ETM Issue?

dikidera · Post by **dikidera** » 12 Jul 2023, 07:51

So I am making a new thread, because the issue seems to be separate and maybe the root cause of some of my symptoms such as poor acceleration and stumbling.

I am thinking my Magnetti Marelli ETM has started to fail. It's not much to go by, but things I have noticed are:
Key in Pos II results in a whine from the ETM.
Acceleration seems to be inconsistent and general feeling of loss of power.
As I press the accelerator and keep my foot steady, I notice the Accel pedal sensor reads 10%(both of them), but the RPMs continue to rise without me pressing harder, and I mean up to 2000 RPM and then maybe start dropping.

A couple of days ago I was using the alternative fuel AND on a busy intersection the car almost stalled, I slammed the accel pedal to get off fast, but the engine almost died, and the car only started to accelerate a couple of seconds later, which put me in a very dangerous situation.

Post by **vtl** » 12 Jul 2023, 08:14

Can you read fuel pump duty cycle and fuel rail pressure in your car? MY2005 2.5T with Bosch ECU has it, but I'm not sure about your N/A engine with Denso ECU.

dikidera · Post by **dikidera** » 12 Jul 2023, 08:23

According to Volvo DHA and the databases I have, there is no such exposed command. And my fuel rail does not have a sensor.

In any case, the stumbling occurred on the alternative fuel. However I also notice a general lack of power when running on petrol as well. I am suspecting a coil or two as well, but there are no codes to tell me what to look for.

Oh yes, one other thing is I believe I may have a ground leak somewhere. Entirely possible, I did have the head off and the wiring loom was dangling here to the side. This is still unconfirmed but I will try tracing.

Post by **vtl** » 12 Jul 2023, 08:32

To me it sounds a fuel pressure problem.

Post by **vtl** » 12 Jul 2023, 08:33

Also is it really an ETM? I thought it was used in 01-02 only.

dikidera · Post by **dikidera** » 12 Jul 2023, 08:40

Was used in all bifuel models, sadly.. And the ECU unfortunately does not expose a direct copy of TPS1 and TPS2 as it does in the other Denso models. I may have to find a copy of it somewhere in RAM, but not sure if I will have the time to reverse engineer some more.

What it does have is Effective throttle angle in percentage, so maybe this is it?

Post by **vtl** » 12 Jul 2023, 08:42

In VIDA you can do a sweep test for ETM. If it passes, your ETM is good. But I think you first need to look at the fuel delivery. Also misfiring 5 cylinder engine shakes like hell, but have no problem reaching high RPM.

dikidera · Post by **dikidera** » 12 Jul 2023, 08:49

Is the sweep test a procedure embedded in the ECU or ETM or does VIDA send incremental commands?

The reason I am asking is because I can use CAN to control the modules, however since I do not have DiCE or other J2534 fully fledged device, I cannot use VIDA directly. The ETM is not documented in Volvo DHA.

If you remember a while back, I was doing a port of Sardine J2534 interface, however I found I had to rewrite a lot of parts of the code to work nicely with the Channels concept. Unfortunately life issues took over and I couldn't finish the project.

Post by **vtl** » 12 Jul 2023, 08:54

People have success using a Mongoose JLR (a Chinese knock off of) with Volvo. It is cheaper than DiCE (a Chinese knock off of). Honestly I don't see how one can successfully own an old Volvo without DiCE/VIDA. OBD codes cover maybe 10-15% of these P2 cars.

I personally don't use DiCE that much these days, but only because I had replicated reading most of the commonly needed parameters in my hobby device (https://github.com/vtl/volvo-ddd). So I knew my alternator was failing a year before it actually failed and see that an 18 years old fuel pump is still okay and operates within permitted range.

dikidera · Post by **dikidera** » 12 Jul 2023, 08:58

I too have developed my own device, based on RPi 4B. It's only limitation is the high current/power requirement. If I can further rewrite the J2534 interface(full spec not API) we can use any CAN device to talk to our cars with VIDA.