FDPP #2

[gnalan]

Is there something around where the ETM is that makes a high pitch humming sound, pretty much the sound the ETM made when I pulled the fuse and put it back in?

It's not the ECM making the sound, I don't think, but it's in the same general area. The sound is there with the ETM fuse installed and when it's removed. Can the ETM be unplugged without removing it? If the humming sound goes away with the ETM unplugged maybe it's just a wiring problem. I'm trying to rule everything else out, and the wiring is the only thing I haven't checked yet. If there is something else that would be making a whing noise near the ETM please let me know.

[gnalan]

$150 just to test? Ouch! The test on VIDA costs nothing.

I ran the VIDA test a few times since my problems started and it says it passes each time. I'm going to run it again and see if I can get a screenshot of the two potentiometers mapped out and post it. I don't know if that'll show anything that's helpful or not, but maybe there's something VIDA isn't catching that'll show up on the graph.

Doesn't the ETM test only check to make sure the two potentiometers are within 13 of each other? It's been under 7 each time I've checked it, but the graph isn't smooth.

[gnalan]

Some more graphs. On the ETM test, I had to zoom out so I could get a screenshot of the flattened out spot. It also flattens out at the bottom, but I don't know if that's by design before doing each of the 4 sweeps.

(I don't like the new Windows snip tool, I preferred the old way of taking a screenshot with the print screen button. It doesn't seem to work with Windows 10, unless I'm doing it wrong.)

[cn90]

I have these parts from a 2005 XC90 2.5T with 90K miles:
- WP (you need to buy the Green Volvo gasket).
This is only half of its lifespan.

- TB
- Mech tensioner
- Idler pulley
These 3 items have another 40K on them. We can talk about this when you need them. Or buy new TB kit for $110, cheaper if buying separate (TB $27, INA tens $33, INA idler $22).

[bmdubya1198]

The potentiometers aren't too far off, however the throttle position desired value versus the actual value are pretty weird looking. It appears the ETM is too slow to respond to throttle input. It could still be failing.

[gnalan]

The potentiometers aren't too far off, however the throttle position desired value versus the actual value are pretty weird looking. It appears the ETM is too slow to respond to throttle input. It could still be failing.

The only area I can get the actual and desired values to match up is just under 3,000rpm and up to 4500rpm. I haven't tried going to redline with it, since I don't want to cause any more problems than what I already have, so they may match up all the way to 6,000rpm.

[cn90]

I wonder if one can swap another ETM from another car (same year, same model).
If this is true, then try to find a similar car (non-turbo) and swap.
If this solves the problem, then you know the answer.

I am not a part-swapper, but sometimes a swap diagnoses things very quikcly.

[bmdubya1198]

I wonder if one can swap another ETM from another car (same year, same model).
If this is true, then try to find a similar car (non-turbo) and swap.
If this solves the problem, then you know the answer.

I am not a part-swapper, but sometimes a swap diagnoses things very quikcly.

They're totally compatible, as long as you use a turbo for turbo and NA for NA. 5/6 cylinder is also different, I believe. '99-'01 should all be the same, so any '99-'01 NA 5 cylinder ETM will be compatible with the OP's car.

[gnalan]

I unplugged the ETM and looked at both connectors, and didn't see any corrosion or anything on either plug. Haven't found much time to do anything else with the car, and it's just been sitting because it's at the point that it doesn't drive very far now. I'm lucky if I can drive it a block before it starts stalling/dieing on me, and I have to restart it to drive about the same amount of distance again. Then it's pretty much wash, rinse, and repeat, until I can get it parked back at home again. I'm at a loss for what to do next.

I still can't tell what the humming sound is that I hear with the ETM fuse out, and with the ETM unplugged, but it sounds like the noise is in the same general area. Is this normal? Can someone tell me what it is that I'm hearing?

[EngineeringBloke]

ETM Sweep Test
The ETM sweep test in the first picture looks fine - no issues with the ETM sensor output. Both sensor outputs are showing clean, smooth sine wave outputs with no noticeable dropouts. There is a small 'step' on the first falling edge, but as it does not appear on the second cycle, it would not represent a worn spot on the throttle sensor strips which would repeat.

But ...

Throttle issues at low plate opening
The second picture shows significant problems with throttle angle actual (red) vs. throttle angle desired (green). The actual angle is not following the desired angle.

These levels are the ones seen at the ECM.

There is also a report of the level from the ETM - throttle position absolute (blue).
This varies from 2% to 16% but often moves in the opposite direction to the throttle position actual, lagging it slightly, so perhaps a response to the unexpected angle values.

NOTE
In the sweep test, the throttle is between 13% and 84%, but in the second test, the throttle angle is operating in a desired range of 7% - 8.3% with the plate being reported as ranging from 1% to 16%.

Perhaps the throttle plate is sticking at low openings, or the sensor strips are worn at low values (below the sweep test). I am surprised that the sweep test would not use a range including the lower values.

• Does anyone have a similar VIDA display from a normal Volvo throttle at near idle?

A few seconds showing the throttle position, desired and actual angles.

• gnalan, is your throttle plate clean?