2005 xc70 red hot turbo at idle

[836howard]

I have a 2005 xc70 that i bought used with a blown engine they were told the turbo went out and took out the engine by the dealer. I replaced the engine with a good used one my problem is its idling very high and the turbo is turning cherry red at an idle. Any ideas what would cause this?

[oragex]

High idle and red turbo makes me think too much unburnt gasoline, perhaps a problem with the mixture ? Running way rich ? That may damage the catalytic converter as well. Or perhaps the cat converter is clogged (maybe from the old damaged engine). Does the converter also look too hot ?

[836howard]

Im not sure on the cat being hot to i dont really want to start it back up and let it run to find out but it seems to have pretty good power so i would lean toward the cat not being plugged

[EngineeringBloke]

- How high is the idle in RPM?
- Did you get any check engine lights, codes? DICE or Torque app.
- How quickly did the turbo get red hot?
- Did you reuse the turbo that killed the old engine?

It is hard to diagnose without more info.

- The Air to Fuel ratio would be good to know - you might be running very lean, but that does not directly indicate a cause for the turbo to be so hot (other than very hot exhaust gases). Also the long term fuel trim.

[836howard]

Idle is about 1200 rpm. I get code p0507. I used the turbo that was on the used motor and i actually bought that car whole and it ran good it was smashed in the rear. I do have the torque app. It was running close to 14.7:1

[zanzabar]

No oil and/or water supply to the turbo so it's not getting cooled?

[836howard]

Not sure i was playing around under the hood with the hoses and electrical connections when i fired it back up idle is good now and the turbo isnt so hot. Not sure why im sure it will be back.

[SuperHerman]

You need to determine if your cat is clogged. First feel how much air is coming out the exhaust. Does it seem sufficient? As it warms up it will get worse and cause the engine to bog down and die. Think banana in the exhaust pipe from HS years.

You can pull the O2 sensor and have a look and also check the exhaust pressure there. With a mirror and flashlight you should be able to see the condition of the honey come. You can also let it run without O2 sensor installed, it will be loud and throw a code, but it should tell you if you have a clog.

I had an S80 that had a bad clogged cat and on 2.9 non turbo. It would run great and then bog down, slowly it got worse and worse. Ultimately it took out the engine. Used engine showed same signs and then we figured out it was the cat - got that fixed and no more issues.

Do a search on checking for clogged cat and follow the various test options. If not have mechanic do an exhaust pressure test.

[jimmy57]

The ECM has strategies for faster engine and catalyst warm up. It uses the CVVT on exhaust cam and retarded ignition timing and high idle RPM to get the combustion delayed to get more exposure to coolant around cylinder walls and that also means more active combustion when exhaust valves open so the exhaust is hotter headed to catalyst. ECT sensor is what usually triggers ECM to do this but If it were unplugged it would have used defaults and set a code. I'd look at the ECT sensor connection and make sure it has no corrosion. You may have a faulty contact there. More Ohms is colder engine so resistance in connection there would trigger the ECM to do cold running routine for longer than normal and get the exhaust H O T !

[RickHaleParker]

Be Careful about being quick to blame the Catalytic converter.

Any Clog in the Exhaust could do it. Could be Resonator, Muffler or Catalytic converter. Open the Exhaust system after the Catalytic converter to determine which one. Resonators and Mufflers cost a whole lot less then Catalytic converter and are a lot less work.