Swedishbricks schreef : <font face="Arial,Helvetica">Replacing RPM or Hall Sensors.</font> <font face="Arial,Helvetica">RPM Sensor: If your car is a non-turbo 89+ model then it has a flywheel reading RPM/Position sensor that is down below the rear of the cylinder head, mounted on the bellhousing through a bracket retained by one bolt that should be a 10mm head on a 89. It is connected to wires above the engine on the firewall.</font> <font face="Arial,Helvetica">Hall Sensor: If it is 89 turbo or pre-89 then it has the Hall switch that is in distributor. The Hall switch is tough as it requires that you knock out a pin and pull out the shaft, then VERY carefully drill out a couple of pins that retain the hall switch. Then you have to be very careful about supporting the distributor base while bradding the retainer pins to retain the new hall switch. If you slip while bradding the pins then you punch out a hole in the base and then you need a new distributor. [Response 2:] Changing that is not for the novice. It is riveted into the distributor. Some dealers offer rebuilt exchange on the distributors. Before you jump to the hall sensor, carefully examine the wires from the firewall to the distributor, which sometimes break inside from years of flexing. These can be repaired with a little work. Also, check the brittle plastic connector where the wires go into the distributor. This can cause intermittent shorting. The plastic fitting is Volvo PN 1346793, about $3.00 as I recall. If you are going to remove the distributor for any reason, carefully scribe a mark to return it to its exact former position so as not to change the timing (the holes in the distributor are slotted). [Response 3:] I've done few of these. Never alone, however. Drill out the old rivets carefully and pry out the sensor. Next, have an assistant you can trust with approximately $ 70.00 hold the new sensor in its proper place on the distributor plate. Place a steel punch of roughly same diameter as the rivets into the bench wise. Have the assistant hold the D. plate in such a way that the rivet is directly over the punch. Now, YOU, using the second punch and a hammer CAREFULLY hit the top part of the rivet. It will take MANY hits since these darn rivets are made of steel. The key here is steady hands, and frequent breaks. One wrong move, and you are done. Simple physics tell you which, steel or aluminum will crack first under constant hammering.</font> <font face="Arial,Helvetica">This is akin to putting a horse shoe onto an a hard boiled egg, possible but very nerve wracking.</font>
