So I'm having some problems getting the AFR's dialled in on a car I'm tuning after the owner installed a new FPR + Walbro 416. The FPR is similar to these ATP ones and has been set to a base pressure of 42.5psi apparently:

http://www.atpturbo.com/mm5/merchant...egory_Code=FUL

The AFR's just go too lean for most of the pull, even though I've dropped the injector scaling back to try and see if it helps and have the fuel map running very low numbers. I've got the injectors scaled at 886 (FIC 1050s) for pump fuel (similar to your 93). Normally I run scaling at 1008 for these injectors which is commonly used I think. I wouldn't have thought you'd need to touch scaling after installing an FPR either...

We're just running on gate pressure (BB FP Green with Turbosmart 22psi actuator) until we can get the fuel mixtures to behave. Not even doing WOT runs as you'll see in the logs below.

I also noticed that the AFRMAP value in EvoScan is hitting a minimum value of 9.089855 in the logs, even though my fuel map has lower to try and richen up the mixtures. See 5000 rpm, 200 load to see what I mean. AFRMAP is showing 9.09855, but I am requesting 8.4 in the map. Is this some sort of a logging or ROM minimum I am hitting?

 

Check the fuel pump is getting a decent power supply during the pull (ie 14V+)

 

Got to be the hardware. IPW and AFR map point strait at that. Go back to the stock FPR and see if that helps, should help isolate either the pump of FPR.

 

Yes we're going to try it with the stock FPR again today to see how it goes. Hopefully it's that and not the pump.

 

Takes 2 seconds to put a multi meter across the pump supply wire, I always check this 1st before putting customers cars on the dyno now. Seems to be a common fault in the older evos, had 3 last week with this issue. A quick rewire with a decent relay fixes it

Phil
Dynotech Industries

 

Yes that's true Phil. This pump came as a kit with the stock cradle and decent wiring already though, so we figured it should be fine.

We changed the FPR back to stock yesterday and the fuel issue went away. So am guessing the aftermarket FPR isn't providing the correct base pressure. We don't have a gauge to dial it in properly, so will look at our options for that, or possibly just bite the bullet and go up to bigger injectors to support the setup properly on E85.

I'm still a bit curious why the AFRMAP values bottomed out at 9.089855 even though I had 8.4 in the map. Is 9.0 as low as you can request in the fuel map? Obviously if your map needs to go that rich and you know your scaling is correct, then you may have a mechanical problem, but just interested to know.