Ok folks, heres the run down. I built myself a 9A 2.0 16v to swap into my scirocco. Over the years Ive gathered lots of new parts to make this a "nice" swap. I got the engine in the car, wired up, and running with no problems. I have put a few hundred miles on the car and it runs great, but, I noticed my fuel economy was not that great.
The engine has a lightly ported head, 50mm intake, and a set of euro cams. I noticed that the engine had a slightly bumpy idle from the get-go, and is a little difficult to crank hot or cold.
As my suspicions arose, I decided to run a few tests and heres what I found. Using the test harness and a digital MA meter, am seeing 37-38 MA at idle. Adjusting the mixture does not change this whatsoever.
After this, I decided to do a fuel pressure test and I have 92 psi between the test port on the fuel distributor and the csv. I would say this is acceptable, but, my residual pressure drops to around 20psi after 10 minutes or so- which is not good. I pretty well know what it will take to fix the residual pressure problem, and am not mostly concerned about that since my system pressure is good while the pump is running.
The third test I did was basically just checking the AFR via wideband while driving. At idle, the car has a AFR of between 38 and 50. I cant recall using a wideband on a CIS motronic car in the past, but, i would say its terribly lean by anybodys standards. While driving under part throttle, I see an AFR thats basically normal- around 14.5-15.5. Under WOT, the AFR drops to 11.2 and stays between there and 12.7 or so all the way to redline.
What would make it so lean at idle, have a really high DPR reading (that doesnt change), and rich at WOT?? is the ECU in limp mode??
I have checked and set the timing to 7 degrees. The Knock sensors, o2 sensor, injectors, CTS, fuel distributor and DPR are all new BOSCH. There are no vacuum lines coming off of the intake other than for the brake booster- which I initially removed and plugged for testing.