37 37 37 37 37 37 37 37
l[5]=39 37 44 44 44 44 44 44 44 44 55 5C
l[6]=37 37 48 48 48 48 48 48 48 55 63 66
l[7]=37 37 55 55 55 55 55 55 55 5C 63 6B
l[8]=37 37 63 63 63 63 63 63 63 66 6B 6B
l[9]=37 43 63 63 63 63 63 63 66 66 6B 6B
l[A]=37 4F 66 66 66 66 66 66 6B 6B 6B 6B
l[B]=6B 6B 6B 6B 6B 6B 6B 6B 6B 6B 6B 6B

Sorry the formatting isn't good. I promise to deal with it ASAP!

Progress so far

Well, the car now runs, and it has taken me to work and back for a good while now. (Short 6 mile trip with a good range of conditions) Initial results are good. The fans come on when they should, the engine warms up at a sensible speed, hot start is excelent, but cold start is not so good!

Coolant and IAT sensors have been calibrated manually. This was a difficult job involving generating an accurate Steinhart-Hart model for each sensor in Excel and recording the temperature reported by the ECU for a selection of known resistances. I could then build correction tables. For some reason EasyTherm always produced the wrong answers (and most often produced non-monatonic curves). More detail on my method can be found in my sensor page.

Over the weeks, autolearn has done a great job with tuning the VE map. It's now very smooth in most areas. It's turned into a rather quick car now - but I still want more!

Bad points are:

Q Is there an easy way to see which cells autolearn has changed in the VE map? (Apart from comparing the current map to an old one...)

  • AFAIK no. Both mcd and the MegaTune get-VE command dumps the learnt VE, not the VE reference. If you read the learnt VE from the ECU, do mvr (revert VE to reference) instead of mvs (save learnt values), you can dump the old values too. But comparison is still needed.

1st Long Tuning Run - 05/02/06

Old stuff now, but left here as a warning to everyone that sometimes no matter how carefully you check the new bits you add, it's the old bits that get you...

Having got a reasonably set up car, I thought we'd take it to a Piston Heads meet near London so I could optimise the "motorway" bits in the map (ie high speed cruising). I shouldn't have bothered as it was a total nightmare.

We filled up with fuel, and the car wouldn't start leaving the petrol station. (Dead battery and poor terminals I think)

All was going fine after that - all settings on the laptop and LCD were perfect until the engine died without warning. I got it started again, but it was running seriously rich (lambda at 0.75 to 0.95) and very rough. Since we were parked on the M-way hard shoulder, we had to move, so I thought we'd be able to limp home - ot was only 7 miles (12km) or so. The rich condition got worse and worse until the back fires got so bad I thought we'd kill the cat. Then saw sense and got towed home.

Possible causes are:

On the plus side, there seems to be no engine damage - compression is good on all cylinders and the plugs are carbon fouled, but not melted or anything. All were even, so it's most likely not an injector problem. The sensors all give sensible values in VEMS too, so I don't think it's died either.

I rigged up a fuel pressure gauge to the fuel rail. There's no pressure building up in the rail. This narrows the problem down a bit... The pressure reg, the pump or both have failed.

Oh well, better write this one down to experience...

Update:

I have got the car back running now. Lots of little things done.

As you can see, most of the problems were old age related and not the fault of VEMS.

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