1995 Volvo 960 transmission help

[rfreely]

I have a 1995 Volvo 960. About 6 weeks ago when we first start the car it would rev up high and then ease back down. Since then while we are driving it the RPMs will shoot up to about 3500 RPMs until I let my foot off the accelerator. We are necessarily driving at a high speed. Then it would do it again. We have replaced the transmission with a used one that had 38,000 miles. After the transmission was replaced there found corrosion on one of the connections. This caused a code of 313 to appear. The corrosion was cleaned from the connection and the codes have been cleared/reset. The only code that comes up is 111, which means there are no fault codes set. The transmission control module was swapped out for another one but the problem remained. It was suggested I replace the engine computer as well.
Could someone please give us some insight/help.

Thanks

Randal Freely
[email protected]

[960]

960 B6304 ECT Sensor Failure. [Tip from Tom Haywood] '95 960 B6304 with Motronic 1.8: the symptoms, in my case, were sudden very high idle surges (2500-3000 RPMs) while sitting at idle and hot-start problems. This engine has two coolant sensors; the rear coolant temperature sensor is Volvo#68 49 350 (SWF#602.101) and apparently plays a roll in fuel injection and various timing functions. It is similar to the front one (FRONT Volvo#35 45 031), but without the 5-inch connector wire. Testing the sensor in heated water indicated normal operating ranges until reaching 180deg.(220 ohms) .....at which point the circuit would open completely (infinite ohms). When the brass housing would heat up it would pull the connector pin away from the thermistor leg. I have further learned that these symptoms can also point to the wiring to this sensor, because of the location between the fire-wall and hot engine parts. I could suggest to anyone with this engine to keep a new sensor handy, because it looks like the car will be dead-in-the-water when it fails. This sensor is at the rear of the head and requires a mirror taped to the firewall and a 19mm "open-end" wrench for removal (drain the antifreeze first). It has a 2-pin D-type connector mounted right on the brass housing. The large size of the connector keeps you from being able to get a good "box-end" wrench on it, but mine was not very tight anyhow (just very hard to get to). [Tom Irwin] Those rear ECT's are a pain in the ass. The harness (surprise!) allows very little slack. As the insulation degrades, the tension on the wires just pops it off. The the epoxy potting around the sensor starts to go.