2006 Volvo S60 2.5 AWD, Endless search of problem

[mrbrian200]

I'm concerned that the throttle body is at least one major contributor to your issues, however... The only things I can think that might cause the engine computer to hold the throttle plate that far open at warm idle aside from a bad coolant temp sensor (reading artificially low which is not the case) would be a restricted air intake/filter, or if the MAF indicating an artificially low air flow than actual.
There is the potential issue where you stated you cleaned the MAF with some sort of brush. If the sensor film element was damaged and reading artificially low that would probably cause the engine computer to open the throttle plate. If this issue existed and didn't change after cleaning the MAF sensor then I suspect you merely brushed over outer plastic parts and didn't affect the sensor element which is somewhat protected under a plastic cover with a slot on each side to channel air across the flat dark metallic looking sensor element - which is the bit that's sensitive to contamination or physical damage.

These MAFs employ the 'hot film' design: Electricity is conducted through the film, heating it up. Air moving across cools it, the more air, the cooler. The film has properties of a thermistor (similar to the coolant temperature sensor) with varying resistance and current flow based on temperature. A self contained computer buried under the epoxy tracks everything and calculates air mass moving through the sensor. The little resistor looking thing attached to the side is an air temperature sensor not affected by air flow - if that looks undamaged it's probably fine.

The other possibility might be resistance in the wiring between the MAF sensor and the engine computer. As the output of the sensor is an analog voltage, this would in effect give a false (low) MAF reading to the engine computer. However, because fuel trims seem to back down to 'normal' at higher engine speeds/loads I would probably discount this as a possibility.

[shiloh51933]

I'm thinking throttle body issue or atleast throttle body issue was my first thought after initially ready this thread. After reading the next 3 pages of post I'm still thinking throttle body issue.

[mrbrian200]

I'm thinking throttle body issue or atleast throttle body issue was my first thought after initially ready this thread. After reading the next 3 pages of post I'm still thinking throttle body issue.

I'm there too, but as the throttle body costs a fair chunk of money it's prudent to cover all bases. I would feel really bad if this guy spends $300+ on a new throttle body and it doesn't make a difference. When I went through this a couple years back I didn't spend the money until after I tore the thing apart to see that the internal mechanism was binding up/absolutely certain.

[Unownreality]

So while having my buddy watch the live feed while I did a longer drive, we noticed a strange trend from the MAF.

The amount of air, usually stays in the normal area of 3-3.5 g/s. However, when I come to a complete stop, it will occasionally plummet down to 1.5 g/s, and jump right back up. It ends up turning into this Sin wave between 3.5 and 1.5. This would point to a vacuum leak pre- MAF no? Filter is brand new, but it shouldn't be plummeting down below 3 at all.

[mrbrian200]

Difficult to say. You might try a used MAF from a pick and pull car and see how it acts. The majority of MAFs acquired this way will be ok, maybe spray it off with MAF cleaner. Do take care to get the right one: there are a couple three different part numbers specific to different engine/drivetrain configurations. They look identical at a glance however the firmware calibration loaded into the self contained computer built into the thing is different and won't work right if installed on a different engine configuration. If you haven't already, you might double check to ensure the MAF you're using is correct for your specific engine.

[abscate]

This one is crying for a VIDA intervention to monitor throttle position in real time

[Unownreality]

Yea, I'll probably go the pick and pull way. I have the part number Throttle body I'll need. Wonder if It would be easier to take the manifold off to get the throttle swapped, or if I can sneak it in with just removing the air hose.

[XC70Rider]

The ETM can be swapped with just removing the air pipe. Need 7mm socket to remove pipe clamps and 10mm to remove the four ETM bolts. It's all feel. You'll need a new ETM gasket and the tourque spec is 10nm.

I would try a new MAF first. It's cheaper and easier to replace. For hints on replacing the ETM search the thread I recently started 'ECM-121b when below freezing"

[Unownreality]

MAF was changed twice. I'll just go poking around to get the throttle body off and get some pictures to see what we are dealing with.

[Unownreality]

Went to pick and pull this morning. Wanted to actually have a throttle body in hand, so if i pulled my throttle body, and I noticed something wrong, I could swap it out in one go. If it ends up bad or not needed, I can exchange it for store credit within 30 days, so why not? haha.

This car died via car accident, so at least I know its not an engine issue (maybe). Here it is. Be aware that im not done cleaning it, I'm going back every half hour and spraying it a bit more.



Anyways, Got a few cosmetic items (it seems like the front clips on the bumper literally flies out on every s60).