Loss of torque in hot weather.

easyrider · Post by **easyrider** » 27 Aug 2020, 04:21

Hello. I have a strange problem. When weather is really hot 30+ celsius and driving in the heavy traffic jams, car looses all the torque, accelerating to 60km/h takes ~20seconds. In second gear I just push pedal to the metal and it feels like ECU is opening throttle very very slowly. Engine Idles perfectly fine. No CEL. Live parameters in VIDA looks ok. I tried to disconnect vvt solenoid, thought maybe the oil in this heat becomes too thin and theres something with VVT, no difference. Have you ever seen anything like this? Where to start looking?

Volvo s60 2007 2.4i 140hp manual

The stuck hot air intake is already modified for always cold air intake.

Thanks.

Edit: the same with LPG and GAS.

Post by **oragex** » 27 Aug 2020, 06:17

I suggest also cleaning the IAT that's on the MAF sensor, you will find it has a thick crust on it (to clean the MAF you need a special MAF spray) www.youtube.com/watch?v=-bejldUOfVs
But I think the problem may be at other place. It's an automatic? Maybe a vacuum leak ? I remember someone had a problem starting on hot engine because of stripped crank pulley splines - I guess it was throwing the timing off limits - but it's a rare situation https://volvoforums.com/forum/volvo-s80 ... ear-89394/

easyrider · Post by **easyrider** » 27 Aug 2020, 06:32

Vida shows correct intake air temperature. Will look further for the vacuum leak. I sprayed breake cleaner around all the intake manifold,injectors and pipes, no signs of leakage. And I guess vacuum leaks would show itself by rough idle? Thanks.

EngineeringBloke · Post by **EngineeringBloke** » 27 Aug 2020, 10:46

Is this really a 2007 S60, as I thought the hot air intake was only on earlier models (not on my 2006 S60)?

Sometimes when it is hot, I get p600, p700, p863 errors, and the transmission indicator goes from D to '-'. When this happens, the automatic transmission appears to be in too high a gear for the low speed and the car is sluggish. As you have a manual, it is not the same problem, but perhaps there is loss of comms to the ECU and the car moderates performance?

I think the issue with my car is overheating of the ECU in hot weather and heavy traffic. MrBrian200 has a solution to this issue and if it is the cause of your problem, it could help - wire up a 12v PC cooling fan:
viewtopic.php?f=5&t=81612

easyrider · Post by **easyrider** » 27 Aug 2020, 12:44

EngineeringBloke wrote: ↑27 Aug 2020, 10:46 Is this really a 2007 S60, as I thought the hot air intake was only on earlier models (not on my 2006 S60)?

Sometimes when it is hot, I get p600, p700, p863 errors, and the transmission indicator goes from D to '-'. When this happens, the automatic transmission appears to be in too high a gear for the low speed and the car is sluggish. As you have a manual, it is not the same problem, but perhaps there is loss of comms to the ECU and the car moderates performance?

I think the issue with my car is overheating of the ECU in hot weather and heavy traffic. MrBrian200 has a solution to this issue and if it is the cause of your problem, it could help - wire up a 12v PC cooling fan:
viewtopic.php?f=5&t=81612

Yes, late 2007. It has the same intake air thermostat, witch was affectd by corrosion and stuck in always hot.

In your case, I believe, oil gets too hot and thin, and automatic gearbox goes into limp mode, it means it is always in third gear, ussualy this is the problem of gearbox inner valve block.

I thought about possibility of ECU overheating, but in this case shouldnt I get multiple random CEL codes coming from ECU? Anyway will inspect the ECU housing. Thank you!

Post by **chrism** » 27 Aug 2020, 17:56

Does the following sound plausible?

Warmer engine and warmer intake air trigger a leaner mixture.

Leaner mixture causes pinging.

Pinging causes a retarded spark.

Retarded spark, in addition to maybe too low octane fuel, reduces power.

Is that to much of a stretch?

Post by **darrylrobert** » 27 Aug 2020, 22:32

If the car is manual the its likely the throttle needing cleaning

easyrider · Post by **easyrider** » 28 Aug 2020, 02:25

I checked the spark timing advance in VIDA hot and cold was the same. The car mostly runs on LPG so detonation is not likely.

Throttle was cleaned 8000km ago.

When checking live parameters in VIDA I noticed the o2 senos was a bit slower to fluctate that other identical s60, but I do not think this can relate to hot weather.

easyrider · Post by **easyrider** » 04 Sep 2020, 05:34

I THINK I'VE FOUND THE COUSE.

There is no current comming to the cooling fan of the ECU enclosure. So in hot weather and traffic ECU becomes burning hot, and it may somehow affect the performance. Next week Im gonna take my darling to the indy Volvo electric guru and will update.

Post by **oragex** » 04 Sep 2020, 07:27

Oh, that small fan must kick in in hot summer days after about 30 min driving, you can hear it from inside the cabin when shutting the engine off - the fan keeps spinning for a few more minutes. Look first the the small connector in the side of the ECM box, maybe someone pulled on the wires. May also tests the fan with a small 9v battery. If it's bad, get a used one but don't drive until fixed because a damaged ECU is the end of the car www.youtube.com/watch?v=d_iEQuRWYL8