Ecm-2100

[abscate]

Almost no fluctuation. These cars don’t regulate fi pressure like the earlier ones, they return excess fuel via a dump.

I’ve not quite figured out how they regulate the injection amount during different loads like the cars with an FPR

[RickHaleParker]

I’ve not quite figured out how they regulate the injection amount during different loads like the cars with an FPR

The injector is PWM ( Pulse Width Modulation ) regulated. The Pulse Width to the fuel injection corresponds to the amount of fuel injected. The Fuel injector does not inject the fuel per se. It is just a valve with a Atomizer nozzle. The Fuel pressure does the injection. That is why injectors have different flow rates at different fuel pressures.

allegory: Turning a garden hose on for 2s vs 1s delivers twice as much water.

[abscate]

Fuel delivered is proportional to injection time * the pressure differential between intake manifold and fuel pressure

Pre ME7 the Volvos used a FPr that sampled intake manifold pressure , presumably to keep the pressure differential constant

ME7 no longer does that , it stays at constant absolute pressure

What’s missing are the details of how ME7 engine management adjusts the injection over varying pressure differential.

It just be that the processor speed is fast enough to control the injector length but I don’t see the injection time change from low manifold vacuum to high when i log it on my ME7 cars

[RickHaleParker]

It just be that the processor speed is fast enough to control the injector length but I don’t see the injection time change from low manifold vacuum to high when i log it on my ME7 cars

I'm trying to visualize your test conditions. How are you changing the manifold vacuum?

Keep an eye on the fuel pressure. That could be a way to regulate the fuel flow for a given injector length.

The ME7 has DECOS ( DEmand COntrolled fuel Supply) means that the fuel pressure is controlled steplessly by varying the output of the fuel pump. The design of the system allows a greater maximum pressure (approximately 6.5 bar) in the fuel pump. This pressure is used in extreme situations, such as heavy engine load for example.


The following components are used for fuel pressure regulation:

• engine control module (ECM)
  the fuel pump control module
  a fuel pressure sensor with a fuel temperature sensor
  a fuel pump (FP) with a by-pass valve.

[FireFly666]

Where did my subject go?

[RickHaleParker]

Where did my subject go?

Subject is still here. You where asking about ECM-2100 and the lean condition. Everything here is related to that.
Well almost everything, the O2 sensor is not related.

[erikv11]

Fuel pressure should not fluctuate much at all.

When this code is is caused by a failing fuel pressure sensor, the engine will occasionally be chugging too.

Can you get to a u-pick junkyard? A bunch of Volvos use that same Bosch fuel pressure sensor and essentially every one of them at the yard is good. I'd just swap one in for troubleshooting purposes, it is an easy job. If that fixes it then shell out $60 for a new one. https://www.fcpeuro.com/products/volvo- ... 10#fitment

[FireFly666]

I bought a new fuel pressure sensor but I’m not taking it out of the package until I can data log what’s going on. But I haven’t been able to get the code to come back now lol. Probably because I unconnected and reconnected the sensor.

[erikv11]

Ah yes, waiting for the code to come back is step zero. If it doesn't come back there is no issue. I thought we were well past that. A random one-off code is worth noting but not worth trying to diagnose or fix.

[RickHaleParker]

Probably because I unconnected and reconnected the sensor.

Sometimes that enough. May of scrape through a layer of oxidation in the terminals and lower the resistance, moved a stray wire strand and opened a short or closed a open. Pretty much proves it is a wiring problem not the sensor.

Is the lean condition gone also?


Possible source
Signal too high:

1. Contact resistance or oxidation in the terminals
2. Short-circuit to supply voltage in the signal cable
3. Open-circuit in the signal cable
4. Open-circuit in the signal ground cable
5. Defective fuel pressure sensor.