Can anyone tell me what the a/f ratio peaks are at 3200,4000,4600,5400,6200 and 7000 rpm. ive looked at other dyno sheets and they are all smooth.Also what is my leanest a/f ratio as it is in lambda.Thanks Roy.
Hi Roy,
I can\'t really see the image. If you could email a higher res version to bill@shurvinton.fsworld.co.uk I\'ll take a closer look. Lambda is AFR/14.7
Without seeing other runs from the same day it will be hard to tell if it was the car or an artifact of the dyno.
I\'ve done some squinting. The monotonic nature of the peaks would suggest something screwy with the engine maps, but the shape of them is not like anything I have seen an ECU able to do, but could be wrong. A surface plot of the maps will show that easily enough ( you are not trying to get this level on a stock ecu are you?)
So, other thoughts:
1. You are bouncing off the boost cut (which will show a lean blip)
2. You are detonating and the knock sensor is causing the ECU to pull back and then advance again.
3. misfiring (either caused by or causing 1&2).
If their lambda was correct you are very rich at the low end getting up to what I would consider about right (11.8:1) at the top end for that level of tune.
Of course AFR is merely one parameter and you really need to see a lot more to get a proper idea.
Bill - what\'s your background if you dont mind me asking?
Thanks for the responce,My mods are powerfc,fmic, intake, dp,mp,blitz nur catback,1200 sec inj,fpr and bosch 044 pump.the car was fine untill shortly after the dyno run(week or so)then started hesitating/stuttering.I changed the coil pack,plugs and leads which cured it for 50 miles and then returned.Bit stumped on this one.
I\'m a chartered electrical engineer (currently resting between jobs) and a student of all things EFI.
I\'ve had a look at a bigger plot now (thanks greg) and you can see a steep rise followed by an exponential decay. This is not normal behaviour and certainly consistent with a limiting function or some sort of misfire.
Beyond that I can\'t tell without some diagnostic work on the car.
Bill
I would hazard a guess that someone has tuned your fuel map not through the base map or Injection map, but has done so on the injector adjust option.
Basically this allows tuners to add fuel either by rev range (1000 rev increments 1000 - 8000 revs, or boost pressure (from boost voltage feed in half volt increments 1 - 4.5 volts).
In your case I think they have added fuel by rev range (1000 rev increments. Makes mapping quicker, but does create those blips between increments.
Regards
Max
Yes,my pim rpm and pim volts have both been played with.I think i better take it somewhere to be adjusted from the pims to the base map.Thanks for everyones help.
UGH. If the Apexi really can be tuned like that then it should come with a health warning. I just hope you didn\'t pay good money for that tune. You have jumps of nearly 2AFR points in 100 RPM. Whilst it isn\'t going dangerously lean, its not a good thing
I got thrown off the computer last night but looking again you are way over rich at the low end, as low as 10:1.
Bill the Power FC does not use the knock sensor it only displays it, therefor it will not retard the ignition on this basis.
The PIM sttings are very useful sometimes, although anyone who knows what they are doing would not use them for tuning.