Where are the MAF MAP and coolant temp sensors located on a 1987 Oldsmobile Ciera?
OK, a late 80GM A & X body. Most Manifold Absolute Pressure sensors are located on the firewall with GM Vehicles. Others arelocated affixed to the top of the engine somewhere along the intake area. Try looking from the center of the firewall on over remotely close to the vacuum booster which is a huge frisbee on its side shaped thing. The MAP is about an inch high, about 1/2 inch thick and about 4 inches wide. there is a small rubber vacuum boot pluged into it with a vacuum capilarey line going to the bottom of the throttle body or manifold, and a connector off of its rear. If the Olds has a Mass Air Flow Sensor, it would be in the same spot as all Mass Air Flow Sensors are put. The greatest air mass travel area of the engines air input. A cylindrical spaped doo-dad that has a screen on both sides, and a wire and or ring shaped thing inside the screened cage. WARNING! Mass air Flow Sensors are super tempremental. Do not remove the screens on the sensor for greater performance or any reason. You could only do more damage than good. If you touch and bend the heat wire on the MAF sensor, the ONLY place you can successfully install it is a slam dunk straight into the garbage can. Funny how so many people don't believe that can be true, and wind up buying a new part for the tune of about 2 to 5 bills (Ben Franklins). The coolant sensors (yes, with an "s") theres two of them. One is a switch and the other a sender. They're pretty important on a GM car. Even if your thermostat and cooling system is physically and mechanically working great, without the switch sensor, overheat is likely to occur, esp. in stop and go summertime. The first more important temp sensor is the coolant fan switch which screws into the engine's cylinder head. It's single usually green lead goes to a relay which is what really supplies the juice to the fan. Note: This relay is a commonly replaced part. It fails after a half million cycles or so, so if you have overheats due to electric coolant fan failure, the relay could likely be the culprit. Try borrow/swapping with one that you know works for a fact. The other coolant temp sensor is located somewhere on the coolant housing between the upper radiator hose coolant inlet and the thermostat housing. Although not as directly critical as the switch that operates the fan relay, this is a sender sensor which means it will have a variable resistance. It has two wires going to it, neither which are grounded by the sensor. The sensor supplies the return signal to the ECU(ECM in this case) telling it the approximate temp range of the engine and provides its portion of information to the computer toward proper engine management. If you are having problems still, Be sure to only visit well trained automotive technicians, such as auto service garages that employ ASE certified technicians.