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Discussion Starter #1
This post is following on from my previous one. as the heading points out I think I may have made some links.. The plot thickens!

Right.
When my Power FC was fitted.. Before I left the garage they adjusted the Throttle position sensor for some reason. I pointed out that it made the throttle response odd.. Now I have driven it more I can describe fully what has happened. I have tried to move it back (although not exactly sure where back is?!) and it hasn't cured the problem.
under normal acceration fine no problem..
when cruising on the motorway at 3150rpm (approximately!) in 5th gear the pedal is depressed by about 2cm. if you lift of a nats whisker it is as if you have suddenly lifted off completely.. the throttle/fuel stop.. if you move back on te gas just a touch again te opposite happens and the car lurches. go much higher on the rpm just 100rpm or so and it goes because the throttle is depressed past this point. Now this isn't the misfire but are they linked? I also noticed the misfire when cruising seems to happen at about this point.
Hard to pick the point the misfire happens under acceleration but I would say it's around the same throttle position even though it's likely it's a lower rpm.

How Can I check or adjust the throttle position sensor?

The final point to note is I expected much better fuel economy after my re-map and see the new air/fuel ratio's however in my first week of driving I seem to be siginificantly worse off..? Now I have notices on the over run the car seems to pop and bang a lot more which would surely imply unburnt fuel? I addition could a dodgy throttle position switch cause over fueling which would also explain the misfire (again it could just be build up of unburnt fuel popping every now and then)? this in tur would explain bad fuel economy as I spend the majority of my journey to work cruising at ust over 3000rpm!

Maybe this answer some other peoples question.. If we can solve it even better!

Cheers
Lee
 

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Most / all PFC appear to have the misfire issue, usually manifests itself as a single misfire event when cruising at around 3000rpm. I`ve had a couple at higher load, but mostly cruising. It may only happen once in a 100mile journey.

You can check tps voltage with the hand commander, closed is 0.4V I think, WOT is 3.8V.

What has the decel fuel cut-off RPM been set to in the PFC? This may explain your sudden decel when throttle is released.

If your running the same level of full load boost as you were before the PFC was fitted, you should see similar (maybe slightly better) fuel economy. If your running more boost now than before the PFC (and your using it FE) is likely to be worse.......
 

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it could also be the map itself. I was mapping someone else's car (R33 GTS-T) a couple weeks ago, and I mapped rich. Why? I might be able to get 15% better mileage, but better to be safe than sorry, especially when you're in a culpable position.
 

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Discussion Starter #4
Will Check the TPS setting and if I can the decel fuel setting.. Bit above me though. The tunning chap is gig to look at it again for me..

What is using it FE mean?

If you mean am I flooring it all over the place then no! I am driving gently!

Cheers
Lee
 

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There is nothing to be gained by mapping low load/rpm zones rich, you get poor fuel economy and just cover the combustion chamber in carbon. You are not in danger of doing damage in this area of the map anyway. The only time I might go a bit rich is with MAP based systems to account for the varability in ambient conditions - but not 15% rich.

FE - fuel economy.
 

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in the "safe" zone, would you call 14-ish rich? high 13s when on a bit of throttle. I used to run my own car closer to 16:1 in the low load/rpm quadrant, but have been running it closer to stoich recently. 15% was a rough number - I think I was trying to say that in mapping someone else's car, one would tend towards the rich end of things, instead of pushing the limit.

Is it really really safe? I've picked up pinging on cars with det cans under 3000rpm on flat roads, would those pings not have enough power to cause piston damage? I don't personally know, so I ironed out my personal map until all pings disappeared.
 

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Most / all PFC appear to have the misfire issue, usually manifests itself as a single misfire event when cruising at around 3000rpm. I`ve had a couple at higher load, but mostly cruising. It may only happen once in a 100mile journey.

really... i di dnot know that. then why are tuners still fitting them? this could definately explain my intermittent misfire as it only happened after the put on AFM`s and the power FC... any suggestions for a cure friend???
 

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Discussion Starter #9
What do you mean..

That is is down to the Power FC or down to other parts on the car?

Hopefully I will get it sorted?

I checked my AFM read out on the commander today and it is AF-1 1.01v and AF-2 0.96v?? I resoldered them and cleaned them fairly recently.. and it was fine before the Power FC?

Also looked at my TPS readout and it was 0.38v.. Is this ok or a bit low?

Cheers
Lee
 

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Discussion Starter #10
By the way ExScooby asked about the Decel rpm value.. How do I check this? not sure I will be changing anything but I am hapy to look and see what it is set at!

Cheers
Chaps
Lee
 
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