Hey guys,

Have a curly one here that I'm stumped on.

My Evo 7 has an interesting issue since fitting an AEM adjustable fuel regulator.
When the RPM is swinging past ~2300 it momontarily leans out to ~17.5-18, then instantly returns to ~15 once past and continues on as normal.
This occurs with any more than ~15-20% TPS and 40 load on board. If I very very lightly accellerate it won't lean out but any sort of 'normal' driving it occurs.
When cruising at 60km/h in 4th it's exactly ~23-2400 and even on light throttle there is light missing and bucking as well.

This is my fault-finding process so far:
- Tried another Aeromotive reg with the same issue occurring.
- Bumped up base pressure from 3bar to 4bar, no change, just a lot richer all over other than ~2300rpm.
- Swapped back to stock regulator with ~3 feet of 5/16 hose to simulate extra hose of the adjustable reg. Problem solved.
- Swapped back to MAF rom, no difference as stock reg proves it's mechanical.
- dropped the hi/low switching in the rom.

Here is the setup of the car.
- 2L.
- ID1300.
- Walbro 416/460 pump.
- AEM rail
- AEM fuel reg with vacuum source to factory outlet on plenum, pressure solenoid is removed.
- factory feed and return lines
- -6 lines from rail to reg, then reg to ethanol content sensor, then to factory return.
- Pump rewired for 13.5V.

The AEM reg has swappable orrifices, I'm running the middle one.

I have tuned plenty of cars with this setup of pump and reg before and the fact that it's fine on the stock reg has me baffled.

Anyone have any ideas?

Cheers
Ben

 

I would assume you are tuned on SD on the stock ECU. Mine does exactly the same thing but at around 1800rpm. Stock regulator and lines for me with a walbro 255 and ID 1000's.

In for suggestions!

 

Mines on SD however still does it on MAF.

 

I have the same issue with the X on an AEM FPR and AMS Fuel rail. Happens around 2500 rpms under light throttle. I never hit full throttle under 3k in any gear and not under 4k in 5th. I'm on ID2000s on SD on my X.