850R aircon issues

Sezbot · Post by **Sezbot** » 21 Jan 2010, 01:47

Hi, I am new to this, but saw this site and thought someone may be able to help.

I have a UK spec Volvo 850 R Manual Gearbox 5 door Estate. The problem that I am hoping someone can diagnose is related to the air conditioning.

When the air conditioning is charged or put up to pressure and I switch it on with the engine running. The revs of the engine do not seem to drop off quick enough compared to when the air con is not switched on or not charged to pressure. When the aircon is on and you rev above 3000 rpm the revs rise quite substantially and take even longer to drop off when changing gear. The previous owner of the car removed the thermostat from the car and very kindly managed to chew the bolts up (problem to be solved this weekend) is this related to the aircon problem or can anyone offer a solution. It makes the car very difficult to drive.

Appart from that great site and I look forward to speaking with you all more in the future. By the way does anyone know how many 850R's in estate with manual gearbox are left in the UK???

Andy.

Post by **jblackburn** » 21 Jan 2010, 08:07

I'm not sure how it compensates for the additional load with the A/C on, but cleaning your throttle body and putting a little grease on the throttle control lever would probably help substantially if it's holding onto the revs.

Sezbot · Post by **Sezbot** » 21 Jan 2010, 11:05

Thanks for the reply I will try that when I sort out the thermostat.

It could explain it, I am just not sure why the revs rise when you press the clutch to change gear but only over 3000rpm. I wonder if the weight of the car is holding the revs down.

I was told that the thermostat could be the problem, but the source that told me that is not reliable, so I see no reason for these being related.

Keep em coming everyone.
Andy

Sezbot · Post by **Sezbot** » 21 Jan 2010, 12:36

Just been thinking again and wondering about this. The previous owner said that the ECU had been changed and he got it from the US. I don't think this car was sold in the US with a manual transmission. I know it needs to be an Bosch 4.3 ECU but is there a difference between the manual and auto ECU's???

Post by **jblackburn** » 21 Jan 2010, 13:01

Ooo, an R manual, nice!

The ECU is basically the same as the auto for a US model with a manual transmission swap done to it, but it really depends how it was done. Keeping the auto ECU in there will work, but usually people like to have them re-mapped to a manual configuration that holds onto the revs a bit longer so it's not quite as jerky when letting off the gas. Since it was re-chipped or re-mapped though by the previous owner, there's no telling what kind of ECU is in there at the moment.

http://volvospeed.com/vs_forum/index.ph ... ge__st__60

Sezbot · Post by **Sezbot** » 21 Jan 2010, 13:20

I've been thinking about a RICA 311hp chip anyway, so maybe this would be the answer to all my problems.