MEFI adjustment ideas for rich idle on a Procharged motor?
 

So my motor is finally up and running, tuned with MEFIburn and AFR looks good throughout the rpm range (11:1 accelerating, 13:1 cruise tapering to 11:1 redline [haven't found WOT yet :evilb:]) except idle. I cannot get her to idle past 11.5:1 on the wideband. Bob at MEFI burn suggested stepping minimum Fuel on MAP and RPM. One step it idles at 11.5 and the next step leaner it stalls. Here are the details:

-Gen 6 7.4 MPI
-Procharger M1 - 12 rib - 5 lb pulley (for now)
-MEFI 2 ECM
-MEFIBurn, Scanner Pro, Tuner Pro EFI tuning
-Delphi 2 bar MAP sensor
-FiveO Motorsports 50lb high impedance injectors
-Aeromotive Boost Referenced Bypass Fuel Pressure Regulator with Aeromotive (not liquid filled) pressure gauge, holding steady stock (43lbs) at idle, referenced 1:1 on boost
-Aeromotive 1000 fuel pump
-Innovate Motorsports MTX-L Wideband 02 sensor & gauge

Idle is currently set at 700rpm.

As with most Procharger kits thermostat is bypassed so I pulled enrichment on coolant temp out (vs stock tune) 50% for 20deg C100% for 40deg C. Scannerpro shows warm idle about 36-40deg C.

Anyone have any ideas?

fixx
 

put a restrictor in it or a 120* thermostat..i never do it the way pro charger hack's them together..i also use a low water pick up for the inter cooler and i hope you have a sea strainer going to the inter cooler from running through sludge at the chain..the lwp gravety feeds the cooler and their is a bypass valve installed so you dont blow up the cooler..this lets the engine warm up so the injectors wont puddle at idle and cause a rich condition when going through no wake zones.

When you say "one step" what exactly do you mean? How much of a change are you bumping the bpw and are you only changing one cell or the range of cells center around your idle rpm/map? Can you copy your base fuel table and post it here?

Lastly, I'd starting looking into what you need to do to get rid of that boost-referenced regulator. As others will confirm....they're junk.

I considered a thermostat / restrictor plates but not for this reason. Can you elaborate on what about the cool heads causes injector puddling at idle? I thought that this only applied to TBI systems, this is MPI so there's really nowhere for fuel to pool.

I'm not sure I'm following you regarding the plumbing. Are you recommending a second (electric) pump and pickup for the intercooler? Everything's currently flowing from the raw water pump through the Procharger designed billet thermostat housing. I don't have a sea strainer on it yet. Bypass valve sounds like a good idea but it sounds like a package deal with the sea strainer and separate water pump as I would no longer be able to visually confirm intercooler flow.

There is a minimum incremental change (step) that will register in the map when you actually save it based on the data resolution (number of bits used to store the number). I have a feeling that MEFI2 may have lower resolution than later ECMs but I have not confirmed.

As far as the boost referenced controller goes this is a very high quality Aeromotive competition grade unit not the Procharger supplied or bargain generic junk unit:

http://aeromotiveinc.com/products-pa...ass-regulator/

Are you saying that even this unit is not a good idea? Why? I'm running an aeromotive air filled fuel pressure gauge on the regulator and it shows rock solid fuel pressure. The injectors and pump can handle the power I'm making without boost referencing but it seems like a good idea not to have relative fuel pressure drop 12% under boost as I'll have to crank up the injector pulse width closer to max which reduces the flow accuracy and power potential.

I have the map on my laptop at home. I'll post this evening.

I am running my intercooler off the sea pump but I am using a pressure relief valve to feed it (nothing through the chiller at idle). I am also feeding the cooler off the intake side of the pump with the use of a check valve. Plumbed in this fashion the check valve will open at higher speed and the cooler will be force fed. This also lets the sea pump feed the motor at its full capacity at speed. I have the pressure relief valve set so it is barely dribbling through the cooler at idle and when I put the throttle on it opens immediately (I had to change a spring in it). One advantage of this is that there is no drag from an external pickup. I run a 120* stat and the guage reads just over 130*. I do not run a sea strainer but I do run a Y type strainer before the pressure relief valve.

Idle will not be the best without a thermistat and will turn to terrible if you are running water through the cooler full time.

what are your MAT vs Run BPW? have you changed the related

I ran an Aeromotive boost-ref regulator as well as one from Bell Engineering. Both "worked" but were very inconsistent and susceptible to weather conditions. I finally ditched it altogether and upgraded to a mefi4 ecm to be able to tune in boost. If you have 50lbs injectors, I don't see why they wouldn't hold up. I still run the stock 42lb injectors and bpw into the 7ms range with no issue. If you remove the boost-ref regulator, install a quality return regulator in its place and you should have no issues with fuel pressure. I've been running mine like that for 4yrs now and zero issues.

No changes to those data points yet. Your suggestions?

I'm curious how much boost are you running and on what motor?

Did you need to change the ECM harness for MEFI4? This is a change that I'm interested to make but there are a few projects in front of it on my wish list.