The richening, Pbanders? Chris Foley? Dirty injectors? 2056 and a strange lean Options

[emerygt350]

Ok, car is running great, but it just wants more fuel than my mps can give. It was almost there before I upgraded to the 2056. I have the mps maxed (inner screw all the way loose, won't go any further). I have the full load stop set at 3inhg and the part load kicking in at 7.5 inhg. I have now been inching up the fuel pressure, at 32 now, but the idles is now so rich it is bothering me.
The ecu idle is full lean.


The fuel injectors are 2 years old fj67s. Pbanders states you should be able to run up to 2.2l on d-jet without a problem.

Did I mention I hate pulling injectors?

Car idles great and the cylinders are all equal as far as what the plugs look like. 1000 miles on the top end rebuild. CHT temperatures are going lower and lower as I have been richening it up. I now rarely hit 370. 70 cruising is 350, even less when I am trying to be nice. Oil temps is still great, mostly because of tangerine racings oil cooler bypass. Night and day predictable temps since I installed that. Can't recommend enough. 5 stars.


Could all the injectors have crudded up equally? This would have happened before the rebuild. Since I started the richening earlier this year.

New fuel filter installed 2.5 years ago when I bought the car. New injectors installed after that. Previous owner had a rich condition (mps shot).

Watching the fuel pressure while I drive shows no change, sticks strong at 32 psi.

This plug has 200 miles on it.

[rjames]

I've been told that the MPS outer screw should begin to engage the part load stop somewhere between 5-7 inHg (when starting from inHG).

I think the location of the outer screw can have a significant impact on the AFR, and getting that right may be part of your equation (if it's not something unrelated to the MPS).

Per Anders' MPS documentation, tightening the outer screw independent of the inner screw will enrich the part load mixture (however, it doesn't say if it's linear across all part load inHg measurements):

Under part-load conditions, the bottom of the outer screw is held against the part-load stop by the pressure differential across the diaphragm. If we tighten the outer screw independently of the inner screw (meaning we prevent the inner screw from turning with respect to the body of the MPS), the middle of the diaphragm is moved away from the part-load stop, decreasing its throw, and decreasing the amount of enrichment under full-load operation. Additionally, tightening the outer screw independently of the inner screw has the same effect on part-load operation as loosening the inner screw, enriching the part-load mixture.