Thermostat? O2 sensor? The ECU won't go into closed loop mode til it is satisfied the engine is at proper operating temperature.
Thanks for the reply. The O2 senser is new. The temp gauge shows it running in the normal range. Is there a senser some where other than the thermostat housing that could be faulty? If so, where is it located.
Thanks for the reply. The O2 senser is new. The temp gauge shows it running in the normal range. Is there a senser some where other than the thermostat housing that could be faulty? If so, where is it located.
There are at least three temp sensors that I know of. The head temp sensor which you have already changed, then there is a couple of them below the upper radiator hose on the thermostat housing. One is a single wire which is for the temp gauge, and then there is a two wire right next to it. That one is called the water temp sensor, and is used primarily when the car is cold. If it doesn't switch as the coolant warms up, it'll stay in open loop. Let the car cool down completely, and with a voltage meter, measure the resistance between the two terminals. There should be resistance cold. Then warm the car up and measure the resistance. If there is still resistance, the sensor is bad.
There are at least three temp sensors that I know of. The head temp sensor which you have already changed, then there is a couple of them below the upper radiator hose on the thermostat housing. One is a single wire which is for the temp gauge, and then there is a two wire right next to it. That one is called the water temp sensor, and is used primarily when the car is cold. If it doesn't switch as the coolant warms up, it'll stay in open loop. Let the car cool down completely, and with a voltage meter, measure the resistance between the two terminals. There should be resistance cold. Then warm the car up and measure the resistance. If there is still resistance, the sensor is bad.
On my car there are 3 sensors in the thermostat housing. 1 with 2 wires to it and 2 of them with 1 wire each. I'll check the 2 wire sensor as you have said, but what about the other 2? If 1 is for the temp gauge, what is the other for? Thanks for the help.
Mikey
After checking the water temp sensor in the thermostat housing and finding it to be in working order, my friend pulled a vacum line off the manifold and the idle went up about 2 or 3 hundred RPM. So I started checking around the car for different places that vaccum could enter the engine. The strangest place that made a change in the idle was pulling the oil dipstick. Now I have never claimed to be a pro engine builder, but I have never seen that happen before. Why would the engine be starving for air so badly? And why would the idle get rough at cold start up when the oil pressure comes up to normal? Mikey.
Try removing the oil cap from the valve cover while the engine is running. You'll notice that it doesn't run worth crap. There is vacuum there. It's normal. I found that the other single wire sensor in the thermostat housing is for the auxillary fuel injector cooling fan. If the water temp sensor is good, and the cylinder head temp sensor is good, timing? Spark plug condition? Wires? Distributor cap and rotor?
Thanks for the info and help JZ82. The plug wires, plugs, cap and rotor are all new. The timing is at 8' btdc as per the sticker on the hood. I have just purchased the factory service manual. Should arive here in a few days. I'll try going through the trouble shoot areas and go from there. The car runs great. Good throttle response in all gears and will sail along over 100 mph all day. I'm guessing at the 100mph since the speedo on my digtal dash only goes to 85. I hope I can get this figured out and still have all this perfomance too.
Its an 83 n/a. I have been tinkering with the air flow meter adjustment screw and it seems to be leaning out a little. I'm going to try to set it without sniffer machine and see if it is where me problem is. Any ideas from anyone?
Emissions nightmare!!
Linear Mode
