Just put new engine in my 850 T5-R, when the car is cold I start it and the RPMs jump up to 3k to 3.5k instantly, the only way to get the RPMs to come down is to put it in any gear. Car will drive normally after this procedure. Please Help!!!

-Stock Head
-2.4 Block
-N/A Cams (timed correctly)
-Stock ECM
-Stock Turbo
-New MAF
-New ECT (Coolant Temp Sensor)
-IAC has Been Cleaned (have try to Different units)

I tried so much to fix this problem, I cant remember all the things I've done or changed or bought!! Will update if I think of anything else I've done or tried.


Here is a video showing the problem with the car.

 

My guess would be that timing is off. Have you aligned timing and checked the back of the cams?

 

Have you pulled the ECU, wait 30 sec then plug it back in?

 

Hey guys thinks for the feedback, I have check the cam timing three times and even got on the the phone with lucky over at ARD about that very same subject.
I will pull the ECU today and got back to you about the results.


I took the motor out to do the swap and may have gotten a vacuum line wrong, is this the right Vacuum Diagram to use for a 850 T5-R?

 

Nope. Looks like one for the '98 cars.

 

My 1994 850 turbo that i just aquired has exactly the same issue. First start on a cold engine will result in a 3k to 4k rpm idle. Shifting into gear will cause it to drop to normal and then the rpm sits where it should. I do believe once it gets some heat in the motor and is shut off and restarted, it will idle as expected but I cant say that 100% for sure. It perplexes me and I'm hoping to figure it out because I dont like shifting with the engine screaming like that. Any ideas?

 

Problem Solved..... Re-did all vacuum line according to this diagram. Some of my EGR vacuum lines were plumed wrong. I believe that high idle cold start is the cars EGR starting in open loop which make it idle like that on start-up. Check all your vacuum lines, use diagram exactly as shown.

Use new Silicon lines, its cheap and will last the life of your Volvo.


Special Thanks to RSPI...

 

I recently changed my vacuum hoses to silicone and put the EGR valve hoses on backwards. All it did for me was just make the car idle very roughly and sometimes stall. I fixed that right up and everything is great. I did the same thing :P