No offense, but maybe you should try a more systematic approach.
The stumbling is caused by SOMETHING, so the task is to determine what that is. One way (common) to do this, is to start changing and "fixing" parts until it goes away. As you are finding, that is an expensive and frustrating process.
The stumbling is caused by either a mixture issue or an ignition issue.
DO you have a copy of Probst? This is the treatise on Bosch EFI. If not, you can borrow mine (I am out of town right now, so I am writing a lot of this from memory...I'll double check it when I get home).
Mixture:
1) If you have a leak somewhere, it will presumably idle badly. Maybe not as badly as an L-Jet with a leak, but, depending on the location of the leak, it may or may not affect it. Try spraying startting fluid, or brake cleaner around every seam and every hose. If the RPM creeps up, then you have found your leak.
2) If the pressure sensors inthe D-Jet are bad, or the harness is bad, then they will register the wrong pressure and the ECU will provide the wrong injection pulse width.
3) If the transistors in the ECU are bad, or have flaky solder joints the injector pulses will be screwy, and this will result in an improper mixture.
4) If the throttle position switch is bad, or improperly set, then the mix at idle will be off. This usually causes a lurching/bucking behavior off throttle
5)If the system grounds are bad, loose, dirty, etc, the signals to the ECU will be screwy (it's a technical term)) and the car will run like crap at all speeds. Ob the later cars (so I assume on the D-Jet as well), Bosch used a direct grounding system. They basically run signal wires AND return wires. The returns typically go to some common points on the engine, and then go back (fewer in number) to the ECU. The engine needs to be properly grounded to the chassis as well. I am not sure where the grounds are on a CSL, but if you trace the injector wires and sensor wires you will find them.
6) The ECU istself may have a problem. Have you tried swapping It with a known good one? You can also check the injector pulses using an oscilloscope. The injectors require a very specific type of pulse to operate properly. I can't recall the type of injectors used on the D-Jet, but the injectors must match the ECU (low vs high impedance) or they will not work properly. It is possible that the injectors you are using are the wrong type.
A broadband O2 sensor will tell you what the mixture is doing by examining the amount of oxygen in the gas. You may know this already, but the mixture needs to operate AROUND 14.7:1 air to fuel. You can run richer than this and get higher power (around 12.5:1), or leaner and get better gas mileage, but only to a point. The combustion process basically consumes oxygen. At 14.7:1 theoretically ALL of the oxygen in the cyliner is consumed (this is called stoichiometric..it's a chemistry term). A normal O2 sensor is like a switch, It changes from o volts to 1 volt between about 14.6:1 and 14.8:1. They use this to keep the mixture at 14.7 by makingthe ECU sweep the mixture back and forth across the 14.7 point. WHe the sensor switches one way, the ECU goes the other, so it oscillates. This is required to run a catalytic converter properly (at the wrong mix the cat doesn't work). A broadband sensor has a less sharp curve, so you can measure the exact mixture much more accurately. This is a useful tool, but good ones are very expensive. I would use a regular O2 sensor, and get an LED display. this is a row of LEDs that light up depending on the output of the O2 sensor. Jaycar sells on in kit form for $25 (see link).
Hope this helps!
S
http://www.jaycarelectronics.com/pr...d2=&pageNumber=&priceMin=&priceMax=&SUBCATID=[/url]
