ECM Issue?
 

I recently had a used engine installed into my 2009 s80 2.9 and there is now a problem starting the car. I have never seen this problem before, when I go to turn the ignition the cars rpms jump way up to like 6000 rpms and then fall back down quickly and the car will not start. After a few tries eventually the car may start or it may take 15-20 times to start the car, once the car is started, however, the car runs great. My mechanic is not sure what the problem is but he says it is "probably" the ecm, which will cost me another grand or so to fix. If I have never had this problem, what are the chances of this occurring after they installed the other engine onto my car? Any other ideas about what could be happening?

Oh and the mechanic said the ecm is not storing any codes when this is happening and I assume it would normally do this, so he thinks this is why its an ecm problem too.

Have him check all the ground connections and also make sure the Positive cable is not to close to the speed sensors for the motor.

Can you explain this process a little more? What do you think the problem is? He said that the problem has something to do with some grounding issue, but I dont remember his exact words. He went to a conference over the weekend with other volvo dealers and he said that a couple of them had some ideas besides the ECM so they will investigate those today and call me back tomorrow. Have you ever experienced this problem? And what made you think that would solve the problem? Any info just to better explain it to this guy is much appreciated!

If the back side of the block was not real clean when it was put in it might not be grounding through the transmission. The cars main ground is on the transmission. He can add a ground wire from the transmission to the block to be sure.

Also on the positive wire where it runs up the back side of the motor if it is to close to the flywheel and cam sensors it will interfere with the signal for the sensors and cause a problem with starting.

Tech ty very much for your help. I am planning on talking to them today, is there any other ideas you have which could cause this problem?

So I talked to the tech there and he said he would check those 2 things, he said that they ran a wire to the transmission and it started right up the first time. But then they turned it off and then tried to start it again and it happened again!??!?!?!
For the second option he said that one of the wires goes up and the other one down so they are not close to each other so if you could shoot me any other ideas or suggestions I would much appreciate it.

Well the one power wire from the fuse box runs along the back side of the motor by the crank sensor and wire for the cam sensor.